BITS Faculty Publications
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Item Aluminium terephthalate (Al-BDC) based metal organic framework decorated carboxymethylated filter cloth for defluoridation application(Elsevier, 2023-06) Chatterjee, SomakCurrent work adopts a novel approach for deposition of aluminium terephthalate-based metal organic framework (MOF) on carboxymethylated filter paper for defluoridation purpose. Aluminium terephthalate-based MOF was prepared using an optimized technique and showed a fluoride uptake capacity of 665 mg/g. However, due to its low yield, synthesized MOF was immobilized on carboxymethylated filter paper, using hydrothermal method. MOF immobilized filter paper (MOF cloth) showed a fluoride uptake capacity of 88 mg/g. Different surface-based characterization for MOF and MOF cloth were performed. Synthesized MOF was quasi-spherical in shape, forming flower like structures, when coalesced together and it showed crystalline property, having lattice fringes of 0.2 nm. Uniform and dense distribution was observed during its deposition process on filter paper. Both functional groups and mineralogical phases present in the MOF were also imparted to the immobilized filter paper. Uptake of fluoride by MOF cloth was governed by monolayer adsorption, as evident from Langmuir isotherm analysis. Uptake capacity increased with temperature and the highest one was recorded at 318 K. Prepared MOF cloth was subjected to dynamic studies via glass-funnel based filtration, where, effects of pH, coexisting ions including an organic pollutant and real-life feed were carried out. Regeneration of the MOF cloth was also studied for four cycles. Leaching study was performed at different time intervals. Finally, comparison was made with different conventional MOF based adsorbents and it was observed that this cloth can be an adaptable and pollution free medium for defluoridation applications.Item Polyaniline-doped sawdust as a promising adsorbent for defluoridation(Elsevier, 2023-11) Chatterjee, SomakFluoride’s presence in groundwater is a growing concern, especially where access to safe drinking water is limited. Traditional water treatment methods have limitations in effectively removing fluoride. Thus, there is a need for an alternative, sustainable and cost-effective solution. This study develops an adsorbent where a conducting polymer (PAni) will be coated on agricultural byproduct (sawdust) for defluoridation application. Introduction of amino-tris-methylene-phosphonic acid (ATMPA) as a dopant into PAni enhances its exchange mechanism, thereby increasing its uptake capacity (58 mg/g). Potential application of this adsorbent lies in water treatment plants, which will cater needs of industry, mankind and agricultureItem Undoped polyaniline-modified sawdust as an adsorbent for lead removal(Elsevier, 2023-12) Chatterjee, SomakHeavy metal ion adsorption employing abundant natural and agricultural wastes appears to be promising. Biodegradable sawdust is promoted as a green and sustainable alternative. In this work, potential application of sawdust has been explored for uptake of lead ions from contaminated water. Specifically, undoped polyaniline, a highly conductive polymer, was added to sawdust to improve its uptake capacity. Highest lead uptake capacity of 218 mg/g was observed at 318 K. Different surface-based characterizations for this material were performed. Morphology of prepared sawdust revealed a one-dimensional flake-like structure having a porous nature. FTIR and XRD analysis inferred successful incorporation of polyaniline into sawdust. In addition, XPS analysis revealed the importance of polyaniline chains during electrostatic adsorption of lead ions. At an adsorbent dosage of 1 g/l, optimal equilibrium conditions were reached. In accordance with Langmuir isotherm analysis, lead ion uptake was mainly driven by monolayer adsorption. As-prepared adsorbent was subjected to batch studies, where, effects of pH and interfering ions were carried out. Regeneration was also studied for four cycles.Item Polyacrylonitrile and polyethersulfone based co-axial electrospun nanofibers for fluoride removal from contaminated stream(Elsevier, 2024-02) Chatterjee, SomakCoaxial electrospun polyacrylonitrile (PAN) and polyethersulfone (PES) based nanofibers were prepared and was used for filtration of fluoride from drinking water for the first time. Well defined fiber geometry was obtained at 1 ml/h of core polymer, i.e., PES flow rate, 1.4 ml/h of shell polymer, i.e., PAN flow rate, voltage of 22 kV, while the distance between the needle tip and the collector was 15–17 cm. Increase in bead like structure in fiber strands was observed with higher PAN concentration, while it decreased for lower PES concentration, thereby giving an optimum composition (6 wt% PAN and 10 wt% PES) for uniform fiber morphology. This nanofiber, abbreviated as N2 acted as an ultrafiltration membrane having permeability in the lower range, i.e., 0.5 × 10−11 m/s Pa and its fluoride removal efficacy was 46%. Fibers were also hydrophilic with considerable porous nature. Uptake of fluoride by this N2 nanofibers were evident from binding energy of 685.2 eV during XPS analysis. It is probable that nitrile and sulfone groups present