Browsing by Author "Dhanesh Tiwary"

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Application of Visual MODFLOW in Groundwater Flow Modeling at the Left Crescent of the Ganga River, Varanasi, India
(Springer, 2021) Sachin Mishra; Shivam Tripathi; Dhanesh Tiwary; Anurag Ohri; Ashwani Kumar Agnihotri; Ashish Kumar Vishwakarma
Groundwater flow modeling is a significant tool for conceptualizing the hydro-geological processes and forecasting the groundwater pollution. To simulate the groundwater flow direction and pollutant fate, Visual MODFLOW and MODPATH are used popularly. Present study focuses on the application of Visual MODFLOW to study the groundwater flow direction, groundwater flow path lines and to predict the leachate contamination from the open unsecured MSW dumping site at the left crescent of the Ganga River in Varanasi, India. Simulation of the model is done for one year by giving input value to the flow setting and transport setting database of the software to know the groundwater flow direction and flow velocity in the study area. Linear isotherm (equilibrium-controlled) with no kinetic reactions is assumed for contaminants transport modeling. The simulated result indicates that the groundwater is flowing from higher heads (water table) to lower heads (towards Ganga River) in the study area. The maximum velocity of groundwater flow is calculated to be 5.7E-06 m/s (5.7 × 10−7 m/s). Simulated groundwater table was ranged from minimum 58 m to maximum 74.93 m. This result is validated with the field monitoring data of water table which was also observed to be between 61.96 m and 78.85 m. TDS transport model results indicate the movement of TDS pollutant towards the groundwater flow direction. TDS transport modeling showing a distinct pollutant path line from MSW dumping site to nearest observed heads (wells) and its path lines are congruent with the groundwater flow direction. This study would be helpful for site-suitability index for landfill strategy makers and the government authorities to safeguard groundwater pollution from potential risk from the landfill. © Springer Nature Singapore Pte Ltd. 2021.
Assessment of ground and surface water quality along the river Varuna, Varanasi, India
(Kluwer Academic Publishers, 2015) Pardeep Singh; R.K. Chaturvedi; Ankit Mishra; Lata Kumari; Rishikesh Singh; D.B. Pal; Deen Dayal Giri; Nand Lal Singh; Dhanesh Tiwary; Pradeep Kumar Mishra
Multivariate statistical techniques were employed for monitoring of ground-surface water interactions in rivers. The river Varuna is situated in the Indo-Gangetic plain and is a small tributary of river Ganga. The study area was monitored at seven sampling sites for 3 years (2010–12), and eight physio-chemical parameters were taken into account for this study. The data obtained were analysed by multivariate statistical techniques so as to reveal the underlying implicit information regarding proposed interactions for the relevant area. The principal component analysis (PCA) and cluster analysis (CA), and the results of correlations were also studied for all parameters monitored at every site. Methods used in this study are essentially multivariate statistical in nature and facilitate the interpretation of data so as to extract meaningful information from the datasets. The PCA technique was able to compress the data from eight to three parameters and captured about 78.5 % of the total variance by performing varimax rotation over the principal components. The varifactors, as yielded from PCA, were treated by CA which grouped them convincingly into three groups having similar characteristics and source of contamination. Moreover, the loading of variables on significant PCs showed correlations between various ground water and surface water (GW-SW) parameters. The correlation coefficients calculated for various physiochemical parameters for ground and surface water established the correlations between them. Thus, this study presents the utility of multivariate statistical techniques for evaluation of the proposed interactions and effective future monitoring of potential sites. © 2015, Springer International Publishing Switzerland.
Biodegradation of Navy N5RL1 carpet dye by Staphylococcus saprophyticus strain BHUSS X3
(Springer Verlag, 2015) Lata Kumari; Ajay Kumar Verma; Dhanesh Tiwary; Deen Dayal Giri; Gopal Nath; Pradeep Kumar Mishra
Biodegradation of Navy N5RL1, a widely used acidic azo dye in carpet industry, was studied by bacterial strain isolated from the dye-contaminated soil collected from a carpet industry premises located in Bhadohi, Sant Ravidas Nagar and Uttar Pradesh, India. The isolated strain was identified as Staphylococcus saprophyticus BHUSS X3 on the basis of morphological, biochemical and 16S rRNA gene sequencing analysis. The strain BHUSS X3 decolorized 95.7 % of dye (100 mg/l) within 6 h at optimum pH 8, temperature 35 °C, inoculum 4.0 % under static condition during 24 h incubation. The isolated bacterial strain BHUSS X3 can toralate dye concentration upto 1,000 mg/l. The dye degradation metabolites were confirmed by analysis of degraded products using UV–Vis spectrophotometric, HPLC and FTIR technique. The phytotoxicity analysis was also conducted on Phaseolus aureus and enhanced seed germination was recorded. © 2015, The Author(s).
