Synthesis of an Eco-friendly Bamboo Cellulose-grafted-ployacrylamide Flocculant and Its Flocculation Performance on Papermaking Wastewater

Flocculation is the first and important step to remove suspended and slightly soluble pollutants in industrial wastewater treatment. Flocculant is just the key element for flocculation process. Polyacrylamide (PAM) is the most widely used flocculant. But it still holds some potential flaws which are ignored by people. An eco-friendly bamboo cellulose-grafted-ployacrylamide flocculant (BC-g-PAM) was then synthesized by free-radical graft copolymerization in homogeneous aqueous solution. The optimal synthesis conditions of the BC-g-PAM was investigated. FTIR, TG, XRD and FESEM were employed to characterize and define its molecular structure and physical characteristics. The BC-g-PAM was also adopted to treat an actual papermaking wastewater. The positive results showed that the BC-g-PAM exhibited an excellent flocculation performance on the papermaking wastewater. The average turbidity removal rate reached 99.7 % and related suspended solids exhibited the corresponding decline. This flocculation also caused a positive effect on the reduction of COD Cr and BOD 5 of the wastewater. Meanwhile, the BC-g-PAM exhibited an excellent biodegradability. Its degradation rate reached 63.4 % at 90 d in soil extracting solution.