Adsorption properties on methylene blue of waste construction slurry cross-linked by guar gum/borax-based hydrogel

The guar gum/borax-based hydrogel system was employed to rapidly consolidate waste construction slurry to form porous soft solid, which could effectively mitigate the impact of waste construction slurry on the environment. The adsorbability of porous soft solid on methylene blue from cationic dye wastewater was studied to explore new utilization way in the paper. For the methylene blue solution with the pH of 8 and concentration of 30 mg·L−1, when the dosage of porous soft solid was 0.15 g·mL−1, the adsorption equilibrium was reached at 32 h, and the removal rate of methylene blue by the porous soft solid was up to 82.96 %. The X-ray diffraction and Fourier Transform Infrared Spectroscopy analysis indicated that both the hydrogel and clay particles in the porous soft solid were involved in the adsorption of methylene blue. The pseudo first-order kinetic equation and the Weber-Morris intraparticle diffusion equation can be used to describe the adsorption process on methylene blue by the porous soft solid.