Novel pervaporation separation of PVA/CS blend membranes for the removal of DMF from industrial wastewater

Abstract

Achieving satisfactory separation of N, N‐Dimethylformamide (DMF)/water is still challenging in industrial wastewater treatment. To address this issue, a novel method involving pervaporation (PV) separation using polyvinyl alcohol/chitosan (PVA/CS) blend films is proposed. Various characterization methods confirmed the strong compatibility between PVA and CS, and the blending improved their mechanical properties and thermal stability. Heat treatment significantly reduced the swelling degree of the membranes. In a binary aqueous system with low concentrations of DMF, controlled separation can be achieved by adjusting the blending ratio of PVA to CS. The membranes exhibited preferential selectivity for DMF when the CS content is 40–75 wt%, which allowed for the concentration and recovery of DMF. At 20 °C with a feed of 10 wt% DMF solution, 2 h heat‐treated PVA/CS‐50 membrane exhibited the best performance, which could be attributed to its strong hydrogen bonding force, with a total flux of 484.09 g m−2 h−1 and a separation factor of 5.41 for DMF. The PVA/CS blend membranes exhibit excellent acid and alkali resistant and are promising candidates for the separation and recovery of DMF from industrial wastewater by membrane technology.