Production of modified bentonite via adsorbing lignocelluloses from spent liquor of NSSC process

In this work, the adsorption of lignocelluloses from spent liquor (SL) of neutral sulfite semi chemical (NSSC) pulping process on bentonite was investigated. It was observed that 0.26 g/g of lignin and 0.27 g/g of hemicelluloses from SL were adsorbed on bentonite under the conditions of 50 °C, 100 rpm and 40 g/g SL/bentonite after 3 h of treatment. The adsorptions of lignin and hemicellulose were increased to 1.8 g/g and 0.45 g/g, respectively, via adding 15 mg/g of polydiallyldimethylammonium chloride (PDADMAC) in the system of SL/bentonite. The turbidity and COD removals were improved from 69% to 93% and from 25% to 38% by adding PDADMAC to the SL/bentonite system, respectively. The increase in the heating value of bentonite (from 0 to 15.4 MJ/kg) confirmed the adsorption of lignocelluloses. The modified bentonite can be used as filler in corrugated medium paper production or as fuel.