Publications by authors named "Yiping Feng"

64 Publications

Superhigh co-adsorption of tetracycline and copper by the ultrathin g-CN modified graphene oxide hydrogels.

J Hazard Mater 2021 Sep 29;424(Pt B):127362. Epub 2021 Sep 29.

Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China.

Development of economic and efficient absorbent for the simultaneous removal of antibiotics and heavy metals is needed. In this study, a three-dimensional porous ultrathin g-CN (UCN) /graphene oxide (GO) hydrogel (UCN-GH) was prepared by co-assembling of UCN and GO nanosheets via the facile hydrothermal reaction. Characterizations indicated that the addition of UCN significantly decreased the reduction of CO and O-CO related groups of GO during the hydrothermal reaction and introduced amine groups on UCN-GH. The UCN-GH exhibited excellent ability on the co-removal of Cu(II) (q = 2.0-2.5 mmol g) and tetracycline (TC) (q = 1.2-3.0 mmol g) from water. The adsorption capacities were increased as UCN mass ratio increasing. The mutual effects between Cu(II) and TC were examined through adsorption kinetics and isotherm models. Characterizations and computational chemistry analysis indicated that Cu(II) is apt to coordinate with the amine groups on UCN than with oxygen groups on GO, which accounts for the enhanced adsorption ability of UCN-GH. In the binary system, Cu(II) acts as a bridge between TC and UCN-GH enhanced the removal of TC. The effects of pH and regular salt ions on the removal of Cu(II)/TC were examined. Moreover, the prepared UCN-GH also showed comparable co-adsorption capacities in practical water/wastewater.
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http://dx.doi.org/10.1016/j.jhazmat.2021.127362DOI Listing
September 2021

The decreased expression of integrin αv is involved in T-2 toxin-induced extracellular matrix degradation in chondrocytes.

Toxicon 2021 Aug 15;199:109-116. Epub 2021 Jun 15.

School of Public Health, Xi'an Jiaotong University, Key Laboratory of Environment and Genes Related to Diseases in the Education Ministry and Key Laboratory of Trace Elements and Endemic Diseases in Ministry of Health, Xi'an, Shaanxi, China. Electronic address:

T-2 toxin is one of the most toxic and common mycotoxins in grains and related products. It is considered a risk factor for Kashin-Beck disease (KBD), an endemic osteoarthritis. Both in vitro and in vivo studies have shown that T-2 toxin can cause extracellular matrix degradation; however, the underlying mechanism is unclear. Integrins have been found to regulate the expression of matrix metalloproteinases (MMPs), the 'scissors' of matrix proteins. In this study, we investigated whether integrin αv played a role in T-2 toxin-induced matrix degradation. Results from our study showed that the expression of integrin αv in the cartilage of rats fed T-2 toxin was reduced compared to that in rats fed a normal diet. Integrin αv was downregulated in T-2 toxin-treated C28/I2 chondrocytes, and selenium was found to have a protective effect. The expression of MMP-1, -3, -10, and -13 increased whereas that of type II collagen (Col II) protein decreased in C28/I2 cells treated with an integrin αv inhibitor. In conclusion, T-2 toxin can downregulate integrin αv expression in chondrocytes. Reduced integrin αv signalling could induce the release of MMPs, leading to matrix degradation.
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http://dx.doi.org/10.1016/j.toxicon.2021.06.006DOI Listing
August 2021

Reduction of Smad2 caused by oxidative stress leads to necrotic death of hypertrophic chondrocytes associated with an endemic osteoarthritis.

Rheumatology (Oxford) 2021 Mar 26. Epub 2021 Mar 26.

Institute of Endemic Diseases, School of Public Health, Xi'an Jiaotong University Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases, Shaanxi, China.

Objective: The occurrence and development of an endemic osteoarthritis Kashin-Beck Disease (KBD) is closely related to oxidative stress induced by free radicals. The aim of the study was to find the key signalling molecules or pathogenic factors as a potential treatment strategy for KBD.

Methods: Real-time PCR and western blotting were performed to detect the mRNA and protein expression levels in cells and tissues. Immunohistochemical staining was assayed in rat models and human samples obtained from children. The type of cell death was identified by Annexin V and PI staining on a flow cytometry.

Results: Oxidative stress decreased levels of Smad2 and Smad3 in hypertrophic chondrocytes both in vitro and in vivo. In the cartilage of KBD patients, the expression of Smad2 and Smad3 proteins in the middle and deep zone were significantly decreased with an observed full deletion in the deep zone of some samples. Reduction of Smad2 protein induced necrotic death of hypertrophic chondrocytes, while reduction of Smad3 protein induced apoptosis. The reduction of Smad2 protein was not accompanied by Smad3 protein reduction in hypertrophic chondrocyte necrosis. Furthermore, the reduction of Smad2 also impaired the construction of tissue-engineered cartilage in vitro.

Conclusion: These studies reveal that oxidative stress causes necrosis of hypertrophic chondrocytes by downregulating Smad2 protein, which enriches the pathogenesis of KBD cartilage. The importance of Smad2 in the development of KBD provides a new potential target for the treatment of KBD.
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http://dx.doi.org/10.1093/rheumatology/keab286DOI Listing
March 2021

Interaction of graphene oxide with artificial cell membranes: Role of anionic phospholipid and cholesterol in nanoparticle attachment and membrane disruption.

Colloids Surf B Biointerfaces 2021 Jun 9;202:111685. Epub 2021 Mar 9.

State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China.

