The efficiency of phosphate removal in aqueous solution by CaO, Ca(OH)2 and CaCO3 has been studied in this work. Batch of experiments conducted with the initial phosphate concentrations from 5 to 1000 ppm have shown that CaCO3 could be applied for phosphate removal at low concentration with the maximum phosphate removal capacity at 4.0 mg/g. In contrast, the highest phosphate removal capacity of CaO and Ca(OH)2 was 287.36 mg/g and 235.21 mg/g at initial concentration of 500 ppm, and phosphate removal rate was 85% and 97% at initial concentration of 5 ppm. Crystalline hydroxylapatite was detected in the precipitate by XRD analysis. The molar ratio of P in the precipitate and Ca in the materials (CaO and Ca(OH)2) was 0.52 and 0.56 at initial concentration of 500 ppm, compared to P/Ca molar ratio of 0.6 in hydroxylapatite. Moreover, hydroxylapatite is the main component of fertilizer that can be applied for agriculture.
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