Faculty Publications
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Item Bed depth service time model for the biosorption of reactive red dye using the Portunus sanguinolentus shell(2010) JagadeeshBabu, P.E.; Krishnan, R.; Singh, M.Biosorption is an efficient and regenerative technique that often uses low-cost adsorbent materials, particularly for the treatment of wastewaters containing dyes and heavy metals. This study investigates the ability of crab shell (Portunus sanguinolentus) to remove reactive red dye in a packed bed up-flow column (internal diameter 2 cm; height 35 cm). Crab shell has high surface area (after proper size reduction) and high regenerative capacity. The experiments were performed with different bed heights (20 and 30 cm) and using different flow rates (12 and 17 ml/min) in order to obtain experimental breakthrough curves. The bed depth service time (BDST) model was used to analyze the experimental data and the model parameters were evaluated. The column regeneration studies were carried out for five different sorption-desorption cycles. The elutant used for the regeneration of the sorbent was 0.01 M EDTA (disodium) solution at pH 9.8 adjusted using NH4OH. This solution was found to have the best bed regeneration capacity and could be reused for several sorption-desorption cycles. The elution efficiency was greater than 99.1% in all seven cycles. Continuous use of the crab shell leads to a decrease in the adsorptive performance, as observed by the breakthrough curves becoming flatter and also because of a broader mass transfer zone. © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.Item Cadmium (II) and nickel (II) biosorption by Bacillus laterosporus (MTCC 1628)(Taiwan Institute of Chemical Engineers, 2014) Kulkarni, R.; Shetty K, V.; Srinikethan, G.Biosorption of heavy metals is a promising technology that involves removal of toxic metals from industrial waste streams and natural waters. The study describes the sorption of cadmium (II) [Cd (II)] and nickel (II) [Ni (II)] by dead biomass of Bacillus laterosporus, MTCC 1628. The biosorption conditions for the removal of Cd (II) and Ni (II) were examined by studying the effect of pH, contact time, biosorbent dosage and initial metal ion concentration. Shake flask studies yielded adsorption equilibrium in almost 120. min, for both the metals. It was found from Langmuir model that the maximum adsorption capacity for Cd (II) and Ni (II) ions was 85.47. mg/g and 44.44. mg/g respectively. Kinetic evaluation of the experimental data showed that the biosorption process followed pseudo-second order kinetics. Thermodynamic analysis showed that biosorption is an endothermic process with ?. H° of 5.45. kJ/mol for Cd (II) biosorption and 24.33. kJ/mol for Ni (II) biosorption. The surface characteristics of B. laterosporus biomass before and after metal biosorption were analyzed by using scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDAX) to study the changes in surface morphology and elemental constitution of the adsorbent. B. laterosporus exhibited a higher and better potential biosorbent for the removal of Cd (II) as compared to Ni (II) from aqueous solution. © 2013 Taiwan Institute of Chemical Engineers.Item Studies on biosorption of methylene blue from aqueous solutions by powdered palm tree flower (Borassus flabellifer)(2014) M Kini, M.S.; Saidutta, M.B.; Ramachandra Murty, V.R.Biosorption experiments were carried out for the removal of methylene blue (MB) using palm tree male flower (PTMF) as the biosorbent at various pH, temperature, biosorbent, and adsorbate concentration. The optimum pH was found to be 6.0. The kinetic data were fitted in pseudofirst-order and second-order models. The equilibrium data were well-fitted in Langmuir isotherm and the maximum equilibrium capacities of the biosorbent were found to be 143.6, 153,9, 157.3 mg/g at 303, 313, and 323 K, respectively. Thermodynamic data for the adsorption system indicated spontaneous and endothermic process. The enthalpy and entropy values for adsorption were obtained as 15.06 KJ/mol and 0.129 KJ/mol K, respectively, in the temperature range of 303-323 K. A mathematical model for MB transported by molecular diffusion from the bulk of the solution to the surface of PTMF was derived and the values of liquid phase diffusivity and external mass transfer coefficient were estimated. © 2014 M. Srinivas Kini et al.Item Selenium Biosorption and Recovery by Marine Aspergillus terreus in an Upflow Bioreactor(American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2016) Raja, C.P.; Jacob, J.M.; Mohan Balakrishnan, R.M.Experiments were conducted to study the Selenium (Se) biosorption and recovery by marine Aspergillus terreus in an upflow bioreactor for a period of 8 days. The Se tolerance of the marine fungus was initially confirmed by visual and microscopic observations that evinced intact fungal cells in an Se-amended medium with sparse changes in the