Characteristics of heavy metal ions adsorption by activated carbon

Through the research on the adsorption of heavy metal ions in electronic industrial wastewater and the thermodynamics by activated carbon, influences of contact time, temperature, pH value and coexistence heavy metal ions on Cu²⁺, Pb²⁺, Zn²⁺ and Cr⁶⁺ adsorption were investigated in terms of experiments. The results showed that the copper adsorption onto activated carbon achieved equilibrium gradually at about 20mins, but for lead, zinc, chromium it needs 60mins to achieve equilibrium. In the pH rage from 2.0 to 8.0, with the increased pH values, their adsorption capacity also increased. The temperature has no effect on the adsorption of heavy metal ions by activated carbon. The coexistence of metal ions adsorption experiment found that the coexistence of metal ions has little effect for the adsorption of Cu²⁺, but greater effect for Pb²⁺. The adsorption models of four heavy metal ions by activated carbon can be well described by Freundlich model.