Fabrication of ZnO–SnO2 nanocomposite and its photocatalytic activity for enhanced degradation of Biebrich scarlet

Environmental Science and Pollution Research - The n–n-type ZnO–SnO2 nanocomposite was fabricated using malic acid following a simple one-pot co-precipitation method. The fabricated...     

Bioleaching of metals from spent lithium ion secondary batteries using Acidithiobacillus ferrooxidans

Bioleaching of spent lithium ion secondary batteries, containing LiCoO2, was attempted in this investigation. The present study was carried out using chemolithotrophic and acidophilic bacteria Acidithiobacillus ferrooxidans, which utilized elemental sulfur and ferrous ion as the energy source to produce metabolites like sulfuric acids and ferric ion in the leaching medium. These metabolites helped dissolve metals from spent batteries. Bio-dissolution of cobalt was found to be faster than lithium. The effect of initial Fe(II) concentration, initial pH and solid/liquid (w/v) ratio during bioleaching of spent battery wastes were studied in detail. Higher Fe(II) concentration showed a decrease in dissolution due co-precipitation of Fe(III) with the metals in the residues. The higher solid/liquid ratio (w/v) also affected the metal dissolution by arresting the cell growth due to increased metal concentration in the waste sample. An EDXA mapping was carried out to compare the solubility of both cobalt and lithium, and the slow dissolution rate was clearly found from the figures.     

Role of blue green algae biofertilizer in ameliorating the nitrogen demand and fly-ash stress to the growth and yield of rice (Oryza sativa L.) plants

Rice is a major food crop throughout the world; however, accumulation of toxic metals and metalloids in grains in contaminated environments is a matter of growing concern. Field experiments were conducted to analyze the growth performance, elemental composition (Fe, Si, Zn, Mn, Cu, Ni, Cd and As) and yield of the rice plants (Oryza sativa L. cv. Saryu-52) grown under different doses of fly-ash (FA; applied @ 10 and 100 tha(-1) denoted as FA(10) and FA(100), respectively) mixed with garden soil (GS) in combination with nitrogen fertilizer (NF; applied @ 90 and 120 kg ha(-1) denoted as NF(90) and NF(120), respectively) and blue green algae biofertilizer (BGA; applied @ 12.5 kg ha(-1) denoted as BGA(12.5)). Significant enhancement of growth was observed in the plants growing on amended soils as compared to GS and best response was obtained in amendment of FA(10)+NF(90)+BGA(12.5). Accumulation of Si, Fe, Zn and Mn was higher than Cu, Cd, Ni and As. Arsenic accumulation was detected only in FA(100) and its amendments. Inoculation of BGA(12.5) caused slight reduction in Cd, Ni and As content of plants as compared to NF(120) amendment. The high levels of stress inducible non-protein thiols (NP-SH) and cysteine in FA(100) were decreased by application of NF and BGA indicating stress amelioration. Study suggests integrated use of FA, BGA and NF for improved growth, yield and mineral composition of the rice plants besides reducing the high demand of nitrogen fertilizers.     

An innovative technique for lake management with reference to aeration unit installed at lower lake, Bhopal, India

Water is key element in human life. All forms of life upon the earth depend upon water for their mere existence. Life & water may be aptly said to be two facets of the same coin. Most of the water bodies are getting polluted due to domestic waste, sewage, industrial waste and agricultural effluent. The present study is designed to ascertain the effectiveness of artificial aeration cum Ozonizer unit installed at Lower Lake, Bhopal for assessment of water quality. Various physico- chemical parameters like pH, Dissolved oxygen, Biochemical Oxygen demand, Chemical oxygen demand, nitrate, phosphate and bacteriological status were studied to assess the extent of deterioration in water quality of Lower lake and at the same time to assess the performance of the dual aeration system in improvement of water quality.     

