Application of Magnetized Cacti Biomass as Flocculants in Water Treatment

Access to adequate quality water in certain rural areas presents a significant research challenge. This study investigates four magnetized materials with potential application in water treatment as alternatives to conventional flocculants based on iron and aluminum salts. Mucilage and cellulose were extracted from the cacti biomass of Stenocereus griseus and Melocactus sp. These biopolymers were subsequently magnetized via crosslinking with magnetite (Fe₃O₄). Jar tests were conducted on natural water samples from selected sources to determine the efficacy and optimal dosage of the resulting bioflocculants for turbidity removal. The physicochemical and magnetic properties of the materials were characterized using Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Performance was assessed by evaluating zeta potential (ζ) values, the percentage reduction in turbidity, and achievement of nephelometric turbidity units (NTU) ≤ 2, conforming to Colombian drinking water standards. Results (removal efficiencies of 98.15% for turbidity, 80.5% for total suspended solids (TSS), and 60.8% for chemical oxygen demand (COD), indicate that magnetic modification of biopolymers, particularly mucilage, offers a promising approach for reducing water turbidity. Furthermore, the influence of pH on the flocculation process was investigated, revealing enhanced performance under acidic conditions. This work has significant implications for the future application of magnetic materials in water treatment and may contribute to addressing water quality challenges in rural communities. This research contributes to the broader pursuit of solutions for social, economic, and environmental issues facing the country, aligning with the United Nations Sustainable Development Goals (SDGs) of the 2030 Agenda.

Graphical Abstract