School Of Environment And Earth Sciences
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Item EVALUATION OF ALGINATE MAGNETIC NANOPARTICLE BEADS FOR IMMOBILIZATION OF QUORUM QUENCHING BACTERIA ISOLATED FROM DAIRY INDUSTRY WASTEWATER TO ALLEVIATE BIOFOULING(Central University of Punjab, 2019) Kaur, Jaskiran; K.N., YogalakshmiMembrane fouling is one of the prominent problem of membrane bioreactors (MBR) during wastewater treatment. Biofouling caused by the bacterial biofilm formation on the membrane surface is considered as one of the major contributor of the overall membrane fouling process. Reduction in hydraulic performance; increase in transmembrane pressure (TMP) and shortening of membrane’s life span are some of the widely encountered adverse effects of biofouling on membrane systems. Various approaches including membrane backwashing, cleaning of membranes employing numerous chemicals, variation in hydrodynamic conditions and membrane modification have been explored to mitigate fouling. But membrane biofouling being a complex multistage process is not effectively eradicated by these approaches. Additionally, the problems of chemical toxicity, foulant accumulation within membrane pores also facilitates the need for development of effective technologies for biofouling control. Bacterial acyl homoserine (AHL) based quorum sensing (QS) mechanism is considered as the regulatory phenomenon for biofilm formation. However, these signalling molecules are disrupted by a special group of bacteria termed the quorum quenching bacteria through the phenomena of quorum quenching (QQ). This phenomenon has been recognized as a promising method to control the problem of membrane biofouling. The QQ bacteria co-exist with the QS bacteria in a wide variety of habitats including rhizosphere, sewage, soil and many other sources but the occurrence of QQ bacteria in dairy waste activated sludge (WAS) remains unexplored. Keeping this in view, an attempt has been made to investigate the potential of QQ bacteria isolated from the dairy WAS collected from Verka milk industry effluent treatment plant situated in Bathinda, Punjab. The QQ bacteria showing higher AHL degrading potential was chosen to alleviate biofouling in MBR. Since, the bacteria are known to have low survival rate in the free-state, they were v immobilized onto the magnetic iron nanocomposite carriers. The nanoparticles in the magnetic nanocomposite beads possessed enough magnetic strength to enable their easy separation from the MBR during operation. The QQ bacteria present in dairy WAS was enriched in the KG medium supplemented with n-hexanoyl homoserine lactone (C6-HSL) as a sole source of carbon and nitrogen. Five bacterial isolates obtained after enrichment were identified as Klebsiella pneumoniae (JYQ1 and JYQ5), Acinetobacter baumannii JYQ2, Pseudomonas nitroreducens JYQ3, and Pseudomonas JYQ4 through 16S ribosomal deoxyribonucleic acid (16S rDNA) analysis. These isolates were submitted in Genbank under accession numbers KP189202 (JYQ1), KP340458 (JYQ2), KP340459 (JYQ3), KU555415 (JYQ4), and KP780263 (JYQ5). The C6-HSL degrading ability of the isolated QQ bacteria was determined quantitatively and qualitatively through biosensor (using Chromobacterium violaceum CV026) assay and GC-MS analysis, respectively. All the five isolates exhibited decolourization zone around the Chromobacterium violaceum CV026 spotted lawns indicating C6-HSL degradation. Maximum degradation percentage of 83.8% was shown by Pseudomonas JYQ4 within 6 h of incubation. Other isolates Klebsiella pneumoniae JYQ1 and JYQ5 showed around 81.5% and 81.4% of C6- HSL degradation, respectively within 24 h of incubation. Pseudomonas nitroreducens JYQ3 degraded 68.4% of C6-HSL in 12 h of exposure. The isolate Acinetobacter baumannii JYQ2 possessed both QS and QQ activity which is evident from its degradation percentage. The isolates Klebsiella pneumoniae JYQ1 and JYQ5 due to their pathogenic nature were exempted and the other three QQ bacterial isolates (Acinetobacter baumannii JYQ2, Pseudomonas nitroreducens JYQ3 and Pseudomonas JYQ4) were immobilized onto the IMN beads by encapsulating magnetic iron nanoparticles and QQ bacteria in sodium alginate mixture. The magnetic iron nanoparticles prepared by co-precipitation method were cubical in shape and ranged in size from 5-19 nm. The FTIR analysis indicated the presence of Fe and O functional groups in the nanoparticles. The nanoparticles exhibited polycrystalline structure with crystallite size of around 6.9 nm and saturation magnetization of 39 emu g-1 . The successful immobilization of QQ bacteria onto the magnetic nanocomposite beads was confirmed through the SEM analysis. The QQ bacteria IMN beads also showed C6-HSL degradation potential. Confirming the preliminary studies, the Pseudomonas JYQ4 IMN beads exhibited the maximum C6-HSL degradation of 90% within 6 h of incubation when compared to other isolates whose degradation percentage varied in the range between 73- 90%. The IMN beads of bacterial consortium (prepared by mixing JYQ2, JYQ3 and JYQ4) showed degradation percentage of 73.9%. The efficiency of QQ bacteria IMN beads in controlling the biofilm developed by Pseudomonas aeruginosa 3541 was then assessed. The SEM analysis demonstrated the growth of less number of bacterial cells on the surface of QQ IMN beads incubated membranes when compared to control. Among the different QQ IMN beads, Pseudomonas JYQ4 IMN beads indicated better biofilm reduction ability. Furthermore, the CLSM analysis confirmed the efficiency of QQ bacteria IMN beads in controlling the biofilm growth and development when compared to control which exhibited signs of Pseudomonas aeruginosa 3541 biofilm maturation in 10 vi days. Among the different QQ bacteria and consortium IMN beads incubated membranes, Pseudomonas JYQ4 IMN beads incubated membranes showed no signs of biofilm maturation till 30 days of incubation. The isolates Acinetobacter baumannii JYQ2 and consortium incubated membrane showed signs of biofilm maturation within 20 days, respectively unlike Pseudomonas nitroreducens JYQ3 that showed biofilm maturation in 30 days. The biofilm structural elucidation by COMSTAT software further supported the results of CLSM analysis by showing less biomass (0.015± 0.001 µm3 /µ2 ) and more surface to biovolume ratio (0.93± 0.003 µm2 /µ3 ) for biofilm developed by Pseudomonas aeruginosa 3541 in 30 days incubation period with Pseudomonas JYQ4 IMN beads when compared to control membrane that showed biomass volume of 0.06± 0.003 µm3 /µ2 and surface to biovolume ratio of 0.21± 0.005 µm2 /µ3 . Microcolony development and biofilm growth is indicated by more biomass volume and lesser surface to biovolume ratio. Further, the flux measurement of the incubated membranes confirmed the delayed biofilm formation in membranes incubated with Acinetobacter baumannii JYQ2, Pseudomonas nitroreducens JYQ3, Pseudomonas JYQ4 and consortium IMN beads that showed 10.4%, 17.7%, 20.3% and 8.1% higher flux, respectively compared to control. The potential of QQ bacteria IMN beads in controlling the biofilm formation by the sludge bacteria was also tested. The light microscopy analysis of glass slides incubated with QQ bacteria IMN beads revealed a significant reduction in the number of sludge bacterial cells when compared with the control slide (without IMN beads). Pseudomonas JYQ4 IMN beads were more efficient in controlling biofilm formation followed by Pseudomonas nitroreducens JYQ3, Acinetobacter baumannii JYQ2 and consortium. The CLSM analysis of the QQ bacteria IMN beads incubated membranes exhibited the less amount of biofilm on the membranes compared to control. Similar to Pseudomonas aeruginosa 3541 studies, Pseudomonas JYQ4 delayed the biofilm maturation up to 30 days showing better biofilm controlling ability compared to other isolates. The biomass volume and surface to biovolume ratio of sludge bacteria biofilm developed on the Pseudomonas JYQ4 IMN beads incubated membrane was calculated to be around 0.019± 0.015 µm3 /µ2 and 0.85± 0.65 µm2 /µ3 , respectively. The control 1 (without IMN beads) incubated membranes however, showed biomass volume of 0.065± 0.061 µm3 /µ2 and surface to biovolume ratio of 0.18± 0.14 µm2 /µ3 , respectively whereas control 2 (blank nanoparticle beads) incubated membranes showed biomass volume of 0.06± 0.02 µm3 /µ2 