Removal of congo red from aqueous solution by bagasse fly ash and activated carbon: kinetic study and equilibrium isotherm analyses

Present investigation deals with the utilisation of bagasse fly ash (BFA) (generated as a waste material from bagasse fired boilers) and the use of activated carbons-commercial grade (ACC) and laboratory grade (ACL), as adsorbents for the removal of congo red (CR) from aqueous solutions. Batch studies were conducted to evaluate the adsorption capacity of BFA, ACC and ACL and the effects of initial pH (pH(0)), contact time and initial dye concentration on adsorption. The pH(0) of the dye solution strongly affected the chemistry of both the dye molecules and BFA in an aqueous solution. The effective pH(0) was 7.0 for adsorption on BFA. Kinetic studies showed that the adsorption of CR on all the adsorbents was a gradual process. Equilibrium reached in about 4h contact time. Optimum BFA, ACC and ACL dosages were found to be 1, 20 and 2 g l(-1), respectively. CR uptake by the adsorbents followed pseudo-second-order kinetics. Equilibrium isotherms for the adsorption of CR on BFA, ACC and ACL were analysed by the Freundlich, Langmuir, Redlich-Peterson, and Temkin isotherm equations. Error analysis showed that the R-P isotherm best-fits the CR adsorption isotherm data on all adsorbents. The Freundlich isotherm also shows comparable fit. Thermodynamics showed that the adsorption of CR on BFA was most favourable in comparison to activated carbons.     

A Grey-Based Taguchi Approach for Characterization of Erosive Wear Phenomenon of Glass–Polyester Fly Ash Filled Composites

Fly ash is a solid waste generated in huge quantities from coal fired thermal power stations during the combustion of coal. In India, less than half of this is used as a raw material for concrete manufacturing and construction; the remaining is directly dumped on land side as land fill or simply piled up. Only a small fraction of it is used in development of high valued product. Due to environmental regulations, new ways of utilizing fly ash are being explored in order to safeguard the environment and provide useful ways for its utilization and disposal. With its richness in various metal oxides, it has tremendous potential to be utilized as a filler material in polymer composites. These days glass reinforced polyester composites find widespread application in erosive environment due to several advantages like high wear resistance, strength-to-weight ratio, and low cost. The cost of the composites can be further brought down using cheaper filler materials. To this end, this work uses fly ash in composite making and thereby suggests a new way of better utility of this industrial waste. It includes the processing, characterization and study of the erosion behavior of a class of such fly ash filled polyester-glass fiber composites. The engineering application of composites demands that it should have high wear resistance, low density and high tensile strength. In order to assess the behavior of composites satisfying multiple performance measures, a grey-based Taguchi approach has been adopted. After thorough analysis of factors, optimal factor settings have been suggested to improve multiple responses viz., erosive wear rate, density, flexural strength and tensile strength. This technique eliminates the need for repeated experiments; thus saves time and material. The systematic experimentation leads to determination of significant process parameters and material variables that predominantly influence the multiple responses.     

Desertification around Hirakud reservoir

Summary A comparative study of Survey of India topo-maps of 1929 and land satellite imageries in False Colour Combination (FCC) of 1975 indicates a loss of 43% and 46% of the reserved forest around Sambalpur and Jharsuguda respectively, besides other forest types in a radius of twenty miles. Deforestation is found to be an accelerating process where the rate of loss is estimated to be more during 1970–75 and 1960–70 in comparison to 1950–60 from a semilogarithmic trend curve between 1929 and 1975. This curve also fits to a hypothesis that the rate of deforestation is faster after 1950 (after developmental plan periods came into force). An analysis of the climatic data indicates a decrease in rainfall and number of rainy days, and morning relative humidity. The mean minimum and maximum temperature, evening relative humidity and atmospheric pressure show increasing trends. Relationships between forest loss and climatic parameters are significant for morning relative humidity, rainy days, maximum temperature and atmospheric pressure. Considering the loss of storage capacity of the Hirakud reservoir due to severe deforestation in the catchment area, suggestions are given for natural forest preservation. Arttabandhu Mishra graduated in Science (Zoology Honours) and Education from Utkal University; postgraduated from Berhampur University, India. At present he is a Lecturer in School of Life Sciences, Sambalpur University and Secretary of Orissa Environmental Consciousness Society. His fields of interests are Productivity and Energetics of Forest Ecosystems, Environmental Education and Community Education. He has published seven papers on the above fields and a number bf popular articles. He tries to use folk literature as media to carry scientific messages. Madhab C. Dash, obtained his B.Sc. (Hens), M.Sc. from Utkal University, India and Ph.D. from University of Calgary, Canada. At present he is Professor and Head, School of Life Sciences, Sambalpur University, a fellow of the Zoological Society of India, the National Institute of Ecology and the National Academy of Sciences, India. His major areas of research and writing are on the functional role of soil organisms in the decomposer subsystem of ecosystems, He has published seventy-five papers on taxonomy, biology, population ecology, metabolic functions, energy flow modelling, role in soft fertility and waste conditioning ability of Oligochaetes, nematodes, protozoa and soil microorganisms. Professor Dash has contributed specialised chapters in major treaties published by Cambridge University Press, UK; John Wiley and Sons, USA; and Academic Press, New York, USA.     

