Publications by authors named "Daohui Lin"

120 Publications

Role of molecular size of volatile organic compounds on their adsorption by KOH-activated micro-mesoporous carbon.

J Hazard Mater 2021 Sep 29;424(Pt B):127355. Epub 2021 Sep 29.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China; Zhejiang University-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou 311200, China. Electronic address:

KOH-activated carbon (KAC) with high surface area and abundant micropores are widely used in adsorbing volatile organic compounds (VOCs). Kinetic diameters (σ) of VOCs are an important factor controlling diffusion of VOCs into pores of adsorbent. Yet the influence of kinetic diameters of VOCs on their adsorption by KAC remains unclear. Here, we investigated the dynamic adsorption of VOCs with various kinetic diameters on a prepared KAC with high surface area of 3100 m/g, pore volume of 2.08 cm/g and average pore width (D) of 2.68 nm. Adsorption affinity was negatively correlated with size difference (D-σ), indicating that pore width of adsorbent should close to σ to obtain a strong interaction between VOCs and adsorbents. Amounts adsorbed were positively correlated with σ at low relative pressures (p/p < 0.01), and negatively correlated with σ at high relative pressures (p/p > 0.044). The above results suggest that larger molecules with higher affinities are preferentially adsorbed at low relative pressures, amounts adsorbed of smaller molecules are larger than that of bigger molecules at high relative pressures. This study provided new insights into adsorption mechanisms mediated by σ and the development of next generation adsorbents for efficient removal of VOCs.
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http://dx.doi.org/10.1016/j.jhazmat.2021.127355DOI Listing
September 2021

Biochar effectively inhibits the horizontal transfer of antibiotic resistance genes via transformation.

J Hazard Mater 2021 Sep 9;423(Pt B):127150. Epub 2021 Sep 9.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China. Electronic address:

The rapid spread of antibiotic resistance genes (ARGs) has posed a risk to human health. Here, the effects of biochar (BC) on the horizontal transfer of ARG-carrying plasmids to Escherichia coli via transformation were systematically investigated. BC could significantly inhibit the transformation of ARGs and the inhibition degree increased with pyrolysis temperature. Rice straw-derived BC showed a stronger inhibitory effect on the transformation of ARGs than that of peanut shell-derived BC from the same pyrolysis temperature. The inhibitory effect of BC from low pyrolysis temperature (300 ℃) was mainly caused by BC dissolutions, while it was mainly attributed to BC solids for high pyrolysis temperature (700 ℃) BC. BC dissolutions could induce intramolecular condensation and even agglomeration of plasmids, hindering their transformation into competent bacteria. The cell membrane permeability was slightly decreased in BC dissolutions, which might also contribute to the inhibitory effect. Plasmid can be adsorbed by BC solids and the adsorption increased with BC pyrolysis temperature. Meanwhile, BC-adsorbed plasmid could hardly be transformed into E. coli. BC solids could also deactivate E. coli and thereby inhibit their uptake of ARGs. These findings provide a way using BC to limit the spread of ARGs in the environment.
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http://dx.doi.org/10.1016/j.jhazmat.2021.127150DOI Listing
September 2021

Iron-carbon material enhanced electrokinetic remediation of PCBs-contaminated soil.

Environ Pollut 2021 Dec 1;290:118100. Epub 2021 Sep 1.

Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou, 310058, China. Electronic address:

The high toxicity and persistence of polychlorinated biphenyls (PCBs) in the environment demands the development of effective remediation for PCBs-contaminated soils. In this study, electrokinetic (EK) remediation integrated with iron-carbon material (Fe/C) was established and used to remediate PCB28 (1 mg kg) contaminated soil under a voltage gradient of 1 V cm. Effects of Fe/C dosage, soil type, and remediation time were investigated. The operational condition was optimized as 4 g kg Fe/C, yellow soil, and 14 d-remediation, achieving PCB28 removal efficiency of 58.6 ± 8.8% and energy utilization efficiency of 146.5. Introduction of EK-Fe/C did not significantly affect soil properties except for slight soil moisture content increase and total Fe content loss. Soil electrical conductivity exhibited an increasing trend from anode to cathode attributed to EK-induced electromigration and electroosmosis. EK accelerated the corrosion and consumption of reactive Fe/FeC in Fe/C by generating acid condition. Fe/C in turn effectively prevented EK-induced soil acidification and maintained soil neutral to weak alkaline condition. A synergistic effect between EK and Fe/C was revealed by the order of PCB28 removal efficiency-EK-Fe/C (58.6 ± 8.8%) > EK (37.7 ± 1.6%) > Fe/C (6.8 ± 5.0%). This could be primarily attributed to EK and Fe/C enhanced Fenton reaction, where EK promoted Fe/C dissolution and HO generation. In addition to oxidation by Fenton reaction generated ·OH, EK-mediated electrochemical oxidation, Fe/C-induced reduction and migration of Fe/C adsorbed PCBs were all significant contributors to PCB28 removal in the EK-Fe/C system. These findings suggest that the combination of EK and Fe/C is a promising technology for remediation of organics-contaminated soil.
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http://dx.doi.org/10.1016/j.envpol.2021.118100DOI Listing
December 2021

Nano-Zoo Interfacial Interaction as a Design Principle for Hybrid Soil Remediation Technology.

ACS Nano 2021 09 23;15(9):14954-14964. Epub 2021 Aug 23.

Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China.

Using nanotechnology to remediate contaminated agricultural soil is promising but faces notable technical and economic challenges. Importantly, widely distributed soil invertebrates can potentially act as natural mobile facilitators for nanoscale remediation of contaminated soil. Herein, we have drawn inspiration from nano-bio interaction and established a hybrid remediation framework using nanoscale zerovalent iron (nZVI) and nematodes for organochlorine-contaminated soil. Approximately 80% pentachlorophenol (PCP, initially 50 mg/kg) was synergistically degraded by nZVI and nematodes within 3 days. Mechanistically, exposure to nZVI stimulated the synthesis of reductive biomolecules (including collagen, glutathione, and l-cysteine) which acted as a bioreductive barrier and significantly mitigated the toxicity of PCP. At the microinterface, collagen distributed in the epidermis chelated nZVI; subsequently, l-cysteine and glutathione strongly accelerated nZVI-induced PCP dechlorination by facilitating the reductive dissolution of nZVI oxide shell and electron transfer from Fe core to PCP. On the basis of the interfacial interaction, an optimized soil remediation approach composed of nZVI, nematodes, and l-cysteine was established, demonstrating a 2.1-fold increase in removal efficiency with only 48.5% nZVI consumption compared with the nZVI treatment alone. This work provides a heuristic model for developing cost-efficient remediation technologies with the synergistic force of functional materials and indigenous biota, which may be widely applicable to a range of environmental contamination scenarios.
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http://dx.doi.org/10.1021/acsnano.1c05180DOI Listing
September 2021

Separation and Analysis of Nanoscale Zero-Valent Iron from Soil.

