Abstract:
In this study we compared utilization of FeCl3 extracted leucaena protein and FeCl3 to treat synthetic Congo
red wastewater. The extraction was done at leucaena seeds kernel to 0.5 M FeCl3 solution ratio 1:20 with various initial
extraction pH (2 to 9). It was observed that pH 2 gave the highest protein concentration of 1.7 mg eq BSA/mL, compared
to other pH. The extract obtained at this condition was further used in the coagulation study. At various initial
coagulation pH (2 to 10), the highest Congo red removal was observed at initial coagulation pH 6. This result indicated
that FeCl3 was the active coagulating agent despite of the presence of leucaena extract, with charge neutralization
coagulation mechanism. Variation of coagulant dosage was done from 4 to 44 mL/L. At dosage 4 to 12 mL/L, low color
removal was observed due to insufficient coagulant to neutralize Congo red molecules. Over addition of coagulant also
lowered the coagulation efficient, and increased the sludge volume due to colloid re-stabilization phenomenon. The best
Congo red removal was observed at coagulant dosage 20mL/L FeCl3 – leucaena extract combination with color removal
of 95% with 9 mL/L sludge volume, slightly higher compared to FeCl3 only. Based on this result, it could be concluded
that FeCl3 could act effectively as coagulant without the presence of leucaena extract.