Inequality in water supply in India: an assessment using the Gini and Theil indices

Provision of drinking water is considered to be an essential public service. Ensuring adequate water supply remains a challenge in Indian cities that are experiencing rapid growth and often exhibit a mismatch between increasing demands and inadequate supply infrastructure. This study quantifies the existing inequality in water supply within Indian cities through Lorenz curve, Gini coefficient as well as Theil indices. Two types of Theil indices are estimated to gain different perspectives: water supply and population-weighted. Both the Theil indices are disaggregated, according to economic and regional categorisation of the cities, to explore the within- and between-group inequality. The water supply and population-weighted Theil indices provide different outlook of the inequality amongst the cities. But the population-weighted index is often better and pragmatic. Further, the inequality in access to tap water in India is studied by estimating modified Lorenz curves and Theil indices. Again, the Theil indices are decomposed into within and between components according to economic and regional grouping of states. The results suggest that there is disparity in supply of water in India, and infrastructure has to be boosted to meet the growing demand. This study is a step towards quantification of water supply inequality. The approach used in the study can contribute to monitoring of water supply equity as well as in formulating sustainable and equitable water policies.     

Application of remote sensing techniques toward the role of traditional water bodies with respect to vegetation conditions

Sri Lanka being an agrarian country, the role of water is important for agricultural production. In Sri Lanka, various tank cascade systems, earthen dams and distribution canals have been accepted as few of the most complex ancient traditional water systems of the world. Rainfall, surface water, groundwater and runoff are linked with each other, they have close interactions to land cover classes such as forests and agriculture. The monitoring of vegetation conditions can show subsurface manifestations of groundwater. In this study, an effort to understand the role of traditional water reservoirs and groundwater recharge was made using remote sensing techniques. We have analyzed various vegetation indices such as Normalized Difference Vegetation Index (NDVI), Enhanced Vegetation Index (EVI-2), Soil-Adjusted Vegetation Index (SAVI), tasselled cap transformation analysis (TCA brightness, greenness and wetness) and their relations with the existence of soil, vegetation and water. Result shows that EVI, SAVI, and TCA-based Greenness Index indicates good relationship with the vegetation conditions as compared to other indices. Therefore, these indices could play a crucial role in depicting the interaction between soil, vegetation, and water. However, multi-temporal observations can provide significant results about these interactions more accurately.     

Characterization and pollutant removal efficiency of biochar derived from baggase,bamboo and tyre

Conversion of broad-spectrum organic waste into carbonaceous biochar has gained enormous interest in past few years. The present study aims to characterize feedstock (FS), i.e. bagasse (Bg), bamboo (Bm) and biochar (BC), i.e. baggase biochar (BBg), bamboo biochar (BBm) and tyre biochar (Ty). Significant changes in elemental composition, atomic ratio, proximate analyses, mineral content and heavy metal content were observed which was well supported by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis. Impregnation with ferric hydroxide was done, and resultant modified biochars (MBC), i.e. iron-impregnated baggase biochar (FeBBg), iron-impregnated bamboo biochar (FeBBm) and iron-impregnated tyre biochar (FeTy), along feedstock and biochar were used for PO₄ ^3?, Pb, Hg and Cu adsorption. In general, BBg, FeBBg, BBm, FeBBm, Ty and FeTy were found to adsorb PO₄ ^3?, Pb, Hg and Cu better than Bg and Bm, except in few cases. Results from adsorption experiments were fitted into Langmuir, Freundlich and Temkin models of isotherms and pseudo-first-order, pseudo-second-order and Elovich models of kinetics. Result of batch study adsorption revealed that maximum adsorption of PO₄ ^3?, Pb, Hg and Cu was done by FeBBg (adsorption mechanism explained by Freundlich model), FeTy (Temkin model), Ty (Langmuir model) and BBm (Langmuir model) respectively. According to R ² values, pseudo-first-order reaction was well suited to PO₄ ^3?, Pb, Hg and Cu adsorption. The optimum pH for maximum adsorption was observed to be 7.4 for PO₄ ^3?, 5 for Cu and 6 for Pb and Hg respectively