From inactive biomass in removing amoxicillin to new active chitosan-biomass composite adsorbents

• Olive leaf biomass was transformed into novel chitosan-biomass composites for amoxicillin removal. • Characteristics techniques confirmed improved functionality with chitosan incorporation. • The composite with the highest chitosan content exhibits superior adsorption capacity. • Composites offer eco-friendly, sustainable water treatment using agricultural and aquacultural by-products. The increasing issue of water pollution by pharmaceuticals, such as amoxicillin, emphasizes the need for sustainable and environmentally friendly solutions that can overcome the shortcomings of traditional methods. This study concentrates on synthesizing and evaluating new chitosan-olive leaf biomass composites (COLCs) for amoxicillin (AMX) removal from water. A combination of olive leaf biomass (OL biomass), derived from a widely available agricultural waste, with different amounts of chitosan, an aquacultural by-product, led to the development of three unique composite adsorbents; 2COLC, 4COLC, and 6COLC. The SEM, BET, EDS, zeta potential, and FTIR analyses were employed to characterize the newly synthesized adsorbents. The COLCs presented a higher surface area than the OL biomass rising from 10.032 m 2 /g for the biomass to 14.404 m 2 /g for 2COLC, 31.279 m 2 /g for 4COLC, and 43.294 m 2 /g for 6COLC, which increased due to the higher chitosan incorporation improving the porosity. The adsorption capabilities of the OL biomass and COLCs for AMX were examined. The OL biomass showed negligible adsorption efficiency while COLCs exhibited enhanced adsorption capacity, which increased with increasing chitosan content. The adsorption capacities, as indicated by the Freundlich constant increased with chitosan content, ranging from 0.011 to 0.04 (mg/g)(L/mg) n for 2COLC and 6COLC, respectively. Thermodynamic studies indicated that the adsorption process for COLCs was spontaneous, endothermic, and thermodynamically favorable. Based on these findings, it can be concluded that the COLCs have the potential as efficient eco-friendly, and sustainable adsorbents for removing pharmaceutical pollutants from water sources such as AMX.