Department Of Environmental Science And Technology
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Item Co-transport and deposition of fluoride using rice husk-derived biochar in saturated porous media: Effect of solution chemistry and surface properties(Elsevier B.V., 2023-02-10T00:00:00) Kumar, Rakesh; Sharma, Prabhakar; Rose, Pawan Kumar; Sahoo, Prafulla Kumar; Bhattacharya, Prosun; Pandey, Ashok; Kumar, ManishFluoride (F?) contamination in water is a global health concern, threatening the well-being of millions. This study investigated the role of ZnCl2/FeCl3-rice husk-modified biochar (Zn-BC and Zn/Fe-BC) in treating F?-contaminated surface and groundwater under the influence of varying solution chemistry, co-existing ions, and biochar-amended through column transport experiments. Modified biochar showed maximum F? adsorption, 99.01% and 91.90% using Zn/Fe-BC and Zn-BC, respectively, than 85.87% using raw biochar (R-BC). Raw/modified biochars were characterized with FESEM-EDAX, FTIR, XRD, particle size, surface area, electro-kinetic potential, and point of zero charge analyses. Langmuir and pseudo-second-order kinetic could explain that F?-biochar interactions are dominated by chemisorption at ambient temperature while physisorption at higher temperatures. The influence of salt concentrations and co-occurring ions reduced F? sorption using Zn/Fe-BC. Increased salt strengths led to reduced electrophoretic mobility of biochar particles, i.e., biochar�biochar particles attract each other and increase the hydrodynamic diameter, which ultimately reduces the active sites on biochar for F? adsorption. Co-transport and deposition of biochar and F? in saturated porous media revealed lower mobility of biochar, and maximum F? adsorption was observed at 10 mM salt strength. Biochar transport is governed by electrostatic interactions, whereas F? transport mainly occurs through chemisorption. In rural areas, hand pumps and tube wells are generally used as source of potable water for drinking and cooking purposes; thus, biochar-mediated sand columns can be utilized for defluoridation. Thus, Zn/Fe-BC can be utilized as a potential bio-adsorbent for F?-contaminated natural surface and groundwater with optimum preparation and treatment costs. � 2023 The AuthorsItem Recent advances in biochar amendments for immobilization of heavy metals in an agricultural ecosystem: A systematic review(Elsevier Ltd, 2023-01-03T00:00:00) Sachdeva, Saloni; Kumar, Rakesh; Sahoo, Prafulla Kumar; Nadda, Ashok KumarOver the last several decades, extensive and inefficient use of contemporary technologies has resulted in substantial environmental pollution, predominantly caused by potentially hazardous elements (PTEs), like heavy metals that severely harm living species. To combat the presence of heavy metals (HMs) in the agrarian system, biochar becomes an attractive approach for stabilizing and limiting availability of HMs in soils due to its high surface area, porosity, pH, aromatic structure as well as several functional groups, which mostly rely on the feedstock and pyrolysis temperature. Additionally, agricultural waste-derived biochar is an effective management option to ensure carbon neutrality and circular economy while also addressing social and environmental concerns. Given these diverse parameters, the present systematic evaluation seeks to (i) ascertain the effectiveness of heavy metal immobilization by agro waste-derived biochar; (ii) examine the presence of biochar on soil physico-chemical, and thermal properties, along with microbial diversity; (iii) explore the underlying mechanisms responsible for the reduction in heavy metal concentration; and (iv) possibility of biochar implications to advance circular economy approach. The collection of more than 200 papers catalogues the immobilization efficiency of biochar in agricultural soil and its impacts on soil from multi-angle perspectives. The data gathered suggests that pristine biochar effectively reduced cationic heavy metals (Pb, Cd, Cu, Ni) and Cr mobilization and uptake by plants, whereas modified biochar effectively reduced As in soil and plant systems. However, the exact mechanism underlying is a complex biochar-soil interaction. In addition to successfully immobilizing heavy metals in the soil, the application of biochar improved soil fertility and increased agricultural productivity. However, the lack of knowledge on unfavorable impacts on the agricultural systems, along with discrepancies between the use of biochar and experimental conditions, impeded a thorough understanding on a deeper level. � 2023 Elsevier LtdItem Adsorption of Zn(II) on Pristine and SPLP/TCLP Leached Rice Straw Biochar: an Interplay of Precipitation and Ion Exchange(Institute for Ionics, 2022-11-15T00:00:00) Bhardwaj, Akanksha; Nag, Shilpa; Hussain, Khadim; Arora, Meenu; Pandey, Puneeta; Babu, J. NagendraThe inorganic mineral content in biochar influences the adsorption of Zn(II) metal ions. Metal ion adsorption on mineral rich rice straw biochar is influenced