and surface to biovolume ratio of 0.16± 0.38 µm2 /µ3 , respectively. The flux studies showed that Pseudomonas JYQ4 IMN beads incubated membranes showed 22% higher flux followed by Pseudomonas nitroreducens JYQ3 (19% higher), Acinetobacter baumannii JYQ2 (16% higher) and consortium (12.6% higher) compared to control membranes within 30 days incubation. The efficiency of the QQ bacteria IMN beads in biofouling control was also investigated in MBR. A submerged aerobic MBR with polyethersulfone hollow fiber membrane of pore size 0.4 µm and working volume of 4.5 L was used for the study. The MBR was operated at hydraulic retention time (HRT) and flux of 8h and 12.5 L/ (m2h), respectively. Synthetic dairy industry wastewater with COD of 4800± 40 mg/L was used as substrate in MBR. The MBR performance was evaluated at three different MLSS (i.e.) 4000, 7000 and 10,000 mg/L. The MBR showed removal efficiencies in the range of 95.6- 99.2% for COD removal; 55.7- 88.4% for TSS removal; 93.6- 94.6% for NH3-N removal and 25.5- 33.2% for phosphate removal at vii the MLSS 4000, 7000 and 10,000 mg/L. The performance of MBR in terms of effluent quality remained the same in QQ-MBR and showed no significant change in removal efficiencies. The membrane fouling potential at three different MLSS (i.e.) 4000, 7000 and 10,000 mg/L were assessed through tightly bound (TB-EPS), loosely bound (LBEPS) and soluble EPS polysaccharides and proteins. At MLSS of 4000 mg/L, the polysaccharides and protein fraction in TB-EPS varied between 32- 42.6 mg/L and 34.2- 50.7 mg/L, respectively which increased to 59.9- 71.3 mg/L and 61.6- 80.3 mg/L at 7000 mg/L MLSS; and 76.6- 92.6 mg/L and 85.9- 115.9 mg/L at 10,000 mg/L MLSS. Likewise, the LB-EPS polysaccharides and proteins were in the range of 11.7- 17.7 mg/L and 38.5- 56.1 mg/L at 4000 mg/L MLSS; 25.5- 36.2 mg/L and 81.1- 115.9 mg/L at 7000 mg/L MLSS; and 40.4- 58.5 mg/L and 124.6- 186.5 mg/L at 10,000 mg/L MLSS. The polysaccharides and proteins in soluble EPS also increased with increase in MLSS and was observed to be 23.4- 31.8 mg/L and 30.3- 48.1 mg/L at 4000 mg/L MLSS; 40.2- 53.2 mg/L and 56.3- 75 mg/L at 7000 mg/L MLSS; and 56.4- 72.3 mg/L and 77.9- 101.1 mg/L at MLSS 10,000 mg/L. Among all the EPS, TB-EPS and LB-EPS showed higher levels of polysaccharides and proteins, respectively. TMP also showed continuous increase and reached 29.8 kPa during MLSS 10,000 mg/L. When the QQ-MBR (Pseudomonas nitroreducens JYQ3 and Pseudomonas JYQ4 IMN beads) was assessed, it showed decreased EPS production in terms of polysaccharide and protein fractions of TB-EPS, LB-EPS and soluble EPS. During the operation of QQ-MBR at 4000 mg/L, 75.3% and 63.2% decrease in polysaccharide and proteins fractions of TB-EPS was observed compared to that of control MBR. Likewise, the QQ-MBR showed 64% and 77% lower LB-EPS and soluble EPS polysaccharides, respectively. The protein of LB-EPS and soluble EPS decreased by 62.2% and 68.7%, respectively in QQ-MBR at MLSS of 4000 mg/L. At MLSS 7000 mg/L, the polysaccharide in TB-EPS, LB-EPS and soluble EPS reduced by 69.7%, 63.1% and 72.3% when compared to control MBR. Similarly, around 57.3%, 63.4% and 61.7% reduction in the protein fraction of TB-EPS, LBEPS and soluble EPS, respectively was attained in the QQ-MBR. At MLSS 10,000 mg/L, the QQ-MBR showed a decrease of around 57.3% and 42.7% in TB polysaccharides and proteins fractions, respectively. LB polysaccharides and proteins reduced by 52.2% and 59.5% and soluble polysaccharides and proteins showed a decrease of around 60.7% and 40.3% in the QQ-MBR at 10,000 mg/L MLSS compared to control. Also, the QQ-MBR showed comparatively slower TMP rise than control MBR. The results concluded that the QQ bacteria Pseudomonas nitroreducens JYQ3 and Pseudomonas JYQ4 can be used effectively for interrupting the QS mechanism in bacteria for controlling the membrane biofouling problem in MBR.Item SLUMS IN LUDHIANA AND BATHINDA CITIES OF PUNJAB: A SOCIO-GEOGRAPHICAL ANALYSIS(Central University of Punjab, 2019) Kaur, Amandeep; Singh, Kiran KumariWellbeing of slum dwellers needs efficient delivery of basic amenities and facilities. Over many decades several programmes and