Electrospun nanofibrous composites based photocatalytic-adsorbents for remediation of Congo red dye from water

Nanofiber is one of the most promising materials used for adsorption and photocatalytic applications in recent times by industries. Treated effluents discharged into water bodies are still toxic to aquatic organisms and human. Industries such as pharmaceutical, textile, food, leather, paper and cosmetic products generate million tons of dyes, and their removal is one of the major concerns for policy makers. The objective of the present work is to develop electrospun nanofibrous composites as potential dye removal membrane-based lab-scale technology for water purification. The hybrid nanofibrous PAN/NiO-ZnO and PAN/CuO-ZnO composites were synthesized by electrospinning-calcination method. The photocatalytic-adsorption properties and their physico-chemical characteristics were investigated using Congo red (CR) dye. Sunlight mediated photocatalytic degradation studies revealed that 98 ± 1.06% and 97 ± 1.15% of CR dye degraded in first 100 min by using 10 mg of PAN/NiO-ZnO and PAN/CuO-ZnO nanocomposites. It was inferred that the photocatalytic reactions followed first order kinetics and corresponding rate constants were evaluated. Adsorption studies under different experimental conditions shows > 85% removal within 25 min and achieved 99% in extended 175 min. Isothermal and kinetics studies have shown that Freundlich model fitted best and follows the pseudo second order kinetics. In a nutshell, we have investigated the dual photocatalytic-adsorption characteristics of nanofibrous composites and studied their dye removal efficacy. Lab-scale experimental results recommended that the validation of such nanofibrous composites could be done at the pilot-scale studies which could be the potential breakthrough for membrane-based technologies in water purification and management.