Anal Chem 2021 07 13;93(29):10187-10195. Epub 2021 Jul 13.

Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Department of Environmental Science, Zhejiang University, Hangzhou 310058, China.

Nanoscale zero-valent iron (nZVI) has become one of the most used engineered nanoparticles for soil remediation. However, isolating nZVI particles from a complex soil matrix for their accurate particle characterizations and transport distance measurements is still challenging. Here, this study established a new analysis approach combining ultrasound-assisted solvent extraction, magnetic separation, and single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) analysis to isolate nZVI particles from soils and quantify their concentration and size. The interference from natural Fe-containing substances on nZVI analysis could be efficiently minimized by magnetic separation and dilution. After the optimization of extraction solvent type/concentration (i.e., 2.5 mM tetrasodium pyrophosphate) and ultrasonication time (i.e., 30 min), acceptable recoveries in both particle number (62.0 ± 10.8%-96.1 ± 4.8%) and Fe mass (70.6 ± 12.0%-119 ± 18%) could be achieved for different sizes (50 and 100 nm) and concentrations (50, 100, and 500 μg g) of spiked nZVI from six soils. The detection limits of particle size and concentration were approximately 43.1 nm and 50 μg nZVI per gram soil, respectively. These results provide a feasible approach to quantify the nZVI concentration and size in complex soil matrices, which will allow the improvements to characterize and track the nZVI particles in the field, promote the use of nZVI particles for soil remediation, and better assess their environmental implications.
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http://dx.doi.org/10.1021/acs.analchem.1c01452DOI Listing
July 2021

Octanol-water partition coefficient (logK) dependent movement and time lagging of polycyclic aromatic hydrocarbons (PAHs) from emission sources to lake sediments: A case study of Taihu Lake, China.

Environ Pollut 2021 Nov 4;288:117709. Epub 2021 Jul 4.

Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China; Key Laboratory of Environmental Pollution and Ecological Health of Ministry of Education, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, 310058, China. Electronic address:

Understanding the movement of polycyclic aromatic hydrocarbons (PAHs) from emission sources to sediments is important for achieving long-term pollution control of PAHs in sediments. In this study, by exploring the correlation of individual PAHs concentrations (C) in Taihu Lake sediments reported in the past twenty years with their annual emissions (E) in the lake region, it was observed that mean concentrations of PAHs with low logK (i.e., logK≤4.00) in Taihu Lake sediments were correlated best with their emissions without lagging between the sediment sampling time and the PAHs emitting time. However, for PAHs with middle logK (i.e., 4.004.57), their mean concentrations in sediments were correlated best with the emissions of PAHs emitted 1 or 2 years before the sediment sampling time. The longer lagging time of PAHs with middle or high logK from emission sources to lake sediments could be attributed to their retardation in soils and river sediments around the lake. Moreover, the retardation in soils and river sediments is dependent on PAHs logK and degradation half-life, indicating the dependence of PAHs concentration in sediments on their environmental behaviors, including sorption and degradation. K dependent movement and the time lagging observed in Taihu Lake for PAHs from emission sources to sediments could be valuable for developing measures to control PAHs, especially for congeners with high logK.
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http://dx.doi.org/10.1016/j.envpol.2021.117709DOI Listing
November 2021

Sorption mechanism of naphthalene by diesel soot: Insight from displacement with phenanthrene/p-nitrophenol.

J Environ Sci (China) 2021 Aug 1;106:136-146. Epub 2021 Feb 1.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Environmental Pollution and Ecological Health of Ministry of Education, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China. Electronic address:

The nonlinear sorption of hydrophobic organic contaminants (HOCs) could be changed to linear sorption by the suppression of coexisting solutes in natural system, resulting in the enhancement of mobility, bioavailability and risks of HOCs in the environment. In previous study, inspired from the competitive adsorption on activated carbon (AC), the displaceable fraction of HOCs sorption to soot by competitor was attributed to the adsorption on elemental carbon fraction of soot (EC-Soot), while the linear and nondisplaceable fraction was attributed to the partition in authigenic organic matter of soot (OM-Soot). In this study, however, we observed that the linear and nondisplaceable fraction of HOC (naphthalene) to a diesel soot (D-Soot) by competitor (phenanthrene or p-nitrophenol) should be attributed to not only the linear partition in OM-Soot, but also the residual linear adsorption on EC-Soot. We also observed that the competition on the surface of soot dominated by external surface was different from that of AC dominated by micropore surface, i.e., complete displacement of HOCs by p-nitrophenol could occur for the micropore surface of AC, but not for the external surface of soot. These observations were obtained through the separation of EC-Soot and OM-Soot from D-Soot with organic-solvent extraction and the sorption comparisons of D-Soot with an AC (ACF300) and a multiwalled carbon nanotube (MWCNT30). The obtained results would give new insights to the sorption mechanisms of HOCs by soot and help to assess their environmental risks.
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http://dx.doi.org/10.1016/j.jes.2021.01.017DOI Listing
August 2021

Binding Force and Site-Determined Desorption and Fragmentation of Antibiotic Resistance Genes from Metallic Nanomaterials.

Environ Sci Technol 2021 07 17;55(13):9305-9316. Epub 2021 Jun 17.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China.

Interfacial interactions between antibiotic resistance genes (ARGs) and metallic nanomaterials (NMs) lead to adsorption and fragmentation of ARGs, which can provide new avenues for selecting NMs to control ARGs. This study compared the adsorptive interactions of ARGs (-carrying plasmids) with two metallic NMs (ca. 20 nm), i.e., titanium dioxide (nTiO) and zero-valent iron (nZVI). nZVI had a higher adsorption rate (0.06 min) and capacity (4.29 mg/g) for ARGs than nTiO (0.05 min and 2.15 mg/g, respectively). No desorption of ARGs from either NMs was observed in the adsorptive background solution, isopropanol or urea solutions, but nZVI- and nTiO-adsorbed ARGs were effectively desorbed in NaOH and NaHPO solutions, respectively. Molecular dynamics simulation revealed that nTiO mainly bound with ARGs through electrostatic attraction, while nZVI bound with PO of the ARG phosphate backbones through Fe-O-P coordination. The ARGs desorbed from nTiO remained intact, while the desorbed ARGs from nZVI were splintered into small fragments irrelevant to DNA base composition or sequence location. The ARG removal by nZVI remained effective in the presence of PO, natural organic matter, or protein at environmentally relevant concentrations and in surface water samples. These findings indicate that nZVI can be a promising nanomaterial to treat ARG pollution.
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http://dx.doi.org/10.1021/acs.est.1c02047DOI Listing
July 2021

Influence of extracellular polymeric substance on the interaction between titanium dioxide nanoparticles and Chlorella pyrenoidosa cells.

