Flocculation kinetics and dewatering studies of quaternized cellulose derived from oil palm empty fruit bunches

Flocculation kinetics and sludge dewatering of kaolin suspension as influenced by various q-EFBC flocculant dosing were studied. In this study, 62.5mg L-1 q-EFBC exhibited the highest turbidity removal efficiency of 99.53 +/- 0.08%. The adsorption rate of kaolin towards 12.5mg L-1 to 112.5mg L-1 q-EFBC dosing increased rapidly for t<60 s and became gradual before completion. The mass transfer coefficient was independent of dosage. The experimental data best-fitted the non-linear pseudo-first order due to the R-2>0.99 and the lowest standard deviation. The highest rate constant of particle aggregation and breakage was consistent with the highest rate constant of particle collision, which led to the highest turbidity removal at the optimal dosage. The rate-limiting steps in the flocculation process were particle collision and aggregation since their rate constant was lower than the other kinetic constants. The lower values of SRF and TTF of treated sludge as compared to the untreated one confirmed the improvement in the dewaterability characteristic. The lowest TTF (37.44 +/- 1.44 s) and SRF (1.49x1010 m kg(-1)) was observed for 62.5mg L-1 q-EFBC. The high turbidity removal and improved sludge dewaterability indicate the potential application of q-EFBC for water treatment.