Removal of Select Chlorinated Hydrocarbons by Nanoscale Zero-valent Iron Supported on Powdered Activated Charcoal PDF Download
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Author: Md Abu Raihan Chowdhury Publisher: ISBN: Category : Chlorohydrocarbons Languages : en Pages : 64
Book Description
Nanoscale Zero Valent Iron (NZVI) has shown limited effectiveness in degrading chlorinated hydrocarbons (CHCs), like 1,1,1-Trichloroethane (1,1,1-TCA) and Trichloroethene (TCE), in aqueous solution. A rapid agglomeration behavior of NZVI particles due to van der waals and magnetic forces can negatively impact its overall effectiveness due to increase in particle size, and decline in CHC degradation kinetics. Different support materials, such as clays and activated carbon, have been used to stabilize NZVI particle and reduce agglomeration in aqueous solution. In this bench-scale study, NZVI supported on Powdered Activated Charcoal (PAC) was selected to prepare a composite, called PAC/NZVI, for a more effective treatment of 1,1,1-TCA and TCE in aqueous solution. The study shows that PAC/NZVI has both adsorption and degradation capability toward 1,1,1-TCA and TCE. PAC exhibited high porosity to accommodate NZVI as a suitable support in order to keep NZVI in suspension in aqueous medium and to minimize agglomeration. Bench-scale experiments with variable concentrations of PAC (0.1{u2013}0.8 g/L) and NZVI (0.2{u2013}0.6 g/L) showed that PAC/NZVI composite can be highly efficient in rapid 1,1,1-TCA removal by adsorption, and effective in overall degradation leading to production of non-chlorinated daughter products. Increase in PAC concentration in the composite was correlated with greater removal of 1,1,1-TCA by sorption whereas lower PAC concentration yielded greater degradation kinetics and higher byproduct yields. PAC/NZVI was found to be active for more than three months presumably because NZVI embedded within hydrophobic pore spaces of PAC did not get oxidized. Cu amendment to NZVI as a secondary/catalysts metal showed faster degradation and higher byproduct yields.
Author: Md Abu Raihan Chowdhury Publisher: ISBN: Category : Chlorohydrocarbons Languages : en Pages : 64
Book Description
Nanoscale Zero Valent Iron (NZVI) has shown limited effectiveness in degrading chlorinated hydrocarbons (CHCs), like 1,1,1-Trichloroethane (1,1,1-TCA) and Trichloroethene (TCE), in aqueous solution. A rapid agglomeration behavior of NZVI particles due to van der waals and magnetic forces can negatively impact its overall effectiveness due to increase in particle size, and decline in CHC degradation kinetics. Different support materials, such as clays and activated carbon, have been used to stabilize NZVI particle and reduce agglomeration in aqueous solution. In this bench-scale study, NZVI supported on Powdered Activated Charcoal (PAC) was selected to prepare a composite, called PAC/NZVI, for a more effective treatment of 1,1,1-TCA and TCE in aqueous solution. The study shows that PAC/NZVI has both adsorption and degradation capability toward 1,1,1-TCA and TCE. PAC exhibited high porosity to accommodate NZVI as a suitable support in order to keep NZVI in suspension in aqueous medium and to minimize agglomeration. Bench-scale experiments with variable concentrations of PAC (0.1{u2013}0.8 g/L) and NZVI (0.2{u2013}0.6 g/L) showed that PAC/NZVI composite can be highly efficient in rapid 1,1,1-TCA removal by adsorption, and effective in overall degradation leading to production of non-chlorinated daughter products. Increase in PAC concentration in the composite was correlated with greater removal of 1,1,1-TCA by sorption whereas lower PAC concentration yielded greater degradation kinetics and higher byproduct yields. PAC/NZVI was found to be active for more than three months presumably because NZVI embedded within hydrophobic pore spaces of PAC did not get oxidized. Cu amendment to NZVI as a secondary/catalysts metal showed faster degradation and higher byproduct yields.
