Abstract:Bentonites organic modified by cetyltrimethyl ammonium bromide (CTAB) was used as coagulant aid. The elimination of PFOS/PFOA and turbidity in water by enhanced coagulation were studied with PAC and CTAB-bentonite. The effects of dosage of PAC and CTAB-bentonite, pH value, initial turbidity on the elimination of PFOS/PFOA were tested. The results showed that CTAB intercalated into bentonite increasing the layer space meanwhile, the specific surface area, cation exchange capacity and organic carbon content were greatly improved after organic modification. PFOS/PFOA removal efficiency reached 76% and 70% respectively by adding 20mg/L of PAC, 30mg of CTAB-bentonite and controlling the pH value among 6 and 7. The removal rates of PFOS/PFOA increased with the increasing dosages of CTAB-bentonite. The best range of pH values was 6~7. The Zeta potential reached the maximum at pH=6.0, while pH=7.0was close to zero in the coagulation process. The removal rates of PFOS/PFOA increased with the turbidity increasing in raw water.
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