in the core and shell of the nanofibers played an active in fluoride uptake, which was estimated as 110 mg/g at 298 K. Isoelectric point was in alkaline range which promoted negative fluoride ion uptake on positive nanofiber surface. Lead played higher masking effect in the uptake of fluoride in comparison to arsenic as coexisting ion. Dynamic cross flow filtration was also studied with this nanofiber in both synthetic and real life feed solution.Item Theoretical investigation of cross flow ultrafiltration by mixed matrix membrane: A case study on fluoride removal(Elsiever, 2015-06-01) Chatterjee, SomakSelective membrane filtration with high throughput can be achieved using mixed matrix membrane (MMM). The application of MMM in integrated membrane processing requires a continuous mode of operation. Therefore, understanding the mechanism of cross flow ultrafiltration of MMM is important from the design and operational point of view. Theoretical analysis based on first principles presented in this study takes into account the simultaneous occurrence of adsorption in the matrix and spatially developing concentration polarization layer over the membrane surface. The change in the filtration regime from adsorption dominated to diffusion governed can be identified. The developed model is validated with cross flow ultrafiltration experiments of fluoride contaminated solution using activated alumina MMM, for different operating conditions. The impact of the adsorption isotherm constants on the system performance is also evaluated.Item Adsorptive removal of potentially toxic metals (cadmium, copper, nickel and zinc) by chemically treated laterite: Single and multicomponent batch and column study(Elsiever, 2017-08) Chatterjee, SomakEfficiency of chemically treated laterite was tested to remove, copper, cadmium, zinc and nickel (potentially toxic metals) from drinking water. Infrared spectroscopy confirms the uptake of these contaminants by treated laterite. Optimum treatment parameters are observed at 10 mg/L adsorbent concentration, 0.26 mm particle size and pH range of 6–9. Maximum uptake capacities are observed to be 3.7 mg/g (0.03 mmol/g), 2.8 mg/g (0.04 mmol/g), 2.8 mg/g (0.04 mmol/g) and 2 mg/g (0.03 mmol/g), for cadmium, copper, zinc and nickel, respectively. Adsorption was endothermic and physical in nature. Fixed bed column study was carried out using a multicomponent feed having concentration 5 mg/L of each potentially toxic metal, and the effect of bed depth and flow rate were observed. Corresponding to a specific process condition, saturation was faster for nickel followed by zinc, cadmium and copper. The column was also tested for a real-life toxic metal contaminated river sample, collected from Yamuna River, New Delhi (GPS location 30° 54/N and 76° 59/E).Item A socio-economic study along with impact assessment for laterite based technology demonstration for arsenic mitigation(Elsiever, 2017-04-01) Chatterjee, Somak; Bhattacharjee, SaikatArsenic contamination mitigation technologies have been adsorption-based, but the most widely-used and traditionally available adsorbents suffered inherent limitations, including cost infeasibility and problems associated with regeneration and disposal of the spent adsorbent. The present technology is based on indigenously developed activated laterite prepared from the naturally and abundantly available material, and can hence easily be scaled up for community usage and large scale implementation. The total arsenic removal capacity is 32.5 mg/g, which is the highest among all naturally occurring arsenic adsorbents. A major issue in earlier adsorbents was that during regeneration, the adsorbed arsenic would be released back into the environment (leaching), and would eventually contaminate the groundwater again. But the adsorbent in this filter does not require regeneration during its five-year lifespan and does not leach upon disposal.Item Chelating polyacrylonitrile beads for removal of lead and cadmium from wastewater(Elsiever, 2018-03) Chatterjee, SomakChelating polyacrylonitrile beads were prepared using phase inversion of polymeric drops in water bath, followed by treatment in sodium hydroxide solution. Applicability of these beads was tested to remove lead and cadmium from contaminated stream. The uptake capacity was 145 mg/g for lead and 156 mg/g for cadmium. Morphology showed that the porosity of the beads decreased upon treatment. Rapid weight loss was noticed in the range of 266–568 °C, during thermal analysis. Infrared studies showed that the nitrile group was rearranged to carboxyl and amine group due to hydrolysis of polyacrylonitrile beads, attracting the heavy metals electrostatically. Maximum removal of lead and cadmium was obtained at 5 g/L and neutral pH. Adsorption was exothermic and chemisorption in nature. Adsorption kinetics showed that the equilibrium was achieved within 600 min. The uptake capacity of individual heavy metals, i.e., lead and cadmium was reduced in multicomponent mixture due to competitive adsorption. Maximum desorption was obtained at acidic pH and the regenerated beads were successfully used for three cycles. The prepared beads were also tested using battery industry effluent, from Exide Industries Ltd., Haldia, West Bengal, India.