Permalink : http://hdl.handle.net/2115/90929

JaLCDOI : 10.14943/bull.fish.73.2.47

KEYWORDS : Biodegradable flocculant;Flocculation;Gelatin;Aluminum;Kaolin

The flocculation ability of aluminum-gelatin (Al-GL) composite flocculant was examined with kaolin suspensions as functions of Al concentration (CAl), GL concentration (CGL) and pH.　The flocculation performance was evaluated in terms of supernatant clarity or clarification efficiency (CE) on jar-test. Under the condition at CAl < 2.0 mM and pH 7±0.5, the ratio, CAl/CGL, was the major factor affecting the flocculation performance of Al-GL composite flocculant.　CE increased sharply with increasing CAl/CGL at CAl/CGL < 20 mmol/g, and decreased gradually at CAl/CGL > 20 mmol/g.　CE increased sharply with increasing pH from pH 4 to pH 5, and decreased sharply with pH from pH 8 to pH 9.　Based on the experimental results and the calculated distribution of hydrolysis products of Al(III), the flocculation mechanism of kaolin by Al-GL composite flocculant was discussed.