Low-Cost Adsorbents for Water Treatment: A Sustainable Alternative for Pollutant Removal

This review addresses the potential of low-cost adsorbents (LCAds) derived from agro-industrial and marine residues as sustainable alternatives for water purification. Although raw biomass offers economic advantages, its application is often limited by low surface area and reactivity. Consequently, this paper examined physicochemical modifications—such as pyrolysis, acid/alkali activation, and surface grafting—that enhance adsorptive properties. The superior performance of these modified materials in removing heavy metals, dyes, pesticides, and pharmaceuticals is highlighted. Furthermore, the transition from laboratory scale to industrial application faces key hurdles, such as biomass variability, reactor engineering, and regulatory gaps. Finally, future perspectives are presented, focusing on the integration of LCAds into hybrid treatment systems and their pivotal role in the circular economy for decentralized water management.