A mechanistic understanding of the interaction of graphene oxide (GO) with cell membranes is critical for predicting the biological effects of GO following accidental exposure and biomedical applications. We herein used a quartz crystal microbalance with dissipation monitoring (QCM-D) to probe the interaction of GO with model cell membranes modified with anionic lipids or cholesterol under biologically relevant conditions. The attachment efficiency of GO on supported lipid bilayers (SLBs) decreased with increasing anionic lipid content and was unchanged with varying cholesterol content. In addition, the incorporation of anionic lipids to the SLBs rendered the attachment of GO partially reversible upon a decrease in solution ionic strength. These results demonstrate the critical role of lipid bilayer surface charge in controlling GO attachment and release. We also employed the fluorescent dye leakage technique to quantify the role of anionic lipids and cholesterol in vesicle disruption caused by GO. Notably, we observed a linear correlation between the amount of dye leakage from the vesicles and the attachment efficiencies of GO on the SLBs, confirming that membrane disruption is preceded by GO attachment. This study highlights the non-negligible role of lipid bilayer composition in controlling the physicochemical interactions between cell membranes and GO.
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http://dx.doi.org/10.1016/j.colsurfb.2021.111685DOI Listing
June 2021

Femtosecond electronic structure response to high intensity XFEL pulses probed by iron X-ray emission spectroscopy.

Sci Rep 2020 Oct 8;10(1):16837. Epub 2020 Oct 8.

SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA.

We report the time-resolved femtosecond evolution of the K-shell X-ray emission spectra of iron during high intensity illumination of X-rays in a micron-sized focused hard X-ray free electron laser (XFEL) beam. Detailed pulse length dependent measurements revealed that rapid spectral energy shift and broadening started within the first 10 fs of the X-ray illumination at intensity levels between 10 and 10 W cm. We attribute these spectral changes to the rapid evolution of high-density photoelectron mediated secondary collisional ionization processes upon the absorption of the incident XFEL radiation. These fast electronic processes, occurring at timescales well within the typical XFEL pulse durations (i.e., tens of fs), set the boundary conditions of the pulse intensity and sample parameters where the widely-accepted 'probe-before-destroy' measurement strategy can be adopted for electronic-structure related XFEL experiments.
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http://dx.doi.org/10.1038/s41598-020-74003-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7545180PMC
October 2020

Synthesis of a carbon dots modified g-CN/SnO Z-scheme photocatalyst with superior photocatalytic activity for PPCPs degradation under visible light irradiation.

J Hazard Mater 2021 01 21;401:123257. Epub 2020 Jun 21.

School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China. Electronic address:

As an emerging carbon nanomaterial, carbon dots (CDs) have superior prospects for applications in the area of photocatalysis due to their unique optical and electronic properties. In this study, a novel CDs modified g-CN/SnO photocatalyst (CDs/g-CN/ SnO) was successfully synthesized by the thermal polymerization. Under visible light irradiation, the resulting CDs/g-CN/SnO photocatalyst exhibited excellent photocatalytic activity for the degradation of indomethacin (IDM). It was demonstrated that a 0.5 % loading content of CDs led to the highest IDM degradation rate, which was 5.62 times higher than that of pristine g-CN. This improved photocatalytic activity might have been attributed to the unique up-conversion photoluminescence (PL) properties and efficient charge separation capacities of the CDs. Moreover, the combination of g-CN with SnO improved the separation of photoinduced carriers and augmented the specific surface area. Reactive species (RSs) scavenging experiments and electron spin resonance (ESR) revealed that superoxide radical anions (O) and photogenerated holes (h) played critical roles during the photocatalytic process. The results of the detection of HO and ESR confirmed that CDs/g-CN/ SnO was a Z-scheme heterojunction photocatalyst. Further, HRAM LC-MS/MS was employed to identify the byproducts of IDM, and the major IDM degradation pathways of the CDs/g-CN/SnO photocatalyst were proposed. This study provides new ideas for the design of novel CDs modified photocatalysts for environmental remediation.
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http://dx.doi.org/10.1016/j.jhazmat.2020.123257DOI Listing
January 2021

Femtosecond laser produced periodic plasma in a colloidal crystal probed by XFEL radiation.

Sci Rep 2020 Jul 1;10(1):10780. Epub 2020 Jul 1.

Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, D-22607, Hamburg, Germany.

With the rapid development of short-pulse intense laser sources, studies of matter under extreme irradiation conditions enter further unexplored regimes. In addition, an application of X-ray Free-Electron Lasers (XFELs) delivering intense femtosecond X-ray pulses, allows to investigate sample evolution in IR pump - X-ray probe experiments with an unprecedented time resolution. Here we present a detailed study of the periodic plasma created from the colloidal crystal. Both experimental data and theory modeling show that the periodicity in the sample survives to a large extent the extreme excitation and shock wave propagation inside the colloidal crystal. This feature enables probing the excited crystal, using the powerful Bragg peak analysis, in contrast to the conventional studies of dense plasma created from bulk samples for which probing with Bragg diffraction technique is not possible. X-ray diffraction measurements of excited colloidal crystals may then lead towards a better understanding of matter phase transitions under extreme irradiation conditions.
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http://dx.doi.org/10.1038/s41598-020-67214-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7329833PMC
July 2020

Decreased Expression of Heat Shock Protein 47 Is Associated with T-2 Toxin and Low Selenium-Induced Matrix Degradation in Cartilages of Kashin-Beck Disease.

Biol Trace Elem Res 2021 Mar 26;199(3):944-954. Epub 2020 Jun 26.

School of Public Health, Health Science Center, Key Laboratory of Trace Elements and Endemic Diseases in National Health Commission of PR of China, Xi'an Jiaotong University, Xi'an, Shaanxi, China.