Sci Total Environ 2021 Jul 13;778:146446. Epub 2021 Mar 13.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China. Electronic address:

The presence of extracellular polymeric substance (EPS) plays a vital role in the accumulation and toxicity of nanoparticles to microorganisms, in which the involved processes and mechanisms are still waiting to be revealed. Herein, we specifically investigated the interfacial interaction between titanium dioxide nanoparticles (nTiO) and algae (Chlorella pyrenoidosa) with/without EPS and the effect of EPS on algal cell internalization of nTiO. Results showed that the presence of EPS on cell surface promoted heteroaggregation between nTiO and algal cells, and induced more nTiO accumulation on algal surface; however, algal cell internalization of nTiO was limited by the presence of EPS. Pearson correlation analysis further proved that the presence of EPS had a positive effect on the surface accumulation of nTiO and a negative effect on the internalization of nTiO. More than 60% of cell internalized nTiO entered algal cells through the energy dependent endocytosis pathway. It is interesting to find that anatase nTiO (nTiO-A) entered algal cells mainly through the clathrin dependent endocytosis, while rutile nTiO (nTiO-R) mainly through the dynamin dependent endocytosis. This difference could be due to the different affinities of nTiO-A and nTiO-R to the mediating receptors referring to different endocytic pathways. The removal of EPS activated the associated mediating pathways, allowing more nTiO to be internalized. These findings address the role of EPS on the interaction between nTiO and algae and promote a deeper understanding of the ecological effect of nTiO.
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http://dx.doi.org/10.1016/j.scitotenv.2021.146446DOI Listing
July 2021

Toxic effects of nano-TiO in bivalves-A synthesis of meta-analysis and bibliometric analysis.

J Environ Sci (China) 2021 Jun 19;104:188-203. Epub 2020 Dec 19.

International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology, Shanghai 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China. Electronic address:

Since the beginning of the 21st century, the increasing production and application of nano-TiO in consumer products have inevitably led to its release into aquatic systems and therefore caused the exposure of aquatic organisms, resulting in growing environmental concerns. However, the safety of nano-TiO in aquatic environments has not been systematically assessed, especially in coastal and estuary waters where a large number of filter-feeding animals live. Bivalves are considered around the world to be a unique target group for nanoparticle toxicity, and numerous studies have been conducted to test the toxic effects of nano-TiO on bivalves. The aim of this review was to systematically summarize and analyze published data concerning the toxicological effects of nano-TiO in bivalves. In particular, the toxicity of nano-TiO to the antioxidant system and cell physiology was subjected to meta-analysis to reveal the mechanism of the toxicological effects of nano-TiO and the factors affecting its toxicological effects. To reveal the cooperation, hot keywords and co-citations in this field, bibliometric analysis was conducted, and the results showed that the toxicological molecular mechanisms of nano-TiO and the combined effects of nano-TiO and other environmental factors are two major hot spots. Finally, some perspectives and insights were provided in this review for future research on nano-TiO toxicology in bivalves.
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http://dx.doi.org/10.1016/j.jes.2020.11.013DOI Listing
June 2021

Re-recognizing micro locations of nanoscale zero-valent iron in biochar using C-TEM technique.

Sci Rep 2021 Mar 3;11(1):5037. Epub 2021 Mar 3.

Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China.

Biochar supported nanoscale zero-valent iron (NZVI/BC), prepared commonly by liquid reduction using sodium borohydride (NaBH), exhibits better reduction performance for contaminants than bare NZVI. The better reducing ability was attributed to attachment of nanoscale zero-valent iron (NZVI) on biochar (BC) surface or into the interior pores of BC particles due to observations by scanning electron microscopy (SEM) and plan transmission electron microscopy (P-TEM) techniques in previous studies. In this study, cross-sectional TEM (C-TEM) technique was employed firstly to explore location of NZVI in NZVI/BC. It was observed that NZVI is isolated from BC particles, but not located on the surface or in the interior pores of BC particles. This observation was also supported by negligible adsorption and precipitation of Fe/Fe and iron hydroxides on BC surface or into interior pores of BC particles respectively. Precipitation of Fe and Fe, rather than adsorption, is responsible for the removal of Fe and Fe by BC. Moreover, precipitates of iron hydroxides cannot be reduced to NZVI by NaBH. In addition to SEM or P-TEM, therefore, C-TEM is a potential technique to characterize the interior morphology of NZVI/BC for better understanding the improved reduction performance of contaminants by NZVI/BC than bare NZVI.
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http://dx.doi.org/10.1038/s41598-021-84685-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7930034PMC
March 2021

Transformation and implication of nanoparticulate zero valent iron in soils.

J Hazard Mater 2021 06 22;412:125207. Epub 2021 Jan 22.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China. Electronic address:

Knowledge of nanoparticulate zero-valent iron (nZVI) transformation in soils and its relationship with the potential impacts on soil properties are crucial to evaluate the environmental implication and application of nZVI. This study investigated nZVI transformation and the effects on soil properties in eight soils with various ageing time and soil moisture content (SMC). Spherical nZVI was gradually oxidized, collapsed, and adhered to clay minerals, and crystalline maghemite and magnetite were the primary oxidation products. Compared with the flooded condition, nZVI oxidation was accelerated under 70% SMC but was limited under 30% SMC. Acidic soil with lower content of dissolved aromatic carbon was advantage to nZVI oxidation under the flooded condition, while carboxymethylcellulose coating and iron oxides on nZVI surface limited nZVI oxidation. The aged nZVI existed mainly in the form of association with soil mineral or organic matter rather than in ion-exchangeable or carbonate form. nZVI treatment promoted soil aromatic carbon sequestration and decreased soil redox potential, and the impacts of nZVI on soil pH, electrical conductivity, ζ-potential, dissolved organic carbon, and catalase and urease activities were dependent on soil type and SMC. The findings are of significance for the evaluation of the environmental risk and proper application of nZVI.
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http://dx.doi.org/10.1016/j.jhazmat.2021.125207DOI Listing
June 2021

Identification and Speciation of Nanoscale Silver in Complex Solid Matrices by Sequential Extraction Coupled with Inductively Coupled Plasma Optical Emission Spectrometry.

