Natural polymer-based bioadsorbents for wastewater treatment

Abstract

Due to rapid urbanization, industrial growth, and rising living standards, the intensification of global water pollution has become a pressing environmental and public health challenge. Effective and sustainable treatment technologies are urgently needed to mitigate these threats. Adsorption is a well-known, effective and sustainable approach because it is simple to operate, cost-effective, and highly efficient. In this context, porous materials derived from natural biopolymers have gained prominence as super-adsorbents for wastewater treatment due to their renewable origin, biodegradability and environmental compatibility. Biopolymers such as cellulose, chitosan, alginate, starch, and gelatin are often functionalized with electron-rich atoms such as nitrogen (N), oxygen (O), sulfur (S), metals, or fillers. These biopolymers exhibit a high affinity for a broad range of pollutants via mechanisms such as ion exchange, hydrogen bonding, and surface complexation. Recent advances in hybrid composites have enhanced the mechanical stability, adsorption capacity, and reusability of these materials, enabling them to achieve pollutant removal efficiencies of up to 99%. This review provides an extensive overview of the modification strategies, adsorption mechanisms, and performance metrics of biopolymer-based porous adsorbents.