Recent evidence suggests a role of type II collagen in Kashin-Beck disease (KBD) degeneration. We aimed to assess the abnormal expression of heat shock protein 47 (HSP47) which is associated with a decrease in type II collagen and an increase in cartilage degradation in KBD. Hand phalange cartilages were collected from KBD and healthy children. Rats were administered with T-2 toxin under the selenium (Se)-deficient diet. ATDC5 cells were seeded on bone matrix gelatin to construct engineered cartilaginous tissue. C28/I2 and ATDC5 cells and engineered tissue were exposed to different concentrations of T-2 toxin with or without Se. Cartilage degeneration was determined through histological evaluation. The distribution and expression of type II collagen and HSP47 were investigated through immunohistochemistry, western blotting, and real-time PCR. KBD cartilages showed increased chondronecrosis and extracellular matrix degradation in deep zone with decreased type II collagen and HSP47 expression. The low-Se + T-2 toxin animal group showed a significantly lower type II collagen expression along with decreased HSP47 expression. Decreased type II collagen and HSP47 in C28/I2 and ATDC5 cells induced by T-2 toxin showed a dose-dependent manner. Hyaline-like cartilage with zonal layers was developed in engineered cartilaginous tissues, with decreased type II collagen and HSP47 expression found in T-2 toxin-treated group. Se-supplementation partially antagonized the inhibitory effects of T-2 toxin in chondrocytes and cartilages. HSP47 plays a role in the degenerative changes of KBD and associated with T-2 toxin-induced decreased type II collagen expression, further promoting matrix degradation.
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http://dx.doi.org/10.1007/s12011-020-02237-1DOI Listing
March 2021

Decorin knockdown affects the gene expression profile of adhesion, growth and extracellular matrix metabolism in C-28/I2 chondrocytes.

PLoS One 2020 30;15(4):e0232321. Epub 2020 Apr 30.

Institute of Endemic Diseases, School of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, PR China.

Decorin is a member of small leucine-rich proteoglycan family, which is involved in multiple biological functions mainly as a structural and signaling molecule, and disturbances in its own metabolism plays a crucial role in the pathogenesis of osteoarthropathy. In this study, we aim to further explore the biological function of decorin and their role in human chondrocyte cell line, C28/I2. Lentivirus-mediated shRNA was applied to down-regulate decorin expression in C28/I2 chondrocytes. Effect of decorin knockdown on gene expression profiles was determined by RNA sequencing followed by bioinformatics analysis. MTT, adhesion assays and flow cytometry were used to investigate the effect of decorin knockdown on cell proliferation, adhesion, and apoptosis. sGAG content in the culture medium was determined by DMMB assay. Stably transfected C28/I2 cells were seeded onto the cancellous bone matrix gelatin (BMG) to construct tissue-engineered cartilage. The histological patterns were evaluated by H&E and Toluidine blue staining. In this study, 1780 differentially expressed genes (DEGs) including 864 up-regulated and 916 down-regulated genes were identified using RNA-Seq. The reliability of the gene expression was further verified by qRT-PCR. GO and KEGG pathway enrichment analysis revealed diverse cellular processes were affected by decorin silencing such as: cell adhesion, growth, and metabolism of extracellular matrix. In addition, we confirmed that down-regulation of decorin significantly suppressed cell proliferation and adhesion and induced apoptosis. The sGAG content in the media was significantly increased after decorin silencing. Engineered articular tissues in the decorin knockdown group exhibited cartilage destruction and proteoglycan loss as evidenced by H&E and Toluidine blue stains. Overall, this combined data helps to provide a comprehensive understanding of the roles of decorin following its knockdown in C28/I2 cells.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0232321PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7192450PMC
July 2020

Photochemical transformation of CN under UV irradiation: Implications for environmental fate and photocatalytic activity.

J Hazard Mater 2020 07 18;394:122557. Epub 2020 Mar 18.

Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China.

In this study, the photo-transformations of bulk CN (CN) and oxidized CN (OCN) under UV-irradiation were examined. Through NO release measurements, we found that the photo-transformation rate of OCN is higher than that of CN. Various characterization results revealed the structural and chemical properties changes of CN and OCN after photo-transformation. We proposed that under reactive oxygen species attack, CN and OCN were gradually broken into smaller fragments and finally mineralized into NO-, CO, and HO through the circular reactions of deamination-hydroxylation-decarboxylation. Through the zeta potential measurements and sedimentation experiments, the influence of photo-transformation on the water stabilities of CN and OCN were assessed. The stability of CN in water increased while the water stability of OCN decreased after photo-transformation, implying that the changes to CN-based materials caused by photo-transformation may significantly impact their environmental behaviors. Moreover, the photocatalytic activities of the photo-transformed OCN and CN substantially decreased, indicating that the structural changes might be the main reason for their photocatalytic activity loss. These findings highlight the non-negligible influence of photo-transformation on the fate of CN in aquatic environments, as well as on the photochemical stability during its use.
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http://dx.doi.org/10.1016/j.jhazmat.2020.122557DOI Listing
July 2020

X-ray free-electron laser wavefront sensing using the fractional Talbot effect.

J Synchrotron Radiat 2020 Mar 12;27(Pt 2):254-261. Epub 2020 Feb 12.

SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.

Wavefront sensing at X-ray free-electron lasers is important for quantitatively understanding the fundamental properties of the laser, for aligning X-ray instruments and for conducting scientific experimental analysis. A fractional Talbot wavefront sensor has been developed. This wavefront sensor enables measurements over a wide range of energies, as is common on X-ray instruments, with simplified mechanical requirements and is compatible with the high average power pulses expected in upcoming X-ray free-electron laser upgrades. Single-shot measurements were performed at 500 eV, 1000 eV and 1500 eV at the Linac Coherent Light Source. These measurements were applied to study both mirror alignment and the effects of undulator tapering schemes on source properties. The beamline focal plane position was tracked to an uncertainty of 0.12 mm, and the source location for various undulator tapering schemes to an uncertainty of 1 m, demonstrating excellent sensitivity. These findings pave the way to use the fractional Talbot wavefront sensor as a routine, robust and sensitive tool at X-ray free-electron lasers as well as other high-brightness X-ray sources.
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http://dx.doi.org/10.1107/S1600577519017107DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7064100PMC
March 2020

Ultrathin AgWO-coated P-doped g-CN nanosheets with remarkable photocatalytic performance for indomethacin degradation.

