H 2 S adsorption performance of alkali lignocarbon/PVA composite membrane

In this work, lignin carbon-based membranes were prepared for H 2 S adsorption. Alkali lignin was carbonized to obtain alkali lignocarbon (CLA). Using the CLA and polyvinyl alcohol (PVA) as raw materials, glycerol and water as plasticizers, and nano-CuO and Cu 2+ as dopants, CLA/PVA, CuO-CLA/PVA-1, and Cu-CLA/PVA-2 composite membranes were prepared by solution casting method. The structures of these membranes and their H 2 S adsorption properties were then analyzed. The results show that with a membrane solution water-alcohol ratio of 3:1 and 2 wt% CLA content, the prepared CLA/PVA membrane can adsorb H 2 S for 30 min. The CuO-CLA/PVA-1 and Cu-CLA/PVA-2 membranes, which were obtained after doping with nano-CuO and Cu 2+ , demonstrate significantly improved deodorization performance compared with that of CLA/PVA. The Cu-CLA/PVA-2 membrane can adsorb H 2 S for up to 75 min and also demonstrates better mechanical properties. The H 2 S adsorption capacity of this membrane is up to 0.27 mol/kg. Structural analysis shows that the veneers of the three composite membranes are smooth and that doped copper is evenly distributed in the membranes as nano-CuO. The surface functional groups of the CLA/PVA, CuO-CLA/PVA-1, and Cu-CLA/PVA-2 membranes are similar and play a positive role in H 2 S adsorption. Nano-CuO is the main active site for H 2 S adsorption in the Cu-containing composite membranes.