Faculty Publications
Permanent URI for this communityhttps://idr.nitk.ac.in/handle/123456789/18736
Publications by NITK Faculty
Browse
8 results
Search Results
Item Activated carbon-polyethylenedioxythiophene composite electrodes for symmetrical supercapacitors(2008) Muthu, M.S.; Bhat, D.K.A symmetrical (p/p) supercapacitor has been fabricated by making use of activated carbon (AC)-poly-ethylenedioxythiophene (PEDPT)-composite electrodes for the first time. The composite electrodes have been prepared via electrochemical deposition of ?-napthalenesulphonate doped PEDPT onto AC electrodes. The characteristics of the electrodes and the fabricated supercapacitor have been investigated using cyclic voltammetry (CV) and AC impedance spectroscopy. The electrodes show a maximum specific capacitance of 158 Fg-1 at a scan rate of 10 mV s_1. This indicates that the in situ electro-polymerization of ethylenedioxythiophene (EDPT) onto AC could improve the performance of carbon electrodes for use in supercapacitors. © 2007 Wiley Periodicals, Inc.Item Studies on the removal of Pb(II) from wastewater by activated carbon developed from Tamarind wood activated with sulphuric acid(2008) Singh, C.K.; Sahu, J.N.; Mahalik, K.K.; Mohanty, C.R.; Mohan, B.R.; Meikap, B.C.The low-cost activated carbon were prepared from Tamarind wood material by chemical activation with sulphuric acid for the adsorption of Pb(II) from dilute aqueous solution. The activated carbon developed shows substantial capacity to adsorb Pb(II) from dilute aqueous solutions. The parameters studied include physical and chemical properties of adsorbent, pH, adsorbent dose, contact time and initial concentrations. The kinetic data were best fitted to the Lagergren pseudo-first-order and pseudo-second order models. The isotherm equilibrium data were well fitted by the Langmuir and Freundlich models. The maximum removal of lead(II) was obtained 97.95% (experimental) and 134.22 mg/g (from Langmuir isotherm model) at initial concentration 40 mg/l, adsorbent dose 3 g/l and pH 6.5. This high uptake showed Tamarind wood activated carbon as among the best adsorbents for Pb(II). © 2007 Elsevier B.V. All rights reserved.Item Biological sulfide oxidation using autotrophic Thiobacillus sp.: Evaluation of different immobilization methods and bioreactors(2009) Ravichandra, P.; Gopal, M.; Jetty, A.Aims: Evaluation of various immobilization methods and bioreactors for sulfide oxidation using Thiobacillus sp. was studied. Methods and Results: Ca-alginate, K-carrageenan and agar gel matrices (entrapment) and polyurethane foam and granular activated carbon (adsorption) efficacy was tested for the sulfide oxidation and biomass leakage using immobilized Thiobacillus sp. Maximum sulfide oxidation of 96% was achieved with alginate matrix followed by K-carrageenan (88%). Different parameters viz. alginate concentration (1%, 2%, 3%, 4% and 5%), CaCl2 concentration (1%, 2%, 3%, 4% and 5%), bead diameter (1, 2, 3, 4 and 5 mm), and curing time (1, 3, 6, 12 and 18 h) were studied for optimal immobilization conditions. Repeated batch experiments were carried out to test reusability of Ca-alginate immobilized beads for sulfide oxidation in stirred tank reactor and fluidized bed reactor (FBR) at different sulfide concentrations. Conclusions: The results proved to be promising for sulfide oxidation using Ca-alginate gel matrix immobilized Thiobacillus sp. for better sulfide oxidation with less biomass leakage. Significance and Impact of the Study: Biological sulfide oxidation is gaining more importance because of its simple operation. Present investigations will help in successful design and operation of pilot and industrial level FBR for sulfide oxidation. © 2009 The Society for Applied Microbiology.Item Adsorption of phenol on granular activated carbon from nutrient medium: Equilibrium and kinetic Study(2009) Dabhade, M.A.; Saidutta, M.B.; Murthy, D.V.R.This paper presents the adsorption of phenol on granular activated carbon (GAC) from nutrient medium suitable for microorganisms' growth and also the subsequent biodegradation. Two parameter Langmuir and Freundlich adsorption isotherm models were studied using large range of phenol concentration (50-1000 mg/L). In low range of phenol concentration (50-300 mg/L), correlation coefficient, normalized deviation "g% and separation factor were 0.9989,2.18% and 0.38-0.78 respectively, while for higher concentration range (400-1000 mg/L), the corresponding values were 0.9719, 1.9% and 0.45- 0.67. Freundlich isotherm gave correlation coefficient of 0.9984, 1/n. value of 0.7269 and normalized deviation of 4.55%. Comparison based on R2, adjusted R2, normalized deviation and root mean square deviation (RMSD) showed that the Redke-Prausnitz isotherm model gives better prediction compared to other models. Adsorption of phenol follows pseudo second order kinetics with correlation coefficient closer to one. Biodegradation study using immobilized cells of Nocardia hydrocarbonoxydans on GAC showed that, biodegradation begins well before GAC reaches the saturation period.Item Removal of acutely hazardous pharmaceuticals from water using multi-template imprinted polymer adsorbent(Ecomed Publishers susanne.kuehbandner@hjr-verlag.de, 2014) Venkatesh, A.; Chopra, N.; Krupadam, R.J.Molecularly imprinted polymer adsorbent has been prepared to remove a group of recalcitrant and acutely hazardous (p-type) chemicals from water and wastewaters. The