J Hazard Mater 2020 06 19;392:122355. Epub 2020 Feb 19.

School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China.

As a metal-free photocatalyst, the photocatalytic activity of graphitic carbon nitride (g-CN) remains restricted due to an insufficient visible-light absorption capacity, the rapid recombination of photoinduced carriers, and low surface area. Consequently, P-doped g-CN (PCN) was successfully prepared via a single -step thermal polymerization technique using phytic acid biomass and urea, which exhibited remarkable photocatalytic activity for the degradation of indometacin (IDM). The IDM degradation rate was 7.1 times greater than that of pristine g-CN (CN). Furthermore, AgWO was loaded onto the surface of the PCN, which formed a Z-scheme heterostructure that promoted the separation of photogenerated carriers. According to analyses of the chemical binding states of PCN, P atoms replaced carbon atoms in the CN framework. According to electron localization function analysis, the low ELF values of P-N facilitated the transfer of photoelectrons. The results of active species scavenging experiments confirmed that superoxide radicals were the primary active species in the photocatalytic degradation system. Finally, the photocatalytic degradation pathways of IDM were predicted through the identification of by-products and IDM reaction sites.
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http://dx.doi.org/10.1016/j.jhazmat.2020.122355DOI Listing
June 2020

Highly active metal-free carbon dots/g-CN hollow porous nanospheres for solar-light-driven PPCPs remediation: Mechanism insights, kinetics and effects of natural water matrices.

Water Res 2020 Apr 9;172:115492. Epub 2020 Jan 9.

School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China. Electronic address:

Pharmaceuticals and personal care products (PPCPs) are increasingly being scrutinized by the scientific community due to their environmental persistence. Therefore, the development of novel environmentally compatible and energy-efficient technologies for their removal is highly anticipated. In this work, a novel metal-free photocatalytic nanoreactor was successfully synthesized by anchoring carbon dots to hollow carbon nitride nanospheres (HCNS/CDs). The unique structure of these hollow nanospherical HCNS/CDs hybrids endowed them with a high population of reactive sites, while enhancing optical absorption due to internal light reflection. Simultaneously, the CDs served as "artificial antennas" to absorb and convert photons with low energy, due to their superior up-converting properties. Consequently, the HCNS/CDs demonstrated excellent photodegradation activities for the degradation of PPCPs under broad-spectrum irradiation. Remarkedly, 10 mg/L of naproxen (NPX) was completely degraded following 5 min of natural solar irradiation. It was further revealed that the O played a significant role during the photocatalytic process, which could lead to the decomposition of NPX. The effects of natural water matrices and the degradation of trace PPCPs further supported that this photocatalytic system may be efficaciously applied for the remediation of PPCPs contamination in ambient waterways.
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http://dx.doi.org/10.1016/j.watres.2020.115492DOI Listing
April 2020

One-step synthesis of phosphorus/oxygen co-doped g-CN/anatase TiO Z-scheme photocatalyst for significantly enhanced visible-light photocatalysis degradation of enrofloxacin.

J Hazard Mater 2020 03 8;386:121634. Epub 2019 Nov 8.

School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China.

Anatase TiO nanoparticles coated with P and O co-doped g-CN were prepared via a single-step procedure. The resulting POCN/anatase TiO demonstrated remarkable performance in the degradation of enrofloxacin (ENFX). The photocatalytic activity of this heterojunction was 28.9 and 3.71 times better than that of the CN and anatase TiO, respectively. The microtopography of the POCN/anatase TiO was revealed in this study. Co-doping with P and O increased the visible light adsorption capacity of the g-CN, whereas the anatase TiO nanoparticles enhanced the adsorption properties of the ENFX and the separation of the photoinduced carriers of the POCN/anatase TiO. The O and h were the main reactive oxidative species in the photocatalytic degradation of ENFX. The results of the detection of HO and ESR confirmed that POCN/anatase TiO was a type Z-scheme photocatalyst. Finally, the ENFX degradation pathways were estimated through the detection of by-products.
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http://dx.doi.org/10.1016/j.jhazmat.2019.121634DOI Listing
March 2020

Phosphate-modified m-BiO enhances the absorption and photocatalytic activities of sulfonamide: Mechanism, reactive species, and reactive sites.

J Hazard Mater 2020 02 13;384:121443. Epub 2019 Oct 13.

School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, 510006, China. Electronic address:

Widespread usage of the sulfonamide class of antibiotics is causing increasing ecotoxicological concern, as they have the capacity to alter ambient ecosystems. Photocatalytic technology is an attractive yet challenging strategy for the degradation of antibiotics. For this work, the phosphate modification of m-BiO (BiO-P) was prepared via a one-step hydrothermal process involving sodium bismuthate and sodium phosphate, which was employed for the degradation of sulfamethazine (SMZ) under visible light irradiation. The 0.5% BiO-P exhibited excellent photocatalytic performance, which was 1.9 times that of pure m-BiO. The photocatalytic degradation kinetics and mechanism of SMZ was investigated at different pH, whereupon it was revealed that m-BiO-P exhibited improved SMZ adsorption and photocatalytic activities in contrast to pure m-BiO. Compared with other four sulfonamide antibiotics, structures that contained additional methyl on the pyrimidine could be more easily attacked by phosphate modified m-BiO. Reactive species (RS) scavenging experiments revealed that h was primarily responsible for the degradation of SMZ. Further studies of RS by ESR technology, and the results of photoelectrochemical properties showed phosphate-modified m-BiO could make greater use of photogenerated carriers, thereby producing additional RS. Based on the HRAM LC-MS/MS and the Frontier Molecular Orbital Theory, the degradation pathways of SMZ were proposed.
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http://dx.doi.org/10.1016/j.jhazmat.2019.121443DOI Listing
February 2020

Transformation of atenolol by a laccase-mediator system: Efficiencies, effect of water constituents, and transformation pathways.

