Achieving Win-Win Outcomes with Cerium-Loaded Porous Aluminum Sludge Hydrogel Microspheres for Enhanced Phosphate Removal

Abstract

Breaking the technical bottleneck of traditional powdered adsorbent in phosphate adsorption application treatment, a macroscopic high adsorption performance aluminum sludge-based composite hydrogel material was constructed to synergistically solve the problems of water eutrophication and aluminum sludge resourceization. In this study, porous Ce-modified aluminum sludge hydrogel microspheres (Ce-AIS-SA) were prepared to improve the surface chemical structure and microscopic morphology of the macroscopic adsorbent material to enhance the adsorption capacity and achieve effective solid-liquid separation. The best adsorption performance of the material (Ce-AIS12-SA1) was obtained when the Ce-modified aluminum sludge:SA:Na2CO3 was 12:1:1, and obtained the optimal adsorption conditions by Response Surface Methodology (RSM) with the dosage = 1.5 mg/L, pH = 4 and Cphosphate = 50 mg/L. The maximum adsorption of 20.36 mg P/g was obtained by the Langmuir model at 303 K, which was 2.92 times more than virgin sludge. According to the Freundlich and pseudo-second-order kinetic model, the adsorption process is chemisorption; the multi-stage adsorption process is reflected in the intraparticle diffusion and film diffusion models. The main mechanisms combined with the characterization analysis are electrostatic gravity, ligand exchange, and inner sphere complexation. Meanwhile, Ce-AIS12-SA1 shows good resistance to interference in the coexistence of multiple ions. Therefore, porous macroscopic Ce modified aluminum sludge hydrogel microspheres can be recognized as a new material with in-depth, diversified and practical needs for resourceful utilization, which is expected to achieve extensive engineering applications in the future.

Keywords: Resourcefulness, Modification, phosphate adsorption, Response surface method, Holemaking