Biological degradation of toluene by indigenous bacteria Acinetobacter junii CH005 isolated from petroleum contaminated sites in India
(Joint Center on Global Change and Earth System Science of the University of Maryland and Beijing Normal University, 2018) Pardeep Singh; Vipin Kumar Singh; Rishikesh Singh; Anwesha Borthakur; Ajay Kumar; Dhanesh Tiwary; P.K. Mishra
The bacterium Acinetobacter junii was isolated from petroleum-contaminated site in India and tested for its efficiency in degradation of toluene under aerobic condition. Within pH range 4–9, the optimum pH for toluene biodegradation was found to be 7.5. With increase in time, there was enhancement in degradation of toluene. Pure culture of Acinetobacter junii was able to degrade 69, 73 and 80% of 150, 100, and 50 ppm toluene, respectively, within 72 h at 37 °C. Simultaneous growth and degradation of toluene by the bacterium indicated the utilization of toluene as carbon source. After 72 h of treatment, toluene biodegradation was nearly stable. Scanning electron microscopic characterization of bacterial cells treated with toluene revealed the changes in surface morphology. Some of the cylindrical cells of bacterium got transformed into ovoid and spherical shape to escape the toluene toxicity. Degradation intermediates were identified by gas chromatography–mass spectroscopy. The major intermediate compounds identified after toluene degradation by bacteria were 1-isopropenyl-4-methyl-1,3-cyclohexadiene; 1,3-Cyclohexadiene; 2-methyl-5-(1-methylethyl); 4-methoxycarbonyl-4-butanolide; and vinyl (2E,4E)-2,4-hexadienoate, which are less-toxic in nature. The degradation of toluene into non-toxic intermediate compounds as well as the growth in the presence of toluene presents the suitability of Acinetobacter junii in biofiltration of toluene-containing petroleum waste. © 2018, Joint Center on Global Change and Earth System Science of the University of Maryland and Beijing Normal University and Springer-Verlag GmbH Germany, part of Springer Nature.
Bioremediation: A sustainable approach for management of environmental contaminants
(Elsevier, 2019) Pardeep Singh; Vipin Kumar Singh; Rishikesh Singh; Anwesha Borthakur; Sughosh Madhav; Arif Ahamad; Ajay Kumar; Dan Bahadur Pal; Dhanesh Tiwary; P.K. Mishra
The release of various inorganic and organic chemicals from various industries such as petrochemicals, textiles, pharmaceuticals, agro-based industries, and tanneries is highly toxic to the environment and human health. Several processes and technologies such as physical, chemical, and advanced oxidation processes are available for treatment of these pollutants. However, these processes and technologies have their own limitations and the end products are also of toxic nature. Therefore, there is a need for identifying and exploring sustainable and eco-friendly methods which require a lesser amount of chemicals, are economically feasible, and produce nontoxic end products. The bioremediation approaches to clean up environmental pollutants are considered as emerging and sustainable methods recently. Bioremediation process is based on an integrated approach employing microbial communities such as actinomycetes, bacteria, fungi, and earthworms. It is considered as a sustainable process for management of organic pollutants-rich solid wastes and wastewater. Many microorganisms metabolize toxic chemicals to produce CO2 or CH4, water, and biomass. These pollutants may be enzymatically altered to metabolites that are less noxious or innocuous. Moreover, the solid residue generated in this process has been found to have a potential influence on soil macro- and micronutrients, indicating its application as organic manure. However, bioremediation technique required more research for its establishment at a larger scale with an emphasis on the environmental consequences of the end products. In this chapter, we have performed a literature survey based on biological methods for the management of organic pollutants. Microbes responsible for degradation processes have also been presented in the later part of the chapter. In this chapter, a thorough understanding of the bioremediation processes and methods applied for abatement and remediation of organic pollutants has been described in detail. © 2020 Elsevier Inc. All rights reserved.
