Publications by authors named "Amit Bhatnagar"

93 Publications

New mechanistic insight into rapid adsorption of pharmaceuticals from water utilizing activated biochar.

Environ Res 2021 Jul 13;202:111693. Epub 2021 Jul 13.

Korea Biochar Research Center, APRU Sustainable Waste Management Program & Division of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea. Electronic address:

The presence of emerging pollutants especially hazardous chemicals and pharmaceuticals in aquatic environments is a matter of grave concern to human health and the environment. In this study, coffee bean waste (CBW) was utilized to synthesize pristine (CBW) and activated (CBW) biochars for the elimination of diclofenac (DF) and levofloxacin (LEV) from water. A facile two-step approach was used to synthesize CBW using chemical pretreatment and pyrolysis under N purging. BET results of CBW revealed that chemical pretreatment increased surface area by approximately 160 times compared to CBW. The calculated I/I ratio from Raman spectra confirmed that CBW had a high functionalized surface. Different operational parameters such as contact time, pH, adsorbent dose, ionic strength, and adsorbate concentration were studied and optimized. Maximum Langmuir adsorption capacity of CBW was found to be 61.17 and 110.70 mg/g for DF and LVX, respectively. Experimental results demonstrated that presence of NaCl in solution enhanced DF removal efficiency due to the salting-out effect. Electrostatic attraction, π-π bonding, and hydrophobic interaction were prominently responsible mechanisms for the adsorption of DF and LVX. Furthermore, continuous-flow mode studies confirmed that CBW can be successfully utilized in large-scale treatment applications.
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http://dx.doi.org/10.1016/j.envres.2021.111693DOI Listing
July 2021

Carbon-based adsorbents for fluoroquinolone removal from water and wastewater: A critical review.

Environ Res 2021 06 29;197:111091. Epub 2021 Mar 29.

Korea Biochar Research Center, APRU Sustainable Waste Management Program & Division of Environmental Science and Ecological Engineering, Korea University, Seoul, South Korea. Electronic address:

This review summarizes the adsorptive removal of Fluoroquinolones (FQ) from water and wastewater. The influence of different physicochemical parameters on the adsorptive removal of FQ-based compounds is detailed. Further, the mechanisms involved in the adsorption of FQ-based antibiotics on various adsorbents are succinctly described. As the first of its kind, this paper emphasizes the performance of each adsorbent for FQ-type antibiotic removal based on partition coefficients of the adsorbents that is a more sensitive parameter than adsorption capacity for comparing the performances of adsorbents under various adsorbate concentrations and heterogeneous environmental conditions. It was found that π-π electron donor-acceptor interactions, electrostatic interactions, and pore-filling were the most prominent mechanisms for FQ adsorption by carbon and clay-based adsorbents. Among all the categories of adsorbents reviewed, graphene showed the highest performance for the removal of FQ antibiotics from water and wastewater. Based on the current state of knowledge, this review fills the gap through methodolically understanding the mechanism for further improvement of FQ antibiotics adsorption performance from water and wastewater.
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http://dx.doi.org/10.1016/j.envres.2021.111091DOI Listing
June 2021

Synthesis of N-Doped Magnetic [email protected] Carbon Using a Diatom Template and Plasma Modification: Visible-Light-Driven Photocatalytic Activities.

ACS Appl Mater Interfaces 2021 Mar 15;13(11):13072-13086. Epub 2021 Mar 15.

Department of Chemical Engineering, Tabriz Branch, Islamic Azad University, 51579-44533 Tabriz, Iran.

Synthesis of three-dimensional photocatalysts offers great potential for chemical conversion and hydrogen generation as appropriate solutions for environmental protection and energy shortage challenges. In this study, the magnetic [email protected] carbon ([email protected]) was synthesized through the evaporation-induced self-assembly method applying diatom frustules as a natural template. Then, plasma modification was used to prepare the N-doped [email protected] ([email protected]) with enhanced photocatalytic activity and durable performance. The WO was embedded in the conductive MC, which was also partially reduced by the carbon precursor within the heat-treatment procedure. The obtained [email protected] was treated by the plasma under an N atmosphere for the production of the final photocatalyst containing both the N-doped WO and MC. As a result, the [email protected] had larger surface area (208.4 m g), narrower band gap (2.3 eV), more visible light harvesting, and confined electron-hole pairs recombination. The H generation rates of net WO nanorods and [email protected] nanocomposite were estimated as 532 and 2765 μmol g h, respectively. Additionally, more than 90% of antibiotics (cephalexin, cefazolin and cephradine) degradation and 76% of total organic carbon elimination were obtained after 120 and 240 min of photocatalytic process under visible light irradiation. Eventually, more than eight intermediates were detected for each antibiotic degradation using the gas chromatography-mass spectrometer method, and based on the obtained results, the possible degradation pathways were suggested.
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http://dx.doi.org/10.1021/acsami.0c21076DOI Listing
March 2021

Recent advances in the application of microalgae and its derivatives for preservation, quality improvement, and shelf-life extension of seafood.

Crit Rev Food Sci Nutr 2021 Mar 12:1-14. Epub 2021 Mar 12.

Beijing Laboratory for Food Quality and Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China.

