A Biomass Resource Strategy for Alginate-Polyvinyl Alcohol Double Network Hydrogels and Their Adsorption to Heavy Metals

•Bacterial alginate-based hydrogel beads were prepared by cross-linked blending.•Alginate was extracted from Pseudomonas aeruginosa.•PVA/ALG and PVA/ALG/CS have good adsorption ability to Pb and Cr, respectively.•After 5 cycles, the adsorption amount of the hydrogel is above 85% of the original.•This study promotes the resource utilization of activated sludge alginate.