Ultrafiltration (UF), as one of the most advantageous technologies in drinking water treatment, has been widely employed. However, serious membrane fouling is still an urgent problem. This work evaluated the effect of chitosan-graft-poly(N-n-alkylacrylamide, a sort of moderately hydrophobic chitosan (MHC) <sup>[1,2]</sup>, on the alleviation of UF membrane fouling and the improvement of permeate water quality. At the same time, according to the characteristics of MHC, the optimal mechanism of membrane fouling control and water quality improvement was discussed in detail. The results showed that, additional trace MHC (0.01 mg/L) could effectively control the UF membrane fouling and improve the quality of permeate water; The backwash solution with the temperature of 40 <sup>o</sup>C (facilely achieved using industrial waste heat) could effectively alleviate membrane fouling and improve the quality of permeate water. The MHC promoted the formation of a relatively uniform modified hydrophilic layer on the PVDF membrane surface. Water contact angle determination on the surface of UF membrane demonstrated that such modified layer had excellent hydrophilicity and could effectively improve the performance. The results of molecular dynamics simulation of pairwise interaction among the flocculant, the membrane matrix, and contaminants provided theoretical basis for the experimental results. In addition, the mechanical strength tests revealed that the high temperature of the backwash solution had no damage to the PVDF membrane.

Role of trace moderately-hydrophobic chitosan in ultrafiltration membrane fouling control

ACS Spring Meeting 2021

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