Seafood is a highly perishable food product due to microbiological, chemical, and enzymatic reactions, which are the principal causes of their rapid quality deterioration. Therefore, ever-increasing consumers' demand for high-quality seafood along with a negative perception of synthetic preservatives creates opportunities for natural preservatives such as microalgae extracts. They are potential alternatives to reduce microbial growth, increase oxidative stability, and protect the sensorial properties of seafood. Research has shown that the inclusion of microalgae extracts into the aquatic animal's diet could enhance their meat quality and increase production. This review focuses on the direct application of various microalgae extracts as seafood preservative, and their functional properties in seafood, such as antioxidant and antimicrobial activities. Besides, the potential nutritional application of microalgae extracts as an alternative in aqua-feed and their impact on seafood quality (indirect application) are also presented. The safety aspects and regulatory issues of products from microalgae are highlighted.
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http://dx.doi.org/10.1080/10408398.2021.1895065DOI Listing
March 2021

Insights into upstream processing of microalgae: A review.

Bioresour Technol 2021 Jun 18;329:124870. Epub 2021 Feb 18.

Department of Separation Science, LUT School of Engineering Science, LUT University, Sammonkatu 12, FI-50130 Mikkeli, Finland. Electronic address:

The aim of this review is to provide insights into the upstream processing of microalgae, and to highlight the advantages of each step. This review discusses the most important steps of the upstream processing in microalgae research such as cultivation modes, photobioreactors design, preparation of culture medium, control of environmental factors, supply of microalgae seeds and monitoring of microalgal growth. An extensive list of bioreactors and their working volumes used, elemental composition of some well-known formulated cultivation media, different types of wastewater used for microalgal cultivation and environmental variables studied in microalgae research has been compiled in this review from the vast literature. This review also highlights existing challenges and knowledge gaps in upstream processing of microalgae and future research needs are suggested.
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http://dx.doi.org/10.1016/j.biortech.2021.124870DOI Listing
June 2021

Effect of nanomaterials on remediation of polycyclic aromatic hydrocarbons-contaminated soils: A review.

J Environ Manage 2021 Apr 2;284:112023. Epub 2021 Feb 2.

Department of Separation Science, LUT School of Engineering Science, LUT University, Sammonkatu 12, Mikkeli, FI-50130, Finland.

The remediation of toxic polycyclic aromatic hydrocarbons (PAHs) in the soil is always an important topic since exposure to contaminated soil with carcinogenic, mutagenic, and teratogenic potential can result in serious health effects. With respect to the remediation of PAHs contaminated soil, nanomaterials (NMs) have recently received a great deal of attention due to the special characteristics arising from their nanoscale sizes. However, the usefulness and potency of these NMs depend on their adaption to specific site conditions and soil properties. Since there is no comprehensive review of the applications of NMs, it is of great importance to analyze, discuss, and interpret the latest progress in the application of NMs for the remediation of contaminated soils containing PAHs. This overview essentially captures the novel advances made in nano zero valent-iron (nZVI), metal oxides, carbon-based NMs, and polymer-based materials. Each characteristic of NMs that contributes to the enhancement of the process is highlighted. Moreover, operational conditions in which the best-obtained results are achieved qualitatively summarize. This review is also given special attention to the type of soil and pollutant, which are major influential factors to affect the performance of the process. Furthermore, the potential implication of NMs and PAHs on soil properties is reviewed in terms of the changes in migration behavior of pollutants, plant phytotoxicity, and soil microbial community composition. Discussion on future perspectives is presented on the use and prospects for the application of NMs in contaminated soils.
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http://dx.doi.org/10.1016/j.jenvman.2021.112023DOI Listing
April 2021

Recent advancements in the synthesis of novel thermostable biocatalysts and their applications in commercially important chemoenzymatic conversion processes.

Bioresour Technol 2021 Mar 17;323:124558. Epub 2020 Dec 17.

Department of Separation Science, LUT School of Engineering Science, LUT University, Sammonkatu 12, FI-50130 Mikkeli, Finland. Electronic address:

Thermostable enzymes are a field of growing interest in bioremediation, pharmaceuticals, food industry etc., due to their ability to catalyze bio reactions at high temperatures. This review aims to provide an overview on extremophiles with a special focus on thermophiles and enzymes produced from extremophilic bacteria. Novel thermostable catalysts, used in producing commercially important chemicals, are discussed in this review. Various classes of enzymes produced by microbes, synthesis of thermozymes and comparison with enzymes produced at optimal conditions are critically discussed. A detailed discussion on immobilized enzymes in comparisons with free enzymes, produced by extremozymes, is included. Different parameters which affect enzyme production are also discussed. The current industrial trends along with the future of biocatalysts in the production of chemicals using efficient methods are also discussed.
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http://dx.doi.org/10.1016/j.biortech.2020.124558DOI Listing
March 2021

Sorption of diethyl phthalate and cadmium by pig carcass and green waste-derived biochars under single and binary systems.

Environ Res 2021 02 8;193:110594. Epub 2020 Dec 8.

Biochar Engineering Technology Research Center of Guangdong Province, School of Environmental and Chemical Engineering, Foshan University, Foshan, Guangdong, 528000, China; Key Laboratory of Soil Contamination Bioremediation of Zhejiang Province, School of Environmental and Resource Sciences, Zhejiang A&F University, Hangzhou, Zhejiang, 311300, China. Electronic address:

