This research explored the feasibility of preparing and utilizing a preformed polymeric solution of Al(Ⅲ) for coagulation in water treatment. Slow base(NaOH) injection into supersaturated aluminum chloride and aluminum sulfate solutions did produce high yields of Al polymers useful to water treatment applications. The method of characterization analysis was based on timed spectrophotometer with ferron as a color developing reagent. The hydrolytic Al species were divided into monomeric(Ala), polymeric(Alb), and precipitate(Alc) from the difference in reaction kinetics.
The analysis of PACㅣ's characteristics showed that the quantity of polymeric Al produced at value of r(OHadded/Al) = 2.2 was 83% of the total aluminum in solution, as showing maximum contents and precipitated Al was dramatically increased when r was increased above 2.35. In addition, the characteristics of polyaluminum sulfate (PAS) showed that polymeric Al contained at r = 0.75 was 18% of the total aluminum in solution. The synthesized PACl and PAS were stable during storing period, as indicating negligible aging effect.
The effect of sulfate ion on PACl was dependent on the concentration of sulfate ion. That is, polymeric species decrease and precipitate species increase as sulfate ion concentration increased. It can be concluded that the sulfate cause the formation of Al(OH)3(s) at low pH. However, The effect of calcium ion was negligible for distribution of Al species.

• 한승우(부경대학교 환경공학과) | Seung Woo Han
• 정철우(부경대학교 환경공학과) | Chul Woo Jung
• 강임석(부경대학교 환경공학과) | Lim Seok Kang