Adsorption of polyvinyl alcohol from wastewater by sintered porous red mud

Several types of red mud-based porous materials (RMPM) and other raw minerals via different processes were prepared and characterized using X-ray diffraction (XRD) analyses and scanning electron microscope (SEM) observations. Using the polymer sponge method, a 72% apparent porosity could be reached compared with 64% by adding a pore-forming agent. These materials were tested for their adsorption of polyvinyl alcohol (PVA) from simulated textile wastewater. The best mass ratio of RMPM to PVA solution was 50:100 with a removal maximum of 25.8% after they were in contact for 50 min. The adsorption rate and kinetics could be better described by Lagergren's pseudo-second-order model in comparison with the pseudo-first-order model.