Microplastic removal from water using mucilage extracted from <i>Opuntia ficus-indica</i> as a natural bio-coagulant

MP pollution has emerged as a critical environmental concern, posing significant risks to aquatic ecosystems and human health. Conventional treatment processes often fail to remove MPs efficiently, highlighting the need for sustainable and cost-effective alternatives. This study investigates the potential of Opuntia ficus-indica mucilage as a natural, eco-friendly coagulant for the effective removal of polyethylene (PE), polystyrene (PS), and polyethylene terephthalate (PET) MPs from water. Experiments were designed using Response Surface Methodology (RSM) to assess the influence of operational parameters, including MPs concentration, mucilage dosage, contact time, and settling time. Laboratory-scale trials were conducted with Opuntia ficus-indica mucilage doses of 30, 65, and 100 mL under varying experimental conditions. The results indicated that removal efficiency increased with dosage up to an optimum level, followed by a decline due to overdosing effects. Maximum removal efficiencies were observed at 65 mL, achieving 77.14% for PE, 83.33% for PET, and 86.67% for PS. SEM analysis revealed floc formation through polymer bridging and adhesion, while EDX confirmed the presence of mucilage-derived elements on MP surfaces. The findings demonstrate that Opuntia ficus-indica mucilage is an effective, eco-friendly coagulant for MP removal, offering a promising sustainable approach for water treatment applications.