Publications by authors named "Raj Mukhopadhyay"

7 Publications

  • Page 1 of 1

Distribution, behaviour, bioavailability and remediation of poly- and per-fluoroalkyl substances (PFAS) in solid biowastes and biowaste-treated soil.

Environ Int 2021 May 5;155:106600. Epub 2021 May 5.

Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, USA; Department of Agronomy, Kansas State University, Manhattan, KS 66506, USA.

Aqueous film-forming foam, used in firefighting, and biowastes, including biosolids, animal and poultry manures, and composts, provide a major source of poly- and perfluoroalkyl substances (PFAS) input to soil. Large amounts of biowastes are added to soil as a source of nutrients and carbon. They also are added as soil amendments to improve soil health and crop productivity. Plant uptake of PFAS through soil application of biowastes is a pathway for animal and human exposure to PFAS. The complexity of PFAS mixtures, and their chemical and thermal stability, make remediation of PFAS in both solid and aqueous matrices challenging. Remediation of PFAS in biowastes, as well as soils treated with these biowastes, can be achieved through preventing and decreasing the concentration of PFAS in biowaste sources (i.e., prevention through source control), mobilization of PFAS in contaminated soil and subsequent removal through leaching (i.e., soil washing) and plant uptake (i.e., phytoremediation), sorption of PFAS, thereby decreasing their mobility and bioavailability (i.e., immobilization), and complete removal through thermal and chemical oxidation (i.e., destruction). In this review, the distribution, bioavailability, and remediation of PFAS in soil receiving solid biowastes, which include biosolids, composts, and manure, are presented.
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http://dx.doi.org/10.1016/j.envint.2021.106600DOI Listing
May 2021

Unravelling the mechanism of amitriptyline removal from water by natural montmorillonite through batch adsorption, molecular simulation and adsorbent characterization studies.

J Colloid Interface Sci 2021 Sep 26;598:379-387. Epub 2021 Apr 26.

Environmental Contaminants Group, Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia.

Amitriptyline (AMI) is one of the most common tricyclic antidepressant personal care medications. Due to its environmental persistence and bioaccumulation, release of AMI into the environment via wastewater streams in elevated levels could lead to significant ecological and human health impacts. In this study, the adsorption of AMI by montmorillonite (SWy-2), a naturally abundant smectite clay with sodium ions as the main interlayer cations, was investigated. Maximum AMI adsorption (276 mg/g) occurred at pH 7-8. After adsorption, examination of the adsorbent's X-ray diffraction pattern indicated that interlayer expansion had occurred, where chemical stoichiometry confirmed cation exchange as the principal adsorption mechanism. AMI adsorption reached equilibrium within 4 h, with kinetic data best fitting the pseudo-second order kinetic model (R = 0.98). AMI adsorption was unaffected by solution pH in the range 2-11, where adsorption was endothermic, and molecular simulations substantiated by Fourier transform infrared spectroscopy and thermogravimetric investigations indicated that the orientation of AMI molecules in the interlayer was via an amine group and a benzene ring. Overall this research shows that SWy-2 has significant potential as a low cost, effective, and geologically derived natural material for AMI removal in wastewater systems.
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http://dx.doi.org/10.1016/j.jcis.2021.04.033DOI Listing
September 2021

Fe(III) loaded chitosan-biochar composite fibers for the removal of phosphate from water.

J Hazard Mater 2021 08 19;415:125464. Epub 2021 Feb 19.

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:

Excess phosphorous (P) in aquatic systems causes adverse environmental impacts including eutrophication. This study fabricated Fe(III) loaded chitosan-biochar composite fibers (FBC-N and FBC-C) from paper mill sludge biochar produced under N (BC-N) and CO (BC-C) conditions at 600 °C for adsorptive removal of phosphate from water. Investigations using SEM/EDX, XPS, Raman spectroscopy, and specific surface area measurement revealed the morphological and physico-chemical characteristics of the adsorbent. The Freundlich isotherm model well described the phosphate adsorption on BC-N, while the Redlich-Peterson model best fitted the data of three other adsorbents. The maximum adsorption capacities were 9.63, 8.56, 16.43, and 19.24 mg P g for BC-N, BC-C, FBC-N, and FBC-C, respectively, indicating better adsorption by Fe(III) loaded chitosan-biochar composite fibers (FBCs) than pristine biochars. The pseudo-first-order kinetic model suitably explained the phosphate adsorption on BC-C and BC-N, while data of FBC-N and FBC-C followed the pseudo-second-order and Elovich model, respectively. Molecular level observations of the P K-edge XANES spectra confirmed that phosphate associated with iron (Fe) minerals (Fe-P) were the primary species in all the adsorbents. This study suggests that FBCs hold high potential as inexpensive and green adsorbents for remediating phosphate in contaminated water, and encourage resource recovery via bio-based management of hazardous waste.
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http://dx.doi.org/10.1016/j.jhazmat.2021.125464DOI Listing
August 2021

Soil salinity under climate change: Challenges for sustainable agriculture and food security.

