Recycling of wastewater from tannery industry through membrane-integrated hybrid treatment using a novel graphene oxide nanocomposite

Abstract

An advanced oxidation-nanofiltration integrated hybrid process is developed in this study for treatment of leather industry wastewater to reusable criteria. The process uses a laboratory-synthesized graphene oxide-based nanocomposite in the final polishing step for ensuring high degree of purification. All investigations are done on live tannery wastewater having high level of recalcitrant pollutants such as chromium (8.2 mg L−1), COD (10,500 mg L−1), TDS (7420 mg L−1), chloride (4620 mg L−1) and sulfide (2560 mg L−1). Performance of the developed membrane is also compared with commercially available counterpart. Detailed characterization (FTIR, SEM-EDX, and BET) and experimental evidences reveal high mechanical strength, hydrophilic nature and high selectivity in removal of ionic contaminants. The integrated process successfully removes chromium (99.5%), COD (>99%) and TDS (>96%) while retaining the essential ions (Ca2+, Mg2+) substantially. A sustained high flux hovering around 200 L/ (m2 h) at 16 bar pressure over a reasonably long period (150 h) is an indicator of development of a potential new technology in effective treatment of leather industry wastewater.