Fabrication of PVA-PVC composite membrane for enhanced TDS removal from tannery effluent: sustainable water treatment approach

The environmental burden of tannery wastewater, characterized by high levels of total dissolved solids (TDS) and other contaminants, presents a significant challenge for sustainable water management. This study addresses this issue by developing a novel polyvinyl alcohol (PVA) and polyvinyl chloride (PVC) composite membrane optimized for efficient TDS removal from tannery effluent. The membrane was fabricated using a solution casting technique, with glutaraldehyde employed as a crosslinking agent to enhance mechanical properties and stability. Characterization techniques, including Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), zeta potential analysis, and contact angle measurements, were used to evaluate the membrane's surface chemistry, morphology, and hydrophilicity, which are crucial for pollutant separation. Performance testing demonstrated that the membrane achieved a TDS removal efficiency of 91.73% at an optimal pH of 8 and a transmembrane pressure of 3.5 bar, with a permeability of 194 Lm^-2 h^-1 bar^-1. Additionally, substantial reductions in turbidity (94.51%), chemical oxygen demand (COD, 91.91%), biological oxygen demand (BOD, 89.70%), salinity (80.57%), and total suspended solids (TSS, 96.45%) were observed. The membrane exhibited impressive mechanical properties, with a tensile strength of 44 ± 0.43 MPa, 150 ± 0.67% elongation at break, Young's modulus of 750 ± 0.47 MPa, and flexibility of 23 ± 0.53%, indicating its flexibility and durability. Its partial biodegradability and potential for scalable production contribute to its environmental sustainability. This work establishes the PVA-PVC composite membrane as a promising and cost-effective solution for industrial wastewater treatment, offering a sustainable approach to mitigating water pollution in the leather industry.