J Environ Manage 2021 Feb 6;280:111736. Epub 2020 Dec 6.

Global Centre for Environmental Remediation, University of Newcastle, Callaghan, NSW, 2308, Australia; Cooperative Research Centre for High Performance Soils, Callaghan, NSW, 2308, Australia.

Soil salinity is one of the major and widespread challenges in the recent era that hinders global food security and environmental sustainability. Worsening the situation, the harmful impacts of climate change accelerate the development of soil salinity, potentially spreading the problem in the near future to currently unaffected regions. This paper aims to synthesise information from published literature about the extent, development mechanisms, and current mitigation strategies for tackling soil salinity, highlighting the opportunities and challenges under climate change situations. Mitigation approaches such as application of amendments, cultivation of tolerant genotypes, suitable irrigation, drainage and land use strategies, conservation agriculture, phytoremediation, and bioremediation techniques have successfully tackled the soil salinity issue, and offered associated benefits of soil carbon sequestration, and conservation and recycling of natural resources. These management practices further improve the socio-economic conditions of the rural farming community in salt-affected areas. We also discuss emerging reclamation strategies such as saline aquaculture integrated with sub surface drainage, tolerant microorganisms integrated with tolerant plant genotypes, integrated agro-farming systems that warrant future research attention to restore the agricultural sustainability and global food security under climate change scenarios.
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http://dx.doi.org/10.1016/j.jenvman.2020.111736DOI Listing
February 2021

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

Comparison of properties and aquatic arsenic removal potentials of organically modified smectite adsorbents.

J Hazard Mater 2019 09 23;377:124-131. Epub 2019 May 23.

Department of Animal and Plant Sciences, The University of Sheffield, Sheffield, S10 2TN, UK.

Arsenic (As) poses a tremendous threat to human health due to exposure through arsenic-contaminated drinking water and/or food. We aimed to develop organically modified clay adsorbents for the removal of As from aqueous solution. We modified a smectite sample using three organic agents, namely hexadecyl trimethylammonium (HDTMA), chitosan and citric acid, and characterized the products using X-ray diffraction, infrared spectroscopy, and scanning electron microscopy techniques. The characterization techniques suggested successful organic modifications of the smectite sample. The surfactant-modified smectite was the most efficient (66.9%) As removing adsorbent with a maximum adsorption capacity of 473.2 μg g. Kinetic study showed that the adsorbents reached As adsorption equilibrium within 3 h, and the data fitted reasonably well to power function and simple Elovich equations (R > 0.89). The adsorption data were explained well by the Freundlich and Sips isothermal models. The surfactant-modified and chitosan-grafted organoclays adsorbed As by electrostatic attraction and anion exchange, whereas the citric acid activated smectite followed ligand exchange and simple anion exchange mechanisms. This study thus demonstrated the potential of surfactant-modified clays in removing As from contaminated waters.
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http://dx.doi.org/10.1016/j.jhazmat.2019.05.053DOI Listing
September 2019

Fe-exchanged nano-bentonite outperforms FeO nanoparticles in removing nitrate and bicarbonate from wastewater.

J Hazard Mater 2019 08 13;376:141-152. Epub 2019 May 13.

ICAR-Central Soil Salinity Research Institute, Karnal 132001, India.

Nitrate (NO) and bicarbonate (HCO) are harmful for the water quality and can potentially create negative impacts to aquatic organisms, crops and humans. This study deals with the removal of NO and HCO from contaminated wastewater using Fe-exchanged nano-bentonite and FeO nanoparticles. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, surface area measurement and particle size analysis revealed that the adsorbents fall under the nano-scale size range with high specific surface area, and Fe was successfully exchanged in the nano-bentonite clay. The kinetics of adsorption was well defined by pseudo-first order and pseudo-second order kinetic models for both NO and HCO. The Fe-exchanged nano-bentonite was a better performing adsorbent of the oxyanions than FeO nanoparticles. According to the Sips isothermal model, the Fe-exchanged nano-bentonite exhibited the highest NO and HCO adsorption potential of 64.76 mg g and 9.73 meq g, respectively, while the respective values for FeO nanoparticles were 49.90 mg g and 3.07 meq g. Thus, inexpensiveness and easy preparation process of Fe-exchanged nano-bentonite make it attractive for NO and HCO removal from contaminated wastewater with significant environmental and economic benefits.
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http://dx.doi.org/10.1016/j.jhazmat.2019.05.025DOI Listing
August 2019