upon washing. Rice straw slow pyrolysis biochar BC1-3, respectively, prepared at 400, 500, and 600��C, were leached under Toxicity Characteristic Leaching Procedure (TCLP) and Synthetic Precipitation Leaching Procedure (SPLP) conditions to furnish BT1-3 and BS1-3, respectively. The Zn(II) adsorption studies were carried out for pH and dose optimization, initial concentration, isotherm fit, and kinetic studies. The Zn(II) adsorption by B(C/S/T)1�3 showed Langmuir and Freundlich isotherm, with pseudo-second-order kinetics at optimum pH 5 and dose 1�g/L. The adsorption of Zn(II) followed the trend BC3(qm 47�mg/g) > BC2 > BC1 > BS2 > BS1 > BS3 > BT2 > BT1 > BT3 (qm 3.5�mg/g), i.e., metal ion adsorption decreased with extent of leaching. The Zn(II) adsorption on biochar involved precipitation as dominant factor for metal ion adsorption on the biochars followed by ion exchange and proton exchange. The precipitation of Zn(II) ions in case of BC1-3 is attributed to the pH of biochar, which increases with proportion of minerals to organic content in biochar. In case of biochar BS1-3 and BT1-3, ion exchange and proton exchange mechanisms driven by demineralization are responsible for Zn(II) adsorption. The adsorption mechanism for Zn(II) on biochar is supported by XPS, solid state NMR studies. Graphical Abstract: [Figure not available: see fulltext.] � 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.Item Lignocellulosic biomass-based pyrolysis: A comprehensive review(Elsevier Ltd, 2021-08-06T00:00:00) K N, Yogalakshmi; T, Poornima Devi; P, Sivashanmugam; S, Kavitha; R, Yukesh Kannah; Varjani, Sunita; AdishKumar, S.; Kumar, Gopalakrishnan; J, Rajesh BanuThe efficacious application of lignocellulosic biomass for the new valuable chemicals generation curbs the excessive dependency on fossil fuels. Among the various techniques available, pyrolysis has garnered much attention for conversion of lignocellulosic biomass (encompasses cellulose, hemicellulose and lignin components) into product of solid, liquid and gases by thermal decomposition in an efficient manner. Pyrolysis conversion mechanism can be outlined as formation of char, depolymerisation, fragmentation and other secondary reactions. This paper gives a deep insight about the pyrolytic behavior of the lignocellulosic components accompanied by its by-products. Also several parameters such as reaction environment, temperature, residence time and heating rate which has a great impact on the pyrolysis process are also elucidated in a detailed manner. In addition the environmental and economical facet of lignocellulosic biomass pyrolysis for commercialization at industrial scale is critically analyzed. This article also illustrates the prevailing challenges and inhibition in implementing lignocellulosic biomass based pyrolysis with possible solution. � 2021Item Studies on the Use of Fly Ash and Crop Residue Biochar in Soil Amelioration and Nutrient Uptake in Wheat(Central University of Punjab, 2018) NAG, SHILPA; Garg, V.K. and Babu, J. NagendraCatalytic pyrolysis of rice straw using fly ash as catalyst was studied in various gravimetric proportions of 1:3, 1:1 and 3:1 (fly ash : rice straw, w/w). The thermogravimetric analysis (TGA ) of the thermal degradation of rice straw in presence of fly ash and its subsequent kinetic analysis by Coats-Redfern equation showed a decrease in the activation energy. The pyrolysis was conducted in a laboratory scale batch reactor maintained at 400, 500 and 600 oC pyrolysis temperatures under slow pyrolysis conditions (10 oC/min). The pyrolysis furnishes three components namely biochar/biochar-fly ash composites (35-90%), bio-oil (4-22%) and syn-gas (6-48%) characteristic of slow pyrolysis conditions. The syn-gas obtained from catalytic pyrolysis were analysed and characterized using GC-TCD analysis to reveal CO2, CH4 and H2 as the major constituents with no traces of CO observed is accounted to fly ash metal oxide catalysed CO to CO2 conversion. The bio-oil obtained from catalytic pyrolysis upon GC-MS analysis, showed an increase in depolymerization of lignin and fragmentation and dehydration of the carbohydrate residues as the major processes operative in presence of fly ash. The results were further affirmed by the Ultimate (CHNO) analysis, 1H-NMR and HSQC 2D-NMR analysis for the catalytic pyrolysis biooil. The biochar and biochar-fly ash composites were characterized for their Ultimate analysis, Functional groups (FTIR and Boehm Titration), SEM-EDS, physico-chemical properties (pH, EC, alkalinity, total phosphate), surface area, micronutrients and its leaching characteristics and Cu(II) adsorption. The O/C and H/C atomic ratios for biochar and biochar fly ash composites decreased with increase in the pyrolysis Name of student Shilpa Nag Registration Number CUP/MPh-PhD/SEES/EVS/2010-11/07 Degree for which submitted Doctor of Philosophy Supervisor Prof. (Dr.) V. K. Garg Co-Supervisor Name Dr. J. Nagendra Babu Department Centre for Environmental Science and Technology School of Studies School