Anal Chem 2021 02 13;93(4):1962-1968. Epub 2021 Jan 13.

Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018, China.

Nanoscale silver (n-Ag) including silver nanoparticles (Ag-NPs), silver chloride nanoparticles (AgCl-NPs), and silver sulfide nanoparticles (AgS-NPs) and their corresponding ionic counterpart, namely, dissolved Ag, may coexist in soils. X-ray absorption near edge spectroscopy (XANES) is used to elucidate the speciation of n-Ag in soils, whereas it possesses drawbacks like high costs, rare availability of the instrument, and providing semiquantitative data. We developed a new method for the identification and speciation of n-Ag in soils and sediments based on a sequential extraction technique coupled with inductively coupled plasma optical emission spectrometry. Extraction conditions were first evaluated, establishing the optimal extraction procedure; Ag-NPs, AgCl-NPs, and dissolved Ag in soil were simultaneously extracted by using an aqueous solution of 10 mM tetrasodium pyrophosphate, followed by selective isolation and quantification via AgCl-NPs dissolution (4.45 M aqueous ammonia), centrifugation (Ag-NPs), and detection. The AgS-NPs remaining in the soil were then extracted with NaS solution at pH 7.0 through selective complexation. Optimal recoveries of Ag-NPs, AgCl-NPs, AgS-NPs, and dissolved Ag were 99.1 ± 2.4%, 112.0 ± 3.4%, 96.4 ± 4.0%, and 112.2 ± 4.1%, respectively. The method was validated to investigate the speciation of n-Ag in soils and sediments, exhibiting the distribution of Ag-NPs, AgCl-NPs, AgS-NPs, and dissolved Ag in each sample, wherein AgS-NPs, the major species of n-Ag, accounted for 35.42-68.87% of the total Ag. The results of n-Ag speciation in soil are comparable to those obtained through the linear combination fitting of XANES. This method thus is a powerful, yet convenient, substitute for XANES to understand the speciation of n-Ag in complex solid matrices.
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http://dx.doi.org/10.1021/acs.analchem.0c04741DOI Listing
February 2021

Combined toxic effects of dioxin-like PCB77 with Fe-based nanoparticles in earthworm Eisenia fetida.

Sci Total Environ 2021 Apr 29;766:144347. Epub 2020 Dec 29.

College of Environmental and Resource Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China; Institute of Environmental Health, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China; National Demonstration Center for Experimental Environment and Resources Education, Zhejiang University, Hangzhou 310058, China. Electronic address:

Iron-based nanomaterials hold promise for in situ remediation of persistent halogenated contaminants such as dioxin-like polychlorinated biphenyls, however, their complex interactions and joint toxicity toward beneficial soil biological functions remain unknown. This study examined the effects of nano-zero valent iron (nZVI) on the physiological and morphological changes, on the bioaccumulation of co-existed dioxin-like 3,3',4,4'-tetrachloro-biphenyls (PCB77), and the joint toxicity of nZVI and PCB77 in earthworms Eisenia fetida. An orthogonally designed experiment was conducted through the exposure of E. fetida to the combined and separate nZVI and PCB77 at various concentrations in soil for 28 days (nZVI at the levels of g-Fe/kg-soil and PCB77 at the levels of mg-PCB/kg-soil). Results indicated that both nZVI and PCB77 inhibited the growth and reproduction of earthworms, and the combined exposure resulted in a synergistic effect. The addition of 10 g/kg nZVI decreased the contents of PCB77 and significantly increased the accumulation of PCB77 to a level ranging 14-97 mg/kg in earthworms in a nZVI dose dependent manner. The observed synergism might relate to the aggravated damage of earthworm epidermis in the presence of nZVI. PCB77 and nZVI at their corresponding high levels (10 mg/kg and 10 g/kg) induced oxidative stress and lipid peroxidation in the earthworms through the increased levels of reactive oxygen species and the subsequent inhibition of antioxidant enzymes including superoxide dismutase and catalase. Further metabolomics analyses revealed that the normal glutamic acid metabolism and tricarboxylic acid cycle were disturbed in earthworms exposed to the combined treatment of 10 mg/kg PCB77 and 10 g/kg nZVI. Our findings suggested that earthworms as a sentinel species could be readily employed in toxicity and tolerance studies to succeed the safe applications of nZVI and interestingly earthworms themselves also hold promise for vermiremediation owing to the high bioaccumulation potential of PCBs from contaminated soils.
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http://dx.doi.org/10.1016/j.scitotenv.2020.144347DOI Listing
April 2021

Interactions of extracellular DNA with aromatized biochar and protection against degradation by DNase I.

J Environ Sci (China) 2021 Mar 2;101:205-216. Epub 2020 Sep 2.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China. Electronic address:

With increasing environmental application, biochar (BC) will inevitably interact with and impact environmental behaviors of widely distributed extracellular DNA (eDNA), which however still remains to be studied. Herein, the adsorption/desorption and the degradation by nucleases of eDNA on three aromatized BCs pyrolyzed at 700 °C were firstly investigated. The results show that the eDNA was irreversibly adsorbed by aromatized BCs and the pseudo-second-order and Freundlich models accurately described the adsorption process. Increasing solution ionic strength or decreasing pH below 5.0 significantly increased the eDNA adsorption on BCs. However, increasing pH from 5.0 to 10.0 faintly decreased eDNA adsorption. Electrostatic interaction, Ca ion bridge interaction, and π-π interaction between eDNA and BC could dominate the eDNA adsorption, while ligand exchange and hydrophobic interactions were minor contributors. The presence of BCs provided a certain protection to eDNA against degradation by DNase I. BC-bound eDNA could be partly degraded by nuclease, while BC-bound nuclease completely lost its degradability. These findings are of fundamental significance for the potential application of biochar in eDNA dissemination management and evaluating the environmental fate of eDNA.
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http://dx.doi.org/10.1016/j.jes.2020.08.017DOI Listing
March 2021

Iron-crosslinked alginate derived Fe/C composites for atrazine removal from water.