Ecotoxicol Environ Saf 2019 Nov 13;183:109555. Epub 2019 Aug 13.

Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China.

In this study, we investigated the transformation of atenolol (ATL) by the naturally occurring laccase from Trametes versicolor in aqueous solution. Removal efficiency of ATL via laccase-catalyzed reaction in the presence of various laccase mediators was examined, and found that only the mediator 2, 2, 6, 6-tetramethyl-1-piperidinyloxy (TEMPO) was able to greatly promote ATL transformation. The influences of TEMPO concentration, laccase dosage, as well as solution pH and temperature on ATL transformation efficiency were tested. As TEMPO concentrations was increased from 0 to 2000 μM, ATL transformation efficiency first increased and then decreased, and the optimal TEMPO concentration was determined as 500 μM. ATL transformation efficiency was gradually increased with increasing laccase dosage. ATL transformation was highly pH-dependent with an optimum pH of 7.0, and it was almost constant over a temperature range of 25-50 °C. Humic acid inhibited ATL transformation through competition reaction with laccase. The presence of anions HCO and CO reduced ATL transformation due to both anions enhanced solution pHs, while Cl, SO, and NO at 10 mM showed no obvious influence. The main transformation products were identified, and the potential transformation pathways were proposed. After enzymatic treatment, the toxicity of ATL and TEMPO mixtures was greatly reduced. The results of this study might present an alternative clean strategy for the remediation of ATL contaminated water matrix.
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http://dx.doi.org/10.1016/j.ecoenv.2019.109555DOI Listing
November 2019

Degradation of triphenyl phosphate (TPhP) by CoFeO-activated peroxymonosulfate oxidation process: Kinetics, pathways, and mechanisms.

Sci Total Environ 2019 Sep 9;681:331-338. Epub 2019 May 9.

Guangzhou Key Laboratory Environmental Catalysis and Pollution Control, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China.

The aryl organophosphate flame retardant triphenyl phosphate (TPhP) has been frequently detected in environment and biota, and the potential risks of TPhP to aquatic organisms have also been demonstrated. The degradation of TPhP by CoFeO activated peroxymonosulfate (PMS) was studied in this work. At initial pH of 7.0, 10 μM TPhP could be removed by 99.5% with 0.25 g/L CoFeO and 0.5 mM PMS after 6 min oxidation, indicating the excellent performance of CoFeO activated PMS process on the treatment of TPhP. The influence of PMS and CoFeO dosage, initial pH, humic acid (HA), and anions (Cl, NO, and HCO) on TPhP degradation were investigated systematically. Results showed that the degradation of TPhP was enhanced with increasing PMS concentrations from 0.1 to 1 mM, while it reduced as CoFeO dosage increased. TPhP degradation efficiencies depended on solution pH with neutral pH showing the optimum degradation conditions. Recycling experiment indicated that the CoFeO nanoparticles (NPs) possessed high potential for reusability. The radical identification experiments were performed and SO• was confirmed as the dominant radicals in TPhP degradation, and activation mechanism of PMS by CoFeO NPs was hence explained. Humic acids (HA) (2-20 mg/L) as the representative organic natural matter existing in environment inhibited TPhP removal. Anions including Cl, NO, and HCO all reduced TPhP degradation. In addition, TPhP degradation products were identified by liquid chromatography-mass spectrometry, and the degradation pathways of TPhP were proposed accordingly.
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http://dx.doi.org/10.1016/j.scitotenv.2019.05.105DOI Listing
September 2019

Fluorescence intensity monitors as intensity and beam-position diagnostics for X-ray free-electron lasers.

J Synchrotron Radiat 2019 Mar 22;26(Pt 2):358-362. Epub 2019 Feb 22.

Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.

For LCLS-II, a fluorescence intensity monitor for the non-invasive, pulse-by-pulse normalization of experiments has been developed. A prototype diagnostic was constructed with a microchannel plate assembly and two photodiodes. The diagnostic was then installed in the LCLS SXR instrument Kirkpatrick-Baez mirror chamber with the detectors located above the vertically reflecting mirror. The linearity, noise and position sensitivity of the detectors have been characterized. The photodiode responsivity is suitable for high pulse energies. The microchannel plate detector shows sufficient responsivity over a wide range of pulse energies. The relative signal from the two photodiodes provides a sensitive measure of the X-ray beam position. The fluorescence intensity monitor provides intensity normalization while being compatible with high incident power, a 0.93 MHz repetition rate and ultra-high vacuum.
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http://dx.doi.org/10.1107/S1600577519001802DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6412172PMC
March 2019

The Macromolecular Femtosecond Crystallography Instrument at the Linac Coherent Light Source.

J Synchrotron Radiat 2019 Mar 22;26(Pt 2):346-357. Epub 2019 Feb 22.

Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.

