KINETICS OF PHARMACEUTICAL WASTEWATER TREATMENT BY COAGULATION USING BLEND OF PERIWINKLE AND SNAIL SHELL DERIVED CHITIN

The kinetics and mechanisms of pharmaceutical wastewater treatment by coagulation with chitin extracted from and blended with periwinkle and snail shells were studied. The objective of the study was to develop a coagulant that is sustainable, inexpensive, and environmentally friendly to replace conventional chemical coagulants such as alum and ferric chloride. The chitin was extracted, characterized by Fourier Transform Infrared Spectroscopy (FTIR), and tested for the treatment of synthetic pharmaceutical wastewater for various operating conditions with respect to pH, dosage, mixing time, and settling time. The study assessed the effect of these parameters on the removal of pollutants, which included Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD), and turbidity. The analysis showed that the optimum was achieved at pH approximately 7.0, dosages of 1.5 g/L, mixing time of 20 minutes, and settling time of 30 minutes. Turbidity reduced from the initial concentration by about 89%, while COD and BOD had a reduction of 81.5% and 82.3%, respectively. The pH of the treated wastewater (7.08) was almost neutral, indicating that the bio coagulant did not bring about significant pH alteration. The blended chitin followed a pseudo-second-order kinetic model (R² = 0.983) suggesting that chemisorption is the rate-limiting step, with interactions of surface functional groups dominating such that diffusion is not significant. In comparison, the blended bio coagulant demonstrated COD reduction to equal or above that by alum and ferric chloride, indicating the superior treatment performance of the introduced blended chitin and compatibility with environmental safety. This shows that blended periwinkle-snail shell chitin is a good option that can be applied commercially in pharmaceutical wastewater treatment