Sci Total Environ 2021 Feb 27;756:143866. Epub 2020 Nov 27.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China. Electronic address:

Fe/C composite is emerging as a promising nanoscale zero-valent iron (nZVI) based material for wastewater treatment to counteract the limitations of nZVI, while its preparation method, structure-activity relationship, and working mechanisms and conditions still need to be studied. In this study, Fe/C composites derived from iron-crosslinked alginate was successfully achieved via high temperature pyrolysis. Ferric ions were only transformed into FeO/γ-FeO at low pyrolysis temperature (≤500 °C), whereas Fe/FeC became the primary Fe species with the formation of graphitic carbon at elevated pyrolysis temperature (≥700 °C). Fe/C composites from higher pyrolysis temperature presented better performance in atrazine (ATZ) removal, and the optimal pyrolysis temperature was 800 °C (Fe/C-800). Batch experiments showed that the removal kinetics of ATZ (10 mg L) by Fe/C-800 (0.2 g L) followed pseudo-second-order model, and 24-h ATZ removal efficiency maintained at 93.5 ± 1.0% within pH 3-9. The adsorption by the graphitic carbon phase of Fe/C-800 was the principal contributor to the pH-independent superior performance in ATZ removal, and the Langmuir model fitted adsorption capacity was 64.8 mg g at pH 6. Although the carbon-phase adsorbed ATZ was basically unavailable for degradation, Fe/FeC-mediated ATZ degradation contributed to the great reactivity of Fe/C-800 at pH 3. Fe/FeC in Fe/C-800 was more efficient for ATZ degradation than commercial nZVI, and oxidative dealkylation by Fe/FeC mediated Fenton reaction was the predominant ATZ degradation pathway rather than reductive dechlorination. Moreover, the produced ATZ degradation intermediates could be further adsorbed by Fe/C-800, mitigating potential secondary pollution. Thus, iron-crosslinked alginate derived Fe/C composites can be an excellent alternative for nZVI in organics-polluted water treatment with great reactivity and wide pH applicability.
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http://dx.doi.org/10.1016/j.scitotenv.2020.143866DOI Listing
February 2021

Release and sedimentation behaviors of biochar colloids in soil solutions.

J Environ Sci (China) 2021 Feb 14;100:269-278. Epub 2020 Aug 14.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China. Electronic address:

The release of biochar colloids considerably affects the stability of biochar in environment. Currently, information on the release behavior and suspension stability of biochar colloids in real soil solutions is scarce. In this study, 20 soils were collected from different districts in China and the release behavior of biochar colloids and their suspension stability in soil solutions were systematically examined. The results showed that both pyrolysis temperature and biomass source had important effects on the formation of biochar colloids in soil solutions. The formation amount of biochar colloids from low pyrolysis temperatures (400 °C) (average amount of 9.33-16.41 mg/g) were significantly higher than those from high pyrolysis temperatures (700 °C) (average amount of less than 2 mg/g). The formation amount of wheat straw-derived biochar colloids were higher than those of rice straw-derived biochar colloids probably due to the higher O/C ratio in wheat-straw biochar. Further, biochar colloidal formation amount was negatively correlated with comprehensive effect of dissolved organic carbon, Fe and Al in soil solutions. The sedimentation curve of biochar colloids in soil solutions is well described by an exponential model and demonstrated high suspension stability. Around 40% of the biochar colloids were maintained in the suspension at the final sedimentation equilibrium. The settling efficiency of biochar colloids was positively correlated with comprehensive effect of the ionic strength and K, Ca, Na, and Mg contents in soil solutions. Our findings help promote a deeper understanding of biochar loss and stability in the soil-water environment.
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http://dx.doi.org/10.1016/j.jes.2020.08.002DOI Listing
February 2021

A new strategy using nanoscale zero-valent iron to simultaneously promote remediation and safe crop production in contaminated soil.

Nat Nanotechnol 2021 02 30;16(2):197-205. Epub 2020 Nov 30.

Department of Environmental Science, Zhejiang University, Hangzhou, China.

Novel versatile nanomaterials may facilitate strategies for simultaneous soil remediation and agricultural production, but a thorough and mechanistic assessment of efficacy and safety is needed. We have established a new soil remediation strategy using nanoscale zero-valent iron (nZVI) coupled with safe rice production in paddy soil contaminated with pentachlorophenol (PCP). In comparison with rice cultivation in contaminated soil with 100 mg PCP per kg soil but without nZVI, the addition of 100 mg nZVI per kg soil increased grain yield by 47.1-55.0%, decreased grain PCP content by 83.6-86.2% and increased the soil PCP removal rate from 49.9 to 83.9-89.0%. The specific role of nZVI-derived root iron plaque formation in the safe production of rice has been elucidated, and the synergistic effect of nZVI treatment and rice cultivation identified in the nZVI-facilitated rhizosphere microbial degradation of PCP. This work opens a new strategy for the application of nanomaterials in soil remediation that could simultaneously enable safe crop production in contaminated lands.
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http://dx.doi.org/10.1038/s41565-020-00803-1DOI Listing
February 2021

In situ growth of TiO nanoparticles on nitrogen-doped TiC with isopropyl amine toward enhanced photocatalytic activity.

J Hazard Mater 2021 Jan 22;402:124066. Epub 2020 Sep 22.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China. Electronic address:

Construction of heterojunction and nitrogen doping is an effective approach for synthesizing photocatalysts with high quantum yield and efficient electron-hole separation. 2D MXene TiC has been considered a good carbonaceous nanomaterial for designing heterojunction, while the original surface groups and stacked structure limit the electron-hole separation. Herein, a hybrid of nitrogen-doped TiC nanosheets and TiO nanoparticles (NPs) composed of TiO NPs in situ growing on isopropyl amine (iPA) modified TiC (iN-TiC) was developed for the first time. The novel iN-TiC/TiO hybrid exhibited an excellent ultraviolet-light photodegradation of methylene blue (MB), with a degradation rate (0.02642 min) significantly higher than that of pure TiO NPs, bulk-TiC/TiO, dimethyl sulfoxide modified TiC/TiO hybrid, and hydrazine monohydrate modified TiC/TiO hybrid. The formation of heterojunction between iN-TiC and TiO and its role in the photocatalysis were systematically analyzed using various characterization techniques and density functional theory calculation. The iPA modification exfoliated TiC and doped N on TiC nanosheets; the in situ grown TiO NPs formed efficient heterojunctions with the nanosheets; the N-doping facilitated electron migration in TiC and inhibited the recombination of photogenerated electron-hole pairs; •OH dominated the photodegradation of MB. This work provides a new approach of constructing efficient photocatalysts for the treatment of organics-polluted water.
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http://dx.doi.org/10.1016/j.jhazmat.2020.124066DOI Listing
January 2021

Isotherm nonlinearity and nonlinear partitioning of organic compounds into resin XAD-7: Insight from displacement experiments.

