Study on preparation and characterization of the adsorbents with sewage sludge

Preparation of efficient adsorbents with sewage sludge and its application in chromium-containing wastewater treatment was discussed. The chemical physics activation method was used to dispose secondary sedimentation tank sludge and the final residual sludge to produce activated carbon, respectively. The effect of concentrations of oxidizer, activated temperature, solid-liquid ratio and activation time on the properties of adsorbent have also been observed. The complex of ZnCl2 and H2SO4 were used to prepare activated carbon. Based on the measurements of iodine number of adsorbents, the optimal processing parameters were determined. Under the optimum conditions, iodine adsorption value of sedimentation tank sludge activated carbon is 458.92 mg/g, which is 50mg/g more than the iodine adsorption value of residual sludge activated carbon. At of pH 5, stirring speed of 120 r/min and concentration of 4 g /L, the chromium ion removal rate was up to 83.2 %.