REMOVAL OF HEAVY METAL IONS FROM WASTEWATERS USING MODIFIED OLIVE POMACE AS BIOSORBENT
Project no. 1396 · Status: Kapanmış · 2018
Summary
In the present study, olive pomace was investigated as a biosorbent to adsorp lead and cadmium ions from their aqueous solutions. Raw olive pomace (H-ZK) was modified with several chemicals at different concentrations such as nitric acid, sulfuric acid, hydrogen peroxide and the others, and their capacity for lead and cadmium adsorption was evaluated. The best result was obtained with the nitric acid modified olive pomace (N-ZK). Batch-wise experiments were conducted with raw and nitric acid modified olive pomace and particle size of the biosorbent, effect of pH of the solution, contact time, initial Pb/Cd concentration, temperature of the environment and desorption experiments were chosen as the process parameters. Regenerative and reusable properties of N-ZK were confirmed by consecutive adsorption-desorption experiments. Temperature study indicated that the adsorption process is feasible and spontaneous. Adsorban characterization was accomplished using van Soest method, BET analyses and “point of zero charge” (pHpzc) measurement of the biosorbents. Kinetic study showed that lead and cadmium adsorption followed a pseudo-second-order model. Lead and cadmium uptake were enhanced by nitric acid modification of the olive pomace from 33 mg/g to 64 mg/g and 8 mg/g to 20.5 mg/g, respectively, using 1 g/L N-ZK at the optimum pH of 5.5 for lead ions and that of 6 for cadmium ions. Redlich-Peterson and Langmuir isotherms were the best fitting models for lead adsorption onto R-OP and N-OP, respectively. However, Langmuir-Freundlich and Radke-Prausnitz models were the best fitting models for cadmium adsorption onto R-OP and N-OP, respectively.