Potentially toxic elements (PTEs) and phthalic acid esters (PAEs) often coexist in contaminated soils. Their co-existence may affect the mutual sorption behavior, and thereby influence their bioavailability and fate in soils. To our best knowledge, the impacts of plant-and animal-derived biochar on the competitive sorption-desorption of PTEs and PAEs in soils with different organic carbon content have not been studied up to date. Therefore, in this study, batch sorption-desorption experiments were conducted to investigate the influence of biochars derived from pig carcass and Platanus orientalis branches on the mono- and competitive sorption of cadmium (Cd) and diethyl phthalate (DEP) in soils with high (HS) and low (LS) organic carbon content. The DEP sorption was well described by Freundlich isotherm model, while Cd sorption fitted better with the Langmuir isotherm model. Application of both biochars enhanced soil sorption of DEP, which increased as the application doses increased. The HS showed a stronger affinity to both DEP and Cd than the LS. In the LS, the pig carcass biochar (PB) addition was more effective to increase the sorption capacity of Cd and DEP and to reduce their desorption than woody biochar (WB) treatments. Moreover, the co-existing of Cd could reduce the sorption of DEP, especially in the LS. The presence of DEP enhanced Cd sorption in LS treated by both biochars, but the sorption of Cd was suppressed with DEP addition in the PB-amended HS. In conclusion, the soil sorption capacity of DEP and Cd was affected by biochar type, application dose and soil organic carbon content. The reciprocal effect between DEP and Cd was also a crucial factor influencing their sorption/desorption by biochar. Therefore, PB and WB, especially PB, can be used for metal/DEP immobilization due to enhanced sorption. This approach is applicable for future remediation of soils contaminated by PTEs and PAEs.
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http://dx.doi.org/10.1016/j.envres.2020.110594DOI Listing
February 2021

SARS-CoV-2 coronavirus in water and wastewater: A critical review about presence and concern.

Environ Res 2021 02 1;193:110265. Epub 2020 Oct 1.

Department of Environmental Engineering & Center for Environmental Risk Management, Chung Yuan Christian University, Taoyuan, 32023, Taiwan. Electronic address:

The presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in water and wastewater has recently been reported. According to the updated literature, the stools and masks of the patients diagnosed with coronavirus disease (COVID-19) were considered as the primary route of coronavirus transmission into water and wastewater. Most coronavirus types which attack human (possible for SARS-CoV-2) are often inactivated rapidly in water (i.e., the survival of human coronavirus 229E in water being 7 day at 23 °C). However, the survival period of coronavirus in water environments strongly depends on temperature, property of water, concentration of suspended solids and organic matter, solution pH, and dose of disinfectant used. The World Health Organization has stated that the current disinfection process of drinking water could effectively inactivate most of the bacterial and viral communities present in water, especially SARS-CoV-2 (more sensitive to disinfectant like free chlorine). A recent study confirmed that SARS-CoV-2 RNA was detected in inflow wastewater (but not detected in outflow one). Although the existence of SARS-CoV-2 in water influents has been confirmed, an important question is whether it can survive or infect after the disinfection process of drinking water. To date, only one study confirmed that the infectivity of SARS-CoV-2 in water for people was null based on the absence of cytopathic effect (CPE) in infectivity tests. Therefore, further studies should focus on the survival of SARS-CoV-2 in water and wastewater under different operational conditions (i.e., temperature and water matrix) and whether the transmission from COVID-19-contaminated water to human is an emerging concern. Although paper-based devices have been suggested for detecting the traces of SARS-CoV-2 in water, the protocols and appropriate devices should be developed soon. Wastewater and sewage workers should follow the procedures for safety precaution against SARS-CoV-2 exposure.
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http://dx.doi.org/10.1016/j.envres.2020.110265DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7528884PMC
February 2021

Advances in algal biochar: Production, characterization and applications.

Bioresour Technol 2020 Dec 7;317:123982. Epub 2020 Aug 7.

University of Edinburgh, School of GeoSciences, UK Biochar Research Centre, King's Buildings, Edinburgh, United Kingdom.

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http://dx.doi.org/10.1016/j.biortech.2020.123982DOI Listing
December 2020

Valorization of plastics and paper mill sludge into carbon composite and its catalytic performance for acarbon material consisted of the multi-layerzo dye oxidation.

J Hazard Mater 2020 11 11;398:123173. Epub 2020 Jun 11.

Department of Environment and Energy, Sejong University, Seoul, 05006, Republic of Korea. Electronic address:

In this work, polyvinyl chloride (PVC) and paper mill sludge (PMS) were co-pyrolyzed under two environments of N and CO. The pyrolysis process was assessed by conducting thermogravimetric analysis (TGA) and monitoring the evolution of gaseous products. The resulting solid composites were characterized using XRD, XPS, BET, and Raman analyzers, and their ability to catalytically activate persulfate (SO) was tested by conducting methyl orange (MO) degradation experiments. Co-pyrolysis of PVC and PMS at the same mass ratio (1:1) in CO resulted in the highest production of H and CO (0.36 mol % H at 480 °C & 1.53 mol % CO at 700 °C). The characterization results revealed that the composite consisted of FeO, highly graphitic carbon, and mesoporous structure. In MO oxidation experiments, the co-pyrolyzed composite actively generated OH and SO by activating SO to achieve complete removal of 5 mg L of MO during 100 min at acidic-neutral pH condition. The composite was also able to complete 3 successive cycles of MO oxidation without deactivation. Consequently, the feasibility of achieving the simultaneous production of energy resources and catalyst via industrial wastes utilization in pyrolytic process was demonstrated.
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http://dx.doi.org/10.1016/j.jhazmat.2020.123173DOI Listing
November 2020

Efficient removal of diclofenac and cephalexin from aqueous solution using Anthriscus sylvestris-derived activated biochar.

Sci Total Environ 2020 Nov 12;745:140789. Epub 2020 Jul 12.

Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.