The Macromolecular Femtosecond Crystallography (MFX) instrument at the Linac Coherent Light Source (LCLS) is the seventh and newest instrument at the world's first hard X-ray free-electron laser. It was designed with a primary focus on structural biology, employing the ultrafast pulses of X-rays from LCLS at atmospheric conditions to overcome radiation damage limitations in biological measurements. It is also capable of performing various time-resolved measurements. The MFX design consists of a versatile base system capable of supporting multiple methods, techniques and experimental endstations. The primary techniques supported are forward scattering and crystallography, with capabilities for various spectroscopic methods and time-resolved measurements. The location of the MFX instrument allows for utilization of multiplexing methods, increasing user access to LCLS by running multiple experiments simultaneously.
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http://dx.doi.org/10.1107/S1600577519001577DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6412173PMC
March 2019

Measurement of the absolute number of photons of the hard X-ray beamline at the Linac Coherent Light Source.

J Synchrotron Radiat 2019 Mar 11;26(Pt 2):320-327. Epub 2019 Feb 11.

Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025, USA.

X-ray free-electron lasers provide intense pulses of coherent X-rays with a short pulse duration. These sources are chaotic by nature and therefore, to be used at their full potential, require that every X-ray pulse is characterized in terms of various relevant properties such as intensity, photon energy, position and timing. Diagnostics are for example installed on an X-ray beamline to specifically monitor the intensity of individual X-ray pulses. To date, these can however only provide a single-shot value of the relative number of photons per shot. Here are reported measurements made in January 2015 of the absolute number of photons in the hard X-ray regime at LCLS which is typically 3.5 × 10 photons shot between 6 and 9.5 keV at the X-ray Pump-Probe instrument. Moreover, an average transmission of ≉62% of the hard X-ray beamline over this energy range is measured and the third-harmonic content of ≉0.47% below 9 keV is characterized.
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http://dx.doi.org/10.1107/S1600577519000250DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6412180PMC
March 2019

Heteroaggregation and sedimentation of graphene oxide with hematite colloids: Influence of water constituents and impact on tetracycline adsorption.

Sci Total Environ 2019 Jan 5;647:708-715. Epub 2018 Aug 5.

State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu 210023, China. Electronic address:

Because the transport of graphene oxide nanosheets (GO) from water to sediments is influenced by their heteroaggregation and sedimentation with natural colloids, knowledge on the interdependence of heteroaggregation and sedimentation for GO is needed to gain a better insight on the environmental fate of these nanosheets. However, this phenomenon is still not well understood. In this study, the heteroaggregation and sedimentation behaviors of GO with hematite nanoparticles (HemNPs) were investigated at various conditions. It has been found that negatively charged GO rapidly underwent heteroaggregation with positively charged HemNPs, leading to the sedimentation of GO. Significant sedimentation occurred when the net charge of the GOHemNP mixture was close to zero. The presence of various natural organic matters suppressed the sedimentation of the heteroaggregates through various mechanisms. Specifically, adsorption of humic acid and alginate reversed HemNP surface charge from positive to negative, leading to a slow sedimentation of the GOHemNP mixtures due to the increase in nanoparticle electrostatic repulsion. Adsorption of bovine serum albumin raised steric hindrance effect between GO and HemNP, which in turn inhibited their heteroaggregation and sedimentation. At high ionic strength conditions, the sedimentation of GO and HemNP was enhanced, possibly through the combination of homo- and hetero-aggregation. At elevated pH, the heteroaggregates were partially disaggregated, probably due to the weakening of GOHemNP bonds as the surface charges of these nanomaterials became more negative. Moreover, heteroaggregation of GO with HemNP likely to occupy the adsorption sites on GO surfaces, thus greatly reduced the adsorption of tetracycline on GO. These findings highlighted the important roles of natural colloids on the fate and transport of GO, together with the importance of heteroaggregation on the adsorption of co-existing pollutants to GO in natural aquatic environments.
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http://dx.doi.org/10.1016/j.scitotenv.2018.08.046DOI Listing
January 2019

Hyperbaric Oxygen Therapy in Liver Diseases.

Int J Med Sci 2018 22;15(8):782-787. Epub 2018 May 22.

Department of Rehabilitation Medicine, The First Affiliated Hospital, Zhejiang University, Hangzhou, China.

Hyperbaric oxygen therapy (HBOT) is an efficient therapeutic option to improve progress of lots of diseases especially hypoxia-related injuries, and has been clinically established as a wide-used therapy for patients with carbon monoxide poisoning, decompression sickness, arterial gas embolism, problematic wound, and so on. In the liver, most studies positively evaluated HBOT as a potential therapeutic option for liver transplantation, acute liver injury, nonalcoholic steatohepatitis, fibrosis and cancer, especially for hepatic artery thrombosis. This might mainly attribute to the anti-oxidation and anti-inflammation of HBOT. However, some controversies are existed, possibly due to hyperbaric oxygen toxicity. This review summarizes the current understandings of the role of HBOT in liver diseases and hepatic regeneration. Future understanding of HBOT in clinical trials and its in-depth mechanisms may contribute to the development of this novel adjuvant strategy for clinical therapy of liver diseases.
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http://dx.doi.org/10.7150/ijms.24755DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6036079PMC
December 2018

Coherent X-rays reveal the influence of cage effects on ultrafast water dynamics.

Nat Commun 2018 05 15;9(1):1917. Epub 2018 May 15.

Department of Physics, AlbaNova University Center, Stockholm University, S-106 91, Stockholm, Sweden.

