Multicomponent steady-state modeling, performance optimization and prediction of cleaning frequency for treatment of cellulosic manmade fibre industry stream using polysodium 4- styrenesulfonate (PSS) incorporated nanofiltration membrane

Abstract

Effect of polysodium 4-styrenesulfonate (PSS) in the skin layer on performance of nanofiltration (NF) membrane was analyzed for treatment of saline stream from manmade fiber industry. The NF membrane with 0.05 % (w/w) PSS concentration in aqueous phase had better hydrophilicity (contact angle: 33°) and water flux of 27 L.m^-2.h^-1 along with significant salt rejection (Na₂SO₄: 90 %, CaSO₄: 85 % and NaCl: 80 %) at transmembrane pressure 8.3 bar and crossflow rate 100 L.h^-1. A long-term study with the wastewater showed that the intermittent cleaning of the membrane every 6 h led to 16 L.m^-2.h^-1 average permeate flux and sulfate rejection above 95 %. A two-component, steady-state model was used to quantify the performance of the selected membrane. Based on the fouling study, a semi-empirical theory was proposed to identify the cleaning frequency. The theory developed is useful for the operation, maintenance and recovery of the divalent salts from reject stream of such industry.