The objective of this study was to investigate the adsorption of diclofenac (DF) and cephalexin (CPX) by Anthriscus sylvestris-derived activated biochar. The raw biochar (R-BC) and activated biochar (ACT-B) were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and elemental analyses techniques to obtain information regarding the morphology, functional groups and elements of the adsorbents. Batch studies were carried out to examine the effect of various operational parameters. The maximum adsorption capacity of ACT-B was 392.94 mg g for DF and 724.54 mg g for CPX. The removal of DF and CPX was influenced by temperature and the co-existing ions. The kinetic data fitted well with the pseudo-second-order kinetic model, whereas the isotherm data showed the best correlation with Langmuir isotherm model. Electrostatic adsorption, hydrophobic interaction and π-π bonding play a key role in adsorption of both adsorbates by ACT-B. Additionally, column studies were conducted using ACT-B at different flow rates and different concentrations of DF and CPX to investigate the practical applicability of ACT-B in removal of the target contaminants. Thus, this study provides a feasible approach to synthesize activated biochar that can minimize pharmaceuticals pollution in water bodies.
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http://dx.doi.org/10.1016/j.scitotenv.2020.140789DOI Listing
November 2020

A review of recent advancements in utilization of biomass and industrial wastes into engineered biochar.

J Hazard Mater 2020 12 17;400:123242. Epub 2020 Jun 17.

Department of Environment and Energy, Sejong University, 209 Neungdong-ro, Gwangjin-gu, Seoul05006, Republic of Korea. Electronic address:

For past few years, biochar has gained a great deal of attention for its versatile utility in agricultural and environmental applications. The diverse functionality and environmental-friendly nature of biochar have motivated many researchers to delve into biochar researches and spurred rapid expansion of literature in recent years. Biochar can be produced from virtually all the biomass, but the properties of biochar are highly dependent upon the types of feedstock biomass and preparation methods. The overall performances of as-prepared biochar in treating soil and water contaminants is generally inferior to activated carbon due to its lower surface area and limited functionalities. This limitation has led to many follow-up studies that focused on improving material characteristics by imparting desired functionality. Such efforts have greatly advanced knowledge to produce better-performing engineered biochar with enhanced capability and versatility. To this end, this review was prepared to compile recent advancements in fabrication and application of engineered biochar, especially with respect to the influences of biomass feedstock on the properties of biochar and the utilization of industrial wastes in fabrication of engineered biochar.
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http://dx.doi.org/10.1016/j.jhazmat.2020.123242DOI Listing
December 2020

Adsorption of As(V) and Ni(II) by Fe-Biochar composite fabricated by co-pyrolysis of orange peel and red mud.

Environ Res 2020 09 14;188:109809. Epub 2020 Jun 14.

Department of Environment and Energy, Sejong University, Seoul, 05006, Republic of Korea. Electronic address:

This study aimed to compare the adsorption performance of Fe-biochar composites (Fe-C-N and Fe-C-CO), fabricated by co-pyrolysis of red mud and orange peel in N and CO, for As(V) and Ni(II). By the syngas production comparison test, it was confirmed that CO was more advantageous than N as a pyrolytic medium gas to produce more CO. The resulting Fe-biochar composite showed the aggregate morphology consisting of different Fe phases (magnetite or metal Fe) from the inherent hematite phase in red mud and carbonized carbon matrix, and there was no distinct difference between the structural shapes of two Fe-biochar composites. Adsorption experiments showed that the adsorption capacities for As(V) and Ni(II) in single mode were almost similar with 7.5 and 16.2 mg g for Fe-C-N and 5.6 and 15.1 mg g for Fe-C-CO, respectively. The adsorption ability of Fe-C-CO for both As(V) and Ni(II) was further enhanced in binary adsorption mode (As(V): 13.4 mg g, Ni(II):17.6 mg g) through additional removal of those ions by Ni(II)-As(V) complexation. The overall results demonstrated CO-assisted pyrolysis can provide a viable platform to convert waste materials into fuel gases and environmental media for co-adsorption of cationic and anionic heavy metals.
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http://dx.doi.org/10.1016/j.envres.2020.109809DOI Listing
September 2020

Implications of layered double hydroxides assembled biochar composite in adsorptive removal of contaminants: Current status and future perspectives.

Sci Total Environ 2020 Oct 28;737:139718. Epub 2020 May 28.

Department of Environmental and Biological Sciences, University of Eastern Finland, P. O. Box 1627, FI-70211 Kuopio, Finland. Electronic address:

In recent years, biochar composites have received considerable attention for environmental applications. This paper reviews the current state of research on Layered Double Hydroxides (LDHs) tailored biochar composites in terms of their synthesis methods, characteristics, and their use as adsorbents for the removal of various pollutants from water, highlighting and discussing the key advancement in this area. The adsorption potential of LDHs-biochar composites for different inorganic and organic contaminants, important factors affecting composites' properties and the adsorption process, and the mechanisms involved in adsorption are discussed in this review. Though the adsorption capacities are high for the composites studied, partition coefficient which suggest the performance of composites remain low for most adsorbents. Despite the recent progress in the synthesis of LDHs-biochar composites, further research is needed to improve the performance of composites for different classes of aquatic pollutants, and to test their applicability in pilot-scale with real wastewater under real environmental conditions.
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http://dx.doi.org/10.1016/j.scitotenv.2020.139718DOI Listing
October 2020

Characterization of activated bentonite clay mineral and the mechanisms underlying its sorption for ciprofloxacin from aqueous solution.

Environ Sci Pollut Res Int 2020 Sep 10;27(26):32980-32997. Epub 2020 Jun 10.

Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland.

