Recent advances in carbon-based adsorbent materials for ammonium removal from water

Abstract

This systematic review examines recent advancements in carbon-based adsorbent materials for ammonium removal from water, a critical issue due to contamination from agricultural, domestic, and industrial sources. Elevated ammonium levels disrupt aquatic ecosystems and compromise water quality. Among various technologies, ion exchange and adsorption using materials such as activated carbon (AC) and biochar are highlighted for their efficiency, cost-effectiveness, and environmental benefits. Modified adsorbents, like manganese oxide-loaded AC, significantly enhance removal performance. Biochars, particularly those modified with NaOH and Mg2+, show improved capacities, especially when combined with heterotrophic nitrifying bacteria (HNB). Carbon nanotubes (CNTs), especially multi-walled CNTs, demonstrate superior adsorption capabilities. Direct contact membrane distillation (DCMD) with CNTimmobilized membranes also shows promise. Lignite, a low-rank coal, proves to be an economical natural adsorbent with enhanced performance through aerobic dewatering and oxidation. Future research should optimize these materials for real-world applications, pilot-scale studies, and complex wastewater matrices.