spore texture and cellular number by the seventh day of biosorption studies in the upflow bioreactor. Further, the effect of pH and contact time on the percentage of Se biosorption, in an upflow bioreactor containing fungal pellets, was investigated. It was analyzed that pH ranges of 6-7 and a contact time of 5 days resulted in 85-87% biosorption of Se by the fungal biomass. The interaction of the fungus with the induced Se stress in the medium was monitored regularly for studying the uptake of the metalloid and the possible biosynthesis of Se nanoparticles. Analyses using ultraviolet visible (UV-Vis) spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) studies revealed the formation of crystalline Se nanocrystals with an average diameter of 500 nm on the fungal cell wall. Fourier transform infrared (FTIR) spectroscopic analysis indicated the possible involvement of fungal protein groups that aid the binding of the biosorbed Se nanoparticles on to the fungal cell wall. © 2015 American Society of Civil Engineers.Item Equilibrium and Kinetic Studies of Hexavalent Chromium Removal Using A Novel Biosorbent: Ruellia Patula Jacq(Springer Verlag, 2017) Saranya, N.; Nakkeeran, E.; Shrihari, S.; Selvaraju, N.The present work utilized Ruellia patula Jacq leaves as biosorbent for hexavalent chromium removal. Sulfuric acid modification was done and checked for enhanced biosorption capacity. Electron microscopy–energy-dispersive X-ray spectroscopy, Fourier transform infrared spectrometry, elemental analysis were performed for characterization of biosorbents. Batch experiments were conducted to optimize contact time, solution pH, initial Cr(VI) concentration, biosorbent dose, agitation speed and temperature for maximum Cr(VI) removal. Also, the study attempted to show polyphenols present in the biosorbent reduce Cr(VI) through adsorption. Equilibrium data were analyzed using Langmuir, Freundlich and Dubinin–Radushkevich isotherms. Monolayer adsorption capacities of raw and acid-modified biosorbents were found to be 37.03 and 62.50 mg/g, respectively. Pseudo-second-order kinetic model suited well than other models like pseudo-first-order and intraparticle diffusion models examined. Determination of ? H?, ? S? and ? G? from thermodynamic studies showed that the biosorption is exothermic, stable and thermodynamically feasible. Desorption studies using NaOH as desorbing agent showed considerable performances up to three cycles. These findings revealed that Ruelliapatula leaves serve as potent biosorbent for the removal of hexavalent chromium from aqueous solutions. © 2017, King Fahd University of Petroleum & Minerals.Item Kinetic and equilibrium modeling of biosorption of nickel (II) and cadmium (II) on brewery sludge(IWA Publishing 12 Caxton Street London SW1H 0QS, 2019) Kulkarni, R.M.; Shetty K, K.; Srinikethan, G.In the current study, utilization of industrial waste brewery sludge for the biosorption of nickel (II) and cadmium (II) has been explored. The suitable conditions for the effective removal of Ni (II) and Cd (II) from aqueous solutions were examined. The kinetic evaluation showed that the biosorption process using the sludge followed pseudo-second order kinetics. In the presence of a metal co-ion, competitive and preferential biosorption was observed. The Langmuir model and Freundlich model were able to describe the sorption equilibrium for biosorption of Ni (II) and Cd (II) ions in single and dual metal systems. The effects of co-ion concentrations onto mono-component isotherm parameters (Langmuir and Freundlich) were studied and the inhibitory effect of co-ion concentration was observed. The effective reusability of biomass was assessed by three cycles of sorption-desorption. The sludge, owing to its high biosorption intensity and large availability from the local supply, is a better biosorbent for the treatment of Ni (II) and Cd (II) contaminated water. © IWA Publishing 2019 Water Science & Technology.Item Mycosensing of soil contaminants by Ganoderma lucidum and Omphalotus subilludens including the insights on growth media requirements(Elsevier Ltd, 2019) Gupta, C.; Mohan Balakrishnan, R.M.; Uddandarao, P.; Arivalagan, A.Heavy metals are regarded as one of the major threats to environmental biota due to prolonged soil residence time. In this scenario, mycoremediation emerged as an effective tool for the removal of heavy metal contaminants. The present study reports the responses of two wild mushroom species Ganoderma lucidum and Omphalotus subilludens under metal stress conditions and the nutritional requirements of the mushroom species. The media was screened wherein the media containing glucose and sucrose as carbon source showed better growth for Ganoderma lucidum and Omphalotus subilludens respectively. In addition, peptone as a nitrogen source is required for the growth of both Ganoderma lucidum and Omphalotus subilludens. Further, it is observed that macronutrients play a crucial role