Development of Magnetically Recoverable Multifunctional Hybrid Spheres Integrating Adsorption, Photocatalysis and Antimicrobial Activity for Water Sanitization

Multifunctional hybrid spheres were developed via ionic gelation, using sodium alginate as an encapsulating matrix to integrate TiO2, Fe3O4, activated carbon, hypochlorite-impregnated clinoptilolite zeolite, and metallic copper, followed by chitosan coating and glutaraldehyde cross-linking to enhance mechanical stability. The material combines photocatalytic, adsorbent, antimicrobial, and magnetic functions in a single system, expected to support partial treatment of contaminated water. X-ray diffraction confirmed the expected crystalline phases with no impurities. Physicochemical evaluation showed reductions in turbidity (1.8 to 0.7 NTU), total hardness (306 to 150 mg/L), iron (0.4 to 0.01 mg/L), and lead (<0.001 mg/L), while free residual chlorine remained within permissible limits. Microbiologically, fecal coliforms decreased from 83 to <1.5 CFU/100 mL and total coliforms from 839 to 19 CFU/100 mL. Photocatalytic activity, evaluated using methylene blue, showed an absorbance decrease from 0.38 to 0.17 A.U. over 4 h, corresponding to a blank-corrected removal of 95.5% relative to clean water, fitted to a pseudo-first-order kinetic model (R2 = 0.8868). These results demonstrate a synergistic effect among adsorption, photocatalysis, disinfection, and magnetic recovery, positioning the hybrid spheres as a promising alternative for sustainable water treatment technologies.