Evaluation of the Capacity of Hydroxyapaptite Prepared from Concrete Sludge to Remove Lead from Water

Abstract

Low-crystallinity hydroxyapatite (HAP) was prepared from concrete sludge as a recycling method for concrete waste. The HAP was prepared from model samples of concrete sludge and phosphorus wastewater, and its capacity to remove lead from water was investigated. Lead ions were quickly removed by the HAP particles. Some of the prepared HAP samples reduced the lead concentration of the water to within the Japanese standard for industrial effluent (0.1 ppm). The lead removal capacity of the concrete sludge-derived HAP (506 mg/g) was comparable to that of reagent grade HAP. Lead in water was removed in the form of Pb3(CO3)2(OH)2. These results indicate that HAP prepared from concrete sludge can be applied to removal of lead ions from water.