زدايش مس و نيكل از محلول هاي آبي به وسيله بنتونيت طبيعي

Removal of Copper and Nickel from Aqueous Solutions by Natural Bentonite

Background: Release of heavy metals and their dispersal in the environment may cause tragic effects on the exposed population. Heavy metals are non-biodegradable, highly toxic which have bioaccumulation properties in living organisms. Therefore, the development of new technology is required to treat wastewaters as an alternative to classical physicochemical processes. Materials and Methods: Adsorption of copper (Cu2+) and nickel (Ni2+) from aqueous solutions at 27±1°C by natural bentonite was studied. The effect of pH, metalsʹ concentration, sorbent dosage and contact time were studied in batch experiments. All divalent metal cation solutions were prepared from nitrate salts with 50 mg/L initial concentration and metals concentration determined by atomic absorption spectrophot ometry. Results: Adsorption data were described by qualitative and quantitative methods. In qualitative method Gileʹs classification and in quantitative method Langmuir and Frundlich isotherm equations were used. Adsorption data was better fitted to Frunlich equation model, with correlation coefficient R2 >0.98 and R2 >0.99 for copper and nickel respectively. The increase in initial metal ions concentration decreased the percentage of adsorption and increased the capacity of metals` uptake per unit of the sorbent (mg/g). Results indicated that the adsorption capacity of natural bentonite increased with an increase in the pH. The uptake of copper was found to be greater than that of nickel. Conclusion: The results of this experiment showed that natural bentonite can be considered as a good substance for removal of heavy metals from industrial wastewater, specially in their low concentrations .