policies have been implemented to ensure decent quality of life to the slum dwellers but parts of many cities are still in the state of deprivation from basic amenities. This study analyses the status of available basic amenities and facilities in two cities of Punjab: Ludhiana and Bathinda. The study also highlighted the effectiveness of policies and programs in slums of both the cities. Field survey was conducted in different phases to collect data on eight basic amenities and facilities in slum areas. The study did not only brought out the status of availability of basic amenities but also analysed the level of satisfaction of the slum dwellers. The study also focused on the gender wise participation of slum dwellers in urban economic activities by examining the factors influencing their participation. The desirable data for the present study was collected from secondary and primary sources. The secondary data for the study was collected from publishes and unpublished resources such as Punjab Municipal Infrastructure Development Company, Municipal Corporations and Town and Country Planning departments of Ludhiana and Bathinda cities, research papers, articles, books, newspapers and other web sources. The primary data was collected through interview schedule and check list from selected notified and non-notified slums of Ludhiana and Bathinda cities. The collected data was analysed by using various statistical methods like descriptive statistics, multiple regression, simple probit and Student’s t test (two tailed). The study revealed that the overall condition of non-notified slums is more severe in iv terms of availability of basic facilities as compare to notified slums. Finding of the study for two cities suggest that slums of Bathinda city are in poor conditions of sewerage and solid waste management and slums of Ludhiana city lack government healthcare facilities, government schools, roads and public transport facilities. The finding calls for urgent attention to ensure the basic amenities in slums of both the cities. The study also advocates to shift the focus of plans and policies towards delivery of basic amenities and services keeping in view the quality of life of slum dwellers. The study brought up suitable recommendations for the upgradation of slums and efficient delivery of basic infrastructures and services in slums.Item WETLAND IN SOCIO-ECONOMIC AND GEOGRAPHICAL CONTEXTS: A STUDY OF HARIKE, ROPAR AND NANGAL WETLANDS(Central University of Punjab, 2019) Kumar, Gaurav; Singh, Kiran KumariWetland ecosystem is regarded as one of most productive system of the earth surface due to its inclusive nature to supports a variety of flora and fauna. There are a number of functions and services provided by the wetland ecosystem which includes purification of water, protection from floods, groundwater replenishment, woods for fuel and commercial uses, fish resources, recreational and social services. Therefore, the study is an attempt to evaluate the socio-economic significance of wetland area and their relation with the livelihood activities of local people in Harike, Ropar and Nangal wetlands of Punjab. The economic value of the wetland products and services have been calculated from direct use value which employed different methods. The study also focused on the threat perceptions related to impact of human developmental activities inside the wetland boundaries. The people participation for the conservation and management of the wetland area has also been studied through their willingness to pay for such actions. The data desirable for the present study are collected from both secondary and primary sources. The secondary data for the study has been collected from published and unpublished resources such as from Department of Forest and Wildlife Preservation (Punjab), Department of Forest and Wildlife preservation (Firozpur), Department of Forest and Wildlife Preservation (Ropar), Harike Sanctuary Office, Punjab State for Science and Technology (PSCST), ENVIS, articles, research papers, newspapers, books and other internet resources. The Primary data has been collected through interview schedule of the iv people of selected