Environ Pollut 2020 Dec 31;267:115563. Epub 2020 Aug 31.

Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China; Key Laboratory of Environmental Pollution and Ecological Health of Ministry of Education, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou, 310058, China. Electronic address:

Nonlinear sorption and isotherm nonlinearity of organic compounds by widely used porous resins such as XAD-7 are commonly interpreted as adsorption due to their large surface area. However, through displacement experiments using saturated 4-nitrophenol as the displacer, we observed that the nonlinear sorption and isotherm nonlinearity of selected organic compounds (i.e., naphthalene, nitrobenzenes, phenols and anilines) by XAD-7 was captured by a nonlinear partition mechanism rather than the adsorption mechanism. Nonlinear sorption of organic compounds by XAD-7 includes a nonlinear/displaced fraction and a linear/non-displaced fraction. A dual-mode (DM) model, including a nonlinear Dubinin-Ashtakhov (DA) model component and a linear model component, was developed to describe the nonlinear/displaced fraction and the linear/non-displaced fraction, respectively. The capacity of these two fractions are dependent on their solubility in water or octanol with positively linear relationships but not their molecular size, supporting the nonlinear partitioning mechanism. Besides van-der-waals force, hydrogen-bonding is primarily responsible for the nonlinear partitioning of phenols and anilines into XAD-7, while π-π interaction is responsible for the nonlinear partitioning of naphthalene and nitrobenzenes. The explored nonlinear partitioning mechanism for XAD-7 implies that the nonlinear sorption of organic compounds by porous resins should be recognized for their recovery and applications as sorbents.
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http://dx.doi.org/10.1016/j.envpol.2020.115563DOI Listing
December 2020

Pentachlorophenol and ciprofloxacin present dissimilar joint toxicities with carbon nanotubes to Bacillus subtilis.

Environ Pollut 2021 Feb 11;270:116071. Epub 2020 Nov 11.

Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou, 310058, China. Electronic address:

Discharged carbon nanotubes (CNTs) likely interact with co-existing organic contaminants (OCs) and pose joint toxicity to environmental microbes. Herein, hydrophobic pentachlorophenol (PCP) and hydrophilic ciprofloxacin (CIP) were used as representative OCs and their joint toxicities with CNTs to Bacillus subtilis were systematically investigated at cellular, biochemical, and omics levels. The 3-h bacterial growth half inhibitory concentrations of CNTs, PCP, and CIP were 12.5 ± 2.6, 3.5 ± 0.5, and 0.46 ± 0.03 mg/L, respectively, and they all could damage cell membrane, increase intracellular oxidative stress, and alter bacterial metabolomics and transcriptomics; while CNTs-PCP and CNTs-CIP binary exposures exhibited distinct additive and synergistic toxicities, respectively. CNTs increased bacterial bioaccumulation of PCP and CIP via destabilizing and damaging cell membrane. PCP reduced the bioaccumulation of CNTs, while CIP had no significant effect; this difference could be owing to the different effects of the two OCs on cell-surface hydrophobicity and CNTs electronegativity. The additive toxicity outcome upon CNTs-PCP co-exposure could be a result of the balance between the increased toxicity from increased PCP bioaccumulation and the decreased toxicity from decreased CNTs bioaccumulation. The increased bioaccumulation of CIP contributed to the synergistic toxicity upon CNTs-CIP co-exposure, as confirmed by the increased inhibition of topoisomerase Ⅳ activity and interference in gene expressions regulating ABC transporters and lysine biosynthesis. The findings provide novel insights into environmental risks of CNTs.
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http://dx.doi.org/10.1016/j.envpol.2020.116071DOI Listing
February 2021

Nonlinear partition of nonionic organic compounds into humus-like substance humificated from lignin.

Sci Total Environ 2021 Apr 16;764:142887. Epub 2020 Oct 16.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Environmental Pollution and Ecological Health of Ministry of Education, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China. Electronic address:

Nonlinear sorption of nonionic organic compounds (NOCs) by soil organic matter (SOM) is a significant behaviour that affecting their distribution, transport and fate in the environment. Sorption of typical NOCs, including phenols, anilines, nitrobenzenes and polycyclic aromatic hydrocarbons (PAHs) by Lig48, a humus-like substance humificated from lignin (the principal component of plant precursors of SOM), is nonlinear and without desorption hysteresis, and interpreted by nonlinear partition mechanism in this study. The positively linear relationship between sorption capacity and water solubility of NOCs is a distinguish characteristic for their nonlinear partition into Lig48. Moreover, the nonlinear partition capacity of NOCs is mainly dependent on the aromaticity of humus-like substances with a positively linear relationship, while the nonlinear partition affinity is mainly dependent on the polarity of humus-like substances with a negatively linear relationship. Competition between phenols, anilines, nitrobenzenes and PAHs was observed for their nonlinear partition into Lig48. In addition to van der Waals force, specific interactions, i.e., hydrogen-bonding and π-π interactions are responsible for the nonlinear partitioning of NOCs into humus-like substances including Lig48. These novel observations are helpful for understanding the nonlinear sorption of NOCs by SOM and elucidating the migration and transport of NOCs in the environment.
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http://dx.doi.org/10.1016/j.scitotenv.2020.142887DOI Listing
April 2021

Synergistic growth inhibition effect of TiO nanoparticles and tris(1,3-dichloro-2-propyl) phosphate on earthworms in soil.

Ecotoxicol Environ Saf 2021 Jan 15;208:111462. Epub 2020 Oct 15.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China. Electronic address:

The co-existence of organic pollutants and nanoparticles in the environment may lead to combined biological effects. The joint toxicity of pollutants and nanoparticles has been receiving increasing attention from researchers, but few studies have focused on soil biota due to the complexity of soil matrices. This study investigated the effects of tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) at 0, 5, and 25 mg/kg and nanoparticulate TiO (nTiO) at 0, 500, and 2500 mg/kg in a 3 × 3 factorial arrangement of treatments for 28 days (d) on Eisenia fetida (earthworm). Compared with the control group (the 0 mg/kg TDCIPP + 0 mg/kg nTiO treatment), all other single (TDCIPP or nTiO) and binary (TDCIPP + nTiO) treatments except for the single 500 mg/kg nTiO treatment significantly reduced the weight gain rate of E. fetida. The binary treatments had significantly greater such effect than their corresponding single treatments, exhibiting a synergistic toxicity between TDCIPP and nTiO2 on the growth of E. fetida. Since TDCIPP and nTiO had no significant effect on their concentrations in the soil or in E. fetida during binary exposure, the synergistic toxicity could be a result of the superimposition of the toxicity pathways of TDCIPP and nTiO. Transcriptomic analysis of E. fetida intestinal region revealed that exposure to 25 mg/kg TDCIPP or 2500 mg/kg nTiO affected nutrient-related or cell apoptosis and DNA damage related genes, respectively; their co-exposure greatly inhibited genes related to nutrient digestion and absorption, while causing abnormal transcription of genes related to the development and maintenance of E. fetida's muscles, leading to synergistic toxicity. These findings provide new insights into the environmental risks of organophosphorus flame retardants, nanoparticles, and their co-exposure.
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http://dx.doi.org/10.1016/j.ecoenv.2020.111462DOI Listing
January 2021

Co-transport of biochar colloids with organic contaminants in soil column.

