Promising adsorptive materials derived from agricultural and industrial wastes for antibiotic removal: A comprehensive review

The development of novel materials and their application as adsorbents to improve water quality is one of the branches of materials science that has advanced significantly in the last decade. Due to the contamination of water resources with antibiotic residues, and the concern to contribute to the development of antibiotic resistance, scientists have tapped into agricultural and industrial wastes in order to transform them into new functional adsorbents that allow the adsorption of these pollutants. This review aims to summarize the different types of adsorptive materials that can be prepared using these residues and their application for removing antibiotics. From the reviewed literature, the adsorbents were classified as raw materials, surface-modified adsorbents, waste-based composites, carbon-based materials, and other adsorbents like zeolite, nano-hydroxyapatite, nano-cellulase, nano-silica, among others. Biochar and hydrochar are two of the most studied carbonaceous materials, with adsorption capacities ranging from 10 to 944 mg/g. Other leading adsorbents from the same family include mesoporous carbons, hierarchical and heteroatoms-doped porous carbons, and bio graphene, with surface area and adsorption performance over 1000 m²/g and 500 mg/g, respectively. The most outstanding material prepared from waste was zeolite analcime, produced from electrolytic manganese residue, removing 1922 mg/g for roxithromycin. In addition, new methodologies or combined methods to produce these adsorbents, including new modifier agents (ionic liquids and deep eutectic solvents), templating, self-templating, doping techniques, and thermo-chemical approaches were reviewed for the first time. Furthermore, particular emphasis was given to photocatalyst-loaded adsorbents due to their synergistic effect of adsorption and degradation of antibiotics. Finally, novel methodologies to regenerate saturated adsorbents were discussed, such as UV radiation-assisted regeneration and ultrasound.