Real sample analysis of persistent Contaminant abatement via synergistic adsorption and Visible-Light Catalysis in continuous flow Reactors

Abstract

The bifunctional nickel ferrite (NiFe₂O₄) decorated zeolitic imidazole framework (ZIF-67) nanocomposite was synthesized using a facile hydrothermal method and employed as an efficient adsorbent with photocatalytic characteristics. The adsorptive and photocatalytic efficacy of NiFe₂O₄ decorated ZIF-67 (NF/ZIF) nanocomposite were analyzed against various antibiotics through a systematic approach. A high removal efficiency of 99 %, 94 %, and 87 % of Tetracycline (TC), Sulfamethoxazole (SM), and Ciprofloxacin (CP) was reported by the developed nanocomposite. Batch removal experiments were performed to examine the impacts of initial solution pH, pollutant concentration, and nanocomposite dosage on the adsorption-assisted photocatalytic degradation performances. The as-obtained NF/ZIF nanocomposite, with a high specific surface area, exhibited superior adsorption abilities towards TC, SM, and CP in aqueous solutions. Langmuir isotherm and Pseudo-second-order kinetic models accurately described the adsorption processes. The NF/ZIF nanocomposite demonstrated excellent photocatalytic degradation of antibiotic contaminants. Enhanced optical properties, including increased visible light absorption and reduced recombination of photo-generated e^-/h⁺ pairs, were achieved by tailoring NF onto ZIF. ESR and reactive species scavenging analyses revealed the vital role of ^•OH and ^•O₂^– in the photocatalytic degradation process. Even after six consecutive cycles, the NF/ZIF nanocomposite showed no substantial decline in its adsorptive and photocatalytic effectiveness. After optimization of parameters, a large-scale continuous-flow photocatalytic reactor was tested, achieving TOC removal efficiencies of 76.51 % − TC, 47.85 % − CP, and 66.26 % − SM, in the treatment of pharmaceutical effluent with diverse contaminants. The proposed bifunctional NF/ZIF photocatalytic adsorbent exhibited excellent potential to revolutionize polluted water sources into purified ones.