Comparative study of dye degradation using TiO2-activated carbon nanocomposites as catalysts in photocatalytic, sonocatalytic, and photosonocatalytic reactor
(Taylor and Francis Inc., 2016) Pardeep Singh; M.C. Vishnu; Karan Kumar Sharma; Rishikesh Singh; Sughosh Madhav; Dhanesh Tiwary; Pradeep Kumar Mishra
In the present study, activated carbon-based TiO2 nanocomposites with carbon loading were synthesized by sol–gel method for photocatalytic, sonocatalytic, and sonophotocatalytic degradation of colored compound in wastewater. The prepared catalysts were characterized by Brunauer–Emmet–Teller surface area analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared analysis (FT-IR). The degradation efficiencies of the synthesized composites were determined by the degradation of Direct Blue-199 dye under three different reactors viz., photocatalytic, sonocatalytic, and sonophotocatalytic. Reaction kinetic modeling was done for these processes and the degradation rate was found maximum for sonophotocatalytic process as compared to individual ones. However, on considering the energy efficiency and degradation efficiency, photochemical reactor was found to be most economical. Therefore, for the treatment of wastewater-containing dye from industries, a photocatalytic process can be applied with further modification. © 2015 Balaban Desalination Publications. All rights reserved.
Current and emerging trends in bioremediation of petrochemical waste: A review
(Taylor and Francis Inc., 2017) Pardeep Singh; Rajat Jain; Neha Srivastava; Anwesha Borthakur; D.B. Pal; Rishikesh Singh; Sughosh Madhav; Pratap Srivastava; Dhanesh Tiwary; Pradeep Kumar Mishra
Various industries release harmful petrochemical contaminants into the environment. To treat these petrochemical contaminants at source, different physical, chemical, and biological methods have been proposed and applied worldwide. However, physical and chemical methods have their own advantages and limitations; in this review, we majorly focused on the biodegradation of petrochemical wastes. First, a background study on the literature available in this field is presented. Second is a review of the toxic effects of petrochemical waste and various physical and chemical processes, followed by elaborate biological processes available for petrochemical waste degradation. Further, different aspects of bioremediation, such as modes, factors, limitations, and future perspectives are critically reviewed and presented. It was found that most of the studies performed on bioremediation of petrochemical waste employed bacteria for the degradation purpose. Some studies also made use of algae, fungi, yeast, genetically modified organisms, biosurfactants, or a consortium of these microbes. Moreover, use of bioremediation is still limited at field scale due to certain limitations, which have been elaborated in this article. Overall, we strongly believe that with bioremediation capturing the attention of environmentalists worldwide, there is still a prevailing need to scale up from lab to land level applications and adaptations. © 2017 Taylor & Francis Group, LLC.
Effect of nanoscale TiO 2 -activated carbon composite on Solanum lycopersicum (L.) and Vigna radiata (L.) seeds germination
(Joint Center on Global Change and Earth System Science of the University of Maryland and Beijing Normal University, 2016) Pardeep Singh; Rishikesh Singh; Anwesha Borthakur; Pratap Srivastava; Neha Srivastava; Dhanesh Tiwary; Pradeep Kumar Mishra
The extensive use of nanoparticles under different industrial processes and their release into the environment are of major concerns in the present global scenario. In the present study, the effects of activated carbon-based TiO 2 (AC-TiO 2 ) nano-composite on the seed germination of Solanum lycopersicum (tomato) and Vigna radiata (mungbean) were investigated. The size of nanoparticles used in the study ranged from 30 to 50 nm, and their concentrations were from 0 to 500 mg L −1 . The composites were synthesized by sol–gel method and further characterized by scanning electron microscopy, Energy-dispersive X-rays spectroscopy (EDX), Raman spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction to investigate all the surface structural and chemical properties of AC-TiO 2 nano-composite. The results showed that increase in nano-composite concentration improves the germination rate and reduces germination time up to a certain concentration. Therefore, employing AC-TiO 2 nano-composites in suitable concentration may promote the seed germination and also reduce the germination time in Solanum lycopersicum and Vigna radiata. Further, it may help to understand the interface of TiO 2 nanoparticles with the environment and agriculture before its application to the field. © 2016, Joint Center on Global Change and Earth System Science of the University of Maryland and Beijing Normal University and Springer-Verlag Berlin Heidelberg.