The dynamics of liquid water feature a variety of time scales, ranging from extremely fast ballistic-like thermal motion, to slower molecular diffusion and hydrogen-bond rearrangements. Here, we utilize coherent X-ray pulses to investigate the sub-100 fs equilibrium dynamics of water from ambient conditions down to supercooled temperatures. This novel approach utilizes the inherent capability of X-ray speckle visibility spectroscopy to measure equilibrium intermolecular dynamics with lengthscale selectivity, by measuring oxygen motion in momentum space. The observed decay of the speckle contrast at the first diffraction peak, which reflects tetrahedral coordination, is attributed to motion on a molecular scale within the first 120 fs. Through comparison with molecular dynamics simulations, we conclude that the slowing down upon cooling from 328 K down to 253 K is not due to simple thermal ballistic-like motion, but that cage effects play an important role even on timescales over 25 fs due to hydrogen-bonding.
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http://dx.doi.org/10.1038/s41467-018-04330-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5953967PMC
May 2018

The facile synthesis of a single atom-dispersed silver-modified ultrathin g-CN hybrid for the enhanced visible-light photocatalytic degradation of sulfamethazine with peroxymonosulfate.

Dalton Trans 2018 May;47(20):6924-6933

School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China.

Enabling the optimal usage of solar energy is considered to be one of the most pressing challenges in the photocatalytic remediation of water resident contaminants. Herein, a single-atom dispersed Ag loaded ultrathin g-C3N4 hybrid (AgTCM/UCN) was prepared through a facile co-polymerization of dicyandiamide with silver tricyanomethanide (AgTCM) and NH4Cl, and used as a visible light driven photocatalyst for the degradation of sulfamethazine (SMT) in the presence of peroxymonosulfate (PMS). Under UV light, visible light and simulated sunlight irradiation, the AgTCM/UCN/PMS process showed higher efficiency for SMT degradation than AgTCM/UCN, UCN/PMS, and g-C3N4/PMS systems. This enhanced photocatalytic activity may be attributed to the synergistic effects encompassing the surface plasmon resonance (SPR) of Ag, high surface area of UCN, and efficient charge separation of PMS. Electron-spin resonance (ESR) and reactive species (RSs) scavenger-quenching experiments revealed that SO4˙- was generated following the addition of PMS, whereas O2˙- and h+ were predominantly responsible for the degradation of SMT. Three degradation pathways of SMT were deduced, including the cleavage of sulfonamide bonds, SO2 extrusion, and the oxidation of the aniline moiety, based on mass spectrometry and theoretical calculations. The degradation of SMT in ambient water revealed that the AgTCM/UCN/PMS photocatalytic process can be efficaciously applied for the remediation of SMT contaminated natural waters, particularly sea water.
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http://dx.doi.org/10.1039/c8dt00919hDOI Listing
May 2018

X-ray spectrometer based on a bent diamond crystal for high repetition rate free-electron laser applications.

Opt Express 2017 Feb;25(3):2852-2862

A precise spectral characterization of every single pulse is required in many x-ray free-electron laser (XFEL) experiments due to the fluctuating spectral content of self-amplified spontaneous emission (SASE) beams. Bent single-crystal spectrometers can provide sufficient spectral resolution to resolve the SASE spikes while also covering the full SASE bandwidth. To better withstand the high heat load induced by the 4.5 MHz repetition rate of pulses at the forthcoming European XFEL facility, a spectrometer based on single-crystal diamond has been developed. We report a direct comparison of the diamond spectrometer with its Si counterpart in experiments performed at the Linac Coherent Light Source.
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http://dx.doi.org/10.1364/OE.25.002852DOI Listing
February 2017

Facile synthesis of carbon quantum dots loaded with mesoporous g-CN for synergistic absorption and visible light photodegradation of fluoroquinolone antibiotics.

Dalton Trans 2018 Jan;47(4):1284-1293

School of Environmental Science and Engineering, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou, 510006, China.

The development of facile and efficient synthetic approaches of carbon quantum dots loaded with mesoporous g-CN (mpg-CN/CQDs) is of critical urgency. Here, a facile strategy was developed to synthesize the mpg-CN/CQDs by using calcinations of the mixture of CQDs, cyanamide, and silica colloid. The obtained composite still retained a considerable total surface area, which could offer a larger population of adsorption sites; therefore enhance the capacity for the adsorption of fluoroquinolones antibiotics (FQs). Under visible light irradiation, mpg-CN/CQDs demonstrated a higher photocatalytic activity for FQs degradation than did bulk g-CN or mpg-CN. This enhancement might have been ascribed to the high surface area of the mpg-CN, unique up-converted photoluminescence (PL) properties, and the efficient charge separation of the CQDs. The eradication of FQs followed the Langmuir-Hinshelwood (L-H) kinetic degradation model and absorption pseudo-second-order kinetic model, indicating that surface reactions and chemical sorption played significant roles during the photocatalysis process. The results of electron spin resonance (ESR) technology and reactive species (RSs) scavenging experiments revealed that the superoxide anion radical (O˙) and photo-hole (h) were the primarily active species that initiated the degradation of FQs. Based on the identification of intermediates and the prediction of reactive sites, the degradation pathways of ofloxacin (OFX) were proposed. A residual antibiotic activity experiment revealed that mpg-CN/CQDs provided very desirable performance for the reduction of antibiotic activity.
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http://dx.doi.org/10.1039/c7dt04360kDOI Listing
January 2018

Degradation of ketoprofen by sulfate radical-based advanced oxidation processes: Kinetics, mechanisms, and effects of natural water matrices.

Chemosphere 2017 Dec 25;189:643-651. Epub 2017 Sep 25.

