Preparation and Green Modification of Banana Peel Micro- and Nanoparticles for River Water Treatment Applications

Natural coagulants have attracted tremendous attention in water treatment applications due to their unique properties such as availability, non-toxicity, and low cost. Here, we enhanced the coagulation performance of banana peel natural coagulant for river water treatment applications. The powder was initially air-dried and heavy-grinded several times, and then, it was modified by multiple microwave treatments maintaining mild temperature (70–85 °C). The particle size distribution of non-modified and modified particles was 978 ± 37 nm and 93 ± 6 nm, respectively. The coagulation performance of both types was investigated at different parameters including dose concentration, pH levels, and sedimentation time for the treatment of Penang River water. The results showed that the optimum dose, pH, and sedimentation time were 0.6 g/L, 7.2, and 30 min for non-modified particles, and 0.4 g/L, 7.2, and 20 min for the modified one, respectively, which removed 84% and 94% of river water turbidity, respectively. Apart from turbidity, modified particles also showed better performance in terms of reducing water color and total dissolved and suspended solids in addition to chemical oxygen demand. Enhancing the coagulation performance and its mechanisms were proven by morphological characterization, sticky surfaces, and porous structure in the nanoparticles increasing their surface area and thus enhancing bridging formation leading to better coagulation performance. Such green modification has great potential as cost-effective technique in river water treatment.