Effect of Niobium Doping on Dielectric, Electrical and Magnetic Properties of Bismuth Copper Titanium Oxide
(Pleiades Publishing, 2025) Biswajit Jena; Anup Kumar; Dinesh Prajapati; Rajni Baranwal; Shail Upadhyay; Narsingh Bahadur R. Singh; Dhanesh Tiwary; Kamdeo Mandal
Abstract: Bi2/3Cu3Ti4 –xNbxO12 (BCTNO) ceramics with compositions x = 0.05, 0.10, and 0.20 were fabricated through a semi-wet route and sintered at 1173 K for 8 h. A detailed study was conducted to investigate the impact of Nb substitution on the structural, dielectric, electrical, and magnetic characteristics of BCTO. The synthesized Bi2/3Cu3Ti4 –xNbxO12 (x = 0.05, 0.10, and 0.20) ceramics were designated as BCTNO-0.05, BCTNO-0.10, and BCTNO-0.20, respectively. X-ray diffraction (XRD) investigation highlights the presence of all characteristic peaks of the pure BCTO compound, confirming the development of a single phase with a well-defined crystal structure upon Nb doping up to a composition of 0.20. Furthermore, the lattice parameter of the synthesized compounds is found to decrease with increasing Nb concentration. Field emission scanning electron microscopy (FE-SEM) was employed to assess the microstructural alterations in the synthesized BCTNO ceramics. High resolution transmission electron microscopy (HR-TEM) images revealed that the BCTNO ceramics’ particle sizes varied from 189 to 191 nm. The valence states of various ions present in the Nb-doped BCTO ceramics were analysed utilizing X-ray photoelectron spectroscopy (XPS). The dielectric permittivity (εʹ) and tangent loss (tan δ) of BCTNO ceramics were found to decrease with rising frequency. Impedance analysis provided confirmation of thermally activated ionic conduction within the ceramics. The magnetization (M) vs. Magnetic field (H) studies revealed antiferromagnetic behaviour at low temperature, with indications of weak ferromagnetism. © Pleiades Publishing, Ltd. 2025.
Emerging trends in photodegradation of petrochemical wastes: a review
(Springer Verlag, 2016) Pardeep Singh; Ankita Ojha; Anwesha Borthakur; Rishikesh Singh; D. Lahiry; Dhanesh Tiwary; Pradeep Kumar Mishra
Various human activities like mining and extraction of mineral oils have been used for the modernization of society and well-beings. However, the by-products such as petrochemical wastes generated from such industries are carcinogenic and toxic, which had increased environmental pollution and risks to human health several folds. Various methods such as physical, chemical and biological methods have been used to degrade these pollutants from wastewater. Advance oxidation processes (AOPs) are evolving techniques for efficient sequestration of chemically stable and less biodegradable organic pollutants. In the present review, photocatalytic degradation of petrochemical wastes containing monoaromatic and poly-aromatic hydrocarbons has been studied using various heterogeneous photocatalysts (such as TiO2, ZnO and CdS. The present article seeks to offer a scientific and technical overview of the current trend in the use of the photocatalyst for remediation and degradation of petrochemical waste depending upon the recent advances in photodegradation of petrochemical research using bibliometric analysis. We further outlined the effect of various heterogeneous catalysts and their ecotoxicity, various degradation pathways of petrochemical wastes, the key regulatory parameters and the reactors used. A critical analysis of the available literature revealed that TiO2 is widely reported in the degradation processes along with other semiconductors/nanomaterials in visible and UV light irradiation. Further, various degradation studies have been carried out at laboratory scale in the presence of UV light. However, further elaborative research is needed for successful application of the laboratory scale techniques to pilot-scale operation and to develop environmental friendly catalysts which support the sustainable treatment technology with the “zero concept” of industrial wastewater. Nevertheless, there is a need to develop more effective methods which consume less energy and are more efficient in pilot scale for the demineralization of pollutant. © 2016, Springer-Verlag Berlin Heidelberg.
