BITS Faculty Publications

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    Magnesium oxide nanoparticles-cellulose acetate based composite beads for lead uptake from contaminated stream: Experimental and DFT based study
    (Elsevier, 2026-02) Garg, Mohit; Chatterjee, Somak
    Groundwater, a primary source of drinking water, is becoming increasingly contaminated with toxic heavy metals, particularly lead. The unregulated discharge of industrial effluents into water bodies further exacerbates the problem. Accordingly, an effective system is required to treat these pollutants. Although there are existing solutions with certain challenges, this study aims to develop efficient composite polymeric beads composed of cellulose acetate and magnesium oxide nanoparticles for effective removal of lead from contaminated water. Prepared beads were spherical, synthesized by the phase inversion of polymer solution with the help of a needle-syringe assembly. As-prepared beads were characterized based on its morphological and chemical characteristics, revealing porous texture with considerable crystallinity. Presence of Pbsingle bondO bond in FTIR spectra post lead adsorption highlighted synergy between lead ions and Mgsingle bondOH groups. Uptake mechanism involved the substitution of hydrogen ions by lead ions, resulting in the formation of stable Mgsingle bondOsingle bondPb complexes. This was facilitated by lead's lower electronegativity in contaminated water. Lead uptake by composite beads was governed by monolayer adsorption as evident from isotherm studies. A maximum uptake capacity of 500 mg/g was observed at 298 K, which increased to 600 mg/g at 318 K. Optimum dosage of 1 g/l was identified as ideal for achieving equilibrium conditions. Thermodynamic parameters confirmed that the adsorption process was spontaneous and endothermic in nature. Regeneration studies showed effective reusability up to two cycles, after which the removal capacity reached saturation. Isoelectric point was obtained at a pH value of 9.7. Presence of MgO helped in stabilising lead ions and prevented precipitate formation in alkaline medium, providing a minor reduction in lead removal, as compared to conventional adsorbents. Furthermore, Density functional theory (DFT) based simulation was performed suggesting collective indication of consistent trends, with both approaches converging towards the same adsorption behaviour and Pbsingle bondO interaction patterns.
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    Rare shungite carbon, carbon nanotubes and magnesium oxide nanoparticle based composite paste electrode for electrochemical lead ion detection
    (Elsevier, 2026-02) Roy, Banasri; Chatterjee, Somak
    Composite paste was synthesized using magnesium oxide nanoparticles with shungite carbon and multi-walled carbon nanotubes, to formulate two-electrode sensor, facilitating lead detection in aqueous stream. A uniform and homogeneously dispersed composite paste was obtained using the powder with a binder, i.e., silicone oil. Working electrode only comprises magnesium oxide nanoparticles, which was paired with reference electrode to measure potential against various lead concentration. Various factors including concentration of MgO, electrolyte pH, temperature, electrode-separation, detection time and real water sample analysis were examined to optimize sensor's performance. Most effective sensor was then chosen for electrochemical characterizations, which include, cyclic voltammetry, electrochemical impedance spectroscopy, differential pulse voltammetry across different electrolyte concentrations, i.e., lead. Amperometric analysis evaluated influence of co-existing ions, whereas leachate solution studies quantified ion content from working electrode. Electrochemically active surface area and surface coverage areas were measured as 0.022 cm2 and 0.036 cm2, and 2.85 mM.cm−2 and 2.39 mM.cm−2 for unmodified and modified electrodes. Sensor exhibited quasi-reversible behavior with sensitivities of 2.75 mA.cm−2.mg.L−1 and 0.0275 mA.cm−2.mg.L−1, along with detection limits of 0.3 μg.L−1 and 57 μg.L−1 over dynamic ranges. This performance, combined with low fabrication cost (~31.6 US$.g−1), presents a competitive and economical alternative against different commercial lead sensors.
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    Graphene oxide-iron oxide based thin film nanocomposite membrane for congo red dye removal and simultaneous salt recovery from aqueous stream
    (Springer Nature, 2025-11) Roy, Banasri; Chatterjee, Somak
    Current work focusses on the synthesis of iron oxide impregnated-graphene oxide incorporated polyvinylidene fluoride based thin-film nanocomposite (TFN) membrane and its application in Congo Red dye removal. Interfacial polymerization with 0.02 wt% graphene oxide significantly improved performance of prepared TFN membranes, achieving over 94% rejection of dye with permeability of 3.6 l/m2·h·bar. Testing performance of the membrane was further validated in the presence of real-life feed wastewater, showing 72% dye rejection over 12 h, while an enhanced 94% rejection was achieved with synthetic dye solution. Superior performance was observed in removal of dissolved solids, conductivity, salinity, nitrate, sulfate and dyes compared to commercial nanofiltration membranes. Effect of different operating conditions on membrane performance were examined, confirming its robust nature. Comprehensive characterization of prepared membrane revealed its superiority in texture and chemical nature. Optimized TFN membrane demonstrated recovery efficiency of 70% for sodium chloride and magnesium sulfate solutions, indicating its potential for desalination approach. Thermal regeneration and long-term filtration studies were conducted to evaluate membrane’s lifespan, indicating long-term durability and effectiveness in industrial applications. Studies also indicated weight loss of 62% over two months, which corroborated biodegradable nature of the membrane samples after exhaustion.