The presence of emerging pollutants such as hazardous chemicals, pharmaceuticals, pesticides, and endocrine-disrupting chemicals in water sources is a serious concern to the environment and human health. Thus, this study focused on exploring the interaction mechanisms between ciprofloxacin (CIP) (antibiotic) and clay (a low-cost adsorbent) during sorption process. Acid activation technique was opted for modifying natural bentonite (NB) to enhance the adsorptive removal of CIP from water. The BET surface area analysis revealed that acid-activated bentonite (AAB) possessed more than two fold higher surface area as compared to NB. Combining pH measurements, effect of solution pH and CIP speciation revealed that CIP sorption onto bentonite is highly dependent on solution pH. Kinetic studies confirmed that CIP sorption mechanism was chemisorption which included ion-exchange and surface complexation mechanisms. The mechanism of CIP sorption onto AAB was successfully explored with the assistance of characterization techniques. Maximal monolayer sorption capacity of AAB was found to be 305.20 mg/g, compared to 126.56 mg/g for NB. Reusability studies demonstrated that AAB could be reused successfully up to 5 cycles. Furthermore, column studies showed satisfactory results confirming that AAB can be successfully used in continuous mode for practical applications.
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http://dx.doi.org/10.1007/s11356-020-09267-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7417422PMC
September 2020

Synthesis and characterization of magnetic biochar adsorbents for the removal of Cr(VI) and Acid orange 7 dye from aqueous solution.

Environ Sci Pollut Res Int 2020 Sep 10;27(26):32874-32887. Epub 2020 Jun 10.

Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland.

In this study, different types of magnetic biochar nanocomposites were synthesized using the co-precipitation method. Two biochar materials, namely, sewage sludge biochar and woodchips biochar, were prepared at two different temperatures, viz., 450 and 700 °C. These biochars were further modified with magnetic nanoparticles (FeO). The modified biochar nanocomposites were characterized using field emission-scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), SQUID analysis, X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR). The potential of prepared adsorbents was examined for the removal of hexavalent chromium (Cr(VI)) and Acid orange 7 (AO7) dye from water as a function of various parameters, namely, contact time, pH of solution, amount of adsorbents, and initial concentrations of adsorbates. Various kinetic and isotherm models were tested to discuss and interpret the adsorption mechanisms. The maximum adsorption capacities of modified biochars were found as 80.96 and 110.27 mg g for Cr(VI) and AO7, respectively. Magnetic biochars showed high pollutant removal efficiency after 5 cycles of adsorption/desorption. The results of this study revealed that the prepared adsorbents can be successfully used for multiple cycles to remove Cr(VI) and AO7 from water. Graphical Abstract.
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http://dx.doi.org/10.1007/s11356-020-09275-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7417418PMC
September 2020

Sustainable nitrogen-doped functionalized graphene nanosheets for visible-light-induced photocatalytic water splitting.

Chem Commun (Camb) 2020 Jun;56(51):6953-6956

Department of Materials Science and Engineering, Gachon University, 1342 Seongnam-daero, Sujeong-gu Seongnam-si, Gyeonggi-do 13120, South Korea.

Nitrogen-doped functionalized graphene nanosheets (N-fGNS) were synthesized by a simple and green method and used for the visible-light-driven water splitting. Under visible light irradiation, N-fGNS produced H2 and O2 (1380 and 689 μM g-1 h-1, respectively) efficiently without co-catalysts. The excellent photocatalytic water splitting performance of N-fGNS is attributed to nitrogen doping and abundant surface defects as active sites.
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http://dx.doi.org/10.1039/d0cc01365jDOI Listing
June 2020

An analysis of the versatility and effectiveness of composts for sequestering heavy metal ions, dyes and xenobiotics from soils and aqueous milieus.

Ecotoxicol Environ Saf 2020 Jul 20;197:110587. Epub 2020 Apr 20.

Institute of Research and Development, Duy Tan University, Da Nang, 550000, Viet Nam; Faculty of Environment and Chemical Engineering, Duy Tan University, Da Nang, 550000, Viet Nam; School of Civil Engineering and Surveying, Faculty of Health, Engineering and Sciences, University of Southern Queensland, West Street, Toowoomba, 4350, QLD, Australia. Electronic address:

The persistence and bioaccumulation of environmental pollutants in water bodies, soils and living tissues remain alarmingly related to environmental protection and ecosystem restoration. Adsorption-based techniques appear highly competent in sequestering several environmental pollutants. In this review, the recent research findings reported on the assessments of composts and compost-amended soils as adsorbents of heavy metal ions, dye molecules and xenobiotics have been appraised. This review demonstrates clearly the high adsorption capacities of composts for umpteen environmental pollutants at the lab-scale. The main inferences from this review are that utilization of composts for the removal of heavy metal ions, dye molecules and xenobiotics from aqueous environments and soils is particularly worthwhile and efficient at the laboratory scale, and the adsorption behaviors and effectiveness of compost-type adsorbents for agrochemicals (e.g. herbicides and insecticides) vary considerably because of variabilities in structure, topology, bond connectivity, distribution of functional groups and interactions of xenobiotics with the active humic substances in composts. Compost-based field-scale remediation of environmental pollutants is still sparse and arguably much challenging to implement if, furthermore, real-world soil and water contamination issues are to be addressed effectively. Hence, significant research and process development efforts should be promptly geared and intensified in this direction by extrapolating the lab-scale findings in a cost-effective manner.
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http://dx.doi.org/10.1016/j.ecoenv.2020.110587DOI Listing
July 2020

Environmentally superior cleaning of diatom frustules using sono-Fenton process: Facile fabrication of nanoporous silica with homogeneous morphology and controlled size.

