Preparation and Coagulation Performance of Polyaluminum Lanthanum Silicate Coagulant

Abstract

In order to address the growing problem of water pollution caused by the excessive discharge of contaminants and provide a better aquatic ecosystem for the public, increasing attention has been paid to the harmlessness and efficiency of coagulation. In this study, polyaluminum lanthanum silicate (PALS) was synthesized through co-polymerization as a novel coagulant to treat wastewater. FTIR, XRD, and SEM were used to analyze the morphology and structure of the material, which further confirmed that the PALS was successfully synthesized. The results indicated that PALS had a great performance in the treatment of a kaolin–humic acid suspension under the optimal synthesis conditions with Al/Si = 3, La/Si = 0.1, and basicity = 0.7. Compared with conventional coagulants, PALS exhibited a better performance at a low coagulant dose and could achieve a good removal effect for an ultraviolet wavelength less than 254 nm (UV254) (83.87%), residual turbidity (0.49 NTU), and dissolved organic carbon (DOC) (69.57%) at the optimal conditions. Additionally, the PALS showed a better effect on phosphate removal than other coagulants did, where the removal efficiency could reach 99.60%. Charge neutralization and adsorption bridging were the potential wastewater treatment mechanisms employed by the PALS, which showed varied contributions under different pH levels. The results indicated that PALS can be a promising coagulant in water treatment.

Recent advances of silicate materials for wastewater treatment: a review

“…This accessibility and advantages of environmental friendliness have spurred significant research interests and widespread applications in diverse fields [30,31]. Notably, silicates have found utility in drug delivery platforms [32], energy conversion [33], lithium-ion batteries [34], and wastewater treatment [35,36]. In the specific context of water purification, silicates, whether synthesized or natural silicate materials have emerged as promising catalysts or adsorbents for removing contaminants from water [37,38].…”