Department Of Environmental Science And Technology
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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 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 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.Item Recycling of lignocellulosic waste as vermicompost using earthworm Eisenia fetida(Springer, 2019) Sharma, K; Garg, V.K.Present study aimed to evaluate the vermicomposting of lignocellulosic wastes employing Eisenia fetida earthworms. The study examined the effectiveness of vermicomposting for 105 days by mixing lignocellulosic waste (LW) with cattle manure (CM) in five different proportions. Results revealed that TOC and C/N ratio decreased gradually till end and in vermicomposts varied between 268–320 g/kg and 12.26–16.85, respectively. Nutrient content (NPK) in the vermicomposts increased with time in all the mixtures. Heavy metals’ content also increased in vermicomposts and benefit ratio for heavy metals ranged between 0.06 and 5.1. Increase in earthworm biomass (22.38–39.64 g) and reproduction (21.27–31.60 hatchlings/worm) was also satisfactory in all the waste mixtures. Based on results, it can be inferred that lignocellulosic waste can successfully be converted into good quality manure employing earthworms. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.Item Source and background threshold values of potentially toxic elements in soils by multivariate statistics and GIS-based mapping: a high density sampling survey in the Parauapebas basin, Brazilian Amazon(Springer, 2019) Sahoo, Prafulla Kumar; Dall’Agnol, R; Salomão, G.N; da Silva Ferreira Junior, J; da Silva, M.S; Martins ,G.C; e Souza Filho, P.W.M; Powell, M.A; Maurity, C.W; Angelica, R.S; da Costa, M.F; Siqueira, J.O.A high-density regional-scale soil geochemical survey comprising 727 samples (one sample per each 5 × 5 km grid) was carried out in the Parauapebas sub-basin of the Brazilian Amazonia, under the Itacaiúnas Basin Geochemical Mapping and Background Project. Samples were taken from two depths at each site: surface soil, 0–20 cm and deep soil, 30–50 cm. The ground and sieved (< 75 µm) fraction was digested using aqua regia and analyzed for 51 elements by inductively coupled plasma mass spectrometry (ICPMS). All data were used here, but the principal focus was on the potential toxic elements (PTEs) and Fe and Mn to evaluate the spatial distribution patterns and to establish their geochemical background concentrations in soils. Geochemical maps as well as principal component analysis (PCA) show that the distribution patterns of the elements are very similar between surface and deep soils. The PCA, applied on clr-transformed data, identified four major associations: Fe–Ti–V–Sc–Cu–Cr–Ni (Gp-1); Zr–Hf–U–Nb–Th–Al–P–Mo–Ga (Gp-2); K–Na–Ca–Mg–Ba–Rb–Sr (Gp-3); and La–Ce–Co–Mn–Y–Zn–Cd (Gp-4). Moreover, the distribution patterns of elements varied significantly among the three major geological domains. The whole data indicate a strong imprint of local geological setting in the geochemical associations and point to a dominant geogenic origin for the analyzed elements. Copper and Fe in Gp-1 were enriched in the Carajás basin and are associated with metavolcanic rocks and banded-iron formations, respectively. However, the spatial distribution of Cu is also highly influenced by two hydrothermal mineralized copper belts. Ni–Cr in Gp-1 are highly correlated and spatially associated with mafic and ultramafic units. The Gp-2 is partially composed of high field strength elements (Zr, Hf, Nb, U, Th) that could be linked to occurrences of A-type Neoarchean granites. The Gp-3 elements are mobile elements which are commonly found in feldspars and other rock-forming minerals being liberated by chemical weathering. The background threshold values (BTV) were estimated separately for surface and deep soils using different methods. The ‘75th percentile’, which commonly used for the estimation of the quality reference values (QRVs) following the Brazilian regulation, gave more restrictive or conservative (low) BTVs, while the ‘MMAD’ was more realistic to define high BTVs that can better represent the so-called mineralized/normal background. Compared with CONAMA Resolution (No. 420/2009), the conservative BTVs of most of the toxic elements were below the prevention limits (PV), except Cu, but when the high BTVs are considered, Cu, Co, Cr and Ni exceeded the PV limits. The degree of contamination (Cdeg), based on the conservative BTVs, indicates low contamination, except in the Carajás basin, which shows many anomalies and had high contamination mainly from Cu, Cr and Ni, but this is similar between