villages/towns falling within one kilometre buffer zone around the Harike, Ropar and Nangal wetlands. The collected data are analysed by using statistical methods like descriptive statistics, regression and probit model. The study came up with suitable recommendations for conservation of wetland.Item Water chemistry and estimation of background levels of elements in surface water bodies from a protected area in the vicinity of Fe deposits, Southeastern Amazon(Taylor and Francis Inc., 2020) Teixeira, S.S; Dall' Agnol, R; Sahoo, P.K; Salomão, G.N; Guimarães, J.T.F; Costa, M.This paper aimed to provide the knowledge of water chemistry and quality and background values of the elements in surface waters around the Fe-ore deposits of N3 and N4WSul of Serra dos Carajas, Brazil. Water samples were collected from 17 monitoring points monthly/quarterly between 2013 and 2016 and the elemental analyses were carried out using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The waters are slightly acidic to slightly alkaline in nature and are classified into "good" and "optimum" water quality category. Seasonal variation impacted water quality, with significantly higher content of metals (such as Fed, Fet, and Ald) during the rainy period that is due to more intense surface-runoff and leaching. Comparing with CONAMA 357/05/WHO limits, nonconformities were mainly observed for pH, Fe and Mn, and in some cases for Ald, Znt, Cud, Cdt and Znt, and were significantly higher in the N4WSul area than in the N3. Although, Fe and Mn mostly enter the water bodies from catchment weathering, the poor correlation between Fe and Mn indicated that their source and transport processes are different. In fact, elevated Mnd concentrations associated with low DO content in the dry period are explained by a reductive dissolution of manganese oxides via bacterial decomposition of OM. The background threshold values (BTVs) of elements were estimated by the upper 95% simultaneous limit (USL95; using ProUCL software) and the median ± 2 Median Absolute Deviation (mMAD) method, while the former was considered as the most suitable method for defining BTVs. The BTVs for Al(d), Fe (d), Mn and Zn are mostly exceeding the maximum limits stipulated by the legislation. However, since these areas are located in a protected region, these values are seen as representative of the natural conditions of the study area and reflect geogenic influence. - 2020, - 2020 Informa UK Limited, trading as Taylor & Francis Group.Item Geochemical mapping in stream sediments of the Carajas Mineral Province: Background values for the Itacaiunas River watershed, Brazil(Elsevier, 2020) Salomao, G.N; Dall'Agnol, R; Sahoo, P.K; Angelica, R.S; de Medeiros, Filho C.A; Ferreira, Junior J.D.S; Sousa da, Silva M; Souza Filho, P.W.M.E; Nascimento, Junior W.D.R; da Costa, M.F; Guilherme, L.R.G; Siqueira, J.O.D.Multi-elemental analysis of high-density (regional-scale) geochemical surveys is an important strategy for multi-purpose applications, particularly in addressing geochemical background concentrations in different sampling media. This approach was applied to the Itacaiunas River Watershed (IRW), which is situated in the most prominent mining area of Brazil, the Carajas Mineral Province. Microcatchment-based mapping (~50 km2 each) covering the whole extent of IRW was delimited using remote sensing techniques and targeted for sampling. A total of 788 samples, including 27 duplicates, were collected in 2017. The <0.177 mm fraction of all samples was digested by aqua regia and 51 elements were analyzed by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Geochemical maps for Fe and potentially toxic elements (PTE; As, Ba, Cd, Co, Cr, Cu, Hg, Mn, Mo, Ni, Pb, Sn, V, and Zn) and microcatchment-based distribution maps based on threshold values were constructed for the whole IRW. The stream sediment geochemistry is mainly controlled by the local geologic setting and underlying lithology. Geochemical background (GB) values for 43 elements in stream sediments of the IRW were determined by a variety of methods (Tukey's inner fences -TIF, median +- 2*median absolute deviation - MAD, and percentile-based techniques). The