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    Layered double hydroxide based composite core–shell electrospun nanofibers for lead and fluoride filtration from contaminated streams
    (RSC, 2025-04) Chatterjee, Somak
    Coaxial electrospinning was used to synthesize polyacrylonitrile–polyethersulfone (PAN–PES) core–shell nanofibers with magnesium–aluminum layered double hydroxide (Mg–Al LDH) for filtration of lead and fluoride from contaminated streams. Fiber geometry was characterized at a 0.5 mL h−1 flow rate for the core polymer (PES/LDH) and 0.8 mL h−1 flow rate for the shell polymer (PAN), with a potential of 23 kV and a distance of 15–17 cm between the collector and the needle head. A homogeneous fiber shape was achieved using an optimal LDH concentration of 0.7%. The prepared nanofibers served as an ultrafiltration membrane with a permeability of 5 × 10−12 m s−1 Pa−1. The uptake capacity of the produced nanofibers for fluoride and lead was estimated to be 948 mg g−1 and 196 mg g−1, respectively at 298 K as per Langmuir's isotherm model. These fibers exhibited hydrophilic properties and possessed a significant level of porosity. XPS study revealed binding energies of 139.3 eV and 685.2 eV, indicating lead and fluoride uptake by the nanofibers. Ether, sulfone, hydroxyl and nitrile groups found in the nanofibers' shell and core most likely contributed to the lead and fluoride uptake. This facilitated the uptake of both ions on the surface of the nanofibers. In terms of the inhibition effect, fluoride had a stronger masking effect compared with lead in a multicomponent solution (consisting of lead and fluoride). Dynamic vacuum filtration was also investigated using the prepared nanofibers in artificial and real-life feed solutions.
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    Application of composite membrane-based technology in treatment of textile industry effluents
    (Springer, 2025-02) Chatterjee, Somak
    Technological innovations have repeatedly made our lives easier over the centuries. Supplies have increased manifold to compete with growing consumer demands. For example, textile industries serve untired to meet the expectations of their end-user by gradually increasing the production. It is mainly characterized by fabric, which essentially starts with fibers, that is processed into making yarns and finally combined. These intermediate steps in a textile plant require huge quantity of freshwater feed, which is eventually converted to an effluent, containing colouring dyes, toxic chemicals and insoluble wastes. Additionally, functional textiles require water-repellent, anti-fungal agents and non-crease fabrics, which are persistent contaminants, thereby adding to environmental degradation. Conventional treatment methods, such as, adsorption, coagulation, oxidation, etc., are employed for their removal. However, these methods have associated limitations. This chapter discusses about a novel approach, i.e., composite membrane-based removal technique, which can prove to be an economic and feasible option for treatment of textile effluents.
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    Aluminium terephthalate (Al-BDC) based metal organic framework decorated carboxymethylated filter cloth for defluoridation application
    (Elsevier, 2023-06) Chatterjee, Somak
    Current 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.
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    Polyaniline-doped sawdust as a promising adsorbent for defluoridation
    (Elsevier, 2023-11) Chatterjee, Somak
    Fluoride’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 agriculture
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    Undoped polyaniline-modified sawdust as an adsorbent for lead removal
    (Elsevier, 2023-12) Chatterjee, Somak
    Heavy 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.
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    Polyacrylonitrile and polyethersulfone based co-axial electrospun nanofibers for fluoride removal from contaminated stream
    (Elsevier, 2024-02) Chatterjee, Somak
    Coaxial 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.
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    Carbonaceous catalysts (biochar and activated carbon) from agricultural residues and their application in production of biodiesel: A review
    (Elsevier, 2024-03) Chatterjee, Somak; Roy, Banasri
    Carbonaceous catalysts obtained from agricultural residue could have potential in the production of biofuels such as biodiesel. This review paper discusses the preparation conditions (temperature, heating rate, hold time, inert gas flow rate, etc play key roles in development of textural characteristics of the catalysts) and functionalization methods of biochar and activated carbon derived from agricultural residues and their application to produce biodiesel. Research works reported in achieving maximum yield of biodiesel in terms of variable precursors, alcohol-to-oil ratio, reaction time and temperatures have been profoundly tabulated. Effect of textural properties of the biochar and activated carbon (such as surface area, total pore volume, average pore size, and functional group attached with the catalyst) on the biodiesel yield are examined. Studies on Regeneration and reusing of the spent catalysts are carefully inspected. The economic evaluation studies for the biochar and activated carbon and the applications of these for biodiesel production are scrutinized. Finally, the strategies to increase biomass and catalyst productivity, future prospect and research directions to enhance biofuel/biodiesel production and for the development of biochar and activated carbon from agricultural residues for sustainable biodiesel production is suggested.