Environ Sci Pollut Res Int 2021 Jan 26;28(2):1574-1586. Epub 2020 Aug 26.

Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China.

Co-transport of biochar (BC) colloids with coexisting organic contaminants (OCs) in soil involves complex interactions among BC colloids, OCs, and soil particles, which is significant for the environmental application and risk assessment of BC and yet has not been well addressed. This study explored co-transports of three typical OCs (i.e., phenanthrene (PHN), atrazine (ATZ), and oxytetracycline (OTC)) and BC colloids obtained from bulk BCs with different charring temperatures (200-700 °C) and particle sizes (250 nm, 500 nm, and 1 μm) in a soil column of 9 cm in height. Considerable transport of BC colloids alone was observed and the maximum breakthrough concentration (C/C) increased from 0.08 to 0.77 as the charring temperature decreased from 700 to 200 °C. The mobilities of PHN, OTC, and ATZ alone were very low but were greatly increased by co-transports with BC colloids, and their maximum C/C values were within 0.05-0.33, 0.03-0.44, and 0.05-0.62, respectively, in the absence and presence of various BC colloids. The enhancement effect of BC colloids on the OC transport decreased with increasing charring temperature or particle size of BC colloids. BC colloids mainly acted as a vehicle to facilitate the transport of OCs, and dissolved organic carbon from BC colloids also contributed to the increased mobility of OCs in dissolved form. These findings provide new insights into co-transport of BC colloids and contaminants in soil.
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http://dx.doi.org/10.1007/s11356-020-10606-5DOI Listing
January 2021

Reciprocal interference of clay minerals and nanoparticulate zero-valent iron on their interfacial interaction with dissolved organic matter.

Sci Total Environ 2020 Oct 20;739:140372. Epub 2020 Jun 20.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China. Electronic address:

With increasing environmental application of nanoparticulate zero-valent iron (nZVI), it is essential to explore the interaction of nZVI with dissolved organic matter (DOM) and clay mineral particles (CMPs) and its potential effect on the formation of DOM-mineral complex that may impact the carbon sequestration. The aggregation and adsorption behaviors of nZVIs (two bare nZVIs of different sizes and one carboxymethyl cellulose coated nZVI (CMC-nZVI)) and CMPs (kaolinite and montmorillonite) coexisting in DOM (humic acid and fulvic acid) solutions were systematically investigated. The bare nZVIs more easily formed heteroaggregates with montmorillonite than kaolinite in DOM solutions, while the CMC-nZVI tended to attach on kaolinite surface. The heteroaggregation and competition between nZVIs and CMPs could change their interfacial interaction with DOM and the ultimate immobilization of DOM was determined by the formed nZVI-CMP complexes, irrelevant to the addition sequence of nZVIs and CMPs. Compared with the individual CMPs alone, the formed bare-nZVIs-CMP heteroaggregates promoted the sequestration of DOM especially its aromatic carbon fractions, while the CMC-nZVI had no such effect. These findings will be helpful for the understanding of nZVI interaction with DOM and CMPs and the effect on the immobilization of organic carbon in the environment.
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http://dx.doi.org/10.1016/j.scitotenv.2020.140372DOI Listing
October 2020

Nonlinear sorption of phenols and anilines by organobentonites: Nonlinear partition and space limitation for partitioning.

Sci Total Environ 2020 Sep 22;736:139609. Epub 2020 May 22.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Key Laboratory of Environmental Pollution and Ecological Health of Ministry of Education, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Hangzhou 310058, China. Electronic address:

Organobentonites, i.e., bentonites coated with surfactants such as cetyltrimethylammonium (CTAB), are superior and low-cost sorbents for removal of organic contaminants from wastewater. Nonlinear sorption of polar organic compounds such as phenols and anilines by organobentonites were widely observed and interpreted by adsorption mechanism. However, in this study, it was observed that the nonlinear sorption of phenols and anilines by CTAB coated bentonites (CTAB-bentonites) should be attributed to nonlinear partition mechanism with the additional space limitation in CTAB-bentonites for nonlinear partitioning, rather than adsorption mechanism. This nonlinear partition mechanism is supported by that (i) organobentonites is a partition medium, identified by the linear isotherms of polycyclic aromatic hydrocarbons (PAHs) and nitrobenzenes; (ii) sorption coefficients (logK), the ratio of adsorbed amount (q) to equilibrium concentration (C), and Dubinin-Ashtakhov (DA) model fitted sorption capacity (logQ) of organic compounds, by a given CTAB-bentonite, are positively correlated with their octanol-water distribution coefficients (logK) and solubility in octanol (logS) respectively; (iii) logK and logQ of a given organic compound by CTAB-bentonites are positively correlated with organic carbon contents (f) of CTAB-bentonites, but not specific surface area. Specific interaction (i.e., hydrogen-bonding interaction), in addition to van der Waals force, is responsible for the nonlinear partitioning of phenols and anilines into CTAB-bentonites, because of the positively linear relationship between DA model fitted sorption affinity (E) and hydrogen-bonding donor parameter (α) of organic compounds. These results could help the recognizing of the nonlinear sorption behaviors of organic compounds by organobentonites and promote their environmental applications in wastewater treatment.
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http://dx.doi.org/10.1016/j.scitotenv.2020.139609DOI Listing
September 2020

Dispersibility and Photochemical Stability of Delaminated MXene Flakes in Water.

Small 2020 09 28;16(36):e2002433. Epub 2020 May 28.

Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China.