results provided from the different methods show a wide range of values, with the MAD method being considered the most appropriate for deriving GB concentrations. A comparison of reference levels for PTE contemplated in the Brazilian regulation in stream sediments, the threshold concentrations obtained for the IRW area, and different study cases around the world is presented in detail. Our findings provide not only valuable information for selecting potential areas for mineral exploration surveys, but also for evaluating geochemical contaminant effects with time-varying treatments. Studies conducted to determine background values at regional scale are needed for environmental decision making, as well as to attest actions in cases of potential contamination. In the absence of these studies, misleading interpretations of the magnitude of contamination levels in a certain area may cause under- or overestimation of ecological and/or human-health risks of PTE. - 2020 Elsevier LtdItem Late-Holocene climate response and glacial fluctuations revealed by the sediment record of the monsoon-dominated Chorabari Lake, Central Himalaya(SAGE Publications Ltd, 2020) Shukla, T; Mehta, M; Dobhal, D.P; Bohra, A; Pratap, B; Kumar, A.We studied a periglacial lake situated in the monsoon-dominated Central Himalaya where an interplay of monsoonal precipitation and glacial fluctuations during the late Holocene is well preserved. A major catastrophe occurred on 16-17 June 2013, with heavy rains causing rupturing of the moraine-dammed Chorabari Lake located in the Mandakini basin, Central Himalaya, and exposed 8-m-thick section of the lacustrine strata. We reconstructed the late-Holocene climatic variability in the region using multi-parametric approach including magnetic, mineralogical and chemical (XRF) properties of sediments, paired with grain size and optically simulated luminescence (OSL) dating. The OSL chronology suggests that the lake was formed by a lateral moraine during the deglaciation phase of Chorabari Glacier between 4.2 and 3.9 ka and thereafter the lake deposited about 8-m-thick sediment sequence in the past 2.3 ka. The climatic reconstruction of the lake broadly represents the late-Holocene glacial chronology of the Central Himalaya coupled with many short-term climatic perturbations recorded at a peri-glacial lake setting. The major climatic phases inferred from the study suggests (1) a cold period between 260 BCE and 270 CE, (2) warmer conditions between 900 and 1260 CE for glacial recession and (3) glacial conditions between ~1370 and 1720 CE when the glacier gained volume probably during the 'Little Ice Age" (LIA). We suggest a high glacial sensitivity to climatic variability in the monsoon-dominated region of the Himalaya. The Author(s) 2020.Item The hazardous 2017-2019 surge and river damming by Shispare Glacier, Karakoram(Nature Research, 2020) Bhambri, R; Watson, C.S; Hewitt, K; Haritashya, U.K; Kargel, J.S; Pratap, Shahi A; Chand, P; Kumar, A; Verma, A; Govil, H.In 2017-2019 a surge of Shispare Glacier, a former tributary of the once larger Hasanabad Glacier (Hunza region), dammed the proglacial river of Muchuhar Glacier, which formed an ice-dammed lake and generated a small Glacial Lake Outburst Flood (GLOF). Surge movement produced the highest recorded Karakoram glacier surface flow rate using feature tracking (~18 ± 0.5 m d−1) and resulted in a glacier frontal advance of 1495 ± 47 m. The surge speed was less than reports of earlier Hasanabad advances during 1892/93 (9.3 km) and 1903 (9.7 km). Surges also occurred in 1973 and 2000-2001. Recent surges and lake evolution are examined using feature tracking in satellite images (1990-2019), DEM differencing (1973-2019), and thermal satellite data (2000-2019). The recent active phase of Shispare surge began in April 2018, showed two surface flow maxima in June 2018 and May 2019, and terminated following a GLOF on 22-23 June 2019. The surge likely had hydrological controls influenced in winter by compromised subglacial flow and low meltwater production. It terminated during summer probably because increased meltwater restored efficient channelized flow. We also identify considerable heterogeneity of movement, including spring/summer accelerations. 