Exploring temple floral refuse for biochar production as a closed loop perspective for environmental management
(Elsevier Ltd, 2018) Pardeep Singh; Rishikesh Singh; Anwesha Borthakur; Sughosh Madhav; Vipin Kumar Singh; Dhanesh Tiwary; Vimal Chandra Srivastava; P.K. Mishra
Religious faith and ritual activities lead to significant floral offerings production and its disposal as waste to the nearby open lands and water bodies. These activities result into various social and environmental nuisances because of their high organic content. Alternatively, it can be used as valuable resources for various biochemical and thermo-chemical processes. Floral refuse has been utilized in natural dye extraction, however, the residual solid refuse is of significant environmental concern due to its nutrient rich nature. This study explores the potential utilization of solid residue of temple floral refuse after natural dye extraction by thermo-chemical decomposition of it. The slow pyrolysis of solid residue was performed at 350 °C and 500 °C, and the biochar yield of 42 and 36% was obtained, respectively. TGA-DTG analysis was performed to observe the thermo-chemical behaviour of floral refuse. The biochar products were further characterized by FTIR, SEM, EDX, BET, XRD, and RAMAN spectroscopy to observe the impact of pyrolysis temperature (PT) on the resulting material, i.e. biochar and its possible application measures. EDX results revealed the presence of various macro-nutrients such as C, N, P, K Ca and Mg in different proportions which showed its soil amelioration potential. Moreover, based on the SEM and BET results, biochar prepared at 500 °C was further explored for adsorption of methylene blue dye at various dose and pH conditions. Based on Langmuir (R2 = 0.98) and Freundlich (R2 = 0.97) isotherms, it is found as a potential adsorbent material for removal of methylene blue dye. The results revealed that biochar conversion of colour extracted floral refuse can be a vital option for quick and efficient management of it in a closed loop approach. © 2018 Elsevier Ltd
Generation and Regeneration of the C(sp3)-F Bond and 1,4-NADH/NADPH via Newly Designed S-gC3N4@Fe2O3/LC Photocatalysts under Solar Light
(American Chemical Society, 2022) Satyam Singh; Rajesh K. Yadav; Tae Wu Kim; Chandani Singh; Pooja Singh; Surabhi Chaubey; Atul. P. Singh; Jin-Ook Baeg; Sarvesh K. Gupta; Dhanesh Tiwary
Due to the pharmaceutical, biological, physical, and chemical properties of fluorinated compounds and 1,4-NADH/NADPH, these species have attracted a lot of attention from researchers across the chemical society. Despite their crucial significance, present methods of regenerating cofactors (1,4-NADH/NADPH) as well as inserting fluorine into organic compounds suffer from ruthless drawbacks. Herein, we designed a highly efficient S-gC3N4@Fe2O3/LC photocatalyst, and its in situ generations were accomplished by calcinations of Fe2O3, melamine (M), thiophenol (T), and lignin carbon (LC). The Fe2O3part performs similar to an additional light harvester, gifting utmost photo-generated electrons, whereas the carbon part bridges a "thoroughfare" to make easy electron transfer from Fe2O3to S-gC3N4(Schemes 1 and 2). Therefore, the newly designed S-gC3N4@Fe2O3/LC photocatalyst is more efficient for the generation and regeneration of the C(sp3)-F bond and 1,4-NADH/NADPH due to its surface active sites and defects. © 2022 American Chemical Society. All rights reserved.
Inorganic Particulates in Removal of Toxic Heavy Metal Ions: Efficient Removal of Cadmium Ions from Aqueous Solutions by Hydrous Manganese Oxide
(R. Oldenbourg Verlag GmbH, 1998) Shuddhodan P. Mishra; Dhanesh Tiwary
Adsorption of cadmium ions from aqueous solutions of Cd(NO3)2 on hydrous manganese oxide (HMO) has been studied as a function of the contact time, concentration (10-2-10-7 M), temperature (303-333 K) and pH (2.80-11.80) of the Cd(II) solution employing 'radiotracer technique'. The results on adsorption of Cd(II) on HMO show that the removal process is essentially complete in ca. 2 h and the steady state values of adsorption at various concentrations agree well with the classical Freundlich adsorption isotherm. The temperature and pH of the bulk solution markedly affect the extent of adsorption and the process is thermodynamically irreversible. The exposure of HMO to neutrons and γ-radiations from a 11.1 GBq (Ra-Be) neutron source having 1.72 Gy/h dose rate or to a high radiation γ-cell (having mean dose rate 4.66 kGy/h) has practically no significant effect on the adsorption capacity of HMO.