Author: Andrew Franze Publisher: ISBN: Category : Bioremediation Languages : en Pages : 89
Book Description
Nanoscale zero valent iron (nZVI) is a remediation technology that can be used to treat chlorinated hydrocarbons (CHCs) in contaminated aquifers. Nanoparticles remain mobile in water and can be transported with groundwater flow to contaminated zones. However, due to magnetic and van der Waals forces, unstabilized nZVI agglomerates. Carboxymethylcellulose (CMC) was used as a polyelectrolyte stabilizer in this study. nZVI serves as an electron donor and can dechlorinate CHCs. nZVI reactivity with CHCs can be enhanced by addition of a secondary metal catalyst. This study evaluates the potential of copper amended nZVI (Cu-nZVI) to degrade select CHCs. The objective of this study was to characterize degradation of select CHCs in batch reactors with regard to degradation kinetics and degradation byproduct distributions. The following CHCs were studied: CF, 1,1,2,2-TeCA, 1,1,1-TCA, 1,1,2-TCA, PCE, TCE, cis-DCE, trans-DCE, and 1,2,3-TCP. Degradation kinetics were quantified using a pseudo first-order rate constant (kobs). Initial degradation of CHCs was reported separately from later degradation, which occurred after 0.5 hr. The change in reaction kinetics with time could be caused by particle aging. The effect of Cu loading and nZVI concentration was evaluated with CF degradation. Increasing Cu loading or nZVI concentrations yielded faster degradation rates. Increasing Cu loading systematically increased methane byproduct production. The loss of reactivity with CF after 0.5 hr was greater for nZVI when compared to Cu-nZVI. Degradation kinetics were faster and byproduct distribution was more favorable for Cu-nZVI than nZVI for all CHCs studied. Cu-nZVI outperformed most other bimetallic nZVI reductants reported in the literature for CF and chlorinated ethanes treatment. Cu-nZVI invokes a-elimination of CF and 1,l,1-TCA, which produces reactive carbene intermediates capable of degrading into benign products such as methane, ethane, and ethene. Cu-nZVI also showed potential for 1,2,3-TCP remediation. However, Cu-nZVI was particularly ineffective at degrading chlorinated ethenes. Chlorinated ethene degradation pathways and mechanisms induced by Cu-nZVI were not clearly identified. Particle longevity experiments showed that reactivity with 1,1,1-TCA decreases as particles age. Unstable Cu-nZVI particles showed a slow linear decline in reactivity with time, whereas CMC stabilized Cu-nZVI particles showed a rapid power function decline in reactivity with time. The unstable particles were 12-fold faster compared to stablized particles 24 hr after particle synthesis. Even with declines in reactivity, 1,1,1-TCA was rapidly degraded (over a few hours) by both stable and unstable Cu-nZVI seven days after particle synthesis. Cu-nZVI hydrogen production was minor and was limited to occurring immediately after particle synthesis. Cu-nZVI shows great potential for treating certain CHCs.
Author: Shirin Ghahghaei Nezamabadi Publisher: ISBN: Category : Environmental sciences Languages : en Pages : 92
Book Description
Nanoscale zero-valent iron (nZVI) injections have proven to be a promising approach for the remediation of aquifers contaminated by chlorinated organic pollutants. This study compares the efficacy of nZVI in sulfidated and unamended forms in degrading selected chlorinated hyrocarbons (CHCs). Results show that nZVI amended with iron monosulfide (FeS) increases the rate of dechlorination of CT, CF and 1,1,1-TCA compared to that by unamended nZVI. The focus of this research was to characterize degradation kinetics and degradation byproduct distributions of CT, CF and 1,1,1-TCA by nZVI coated by iron monosulfide, which is represented as nZVI/FeS. To prevent nZVI particles from agglomerating, carboxymethylcellulose (CMC) was used as a stabilizer in all experiments. Results indicated that the nZVI/FeS system was faster and produced less toxic byproducts than nZVI for all CHCs studied. a-elimination in nZVI/FeS system was an important degradation pathway for CF and 1,l,1-TCA: it produces reactive carbene intermediates capable of degrading into benign products such as methane, ethane, and ethene. The effect of sulfide loading on degradation was evaluated with all CHCs studied. Regardless of CHC type, the rate constant (kobs) increased with increasing sulfide loading, reaching the highest amount at 1 wt% sulfide, and then decreased with higher sulfide loading. An additional study focused on the effects of varying of the concentration of nZVI and CMC, and particle longevity on the degradation of 1,1,1-TCA in the nZVI/FeS system with 1 wt.% sulfide. Particle longevity experiments showed that reactivity with 1,1,1-TCA decreases as particles age. nZVI/FeS particles showed a rapid power function decline in reactivity with time. Increasing the amount of iron-reducing chemical during nZVI/FeS synthesis improved reactivity by 43%. The addition of a polyelectrolyte stabilizer at an optimized concentration of 4.0 g/L further increased nZVI/FeS reactivity by 350%. nZVI/FeS shows great potential for treating certain CHCs.
Author: Maulin P. Shah Publisher: Royal Society of Chemistry ISBN: 1839162791 Category : Science Languages : en Pages : 437
Book Description
Biological Treatment of Industrial Wastewater presents a comprehensive overview of the latest advances and trends in the use of bioreactors for treating industrial wastewater.