2020, The Author(s).Item Assessment of surface water and groundwater interaction using hydrogeology, hydrochemical and isotopic constituents in the Imphal river basin, Northeast India(Elsevier, 2020) Kshetrimayum, K.S; Laishram, P.The surface water and groundwater interaction in the Imphal River Basin in Northeast India using hydrogeology, hydrochemical and isotopic constituents has examined to elucidate hydrochemical evolution, surface water and groundwater mixing and recharge condition. Groundwater is characterized by Ca2+Cl - HCO3 -facies while surface water exhibits Ca2+ Cl- type. Surface water prevailed the intermediate stage of chemical evolution while groundwater characterizes the late stage of chemical evolution. Analysis of flow net combined with hydrogeologic sections revealed significant relationship of surface water and groundwater in the basin. The upper and lower reaches are characterized by contour heads showing an upstream pointing curvature due to depression induced by groundwater discharge where contour lines cross a gaining stream. The middle reach is marked by contour curvature pointing downstream owing to mounding induced by groundwater recharge where it crosses a losing stream. Groundwater shows markedly depleted isotopic composition than surface water. Both surface water and groundwater fall below Global Meteoric Water Line and Local Meteoric Water Line indicating the source of water through infiltratio,n of modern precipitation. The slope of the evaporation line and the original composition of water are identified as 4.92 and 6.58‰ and 42.17‰, respectively. Isotopic d-excess values revealed isotopic composition of semi-arid climate. 2020 Elsevier B.V.Item Pb2+ and Cd2+ recovery from water using residual tea waste and SiO2@TW nanocomposites(Elsevier, 2020) Joshi, S; Kataria, N; Garg, V.K; Kadirvelu, K.This work reports the fabrication of SiO2@TW nanocomposites and their application for Pb2+ and Cd2+ ions sequestration from simulated water. Residual tea waste has also been used for metal ions sequestration to compare the potential of SiO2@TW nanocomposites. The SEM, TEM, BET, FTIR and EDX techniques were employed for the characterization of SiO2@TW nanocomposites and residual tea waste. Particle sizes of SiO2@TW nanocomposites was in the range of 6.8-12 nm. The experiments were carried out in batch mode to explore the effect of various operating parameters on the sequestration of Pb2+ and Cd2+ ions from water. The experimental data was subjected to various thermodynamic, kinetic and isothermic models. According to Langmuir model, the maximum adsorption efficiency of the SiO2@TW nanocomposites was 153 mg/g for Pb2+ and 222 mg/g for Cd2+ but maximum adsorption efficiency of residual tea waste for Pb2+ was 125 mg/g and for Cd2+ was 142.9 mg/g. This study suggested that due to the presence of active sites SiO2@TW nanocomposites has greater potential for metal sequestration than residual tea waste. 2020 Elsevier LtdItem Green synthesized SiO2@OPW nanocomposites for enhanced Lead (II) removal from water(Elsevier B.V., 2020) Saini J.; Garg V.K.; Gupta R.K.The orange peel waste (OPW) was chemically spiked with silica nanospheres, to develop a novel, nanocomposite (SiO2@OPW) with enhanced adsorption capacity for heavy metals. The dispersion of silica nanospheres into orange peel waste was confirmed by XRD, FTIR, TEM, SEM and EDX. Adsorption of Pb2+ ions onto SiO2@OPW was studied in batch mode under varying process conditions such as pH, metal concentration, contact time and adsorbent dosage. The maximum adsorption capacity for OPW and SiO2@OPW was 166.7 mg/g and 200.0 mg/g, respectively calculated employing the Langmuir isotherm model. The kinetic data followed pseudo second order and intraparticle diffusion models. The maximum removal of Pb2+ ions was at pH = 6.0, adsorbent dosage = 0.02 g/L and contact time 60 min. Regeneration and reusability of SiO2@OPW was studied for five cycles. Owing to reusability and high adsorption capacity, SiO2@OPW nanocomposites may be considered as a promising adsorbent for the removal of heavy metals from water and wastewater.