Narrow Results

In this study, we focused on the investigation of phosphate removal using calcium oxide (CaO) and calcium hydroxide (Ca(OH)₂) which are mainly from the calcined shells as adsorbents. Hydroxylapatite Ca${}_{10}$(PO₄)₆(OH)₂, the component of industrial fertilizer was formed after the adsorption process following the XRD results. The phosphate removal increased from 20% to 97% with the aid of the mixture of flocculants alginic acid (AA), NaHCO₃ and CaCl${}_2\cdot$ 2H₂O in the case of 50 ppm phosphate concentration when the samples were filtered through 2.7 $\mu$m particle retention filter paper which is roughly equivalent to the case of phosphate removal rate of 0.2 $\mu$m membrane filter paper without flocculants (99%). The results suggest that AA, NaHCO₃ and CaCl${}_2\cdot$2H₂O as the flocculants are effective for phosphate removal from 20 to 100 ppm.