Absorption of copper (Cu2+) and nickel (Ni2+) from aqueous solutions by volcanic ash soil

Introduction: Natural volcanic ash soil is one of minerals whose major contents are metal oxides. In this study absorption of copper (Cu2+) and nickel (Ni2+) on natural volcanic ash soil has been investigated at 27±1c as a function of PH, metal concentration, contact time and the amount of sorbet, using batch experiments. Methods: The necessary samples of natural volcanic ashes were collected from Anar region in Kerman province, Iran. The samples were analyzed by using quantitative and qualitative methods. In qualitative method, Gile’s classification and in quantitative method, Langmuir and Freundlich isotherms were used. Results: Both Langmuir and Freundlich models described the Cu2+ and Ni2+ absorption processes adequately, with correlation coefficient (R2) values ranging from 0.97-0.99. The results show that equilibrium is reached quickly, indicating that the adsorption sites are well exposed. The increase in initial metal ions concentration decreased the percent adsorption and increased the amount of metals uptake perunit weight of the sorbet (mg/g). Conclusion: The results indicated that the absorption capacity of the volcanic ash soil increased with an increase in the pH. The uptake of copper was found to be greater than nickel