Sustainable composites based on banana and pomegranate waste incorporated into Polyvinyl Chloride Matrix for...

The release of synthetic dyes into water bodies presents a major environmental risk, highlighting the need for sustainable treatment methods. Biosorbents derived from agricultural waste demonstrate high effective candidate for dye removal, however their practical application is limited by the challenge of separating of their fine powder from treated water. In this study, eco-friendly, low-cost, and easily recoverable biosorbent materials were developed for the removal of methylene blue (MB) from wastewater. Banana and pomegranate wastes were micro-ground using ball mill, then incorporated into polyvinyl chloride (PVC) (10% agricultural waste relative to the polymer) to form composite films [PVC as a blank, PVC-Banana (PVC-B) and PVC-Pomegranate (PVC-P)] in order to facilitate their harvesting after their usage in the treatment process. Investigation techniques revealed that the synthesized composite films exhibited a highly porous architecture with a porosity ranging from 70% to 73% and a swelling capacity between 472 and 488 wt%. SEM revealed the porous structural of the composite and ART- FTIR revealed successfully incorporated of the agricultural waste within the polymer matrix. Brunauer-Emmett-Teller (BET) analysis revealed remarkably high specific surface areas of 1057 m²/g for PVC-B and 531.9 m²/g for PVC-P, with pore volumes of 1.90 and 1.08 micrometer, respectively. The composite films were optimized for MB removal by studying the effect of each variable factors via One Factor at a Time (OFAT) followed by factorial design experiments. Results showed that, MB adsorption capacity reached about 75.2 and 66.4 mg/g using 4 g/l PVC-B and PVC-P films, respectively. The adsorption data were best described by the Langmuir isotherm model (R² = 0.997 for PVC-B and 0.998 for PVC-P), with a maximum adsorption capacity (q ^max) of 79.89 and 70.92 mg/g, respectively. Kinetic studies revealed that the adsorption process followed the pseudo-second-order model (R² ≥ 0.998), suggesting a chemisorption mechanism. The PVC-B and PVC-P displayed good adsorption efficiency and stability in the removal, recovery and reuse of MB for five cycles. Lastly, it can be concluded that the composite films are eco-friendly, cost effective and easily recoverable biosorbents for MB removal.