The environmental stability of 2D MXene flakes must be systematically studied before their further application. Herein, the colloidal dispersibility and photochemical stability of delaminated Ti C T MXene flakes modified with hydrazine (HMH) and KOH and with water as the control (HMH-Ti C , KOH-Ti C , and H O-Ti C , respectively) are experimentally and theoretically studied. Modification greatly increases the dispersibility of Ti C T flakes. Their critical coagulation concentrations are 28.7, 106, and 49.1 mm NaCl, and their Hamaker constants are 23.7 × 10 , 19.1 × 10 , and 37.7 × 10 J, respectively; the colloidal interaction follows the classical Derjaguin-Landau-Verwey-Overbeek theory. HMH-Ti C and KOH-Ti C exhibit higher photochemical stability, as indicated by their stronger resistance to oxidation under UV and visible light irradiation. Changes in their physicochemical properties and the generation of reactive oxygen species (ROS) are assayed. Spin-polarized density functional theory calculations and molecular dynamics simulations are used to determine the mechanisms underlying the differences in the photochemical stability of Ti C T flakes. K ions protect the flakes from oxidation by acting as a middle layer to reduce the coupling between Ti and ROS, while HMH provides stronger protection by absorbing photoelectrons or reacting with ROS. These findings provide new insight into the environmental transformation and design of functional MXenes.
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http://dx.doi.org/10.1002/smll.202002433DOI Listing
September 2020

Construction and visible-light-photocatalysis of a novel ternary heterostructure BiOI/(001)TiO/TiC.

Nanotechnology 2020 Aug 6;31(34):345603. Epub 2020 May 6.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, People's Republic of China.

Constructing effective heterojunctions between semiconductors and appropriate cocatalysts and exposing highly active crystal facets have been considered an effective approach to obtain efficient photocatalysts. Herein, a novel BiOI/(001)TiO/TiC (BTT) hybrid was for the first time synthesized by in situ growing (001)TiO nanosheets on a 2D MXene nanomaterial (TiC) and subsequent deposition of flower-like nanoflake BiOI on the obtained (001)TiO/TiC hybrid. The BTT hybrid exhibited excellent photocatalytic performance for degradation of Rhodamine B under visible light irradiation, with the highest degradation rate being 6.26, 1.72, and 1.35 times of that of a pure BiOI, BiOI/TiO hybrid, and BiOI/TiC hybrid, respectively. The staggeringly enhanced photoactivity of BTT was attributed to the separation of photogenerated carriers by a multiple charge transfer channels because of the formed p-n and Schottky double junctions. This study demonstrates that (001)TiO/TiC obtained by simple hydrothermal oxidation of TiC can be a good cocatalyst for fabricating excellent visible-light-driven photocatalyst.
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http://dx.doi.org/10.1088/1361-6528/ab90baDOI Listing
August 2020

Multi-omics analyses reveal molecular mechanisms for the antagonistic toxicity of carbon nanotubes and ciprofloxacin to Escherichia coli.

Sci Total Environ 2020 Jul 13;726:138288. Epub 2020 Apr 13.

Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China. Electronic address:

With the increasing production and application, engineered nanomaterials (ENMs) are being discharged into the environment, where they can interact with co-existing contaminants, causing complicated joint toxicity to organisms that needs to be studied. The case study of ENMs-contaminant joint toxicity and the understanding of relative mechanisms are very insufficient, particularly the mechanisms of molecular interactions and governing processes. Herein, a typical ENMs, carbon nanotubes (CNTs, 0-60 mg/L), and a common antibiotic, ciprofloxacin (CIP, 0-900 mg/L), were selected as the analytes. Their joint toxicity to a model microbe Escherichia coli was specifically investigated via biochemical, transcriptomics, and metabolomics approaches. The result revealed an antagonistic effect on growth inhibition between CNTs and CIP. Mitigations in cell membrane disruption and oxidative stress were involved in the antagonistic action. CIP (48.8-244 mg/L) decreased the bioaccumulation of CNTs (7.2 mg/L) via reducing cell-surface hydrophobicity and hindering the bio-nano interaction, which could attenuate the toxicity of CNTs to bacteria. CNTs (7.2 and 14.4 mg/L) alleviated the disturbance of CIP (122 and 244 mg/L) to gene expressions especially related to nitrogen compound metabolism, oxidoreductase activity, and iron-sulfur protein maturation, probably through relieving the CIP-induced inhibition of DNA gyrase activity. Further, CNTs (7.2 and 14.4 mg/L) offset the impact of CIP (122 and 244 mg/L) on bacterial metabolome via the regulation of biosynthesis of unsaturated fatty acids and metabolisms of some amino acids and glutathione. The findings shed new light on the molecular mechanisms by which ENMs present joint effect on contaminant toxicity, and provide important information for risk assessments of CNTs and fluoroquinolones in the environment.
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http://dx.doi.org/10.1016/j.scitotenv.2020.138288DOI Listing
July 2020

Multigenerational exposure to TiO nanoparticles in soil stimulates stress resistance and longevity of survived C. elegans via activating insulin/IGF-like signaling.

Environ Pollut 2020 Aug 16;263(Pt A):114376. Epub 2020 Mar 16.

Department of Environmental Science, Zhejiang University, Hangzhou, 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou, 310058, China. Electronic address:

With increasing release of nanoparticles (NPs) into the environment, soil organisms likely suffer from high dose and long duration of NPs contamination, while the effect of NPs across multiple generations in soil is rarely studied. Herein, we investigated how multigenerational exposure to different crystal forms (anatase, rutile, and their mixture) of TiO NPs (nTiO) affected the survival, behavior, physiological and biochemical traits, and lifespan of nematodes (C. elegans) in a paddy soil. The soil property changed very slightly after being spiked with nTiO, and the toxicities of three nTiO forms were largely comparable. The nTiO exposure adversely influenced the survival and locomotion of nematodes, and increased intracellular reactive oxygen species (ROS) generation. Interestingly, the toxic effect gradually attenuated and the lifespan of survived nematodes increased from the P0 to F3 generation, which was ascribed to the survivor selection and stimulatory effect. The lethal effect and the increased oxidative stress may continuously screen out offspring possessing stronger anti-stress capabilities. Moreover, key genes (daf-2, age-1, and skn-1) in the insulin/IGF-like signaling (IIS) pathway actively responded to the nTiO exposure, which further optimized the selective expression of downstream genes, increased the antioxidant enzyme activities and antioxidant contents, and thereby increased the stress resistance and longevity of survived nematodes across successive generations. Our findings highlight the crucial role of bio-responses in the progressively decreased toxicity of nTiO, and add new knowledge on the long-term impact of soil nTiO contamination.
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http://dx.doi.org/10.1016/j.envpol.2020.114376DOI Listing
August 2020
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