Adsorption studies on fruits of Gular (Ficus glomerata): removal of Cr(VI) from synthetic wastewater.
ABSTRACT The adsorption of Cr(VI) was studied in batch system using fruits of Ficus glomerata as adsorbent. The effect of temperature, pH, initial Cr(VI) concentration and time was investigated. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) was used to investigate surface morphology and active functional groups present on the adsorbent surface. Thermodynamic parameters like free energy change (DeltaG(0)), enthalpy (DeltaH(0)) and entropy (DeltaS(0)) indicate the spontaneous, endothermic and increased randomness nature of Cr(VI) adsorption. Equilibrium data were fitted well with Langmuir isotherm at 50 degrees C. The magnitude of mean free energy indicates chemical nature of adsorption. The breakthrough and exhaustive capacities were found to be 5 and 23.1 mg g(-1) respectively. The applicability of the adsorbent has been demonstrated by removing Cr(VI) from electroplating wastewater.
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ABSTRACT: Fruit and vegetable wastes produced in astronomical quantities from food processing and agriculture industries often cause nuisance in municipal landfills owing to their high biodegradability. Biosorption by these waste-based adsorbents can be used as a cost effective and efficient technique for the removal of toxic heavy metals and dyes from wastewater. Recently, many papers claiming the feasible use of these biosorbents for water decontamination, treatment of industrial and agricultural wastewater and valuable metal recovery have been published. The organic waste-based adsorbents, characterized by good uptake capacity and rapid kinetics are expected to be economically and ecologically viable. This paper presents a judicious and pragmatic review depicting the key advances in implications of the fruit and vegetable wastes in pollution mitigation, the underlying mechanisms, major challenges and the future implementations. This compilation is expected to provide an impetus to the bioremediation research and promote green technology.Reviews in Environmental Science and Bio/Technology 12/2012; · 2.34 Impact Factor
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ABSTRACT: The magnetic-poly(divinylbenzene-1-vinylimidazole) [m-poly(DVB-VIM)] microbeads (average diameter 53-212 μm) were synthesized and characterized; their use as adsorbent in removal of Cr(VI) ions from aqueous solutions was investigated. The m-poly(DVB-VIM) microbeads were prepared by copolymerizing of divinylbenzene (DVB) with 1-vinylimidazole (VIM). The m-poly(DVB-VIM) microbeads were characterized by N(2) adsorption/desorption isotherms, ESR, elemental analysis, scanning electron microscope (SEM) and swelling studies. At fixed solid/solution ratio the various factors affecting adsorption of Cr(VI) ions from aqueous solutions such as pH, initial concentration, contact time and temperature were analyzed. Langmuir, Freundlich and Dubinin-Radushkvich isotherms were used as the model adsorption equilibrium data. Langmuir isotherm model was the most adequate. The pseudo-first-order, pseudo-second-order, Ritch-second-order and intraparticle diffusion models were used to describe the adsorption kinetics. The apparent activation energy was found to be 5.024 kJ mol(-1), which is characteristic of a chemically controlled reaction. The experimental data fitted to pseudo-second-order kinetic. The study of temperature effect was quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes. The thermodynamic parameters obtained indicated the endothermic nature of adsorption of Cr(VI) ions. Morever, after the use in adsorption, the m-poly(DVB-VIM) microbeads with paramagnetic property were separeted via the applied magnetic force. The magnetic beads could be desorbed up to about 97% by treating with 1.0 M NaOH. These features make the m-poly(DVB-VIM) microbeads a potential candidate for support of Cr(VI) ions removal under magnetic field.Water Air and Soil Pollution 06/2012; 223(5):2387-2403. · 1.75 Impact Factor
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ABSTRACT: In this study, natural Akadama clay was used for Cr (VI) removal from aqueous solution. Batch experiments were carried out to investigate the effect of contact time, initial pH, and adsorbent dose on Cr (VI) adsorption. Results showed that Cr (VI) adsorption on natural Akadama clay reached equilibrium in 180min. The Cr (VI) removal efficiency of 46.8% without pH adjustment increased to 73.8% at the optimum initial pH of 2. The maximum adsorption capacity was 4.29mgg(-1) at an initial concentration of 50.0mgL(-1) and adsorbent dosage of 5gL(-1). The equilibrium data fitted Freundlich isotherm better than Langmuir isotherm, and they were well explained by pseudo-second-order kinetic model. Adsorption mechanism analysis proved that electrostatic adsorption dominated during the removal process. Results from this study demonstrate that natural Akadama clay has the potential to be an efficient adsorbent for Cr (VI) adsorption compared to other natural mineral adsorbents.Journal of Colloid and Interface Science 01/2013; · 3.17 Impact Factor