Study on removal of Cu2+ from wastewater by excess sludge

With the social development, the increasing sludge and its subsequent treatment are very severe environmental problems.The adsorption experiments were carried out using different pretreated exess sludge as adsorbent for Cu2+. The sludge of NaOH-H2O2 treated improve the adsorption capacity which reached 56.12mg/g,however the adsorption capacity of the sludge using ZnCl2-Carbonization treated decrease.Both Langmuir and Freundlich isotherm models fit the adsorption data well with the three types of sludge . The value of R-2 exceeds 0.96 in most cases. Relative to the Pseudo first order kinetic model,the pseudo second orderkinetic model fit the adsorption data more well with the adsorbents. The value of R-2 reached about 1. The maximum adsorption efficiency for optimum pH is about 6. With the increase of adsorption mass, the removal efficiency of sludge increases.For 150mL copper ion solution which concentration was 100 mg/L,the optimum sludge mass corresponds to maximum adsorption efficiency was found to be 1.5g.