Modified Laterite Adsorbent for Cadmium Removal from Wastewater

摘要

Being a toxic metal, the presence of cadmium in water leads to damage of health in human beings. Effluents from various processes and industries inevitably contain cadmium as remnant, and its removal is necessary to meet with the existing statutory norms. So far, many adsorbents are used in the industry, but most of them are rather costly. Therefore, a cheaper and effective adsorbent, modified laterite is used in the present investigation as an alternative. Batch studies are conducted to elicit information on operating variables (pH, temperature, adsorbent dosage, initial concentration and contact time). In the present study, optimum values for these variables are reported as 7.0, 30 °C, 6 g/L, 100 mg/L and 30 min, respectively. Maximum cadmium uptake obtained was 100 mg/g. The kinetic data were in good agreement with pseudo-second-order model. Also Langmuir, Freundlich and Temkin isotherms were obeyed. From thermodynamic calculations, a change in enthalpy was found to be 170J/mol.