surface and deep soils indicating that the observed high anomalies are strictly related to geogenic control. This is supported when the Cdeg is calculated using the high BTVs, which indicates low contamination. This suggests that the use of only conservative BTVs for the entire region might overestimate the significance of anthropogenic contamination; thus, we suggest the use of high BTVs for effective assessment of soil contamination in this region. The methodology and results of this study may help developing strategies for geochemical mapping in other Carajás soils or in other Amazonian soils with similar characteristics. © 2019, Springer Nature B.V.Item Green synthesis, activation and functionalization of adsorbents for dye sequestration(Springer, 2019) Mudhoo, A; Gautam, R.K; Ncibi, M.C; Zhao, F; Garg, V.K; Sillanpää, M.The release of recalcitrant dyes into the biosphere is a threat because of pollution and environmental health issues. Adsorption using commercial activated carbon has been effective in industrial dye-loaded effluent remediation to some acceptable extent. However, commercial activated carbon suffers from limitations related to cost, relatively lower adsorption capacity, fewer microporous and mesoporous networks in comparison with other competing adsorbents, and reduced adsorption efficiency after regeneration. Here we review the recent developments in applying microwave irradiation, ultrasonication, ionic liquids and nanoscience for the preparation, activation, and physical, chemical and biological functionalization of novel and more potent adsorbents such as metal, mineral, carbon and polymer-based nanoparticles for dye removal. We observed that microwave and ultrasound irradiation and the use of ionic liquids are highly beneficial for the preparation of adsorbent materials; those adsorbents display enhanced porous structures and morphologies that account for much larger surface areas for faster adsorption interactions. Graphene-based, magnetic, cellulose-based and nanocomposite adsorbents are more selective and thermally more stable, faster in dye adsorption kinetics, have higher adsorption capacities for many dyes and can be regenerated for reuse without significant decrease in adsorption capacity. The scales of fabrication of green adsorbents do not go beyond the kilogram scale. © 2018, Springer Nature Switzerland AG.Item Biotransformation of bakery industry sludge into valuable product using vermicomposting(Elsevier, 2019) Yadav, A; Garg, V.K.The aim of present work was to evaluate periodic changes in bakery industry sludge during vermicomposting. Six different blends of cow dung (CD) and bakery industry sludge (BIS) containing 10 to 50% of BIS were assessed in this study. Changes in physico-chemical parameters were evaluated at 21 days interval up to 105 days. Earthworms significantly increased NPK content and EC, while decreased pH, TOC and C: N ratio of BIS. After vermicomposting, TKN, TAP and TK contents increased 2.0–3.5, 1.2–1.9 and 1.2–1.4 times, respectively as compared to initial blends. A significant reduction (65.4–83.5%) in C: N ratio was observed in all blends. The concentrations of metals were found to be higher in the vermicomposts as compared initial blends. It was inferred that bakery industry sludge spiked with cow dung can be biotransformed into valuable manure employing earthworms. © 2018 Elsevier LtdItem Application of EDTA modified Fe3O4/sawdust carbon nanocomposites to ameliorate methylene blue and brilliant green dye laden water(Academic Press, 2019) Kataria, N; Garg, V.K.This work explored the potential of magnetic sawdust carbon nanocomposites for cationic dyes removal from aqueous medium. EDTA modified magnetic sawdust carbon nanocomposites (EDTA@Fe3O4/SC ncs) were prepared by biogenic green reduction and precipitation approach. The surface properties, structure and composition of nanocomposites were characterized by HRTEM, FESEM, XRD, EDX, BET, FTIR etc. The Fe3O4 nanoparticles were 10–20 nm in diameters and having 14 m2/g surface area. Removal of Methylene blue (MB) and Brilliant green (BG) dyes from aqueous medium was studied in batch mode experiments. The maximum removal was achieved at neutral pH 7.0 with in 30 min. Adsorption capacity of EDTA@Fe3O4/SC for MB and BG dyes was 227.3 mg/g and 285.7 mg/g, respectively. Dye adsorption behaviour is well explained by Freundlich model. The rate of cationic dye adsorption is explained by pseudo-second order model. The value of thermodynamic parameters confirmed that adsorption process was spontaneous and favourable. Desorption and reusable efficiency of nanocomposites was also evaluated. © 2019 Elsevier Inc.