polymer adsorbent exhibited twofold higher adsorption capacity than the commercially used polystyrene divinylbenzene resin (XAD) and powdered activated carbon adsorbents. Higher adsorption capacity of the polymer adsorbent was explained on the basis of high specific surface area formed during molecular imprinting process. Freundlich isotherms drawn showed that the adsorption of p-type chemicals onto polymer adsorbent was kinetically faster than the other reference adsorbents. Matrix effect on adsorption of p-type chemicals was minimal, and also polymer adsorbent was amenable to regeneration by washing with water/methanol (3:1, v/v) solution. The polymer adsorbent was unaltered in its adsorption capacity up to 10 cycles of adsorption and desorption, which will be more desirable in cost reduction of treatment compared with single-time-use activated carbon. © 2014 Springer-Verlag Berlin Heidelberg.Item Surface characterization and methylene blue adsorption studies on a mesoporous adsorbent from chemically modified Areca triandra palm shell(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2016) Thangappan, H.; Valiya Parambathu, A.; Joseph, S.Activated carbon was prepared from Areca triandra palm shell (ATPS) by chemical activation with sulphuric acid, and its application for the adsorption of methylene blue dye from aqueous solution was investigated. FTIR spectral analysis and Boehm titrations were used to examine the oxygenated surface functional groups tailored to adsorb cationic toxins from solutions, point of zero charge estimated the surface charge for electronic affinity induced by chemical treatment. BET and SEM analyses revealed mesoporous adsorbent with homogenous pores and the BET surface area is 27.3 m2/g. The influence of process parameters, namely contact time, initial concentration, adsorbent dosage and pH was evaluated by batch adsorption studies. The equilibrium adsorption data were fitted with three isotherm models, among them Langmuir isotherm model best fitted and the maximum adsorption capacity of methylene blue was found to be 312.5 mg/g. The kinetic adsorption data best fitted with pseudo-second-order kinetics out of three kinetic models tested. The thermodynamic parameters, Gibb’s free energy change (?G°), enthalpy change (?H°) and entropy change (?S°) ascertain that the adsorption is a spontaneous endothermic process with high affinity between surface and dye. The results of the present study suggest that the adsorbent prepared from ATPS is a potential adsorbent for the treatment of effluent containing cationic dyes. © 2015 Balaban Desalination Publications. All rights reserved.Item Comparative evaluation of phosphate abatement using laterite soil and activated carbon(Center for Environmental and Energy Research and Studies editor@ijest.org, 2019) Sreekumar, U.; Thalla, A.K.; Nair, V.V.Abstract: The present study aims to evaluate and compare the suitability of thermally activated laterite soil (TAL) and activated carbon (AC) as adsorbents in the abatement of phosphates (PO4 3?) from synthetic wastewater. The AC was derived from the wasted sludge of an activated sludge process by subjecting it to an activation temperature of 600 °C. The impregnation ratio of 1 (sewage sludge): 1 (KOH) was used for the present study. The soil and wasted sludge were characterized to determine the constituents, and the adsorbents were prepared by thermal and chemical activation, respectively. The AC exhibited a maximum iodine number of 837.51 mg/g using KOH as an activating agent. Batch and column studies were conducted to determine the dependency on pH, contact time, adsorbent dosage and initial PO4 3? concentration. An optimum PO4 3? removal using TAL and AC was achieved around pH 6. The removal efficiency of AC was found to be slightly higher than the efficiency obtained from TAL. The percentage removal of PO4 3? obtained from batch adsorption studies was found to be higher than that obtained by column studies. The equilibrium adsorption data from batch studies were attempted to fit with linear, Langmuir and Freundlich isotherm models. Residual and least square analysis confirms the Freundlich isotherm to be the best fit. Graphical abstract: [Figure not available: see fulltext.] © 2018, Islamic Azad University (IAU).Item Enhanced degradation of azo dye using mixed cultures of white-rot fungi in a modified rotating packed disc bioreactor and reuse of treated water(Elsevier Ltd, 2023) Kalnake, R.P.; Raval, R.; Murthy, D.V.R.; Vanzara, P.B.; Raval, K.Reactive azo dyes are toxic and carcinogenic. In this study, mixed cultures of white-rot fungi (WRF) are used to treat synthetic reactive black 5 (RB-5) wastewater in a modified rotating packed disc bioreactor (RPDB). The continuous degradation studies were carried out for 25 days under the influence of the recycle stream in which 3665 L of synthetic effluent was treated. The dye wastewater was completely decolorized with more than 93 % chemical oxygen demand (COD) reduction using the mixed fungal culture. During the continuous operation, the COD of influent reduced more than 85 % for successive 25 days of continuous operation at hydraulic retention time of 10.8 h. The dry biomass loading was about 0.14 g/g GAC at the end of the continuous process. The rate of COD removal followed first order kinetics with a rate constant of 0.026 per hour. The treated water was reused to produce melanin from microbial culture. © 2023 Elsevier Ltd