Removal of lysozyme as protein waste using weak ion exchange nanofiber membrane in a batch system: Linear and nonlinear model analysis

This study investigates the removal of lysozyme, a common waste protein, using weak ion-exchange nanofiber membranes (P-COOH) to address challenges in protein waste management and wastewater treatment. Protein waste, prevalent in industrial and biological processes, contributes to environmental pollution and increases treatment complexity if not effectively managed. Conventional methods often face limitations in selectivity and efficiency, highlighting the need for innovative solutions. The P-COOH nanofiber membrane, with its high surface area and tailored functional groups, was engineered to optimize protein removal. The removal process was analyzed in a batch system at an optimal pH of 7. Various kinetic models, such as pseudo-first-order, pseudo-second-order, Avrami, and intra-particle diffusion, were applied to elucidate rate-controlling steps. In contrast, isotherm models, including Langmuir, Freundlich, and Temkin, characterized the equilibrium of the removal process. Complete elution of removed lysozyme was achieved using a 0.3 M NaCl solution, yielding an equilibrium binding capacity of 315.24 mg/g on the nanofiber membranes. These findings indicate that the Avrami nonlinear model best describes lysozyme removal's complex, multi-step kinetics. In contrast, the Langmuir linear model accurately fits the equilibrium data, suggesting monolayer removal on a homogeneous surface. The successful reusability of the membranes underscores their potential for sustainable lysozyme removal from wastewater, offering a viable solution for improved waste management in industrial applications.