Characteristics changes in banana peel coagulant during storage process

A banana peel coagulant and its antiseptic modifier were developed using peel of banana, and the changes of surface morphology, bond structure and pH during storage process were investigated with scanning electron microscopy, Fourier-transform infrared spectrometer and pH meter, respectively. Coagulation performance in treating a simulated humic acid water was also studied. The results indicated the number and size of bacterial plaques in banana peel coagulant quickly increased, while the number and size of antiseptic modifier firstly increased, followed by a reduce and then increased again. The main constituent contains carbohydrates, cellulose, lignin, protein, etc. Within storage time of 1–6 days, lots of microorganisms appeared in banana peel coagulant, leading to a rapid decrease in pH and then a rise, while the pH of antiseptic modifier decreased slowly first and finally tended to be stable. Turbidity and color removal by banana peel coagulant decreased from 85.2% and 76.5% at 0 day to 79.5% and 65.9% at 6 days, and to 52% and 44% at 11 days, respectively, while turbidity and color removal by antiseptic modifier decreased firstly and then followed by an increase, only decreasing by 5 and 4.5% at 30 days compared with that at 0 day, respectively. The coagulation performance of antiseptic modifier was a co-coagulation action conducted by natural organic polymers and microorganisms, rather than an individual effect of any of them. Banana peel coagulant and its antiseptic modifier are eco-friendly coagulants probably giving extensive applications in water treatment due to lower cost and biodegradability.