The hydroxyapatite(HAp) for the present study was prepared with the wastewater sludge from semiconductor fabrication process and it was crystallized in an electric furnace for 30 min at 900℃. The adsorption characteristics of HAp for phosphate ion in aqueous solution has been investigated. The adsorbed ratio of phosphate ion for HAp were investigated according to the reaction time, amount of HAp, concentration of standard solution, pH of solution, and influence of concemitant ions. The amount of adsorbed phosphate ion decreased with the increase of pH due to the mutual electrostatic repulsion between adsorbed phosphate ions and competitive adsorption between phosphate ion and OH- ion in aqueous solution. The maxium amount of the adsorption equilibrium for phosphate ion was about 24 mg/g of HAp. The HAp would likely to be a possible adsorbent for the removal of phosphate ion in the waste water.

The hydroxyapatite(HAp) as a carrier the for ion exchange agent of Ag+ions was prepared in semiconductor fabrication, The Ca/P molar ratio of the HAp was 1.65. The HAp is molded in shape of the antimcrobial ball and then sintered at 1000℃. Ag-containing HAp(HAp-Ag) was prepared by incorporating Ag+ions in HAp crystals through an ion-exchange reaction in solutions containing 0.01M AgNO3. The antimicrobial effect of HAp-Ag for bacteria such as Escherichia coli and Staphylococcus aureus has been investigated. The concentrations of silver in the antimicrobial ball was determined by inductively coupled plasma and the amount of Ag+ion was 9.0㎍/g. The HAp-Ag exhibited excellent antimicrobial effect for bacteria such as E. coli and S. aureus. The bactericidal activity was considered to be caused by direct contact of bacteria with Ag+ions in the HAp crystals. The HAp would likely to be possible as a carrier of antimicrobial metal ions such as Ag, Cu, and Zn by recycling of waste sludge in the semiconductor fabrication process.

The hydroxyapatite (HAp) for the present study was prepared by precipitation method in semiconductor fabrication and the crystallized at ambient to950℃ for 30min in electric furnace. The ion-exchange characteristics of HAp for various heavy metal ions such as Cd2+, Cu2+, Mn2+, Zn2+, Fe3+, Pb2+, Al3+, and Cr6+ in aqueous solution has been investigated. The removal ratio of various metal ions for HAp were investigated with regard to reaction time, concentration of standard solution, amount of HAp and pH of solution. The order of the ions exchanged amount was as follows: Pb2+, Fe3+>Cu2+>Zn2+>Al3+>Cd2+>Mn2+>Cr6+. The Pb2+ ion was readily removed by the HAp, even in the strongly acidic region. The maximum amount of the ion-exchange equilibrium for Pb2+ ion was about 45 ㎎/gram of HAp. The HAp would seem to be possible agent for the removal of heavy metal ions in waste water by recycling of waste sludge in semiconductor fabrication.