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Item From non-renewable waste to activated carbon: A smart move towards sustainable development and environmental protection in a circular economy(Elsevier Ltd, 2025) Patil, S.S.; Kisiela-Czajka, A.M.; Prasad Dasari, H.P.Waste generation is unavoidable as the population grows and globalisation/modernisation occurs. Ineffective garbage management and treatment raise major environmental concerns. This study provides a comprehensive and unique compilation of available knowledge on the potential use of various non-renewable waste materials to produce activated carbon (AC). One document brings together and evaluates the potential for converting hazardous and non-hazardous waste – from industrial and municipal to recyclable and medical waste – into a valuable resource with wide-ranging applications. The appropriately selected conversion method is key to converting waste into a valuable activated carbon product. It must consider both the applicable legal regulations and the key technological parameters that determine the quality and suitability of the final product for a specific application. The numerous carbonisation and activation methods employed to convert waste to AC include hydrothermal, ionothermal, pyrolysis and microwave-assisted methods. AC's elemental composition and functional groups are analysed using elemental analysis, XPS and FTIR. Crystal structure and phase identification are performed via XRD, SEM and TEM. Surface area and porosity are determined using the BET and BJH methods, along with the iodine index. Following the thermal conversion of various waste materials into AC, it is widely used in multiple disciplines, including energy and the environment. AC is used as an adsorbent to effectively remove harmful elements from water, including pharmaceutical contamination, dyes and heavy metals. AC has excellent electrochemical characteristics and is highly efficient in CO2 capture. AC also extracts valuable products such as hydrocarbons, methane and uranium. © 2025 The Author(s)Item The direct conversion of benzene to phenol by hydroxylation with hydrogen peroxide was carried out over various transition metals impregnated on MCM-41 and activated carbon. Copper-, iron-, and vanadium-impregnated on activated carbon gave better yields of phenol when compared to the corresponding reactions using cobalt-, nickel-, manganese-, and titanium-impregnated catalysts. Comparison of the MCM-41 and activated carbon-supported catalysts showed that activated carbon-supported catalysts gave a higher yield of phenol than did the MCM-41-supported catalysts. The activity of the transition metals supported on activated carbon in the production of phenol was V > Fe > Cu; the corresponding activity of the transition metals supported on MCM-41 was Cu > Fe > V. In addition to the role of transition metals in catalyzing the hydroxylation reaction, the hydrophobic nature of the activated carbon surface seems to enhance the performance of these catalysts relative to the MCM-41-supported catalysts.(Benzene hydroxylation to phenol catalyzed by transition metals supported on MCM-41 and activated carbon) Choi, J.-S.; Kim, T.-H.; Saidutta, M.B.; Sung, J.-S.; Kim, K.-I.; Jasra, R.V.; Song, S.-D.; Rhee, Y.-W.2004Item The direct conversion of benzene to phenol by hydroxylation with hydrogen peroxide was carried out over catalyst containing various transition metals impregnated on activated carbon. Iron and vanadium impregnated catalysts gave better yields of phenol compared to copper impregnated catalysts. The activity of transition metals supported on activated carbon catalyst in the production of phenol was V > Fe > Cu. In addition to the role of transition metals in catalyzing the hydroxylation reaction, the hydrophobic nature of the activated carbon surface and also the surface acidity and basicity seems to have enhanced the performance of these catalysts. © 2005 Springer Science + Business Media, Inc.(Transition metals supported on activated carbon as benzene hydroxylation catalysts) Choi, J.-S.; Kim, T.-H.; Choo, K.-Y.; Sung, J.-S.; Saidutta, M.B.; Song, S.-D.; Rhee, Y.