Author: Srabanti Ghosh Publisher: CRC Press ISBN: 1000485323 Category : Technology & Engineering Languages : en Pages : 488
Book Description
Offering a comprehensive view of water-treatment technologies, Nanomaterials for Water Treatment and Remediation explores recent developments in the use of advanced nanomaterials (ANMs) for water treatment and remediation. In-depth reaction mechanisms in water-treatment technologies, including adsorption, catalysis, and membrane filtration for water purification using ANMs, are discussed in detail. The book includes an investigation of the fabrication processes of nanostructured materials and the fundamental aspects of surfaces at the nanoscale. The book also covers the removal of water-borne pathogens and microbes through a photochemical approach. FEATURES Explains various chemical treatments for the removal and separation of hazardous dyes, organic pollutants, pharmaceuticals, and heavy metals from aqueous solutions, including adsorption, advanced oxidation process, and photocatalysis Discusses the rational design of nanoporous materials with a tunable pore structure and fabrication of nanomaterials by surface chemistry engineering Covers the role of nanomaterials-assisted oxidation and reduction processes, design of nano-assisted membrane-based separation, and multifunctional nanomaterials and nanodevices for water treatment Provides an understanding of the structure–activity relationship and stability of ANMs under critical experimental conditions Identifies potential challenges in the application of multifunctional ANMs for future research Nanomaterials for Water Treatment and Remediation is aimed at researchers and industry professionals in chemical, materials, and environmental engineering as well as related fields interested in the application of advanced materials to water treatment and remediation.
Author: David M. Kempisty Publisher: CRC Press ISBN: 0429945027 Category : Science Languages : en Pages : 495
Book Description
Per- and polyfluorinated alkyl substances (PFAS), often referred to as per- (and poly) fluorinated compounds (PFCs), have been used for years in many everyday3⁄4 and some lifesaving3⁄4 products. However, their use has been linked to adverse health effects in humans, a problem compounded by their persistence in the environment. This book discusses the various challenges of PFAS in our environment today, including their historical use as well as their chemical and toxicological properties. It also presents robust discussion of analytical challenges and special considerations in sampling. The work goes on to give practical recommendations for dealing with these compounds in today's dynamic regulatory landscape and includes several chapters on various remediation techniques. Key Features: Comprehensive overview of per- and polyfluorinated alkyl substances (PFAS) historical use and chemical/physical properties which help us understand their persistence, transport, and transformation pathways in the environment In-depth analysis of PFAS toxicology Detailed descriptions of conventional and state-of-the-art remediation technologies Practical recommendations for dealing with PFAS in a dynamic regulatory landscape Robust discussion of important sampling and analytical considerations Perfluoroalkyl Substances in the Environment: Theory, Practice, and Innovation explores the challenges across the topical areas of regulation and management, toxicology, environmental remediation, and analytical sampling and analysis.Readers will find this text helpful in understanding complexities associated with PFAS and informing management strategies to effectively protect this and future generations.
Author: Mattia Bartoli Publisher: BoD – Books on Demand ISBN: 1789845866 Category : Science Languages : en Pages : 190
Book Description
Carbon-Based Material for Environmental Protection and Remediation presents an overview of carbon-based technologies and processes, and examines their usefulness and efficiency for environmental preservation and remediation. Chapters cover topics ranging from pollutants removal to new processes in materials science. Written for interested readers with strong scientific and technological backgrounds, this book will appeal to scientific advisors at private companies, academics, and graduate students.
Author: Vinod Kumar Publisher: Agro Environ Media, Publication Cell of AESA, Agriculture and Environmental Science Academy, ISBN: 8194201721 Category : Young Adult Nonfiction Languages : en Pages : 214
Book Description
The compliance of this book is helpful for academicians, researchers, students, as well as other people seeking the relevant material in current trends of studies on the topic of environmental degradation.
Author: Ram Prasad Publisher: Springer Nature ISBN: 9811554994 Category : Technology & Engineering Languages : en Pages : 501
Book Description
This book presents state-of-the-art environmental remediation processes. Environmental protection and management is a global concern, especially in the context of industrial regions. Over the years, several conventional, engineering-based physicochemical decontamination methods have used in the remediation of polluted sites. However, these methods are expensive and have limited efficiency. Drawing on research and examples from around the world, this book offers a comprehensive review of and insights into green technologies and sustainable remediation alternatives. It discusses the emerging importance of nanotechnology, chemo and biosensors, indicator species, microbe-based remediation of organic compounds, and ex-situ remediation methods. Addressing the growing global need for a holistic overview of the environmental remediation of polluted sites, it will appeal to teachers, researchers, scientists, capacity builders, and policymakers. It also serves as additional reading material for undergraduate and graduate students of biotechnology and environmental sciences.
Author: Md Abu Raihan Chowdhury
Author: Md Abu Raihan Chowdhury
Author: Andrew Franze
Author: Bina Mukund Indelicato
Author: Shirin Ghahghaei Nezamabadi
Author: Maulin P. Shah
Author: Srabanti Ghosh
Author: David M. Kempisty
Author: Mattia Bartoli
Author: Vinod Kumar
Author: Ram Prasad