Application of synthesized Fish Scale Chito-Protein (FSC) for the treatment of abattoir wastewater: Coagulation-flocculation kinetics and equilibrium modeling

This work explores the use of chito-protein synthesized from fish scale as a bio-coagulant in Abattoir wastewater (AW) treatment. The effect of settling time, pH, adsorbent dosage, and temperature of coagulation on Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), turbidity, and Color from the AW sample were studied. The kinetic study was carried out using four process equilibrium models which are Langmuir, Freundlich, Frumkin, and Tempkin to investigate the mechanism of the reaction. SEM and FTIR spectral analyses were used to evaluate the surface morphology and chemical composition of the bio-coagulant. A low pH, 3 g of dosage in 250 mL vessel, settling period of 30 to 35 min, and temperatures of 323 K for all parameters resulted in the most efficient pollutant elimination. Turbidity, however, had an optimal temperature of 313 K. The result of the study shows that Langmuir model provided the best fit from the equilibrium models compared to Freundlich, Frumkin, and Temkin's models. The experimental data suited the Elovich, Pseudo-first, and Second order kinetic models’ analysis and the high values of the regression coefficient of 0.90 supported the idea of perikinetic as the governing mechanism of coag-flocculation in the study. It can be inferred from this study that fish scale as a bio-coagulant provides a significant resource for abattoir wastewater treatment.