-W.2005Item The direct conversion of benzene to phenol by hydroxylation with hydrogen peroxide was carried out over catalysts containing iron impregnated on activated carbon. Iron was impregnated on various surface modified activated carbons. The catalyst that was made by treating activated carbon with nitric acid, that was treated thermally in the presence of nitrogen at 600 °C and impregnated with 5 wt.% iron, gave a phenol yield of 20%. It was found that the synergistic interactions of surface groups and the impregnated iron have enhanced the performance of these catalysts. © 2005 Elsevier B.V. All rights reserved.(Direct synthesis of phenol from benzene on iron-impregnated activated carbon catalysts) Choi, J.-S.; Kim, T.-H.; Choo, K.-Y.; Sung, J.-S.; Saidutta, M.B.; Ryu, S.-O.; Song, S.-D.; Badekai Ramachandra, B.; Rhee, Y.-W.2005Item 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 Modelling, analysis and optimization of adsorption parameters for H3PO4 activated rubber wood sawdust using response surface methodology (RSM)(2009) Helen Kalavathy, M.H.; Iyyaswami, I.; Ganesapillai, M.G.; Miranda, L.R.Adsorption capacity of Cu2+ from aqueous solution onto H3PO4 activated carbon using rubber wood sawdust (RSAC) was investigated in a batch system. Kinetic and isotherm studies were carried out, the thermodynamic parameters like standard Gibb's free energy (?G°), enthalpy (?H°) and entropy (?S°) were evaluated. The pseudo-second-order model was found to explain the kinetics of Cu2+ adsorption most effectively. The process optimization was performed through Central Composite Rotary Design using response surface methodology (RSM) by Design Expert Version 5.0.7 (STAT-EASE Inc., Minneapolis, USA). An initial concentration of 35 mg L-1, temperature of 26 °C, carbon loading of 0.45 g (100 mL)-1, adsorption time 208 min and pH of 6.5 was found to be the optimum conditions for the maximum uptake of copper ions of 5.6 mg g-1 in batch mode. © 2009 Elsevier B.V. All rights reserved.Item Equilibrium and kinetic study for the removal of malachite green using activated carbon prepared from Borassus flabellofer male flower(2010) JagadeeshBabu, P.E.; Kumar, V.; Visvanathan, R.Activated carbon was prepared from dried Borassus flabellofer male flower and batch adsorption experiments were conducted to study its potential to remove malachite green (MG) dye. The process was further optimized by studying the operating variables like initial pH of the stock solution, activation temperature, initial dye concentration, adsorbent loading and contact time. The optimized pH and activation temperatures were found to be 7.55 and 450.C respectively, where further analysis was made using these optimal variables. Linear, Freundlich and Langmuir isotherms were studied and it was found that the Langmuir isotherms have the highest correlation coefficients compared to the others. Further, the sorption kinetics were analysed using pseudo-first-order and pseudo-second-order kinetic models. The data showed that the second-order equation was the more appropriate, which indicate that the intra-particle diffusion is the rate limiting factor. © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.Item Nano ZnO-activated carbon composite electrodes for supercapacitors(2010) Muthu, M.S.; Bhat, D.K.; Aggarwal, A.; Prahladh Iyer, S.; Sravani, G.A symmetrical (p/p) supercapacitor has been fabricated by making use of nanostructured zinc oxide (ZnO)-activated carbon (AC) composite electrodes for the first time. The composites have been characterized by field emission scanning electron microscopy (FESEM) and X-ray diffraction analysis (XRD). Electrochemical properties of the prepared nanocomposite electrodes and the supercapacitor have been studied using cyclic voltammetry (CV) and AC impedance spectroscopy in 0.1 M Na2SO4 as electrolyte. The ZnO-AC nanocomposite electrode showed a specific capacitance of 160 F/g for 1:1 composition. The specific capacitance of the electrodes decreased with increase in zinc oxide content. Galvanostatic charge-discharge measurements have been done at various current densities, namely 2, 4, 6 and 7 mA/cm2. It has been found that the cells have excellent electrochemical reversibility and capacitive characteristics in 0.1 M Na2SO4 electrolyte. It has also been observed that the specific capacitance is constant up to 500 cycles at all current densities. © 2010 Elsevier B.V. All rights reserved.