逆洗を伴うクロスフロー精密ろ過による重金属水酸化物の分離

抄録

Crossflow microfiltration has attracted attention for use in separating heavy metal hydroxides from wastewater from metal finishing processes, and is slated to replace conventional coagulation-precipitation. We determined the specific cake resistance and compressibility of filtrated metal hydroxide suspensions in constant-pressure dead-end filtration. Crossflow microfiltration experiments were done at a constant pressure and filtrate flux was measured for different crossflow velocities, transmembrane pressures, and concentrations. Results showed that 1) little difference existed in filtration properties within the pH range (9-11) studied; 2) the initial stage of filtration process was described by a cake filtration model; 3) the mean filtrate flux with backwashing was estimated roughly from filtration results without backwashing; and 4) the mean flux of highly concentrated suspensions depended strongly on crossflow velocity and weakly on transmembrane pressure, i. e., the critical flux existed at a lower transmembrane pressure.