Organic phosphine removal from discharged circulating cooling water of power plant by steel slag

Organic phosphine in the discharged circulating cooling water of power plants was removed by hot splashing slag and rotating furnace slag. Effects of diameter, stirring rate and initial pH on phosphine removal (PR) by steel slag were investigated, and the PR kinetics was analyzed. Diameter of steel slag greatly affected PR efficiency with small steel slag obtained higher removal rate and equilibrium adsorption capacity. The second-order kinetics was propitious to describe PR by small-diameter steel slag, while the first-order kinetics was suitable for the steel slag with diameter higher than 1.25 mm. Stirring could enhance PR efficiency, but the stirring rate showed insignificant effects on PR when reaching a certain value. The acidic environment was in favor of PR by rotating furnace slag, while with the increasing pH, the PR rate of hot splashing slag increased but the equilibrium adsorption capacity dropped. The optimal pH values for PR efficiency by the two kinds of steel slag were both 5.0.