Ultrason Sonochem 2020 Jun 26;64:105044. Epub 2020 Feb 26.

Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland.

Existing techniques for the preparation of silica structures from diatom cells include cleaning of frustules through baking at high temperature and oxidant cleaning using concentrated sulfuric acid, hydrogen peroxide, nitric acid, or sodium dodecyl sulfate (SDS)/ethylenediaminetetraacetic acid (EDTA). In this study, sono-Fenton (SF) process was examined to prepare nanoporous silica through cleaning diatom frustules, while preserving their structural features. Single colonies of Cyclotella sp. were cultivated in batch mode f/2-enriched seawater. Combination of Fenton process with ultrasonication was found to be more efficient than the sum of individual processes in the removal of organic compounds from Cyclotella sp. structure. The optimized amounts of operational parameters were determined as suspension pH of 3, diatom cell density of 4.8 × 10 cell mL, HO concentration of 60 mM, Fe concentration of 15 mM, ultrasound irradiation power of 400 W and the temperature of 45 °C. The results of energy-dispersive X-ray spectroscopy (EDX) and thermal gravimetry (TG) analyses proved that organic materials covering the cell wall were significantly removed from the frustules through SF process. Scanning electron microscopy (SEM) images showed that after SF treatment, silica nanostructures were produced having uniform pores less than 15 nm in diameter. N adsorption-desorption isotherms demonstrated that almost non-porous structure of diatom frustules became mesoporous during removing the organic matrix. Lipids, amino acids, carbohydrates and organic acids or their oxidized products were identified using GC-MS analysis as the main organic compounds released from diatom cells to the solution after SF treatment. Treated frustules exhibited adsorption capability of 91.2 mg/g for Methylene Blue, which was almost 2.5 times higher than that of untreated frustules (34.8 mg/g).
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http://dx.doi.org/10.1016/j.ultsonch.2020.105044DOI Listing
June 2020

Multifaceted applications of isolated microalgae Chlamydomonas sp. TRC-1 in wastewater remediation, lipid production and bioelectricity generation.

Bioresour Technol 2020 May 11;304:122993. Epub 2020 Feb 11.

Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh 201313, India. Electronic address:

Green microalga, Chlamydomonas sp. TRC-1 (C. TRC-1), isolated from the outlet of effluent treatment plant of textile dyeing mill, was investigated for its competence towards bioremediation. Algal biomass obtained after remediation (ABAR) was implied for bioelectricity and biofuel production. C. TRC-1 could completely decolorize the effluent in 7 days. Significant reduction in pollution-indicating parameters was observed. Chronoamperometric studies were carried out using cyclic voltammetry and electrochemical impedance spectroscopy (EIS). Maximum current density, power and power density of 3.6 A m, 4.13 × 10 W and 1.83 W m, respectively were generated in ABAR. EIS studies showed a decrease in resistance of ABAR, supporting better electron transfer as compared to algal biomass before remediation (ABBR). Its candidature for biofuel production was assessed by estimating the total lipid content. Results revealed enhancement in lipid content from 46.85% (ABBR) to 79.1% (ABAR). Current study advocates versatile potential of isolated C. TRC-1 for bioremediation of wastewater, bioelectricity production and biofuel generation.
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http://dx.doi.org/10.1016/j.biortech.2020.122993DOI Listing
May 2020

Modified biochar from Moringa seed powder for the removal of diclofenac from aqueous solution.

Environ Sci Pollut Res Int 2020 Mar 28;27(7):7318-7327. Epub 2019 Dec 28.

Department of Environmental and Biological Sciences, University of Eastern Finland, FI-70211, Kuopio, Finland.

In this study, Moringa seed powder (M) was pyrolyzed at 450 °C to synthesize Moringa seed powder biochar (MB) and treated with phosphoric acid (HPO) to synthesize phosphate-modified Moringa seed powder biochar (MB-HPO) as an adsorbent for the removal of diclofenac (Dfc) from aqueous solution. Fourier transform infrared (FTIR) analysis, energy dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM), and pH point of zero charge (pH) were conducted to give more insight into the adsorbent's properties. The SEM analysis showed the transformations in the surface morphology from the parent material to the synthesized materials after the thermal and acid treatment. EDS analysis revealed the variation in the elemental composition of the materials prior to and after adsorption of Dfc ions. The FTIR analysis showed changes and peak intensities of functional groups involved in Dfc removal. The pH showed the charge carried by MB-HPO in different pH conditions. Isotherm data best matched the Sips model, and the pseudo-second-order model best described the adsorption kinetics. The maximum adsorption capacity of MB-HPO by Sips model was found to be 100.876 mg g.
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http://dx.doi.org/10.1007/s11356-019-06844-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7046576PMC
March 2020

Treatment of furazolidone contaminated water using banana pseudostem biochar engineered with facile synthesized magnetic nanocomposites.

Bioresour Technol 2020 Feb 21;297:122472. Epub 2019 Nov 21.

Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea; Institute for Ubiquitous Information Technology and Applications (CBRU), Konkuk University, Seoul 05029, Republic of Korea. Electronic address:

The present study enlightens facile synthesis and characterization of magnetic biochar derived from waste banana pseudostem biomass for the removal of nitrofuran antibiotic 'furazolidone' (FZD). Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), magnetic hysteresis, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) revealed successful hybridization of magnetic nanocomposites with biochar (BPB). The maximum adsorption capacity of magnetic BPB was 96.81% (37.86 mg g), which was significantly higher than the non-coated BPB (77.25%; 31.45 mg g). Adsorption kinetics data fitted well with pseudo-second order, and Elovich model demonstrating dominance of the chemisorption mechanism. Furthermore, the response surface methodology (RSM) was applied to evaluate the interactive effect of pH, temperature, and FZD concentration on adsorption. Therefore, the results of present study would provide an effective strategy to tackle antibiotic contaminants responsible for the antibiotic resistance genes or bacteria that decreases the therapeutic value of antibiotics.
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http://dx.doi.org/10.1016/j.biortech.2019.122472DOI Listing
February 2020

Enhanced interlayer trapping of Pb(II) ions within kaolinite layers: intercalation, characterization, and sorption studies.

Environ Sci Pollut Res Int 2020 Jan 23;27(2):1870-1887. Epub 2019 Nov 23.

Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland.

Lead (Pb(II)) pollution in water poses a serious threat to human health in many parts of the world. In the past decades, research has been aimed at developing efficient and cost-effective methods to address the problem. In this study, dimethyl sulfoxide (DMSO) and potassium acetate (K-Ac) intercalated kaolinite complexes were synthesized and subsequently utilized for Pb(II) removal from water. The intercalation of kaolinite with DMSO was found to be useful for expanding the interlayer space of the clay mineral from 0.72 to 1.12 nm. Kaolinite intercalation with K-Ac (KDK) increased the interlayer space from 1.12 to 1.43 nm. The surface area of KDK was found to be more than threefold higher as compared to natural kaolinite (NK). Batch experimental results revealed that the maximum Pb(II) uptake capacity of KDK was 46.45 mg g which was higher than the capacity of NK (15.52 mg g). Reusability studies showed that KDK could be reused for 5 cycles without substantially losing its adsorption capacity. Furthermore, fixed-bed column tests confirmed the suitability of KDK in continuous mode for Pb(II) removal. Successful application of intercalated kaolinite for Pb(II) adsorption in batch and column modes suggests its application in water treatment (especially removal of divalent metals).
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http://dx.doi.org/10.1007/s11356-019-06845-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6994523PMC
January 2020

Biomass-derived Carbon Quantum Dots for Visible-Light-Induced Photocatalysis and Label-Free Detection of Fe(III) and Ascorbic acid.

Sci Rep 2019 10 21;9(1):15084. Epub 2019 Oct 21.

Department of Bionanotechnology, Gachon University, 1342 Seongnam-daero, Sujeong-gu Seongnam-si, Gyeonggi-do, 13120, South Korea.

Visible-light-driven photocatalysts prepared using renewable resources are crucial but challenging to develop for the efficient degradation of organic pollutants, which is required to solve ever-increasing water deterioration issues. In this study, we report a visible-light-responsive photocatalyst for the efficient degradation of methylene blue (MB) as a model pollutant dye. Green-emissive carbon quantum dots (CQDs) were synthesized from pear juice via a facile, scalable, one-pot solvothermal process. The as-synthesized CQDs exhibit superior photocatalytic activity under visible-light irradiation owing to their efficient light absorption, electron transfer, and separation of photogenerated charge carriers, facilitating ~99.5% degradation of MB within 130 min. A possible mechanism for the photocatalysis is proposed on the basis of comprehensive active species trapping experiments. Furthermore, the CQDs were used in a specific sensitive assay for Fe(III) and ascorbic acid (AA), even with interference from other metal ions. The fluorescence emission of CQDs was "turned off" specifically upon binding of Fe(III) and "turned on" with AA. The prepared CQDs represent efficient photocatalysts and fluorescent probes that are not restricted by toxicity, cost, or lack of scalability.
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http://dx.doi.org/10.1038/s41598-019-49266-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6803716PMC
October 2019

Tuning tetracycline removal from aqueous solution onto activated 2:1 layered clay mineral: Characterization, sorption and mechanistic studies.

J Hazard Mater 2020 02 25;384:121320. Epub 2019 Sep 25.

Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland.

Water pollution due to emerging contaminants (especially pharmaceuticals) is a major environmental threat which results in the development of antibiotic-resistant bacteria/resistance genes in the aquatic environment. Therefore, robust and cost-effective methods are required to address this problem. In this study, thermal activation was opted for the modification of natural bentonite clay (BC) and utilized to investigate the adsorptive removal of tetracycline (TC) from aqueous solution. The physicochemical surface properties of the raw and modified bentonite samples were also investigated. The BET analysis revealed that the thermally activated bentonite (TB) has better properties than BC. The surface area of TB was found to be more than two-fold higher compared to that of BC. The FTIR spectra exhibited the existence of AlOH, SiO and SiOSi functional groups in the samples, confirming the presence of hydrated aluminosilicate in the clay. The effects of various operating parameters were analyzed via optimization studies. The maximum monolayer adsorption capacity estimated by Langmuir model was found to be 156.7 and 388.1 mg g for BC and TB, respectively. Furthermore, fixed-bed column studies were performed to get insights into the adsorption behavior of TB in a dynamic system. The mechanism of TC adsorption by TB was successfully explored.
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http://dx.doi.org/10.1016/j.jhazmat.2019.121320DOI Listing
February 2020

Waste-derived compost and biochar amendments for stormwater treatment in bioretention column: Co-transport of metals and colloids.

J Hazard Mater 2020 02 16;383:121243. Epub 2019 Sep 16.

Korea Biochar Research Center, O-Jeong Eco-Resilience Institute (OJERI) & Division of Environmental Science and Ecological Engineering, Korea University, Seoul, 02841, Republic of Korea.