Institute of Environmental Health and Pollution Control, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou, Guangdong 510006, China. Electronic address:

Ketoprofen (KET) is a mostly used nonsteroidal anti-inflammatory drug that has been frequently detected in wastewater effluents and surface waters. In this study, we investigated the degradation of KET by sulfate radical (SO) based advanced oxidation processes (SR-AOPs) in aqueous solution. The degradation kinetics, mechanisms, and effects of natural water matrices on thermally activated persulfate (TAP) oxidation of KET were systematically investigated. Increasing the temperature and persulfate (PS) concentrations greatly enhanced the degradation of KET. KET degradation is pH-dependent with an optimum pH of 5.0. Reactions in the presence of radical quenchers revealed the dominant role of SO in oxidizing KET. Water matrix significantly influenced the degradation of KET. The common inorganic anions present in natural waters exhibited inhibitory effect on KET degradation, and the inhibition followed the order of Cl > CO > HCO > NO; however, no significant inhibition of KET degradation was observed in the presence of Ca and Mg cations. The presence of natural organic matter (NOM) suppressed KET degradation, and the suppression increased as NOM concentration increase. Products identification and mineralization experiments revealed that KET and its degradation intermediates were finally transformed into CO and HO. The results of this study indicated that applying SR-AOPs for the remediation of KET contaminated water matrix is technically possible.
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http://dx.doi.org/10.1016/j.chemosphere.2017.09.109DOI Listing
December 2017

Bevacizumab for the Treatment of Gammaknife Radiosurgery-Induced Brain Radiation Necrosis.

J Craniofac Surg 2017 Sep;28(6):e569-e571

*Operating Room†Neurosurgery, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China.

Background: Radiation necrosis is one of the complications of Gammaknife radiosurgery. The traditional treatment of radiation necrosis carries a high risk of failure, Bevacizumab is an antiangiogenic monoclonal antibody against vascular endothelial growth factor, a known mediator of cerebral edema. It can be used to successfully treat brain radiation necrosis.

Patient Description: Two patients with a history of small cell lung cancer presented with metastatic disease to the brain. They underwent Gammaknife radiosurgery to brain metastases. Several months later, magnetic resonance imaging showed radiation necrosis with significant surrounding edema. The patients had a poor response to treatment with dexamethasone. They were eventually treated with bevacizumab (5 mg/kg every 2 weeks, 7.5 mg/kg every 3 weeks, respectively), and the treatment resulted in significant clinical and radiographic improvement.

Conclusion: Bevacizumab can be successfully used to treat radiation necrosis induced by Gammaknife radiosurgery in patients with cerebral metastases. It is of particular benefit in patients with poor reaction to corticosteroids and other medications.
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http://dx.doi.org/10.1097/SCS.0000000000003874DOI Listing
September 2017

Study of the simulated sunlight photolysis mechanism of ketoprofen: the role of superoxide anion radicals, transformation byproducts, and ecotoxicity assessment.

Environ Sci Process Impacts 2017 Sep;19(9):1176-1184

School of Environmental Science and Engineering, Guangdong University of Technology, No. 100 Waihuan Xi Road, Guangzhou Higher Education Mega Center, Panyu District, Guangzhou 510006, China.

The aim of this study was to investigate the photolysis mechanism of ketoprofen (KET) under simulated sunlight. The results demonstrated that the photolysis of KET aligned well with pseudo first-order kinetics. Radical scavenging experiments and dissolved oxygen experiments revealed that the superoxide anion radical (O˙) played a primary role in the photolytic process in pure water. Bicarbonate slightly increased the photodegradation of KET through generating carbonate radicals, while DOM inhibited the photolysis via both attenuating light and competing radicals. Moreover, Zhujiang river water inhibited KET phototransformation. Potential KET degradation pathways were proposed based on the identification of products using LC/MS/MS and GC/MS techniques. The theoretical prediction of reaction sites was derived from Frontier Electron Densities (FEDs), which primarily involved the KET decarboxylation reaction. The ecotoxicity of the treated solutions was evaluated by employing Daphnia magna and V. fischeri as biological indicators. Ecotoxicity was also hypothetically predicted through the "ecological structure-activity relationship" (ECOSAR) program, which revealed that toxic products might be generated during the photolysis process.
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http://dx.doi.org/10.1039/c7em00111hDOI Listing
September 2017

Heteroaggregation of Graphene Oxide with Nanometer- and Micrometer-Sized Hematite Colloids: Influence on Nanohybrid Aggregation and Microparticle Sedimentation.

Environ Sci Technol 2017 Jun 2;51(12):6821-6828. Epub 2017 Jun 2.

Department of Environmental Health and Engineering, Johns Hopkins University , Baltimore, Maryland 21218-2686, United States.

Heteroaggregation of graphene oxide (GO) with nanometer- and micrometer-sized hematite colloids, which are naturally present in aquatic systems, is investigated in this study. The heteroaggregation rates between GO and hematite nanoparticles (HemNPs) were quantified by dynamic light scattering, while the heteroaggregation between GO and micrometer-sized hematite particles (HemMPs) was examined through batch adsorption and sedimentation experiments. The heteroaggregation rates of GO with HemNPs first increased and then decreased with increasing GO/HemNP mass concentration ratios. The conformation of GO-HemNP heteroaggregates at different GO/HemNP mass concentration ratios was observed through transmission electron microscopy imaging. Initially, GO underwent heteroaggregation with HemNPs through electrostatic attraction to form primary heteroaggregates, which were further bridged by GO to form bigger clusters. At high GO/HemNP mass concentration ratios where GO outnumbered HemNPs, heteroaggregation resulted in the formation of stable GO-HemNP nanohybrids that have a critical coagulation concentration of 308 mM NaCl at pH 5.2. In the case of HemMPs, GO adsorbed readily on the microparticles and, at an optimal GO/HemMP ratio of ∼0.002, the sedimentation of HemMPs was the fastest, most likely because of the formation of "electrostatic patches" leading to favorable aggregation of the microparticles.
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http://dx.doi.org/10.1021/acs.est.7b00132DOI Listing
June 2017
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