in the stimulation of enzymes and the micronutrients are mandatory for intermediary metabolism of the fungi in both the species. Tolerance studies are carried out in-vitro and the results reveal that the Ganoderma lucidum showed tolerance towards Cr (VI), Ni (II), Pb (II) and Cd (II) at maximum tolerant concentrations of 1000 mg/kg, 500 mg/kg, 100 mg/kg and 10 mg/kg, in case of, Omphalotus subilludens showed tolerance towards Cr (VI), Ni (II) and Pb (II) at maximum tolerant concentration of 700 mg/kg, 700 mg/kg and 500 mg/kg respectively. Moreover, FTIR spectral analysis indicated the presence of components like oxalic acid and thiol compounds during metal stress conditions. © 2019 Elsevier LtdItem Pelletization of pristine Pteris vittata L. pinnae powder and its application as a biosorbent of Cd(II) and Cr(VI)(Springer Nature, 2020) Prabhu, S.G.; Srinikethan, G.; Hegde, S.Mobility of toxic metals, originating from natural or anthropogenic sources, from soil to groundwater is a matter of utmost concern to human health. Remediation of the contaminated groundwater is of the highest priority as groundwater is an alternate source of freshwater that is used all over the world for drinking purpose. Hence, in the present study, Pteris vittata L. is used as a simple, biodegradable and efficient biosorbent of toxic metals in its non-living and pelletized form by employing organic binders and a simple manual pellet press. The capacity of the pelletized Pteris vittata L. to sequester the metals Cd(II) and Cr(VI) from an aqueous solution is determined through the study on the effect of operating conditions, isotherm and kinetic models. The metal removal capacity of the biosorbent pelletized using corn starch as the binder is 13.51 mg/g for Cd(II) at pH 6 and 1.66 mg/g for Cr(VI) at pH 2 as obtained from the Langmuir isotherm model. The diffusion of the metal ions into the micropores of the pellets aids its biosorption. Physical adsorption, ion exchange, covalent bonding and complexation are deduced to be few of the biosorption mechanisms involved. The findings contribute to the existing data in the biosorption technology. The novelty lies in the use of a weedy fern, Pteris vittata L., pelletized with desired structural characteristics as a potential low-cost biosorbent of toxic metals from groundwater. © 2019, Springer Nature Switzerland AG.Item Novel application of maghemite nanoparticles coated bacteria for the removal of cadmium from aqueous solution(Academic Press, 2020) Devatha, C.P.; S, S.Heavy metals are classified as persistent pollutants owing to their nature of bioaccumulation and affect human life and environment, even in minor concentrations. Divalent Cadmium (Cd2+) is one of the heavy metal pollutants that are highly toxic. The present study investigates the novel application of maghemite nanoparticles coated Bacillus subtilis for the removal of Cd2+ ions from its aqueous solution by batch adsorption studies. Surface characterization of the biosorbent done by Scanning Electron Microscope (SEM) and the presence of maghemite nanoparticle coat was confirmed. Parameters like pH, initial metal ion concentration, contact time, and temperature that affect the biosorption of cadmium ions are analyzed, and the equilibrium adsorption capacity expressed as a function of each of the parameters. The mechanism of biosorption was studied by plotting adsorption isotherms, and it follows pseudo-second-order kinetics. Thermodynamic studies showed the process to be spontaneous and endothermic. At optimum conditions of pH 4, 30 °C, 120 rpm, maximum removal percentage of 83.5%, which accounts for an equilibrium adsorption capacity of 32.6 mg/g of biosorbent. There was a recovery of 76.4% of the biosorbent after adsorption studies. Based on the adsorptive capacity and good recovery of the biosorbent, maghemite coated Bacillus subtilis proves to be an efficient adsorbent for the removal of Cd2+ ions from its aqueous solution. © 2019 Elsevier LtdItem Efficient biosorption of Pb(II) on Pteris vittata L. from aqueous solution using pulsed plate column technique(Bellwether Publishing, Ltd. customerservice@taylorandfrancis.com, 2020) Prabhu, S.; Srinikethan, S.; Hegde, S.Biosorption is an alternative method of remediation that is devoid of the limitations associated with physiochemical techniques. This paper investigates the ability of the pteridophyte, Pteris vittata L., proven to have heavy metal hyper-accumulation capacity in living forms, to adsorb Pb(II) from an aqueous system in its powdered and pelletized form. At best-operating conditions, P. vittata L. pinnae powder exhibited Pb(II) biosorption capacity of 125 mg/g. Bench-scale Pulsed Plate column studies using pelletized biosorbent demonstrated continuous Pb(II) removal efficiency of 99.93%. With no commercial value and application, untreated P. vittata is a potential resource that will contribute to biosorption technology. © 2019 Taylor & Francis Group, LLC.