Bioretention systems, as one of the most practical management operations for low impact development of water recovery, utilize different soil amendments to remove contaminants from stormwater. For the sake of urban sustainability, the utilization of amendments derived from waste materials has a potential to reduce waste disposal at landfill while improving the quality of stormwater discharge. This study investigated the efficiency of food waste compost and wood waste biochar for metal removal from synthetic stormwater runoff under intermittent flow and co-presence of colloids. Throughout intermittent infiltration of 84 pore volumes of stormwater, columns amended with compost and biochar removed more than 50-70% of influent metals, whereas iron-oxide coated sand was much less effective. Only a small portion of metals adsorbed on the compost (< 0.74%) was reactivated during the drainage of urban pipelines that do not flow frequently, owing to abundant oxygen-containing functional groups in compost. In comparison, co-existing kaolinite enhanced metal removal by biochar owing to the abundance of active sites, whereas co-existing humic acid facilitated mobilization via metal-humate complexation. The results suggest that both waste-derived compost and biochar show promising potential for stormwater harvesting, while biochar is expected to be more recalcitrant and desirable in field-scale bioretention systems.
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http://dx.doi.org/10.1016/j.jhazmat.2019.121243DOI Listing
February 2020

Mechanobiology of the abluminal glycocalyx.

Biorheology 2019 ;56(2-3):101-112

Department of Biomedical Engineering and Intercollege Graduate Program of Bioengineering, The Pennsylvania State University, University Park, PA, USA.

Background: Endothelial cells (ECs) sense the forces from blood flow through the glycocalyx, a carbohydrate rich luminal surface layer decorating most cells, and through forces transmitted through focal adhesions (FAs) on the abluminal side of the cell.

Objectives: This perspective paper explores a complementary hypothesis, that glycocalyx molecules on the abluminal side of the EC between the basement membrane and the EC membrane, occupying the space outside of FAs, work in concert with FAs to sense blood flow-induced shear stress applied to the luminal surface.

Results: First, we summarize recent studies suggesting that the glycocalyx repels the plasma membrane away from the basement membrane, while integrin molecules attach to extracellular matrix (ECM) ligands. This coordinated attraction and repulsion results in the focal nature of integrin-mediated adhesion making the abluminal glycocalyx a participant in mechanotransduction. Further, the glycocalyx mechanically links the plasma membrane to the basement membrane providing a mechanism of force transduction when the cell deforms in the peri-FA space. To determine if the membrane might deform against a restoring force of an elastic abluminal glycocalyx in the peri-FA space we present some analysis from a multicomponent elastic finite element model of a sheared and focally adhered endothelial cell whose abluminal topography was assessed using quantitative total internal reflection fluorescence microscopy with an assumption that glycocalyx fills the space between the membrane and extracellular matrix.

Conclusions: While requiring experimental verification, this analysis supports the hypothesis that shear on the luminal surface can be transmitted to the abluminal surface and deform the cell in the vicinity of the focal adhesions, with the magnitude of deformation depending on the abluminal glycocalyx modulus.
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http://dx.doi.org/10.3233/BIR-190212DOI Listing
April 2020

Clay-polymer nanocomposites: Progress and challenges for use in sustainable water treatment.

J Hazard Mater 2020 02 29;383:121125. Epub 2019 Aug 29.

Korea Biochar Research Centre & Division of Environmental Science and Ecological Engineering, Korea University, Seoul, Republic of Korea. Electronic address:

Contaminant removal from water involves various technologies among which adsorption is considered to be simple, effective, economical, and sustainable. In recent years, nanocomposites prepared by combining clay minerals and polymers have emerged as a novel technology for cleaning contaminated water. Here, we provide an overview of various types of clay-polymer nanocomposites focusing on their synthesis processes, characteristics, and possible applications in water treatment. By evaluating various mechanisms and factors involved in the decontamination processes, we demonstrate that the nanocomposites can overcome the limitations of individual polymer and clay components such as poor specificity, pH dependence, particle size sensitivity, and low water wettability. We also discuss different regeneration and wastewater treatment options (e.g., membrane, coagulant, and barrier/columns) using clay-polymer nanocomposites. Finally, we provide an economic analysis of the use of these adsorbents and suggest future research directions.
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http://dx.doi.org/10.1016/j.jhazmat.2019.121125DOI Listing
February 2020

Hexavalent chromium removal from water by microalgal-based materials: Adsorption, desorption and recovery studies.

Bioresour Technol 2019 Dec 26;293:122064. Epub 2019 Aug 26.

Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211 Kuopio, Finland. Electronic address:

The current study presents a comprehensive comparison towards the potential of different microalgal-based materials for the removal of hexavalent chromium (Cr(VI)) from water. Among the tested materials, microalgal biochar showed the highest removal efficiency (100%) of Cr(VI). The highest monolayer estimated adsorption capacities were 23.98, 25.19 and 24.27 mg/g at 5, 22 and 35 °C, respectively. Experimental data showed good compliance with pseudo-second-order kinetic model. The results of continuous column studies showed that the column removal efficiency increased from 52.33 to 57.58% by increasing the adsorbent dose from 0.125 to 0.200 g. Desorption efficiency of Cr(VI) by 0.1 M NaOH was increased from 51.16 to 59.41% by sonication bath as compared to roller shaker. More than 97% of desorbed Cr(VI) was recovered in less than 10 min by BaCl. This study shows that non-living microalga materials are more effective than living cells in the removal and recovery of Cr(VI) from water.
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http://dx.doi.org/10.1016/j.biortech.2019.122064DOI Listing
December 2019
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