抄録
The efficiency of removing boron from industrial wastewater by coagulation sedimentation with the coagulant cerium chloride (CeCl3) was determined. The optimum processing conditions were investigated in a batch processing experiment conducted by supplying 100 mg ·l-1 boron to a reactor. The optimum processing conditions were a pH of about 10, cerium addition to give a Ce/B molar ratio (molarity of Ce/molarity of B ) of 2 or more, and a processing time in the range of 5-30 minutes. The removal efficiency for boron decreased when sulphate ions were coexisted at a concentration of about six times or more of boron concentration. However, it was improved by performing coagulation sedimentation using calcium chloride (CaCl2) and by increasing CeCl3 concentration. When the effect of processing was examined using actual industrial wastewater under the determined optimum processing conditions, the removal efficiency for boron was in the range of 87-92%. When a field processing experiment was conducted by setting up small batch experiment equipment next to the wastewater treatment equipment, the removal efficiency for boron was 93%. This was about 58% higher than that of actual wastewater treatment equipment. Moreover, fluorine and SS (suspended solid) were successfully removed in addition to boron.
