Optimization, Characterization, and Ammonia Nitrogen Adsorption Study of Novel PVA-SA-VMT Composite Carrier

School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin 300401, P.R. China

^* Renzhijun: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

To address the low ammonia nitrogen removal efficiency of traditional activated sludge processes under low-temperature conditions, this study developed a novel PVA-SA-VMT composite immobilization carrier using polyvinyl alcohol (PVA), sodium alginate (SA), and vermiculite (VMT). The optimal formulation (7% PVA, 2.5% SA, and 2% VMT) was determined through single-factor experiments. The results indicate that the composite carrier possesses high mechanical strength and excellent chemical stability, with a 24-hour TOC leaching amount of only 14.1 mg/L, 72% lower than that of the pure PVA-SA carrier. The interior of the composite carrier features a porous structure, which enhances the effective diffusion coefficient of ammonia nitrogen. Its adsorption mechanism follows second-order kinetics and the Freundlich isotherm, with vermiculite interlayer ion exchange being a spontaneous endothermic process. The synergistic mechanism of ’scaffold support–adsorption enrichment’ provides a solid material foundation for constructing an efficient low-temperature nitrification system in wastewater treatment.