Biosorption of heavy metals from aqueous solutions by chemically modified orange peel

The current review paper deals with critical evaluation of the thermodynamic parameters of adsorption equilibrium uptakes of heavy metals, dyes and other organic pollutants from the wastewater using low-cost adsorbents, activated carbon derived from agricultural waste, industrial wastes and other important adsorbent materials. Present review paper focus the spontaneity of adsorption processes when the thermodynamic parameters were assessed with the compensation effects of standard enthalpy change (ΔHo) and standard entropy change (ΔSo) with temperature. This paper also investigates the spontaneity of adsorption on the basis of thermodynamic criteria of spontaneity and the temperature range to predict feasibility of the adsorption processes.

Adsorption thermodynamics to clean up wastewater; critical review

Lignin-related material found in wastewater from thermomechanical pulping resists conventional biological treatment, entailing the use of advanced removal methods. In this work, the use of adsorption for removing lignin-related material was investigated. Activated charcoal and fly ash were used to study the adsorption behavior of lignin and to determine the adsorption capacities of these two adsorbents. Experimental data were fitted to various isotherm equations to find the best description of the sorption systems, and the corresponding thermodynamic parameters were calculated. Fly ash exhibited good sorption properties, although its sorption capacity was inferior to that of activated charcoal. Both the Freundlich and Langmuir equations provided reasonable models of the sorption processes, and the thermodynamic parameters indicated that sorption onto activated charcoal is endothermic, whereas sorption onto fly ash appears to be exothermic. Fly ash is a low-cost material that is often available on-site and...

Removal of Lignin from Wastewater Generated by Mechanical Pulping Using Activated Charcoal and Fly Ash: Adsorption Isotherms and Thermodynamics

A new inorganic ion exchange sorbent, zirconium aluminophosphate, has been prepared with Na+ ion exchange capacity (iec) equal to 2.10 mequiv/dry g. Its X-ray diffraction studies suggest that it is amorphous in nature. Its characterization has also been done by IR, TGA, and DSC so as to identify various functional groups and ion exchange sites present in the material. Further, various ion exchange studies such as determination of iec, elution behavior, pH titration, and distribution behavior have been performed on this material. Distribution coefficients for some heavy metal ions have also been determined to explore its separation potential. This material shows a high selectivity for Pb(II). On this basis some possible binary separations may be Pb(II)−Cd(II) and Pb(II)−Mg(II) on a column of this material.

Synthesis and characterization of zirconium aluminophosphate. A new cation exchanger

Determination of ion-exchange kinetic parameters for the poly-o-methoxyaniline Zr(IV) molybdate composite cation-exchanger

Synthetic, analytical and kinetic studies on a crystalline and thermally stable phase of antimony(V) arsenosilicate cation exchanger

The adsorption of carbofuran on the surface of antimony(V) arsenosilicate: a thermodynamic study

A method has been developed for the standardization of Indian ayurvedic drugs containing iron, using inorganic ion exchange material antimony (V) arsenosilicate cation exchanger. The iron present in the drug was absorbed quantitatively on the columns of the exchanger, eluted with a suitable solvent and then titrated against a standardized EDTA solution.

Use of antimony (V) arsenosilicate beads for estimation of iron content of ayurvedic and allopathic preparations.

A newphase of antimony(V) phosphate has been synthesizedand characterized usingX-ray, JR, SEM, TGA and DTG studies in addition to ion exchange studies such as determination of ion exchangecapacity, e1ution,pH titration and distribution behaviour. On the basis of the distribution behaviour, the material has been found to behighly selectivefor lead. Somebinary separationsof metal ionshavealso beenperformed on a column of this material. The X-ray studies reveal the amorphous nature of the material.

http://nopr.niscair.res.in/bitstream/123456789/40320/1/IJCA%2034A%2811%29%20888-891.pdf

Alka Gupta

Papers

Synthetic, analytical and kinetic studies on a crystalline and thermally stable phase of antimony(V) arsenosilicate cation exchanger

The adsorption of carbofuran on the surface of antimony(V) arsenosilicate: a thermodynamic study

Use of antimony (V) arsenosilicate beads for estimation of iron content of ayurvedic and allopathic preparations.

Synthesis, characterization and ion exchange behaviour of a new phase of antimony(V) phosphate cation exchanger: Selective adsorption of lead(II)