Rapid solidification of Portland cement/polyacrylamide hydrogel (PC/PAM) composites for diverse wastewater treatments

Cementitious solidification is an effective but time-consuming method for waste disposal, and the incorporation of polyacrylamide hydrogel in Portland cement paste is a simple way to enhance the time-efficiency of cementitious solidification. In this study, a series of Portland cement/polyacrylamide hydrogel (PC/PAM) composites suitable for the wastewater treatment were prepared by a one-pot method and their time-dependent reaction processes, mechanical properties and microstructures were tested. Based on the gelation time method, PC/PAM composites showed great solidification efficiency when treating simulated radioactive liquids, organic dye waste and solutions with strong alkalinity and acidity. At temperatures ranging from 5 °C to 40 °C, it took only a few minutes for these composites to solidify wastes. Also, PC/PAM composites containing wastes had a compressive strength that is more than 2 MPa after reacting for 3 days and were suitable for landfill or secondary treatments. The rapid gelation and sufficient strength development demonstrated that PC/PAM composites have great potential for application in solidifying multi-component wastes, especially in some emergency circumstances. Novel and stable PC/PAM composites were designed and could serve as a matrix for rapid solidification of various wastewaters, greatly facilitating the applicability of the cementitious solidification method in emergency circumstances.