of Environment and Earth Sciences Key words Crop residue, Biochar, Fly ash, Soil, Wheat iv temperature. Functional group analysis further reiterated the results with oxygenated functional groups like lactone and carboxylic acids present at lower temperature biochar whereas only phenols were present in case of high temperature biochar. Biochar were alkaline and with increase in the fly ash content the pH of the composites tend to be less basic. Cu(II) adsorption was characteristically observed to increase with increase in the fly ash content in the biochar obtained from catalytic pyrolysis at 500 oC. The biochar and biochar-fly ash composites were ameliorated to soil and changes in the physicochemical properties namely pH, EC, CEC, water holding capacity, total Phosphorus and available Phosphorus, of soil were characterized. The biochar-fly ash composite also prepared externally using biochar obtained at various pyrolysis temperatures with fly ash, mixed in proportion as calculated for the catalytic pyrolysis biochar obtained. The soil ameliorated with biochar-fly ash composite prepared from catalytic pyrolysis were compared with the soil ameliorated with externally mixed biochar-fly ash composite for various soil physicochemical properties. The plant growth of Triticum aestivum was studied for the full crop cycle. The plant growth parameters namely – root length, shoot length, photosynthetic pigments, cellular respiration, antioxidant enzymes, crop height were studied. The results of the study were compared statistically using one way and two way ANOVA. The ANOVA analysis revealed that all the plant growth parameters tend to show a significant change with the biochar/biochar-fly ash composites obtained at various pyrolysis temperatures and their composition. Regression analysis revealed the significant change with all the chemical and biological properties measured at different stages of Triticum aestivum and biochar/biochar-fly ash composite ameliorated soil physicochemical properties. The parameters indicate oxidative stress in case of the plants grown on the biochar and biochar-fly ash ameliorated soils.Item Impact of rice-husk ash on the soil biophysical and agronomic parameters of wheat crop under a dry tropical ecosystem(Elsevier, 2019) Singh, R; Srivastava, P; Singh, P; Sharma, Archana Kumari; Singh, H; Raghubanshi, A.S.Several alternative amendments like organic manure and biochar have been proposed for revitalizing the degrading soil viability and fertility for sustainable agriculture, globally. However, detailed field-scale studies focussing on the soil and agronomic parameters of crops under these amendments are limited in dry tropical ecosystems. Therefore, we studied the impact of various soil amendments viz., rice-husk ash (RHA) and farm-yard manure (FYM) along with mineral fertilizer on soil biophysical and agronomic parameters of wheat crop. We specifically explored the impact of the amendments on soil CO2 efflux (SCE, under different growth stages) and the harvest index of wheat crop, which are considered as the key indicators of soil viability and agronomic efficiency, respectively. SCE, soil moisture, soil temperature, soil N, microbial biomass and soil pH were found significantly varying under different treatments (P < 0.05). SCE was found maximum under sole FYM applied and minimum under mineral fertilizer applied treatments, whereas RHA application lowered the SCE as compared to sole FYM application. Moreover, SCE showed variation with plant growth stages, and found maximum during stem elongation followed by heading stage whereas minimum during ripening stage. Soil moisture was found to have considerable regulation for the overall variation in SCE (r2 = 0.17; P = 0.04). In contrast to the soil properties, agronomic parameters (except harvest index) were found higher under mineral fertilizer applied treatments followed by sole FYM and combined FYM + RHA treatments, whereas sole RHA applied treatment showed minimum values. However, significant variations were observed only for harvest index, aboveground dry matter, grain and straw yields (P < 0.05). Further, harvest index was found highest under sole and combined FYM and RHA applied treatments whereas lowest in mineral fertilizer applied treatments. Soil C/N ratio (r2 = 0.16; P = 0.04) and panicle length (r2 = 0.18; P = 0.03), respectively as soil and agronomic parameters, have been found to have considerable control over harvest index. The findings revealed that soil viability is higher under sole FYM and combined FYM + RHA treatments whereas mineral fertilization enhances agronomic performance. Based on the studied two indicators, we conclude that both soil and agronomic sustainability can be maintained by using a combination of organic (FYM and RHA) fertilization with reduced inputs from mineral fertilizers. However, it further needs exploration for various soil and plant eco-physiological parameters of different crops at field level for wider adaptation in the dry tropical region. © 2018 Elsevier Ltd