Ion exchangers in radioactive waste management-V. A case of efficient removal of Ba(II) from aqueous solutions by TiO2 powder-radiotracer study
(1992) Shuddhodan P. Mishra; N. Srinivasu; Dhanesh Tiwary
The adsorption behaviour of Ba(II) on titanium(IV) oxide in an aqueous solution was studied by means of batch technique as a function of Ba(II) concentration, temperature and solution pH using Ba-140 as radiotracer. The results show that adsorption is essentially complete in ca 2 h and that the steady state values of adsorption at various concentrations agree well with the classical Freundlich isotherm and follow first order kinetics. The pH and temperature of the solution markedly affect the extent of adsorption. The nature and mechanism of adsorption are discussed. © 1992.
Ion Exchangers in Radioactive Waste Management. Part VIII: Radiotracer Studies on Adsorption of Strontium Ions on Hydrous Manganese Oxide
(1995) Shuddhodan P. Mishra; Dhanesh Tiwary
Hydrous manganese oxide (HMO) is exploited as adsorbent for the decontamination study of strontium ions from aqueous radio-active waste solutions under simulated conditions using batch technique. The dependences of removal on various physicochemical conditions, such as contact time, concentration, temperature and pH of the adsorptive solution, were established using radiotracer technique. The results show that adsorption essentially reaches a plateau value in ca. 90 min, and the data thus obtained fit well into the classical Freundlich adsorption isotherm over a wide range of concentrations (10-2 —10-7 M). Lower desorption values, little affected by increase in temperature, show the process to be irreversible. The exposure of HMO to neutrons and y-radiations from a 11.1 GBq neutron source up to certain periods results in a nominal change in sorption characteristics, indicating it be radiation-stable. © R. Oldenbourg Verlag, München 1995
Ion exchangers in radioactive waste management. Part XI. Removal of barium and strontium ions from aqueous solutions by hydrous ferric oxide
(Elsevier Science Ltd, 1999) Shuddhodan P. Mishra; Dhanesh Tiwary
The uptake of Ba(II) and Sr(II) by hydrous ferric oxide (HFO) was studied as a function of contact time, concentration, temperature and pH of the respective adsorptive solutions employing the 'radiotracer technique'. The uptake of both the ions was found to increase with the increase in concentration, temperature and pH of the adsorptive solutions. Concentration dependence data fitted well to the Freundlich adsorption isotherm over the entire range of concentration (10-2-10-7 M) and the uptake process followed first-order rate kinetics. The desorption experiments demonstrate the irreversible nature of the uptake process, however, in the presence of H+ ions, i.e. on acidification, an appreciable amount of metal ions were removed in the bulk solution. The radiation stability of hydrous ferric oxide towards the uptake of Ba(II) and Sr(II) was also examined by using samples of hydrous ferric oxide irradiated by neutrons and γ-rays prior to be employing as sorbents. The presence of some mono- and divalent co-ions along with the studied ions suppressed their removal appreciably.; The uptake of Ba(II) and Sr(II) by hydrous ferric oxide (HFO) was studied as a function of contact time, concentration, temperature and pH of the respective adsorptive solutions employing the 'radiotracer technique'. The uptake of both the ions was found to increase with the increase in concentration, temperature and pH of the adsorptive solutions. Concentration dependence data fitted well to the Freundlich adsorption isotherm over the entire range of concentration (10-2-10-7 M) and the uptake process followed first-order rate kinetics. The desorption experiments demonstrate the irreversible nature of the uptake process, however, in the presence of H+ ions, i.e. on acidification, an appreciable amount of metal ions were removed in the bulk solution. The radiation stability of hydrous ferric oxide towards the uptake of Ba(II) and Sr(II) was also examined by using samples of hydrous ferric oxide irradiated by neutrons and γ-rays prior to be employing as sorbents. The presence of some mono- and divalent co-ions along with the studied ions suppressed their removal appreciably.
Microplastic in the Aquatic Ecosystem and Human Health Implications
(wiley, 2022) Ankita Ojha; Ankitendran Mishra; Dhanesh Tiwary
xOver the past few decades plastic pollution has become a matter of grave concern, and combatting it has been challenging for environmentalists. Massive dumping of plastic wastes has undoubtedly created a threatening situation for aquatic ecosystems and human health. Microplastics (MPs) are defined as plastic fragments with a size <5â€‰mm in length that tend to stay in marine and freshwater systems. Their concentration varies from location to location, and so does their effect on human health. The capturing of these MPs has created a significant issue in the aquatic fauna. Their engulfment or entanglement by freshwater and marine animals makes their entry into the human food chain a certainty. Entering these MPs into the human system can create significant health impacts such as neural, renal, hepatic, and congenital disorders. They are not only harmful as such, but are known to be a potent carrier for many organic and inorganic pollutants. This chapter focuses on the rising impact of these MPs on human health and considers various organ systems that are affected by them. Some of the case studies and plausible solutions will also be considered while discussing these environmental hazards. © 2022 John Wiley & Sons Ltd. All rights reserved.
Modes of electron loss from triphenyl phosphonium bromide: An unusual structural switch
(Elsevier, 1996) Shuddhodan P. Mishra; Dhanesh Tiwary; Martyn C.R. Symons
The exposure of dilute solutions of triphenyl phosphonium bromide in CFClC3 to ionizing radiation at 77 K gave a species whose ESR spectrum was characteristic of the phosphoryl radical, Ph3P+ , with a small extra doublet splitting assigned to the H-Br proton. On annealing, these features were lost irreversibly and replaced by new features with large splitting from 1p and an extra quartet splitting from bromine without any resolved proton splitting. This change comprises the movement of a proton out of the 3 bonds on the righthand side sign P ··· H-Br σ region, whilst remaining bound to bromine (spin density on bromine: only ca. 25%).
Photocatalytic degradation of Acid Red dye stuff in the presence of activated carbon-TiO2 composite and its kinetic enumeration
(Elsevier Ltd, 2016) Pardeep Singh; M.C. Vishnu; Karan Kumar Sharma; Anwesha Borthakur; Pratap Srivastava; D.B. Pal; Dhanesh Tiwary; Pradeep Kumar Mishra
The present paper deals with photocatalytic degradation of effluents from dye industries which have known toxic impacts on flora and fauna. Nano composite of titanium dioxide having activated carbon (TiO2/AC) base was synthesized using sol-gel method. The synthesized catalyst was then characterized by Fourier Transform-Infrared (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM), X-ray Diffractometry (XRD) and Brunauer Emmet Teller (BET) surface area analyzer. A synthetic solution of AR-131 dye was subjected to photocatalytic degradation using TiO2/AC nano composite as catalyst. The degradation mechanisms of dye (AR-131) via photo-catalysis were found to follow a first order kinetics mechanism (vis. Langmuir- Hinshelwood Model). Toxicity of spent catalysts was further investigated in seed germination of Vigna radiata. Enhanced seed germination along with elongation of root and shoot was noticed up to the concentration of 500 ppm confirming its non toxicity. © 2016 Elsevier Ltd.
Plastic and Microplastic in the Environment: Management and Health Risks
(wiley, 2022) Arif Ahamad; Pardeep Singh; Dhanesh Tiwary
In Plastic and Microplastic in the Environment: Management and Health Risks, a team of distinguished environmental researchers delivers an up-to-date exploration of plastic and microplastic environmental contamination, conventional and advanced plastics management techniques, and the policies adopted across the globe to combat the phenomenon of plastics contamination. Containing a balanced focus on both conventional plastics and microplastics, this book discusses the potential health issues related to plastic and microplastic infiltration in a variety of global environments and environmental media, including freshwater environments, oceanic environments, soil and sediment, and air. Insightful treatments of commercial and social issues, including the roles of corporate social responsibility initiatives and general education in the fight against plastic and microplastic pollution, are provided as well. Plastic and Microplastic in the Environment also includes: A thorough introduction to plastic debris in global environments, including its accumulation and disintegration Comprehensive explorations of policies for strengthening recyclable markets around the world Practical discussions of the prevalence of microplastics in the marine environment, air, soil, and other environmental media In-depth examinations of wastewater treatment plants as a potential source point of microplastics, as well as conventional and advanced microplastic particle removal technologies Perfect for academics, postgraduates and advanced undergraduates in fields related to environmental science and plastics, Plastic and Microplastic in the Environment: Management and Health Risks will also earn a place in the libraries of professionals working in the plastics industries and environmental policymakers. © 2022 John Wiley & Sons Ltd. All rights reserved.