Liu Xiao,Zhang Wenyi,Mao Linqiang,Yin Yong,Hu Linchao
Abstract FeOCl-MoS 2 was synthesized via calcination, which possessed excellent adsorption performance for methyl orange (MO). The characterization results showed that the FeOCl-MoS 2 was formed between MoS 2 and FeOCl phases, while a remarkable improvement in specific surface area and porosity was obtained in comparison with pure FeOCl and MoS 2 . The adsorption experiment results showed that the adsorption capacity of MO dye at 25 °C could reach 1615.11 mg/g. In addition, the pseudo-second-order kinetic model (R 2 > 0.99) has a good applicability to describe the adsorption of MO onto FeOCl-MoS 2 . Langmuir isotherm model (R 2 > 0.99) can describe the adsorption process well, proving that the adsorption is surface-controlled monolayer adsorption. Thermodynamic analyses showed the adsorption is an exothermic process and has spontaneity in nature. The adsorption of MO onto FeOCl-MoS 2 is attributed to electrostatic interaction. In particular, the adsorption capacity could still reach 82.1% of the initial adsorption capacity by alkali washing after five cycles. Hence, this study reveals that FeOCl-MoS 2 could be a high-efficient adsorbent for dyes removal from wastewaters. Graphical abstract
The combination of advanced oxidation (AOPs) and membrane separation technology provides a prospect for catalyst recovery and alleviation of membrane fouling . Herein, we prepared FeOCl/MoS 2 catalysts for activating peroxymonosulfate (PMS) by a simple partial thermal decomposition method. Then, the FeOCl/MoS 2 was immobilized onto a polyvinylidene fluoride (PVDF) membrane coated by polydopamine (PDA) through vacuum filtration. FeOCl/MoS 2 can remove 96.9% of rhodamine B (RhB) within 5 min. Notably, with a pH range from 3 to 9, FeOCl/MoS 2 exhibited high catalytic efficiency. Besides, the surface hydrophilicity of the PVDF membrane was significantly improved by the modification. The flux recovery rate (FRR) of the modified membrane reached 97.6%, which was 42.7% higher than that of the pristine membrane. With dead-end filtration, 72.2% of the pollutants can be removed. After 5 runs, the fabricated FeOCl/MoS 2 membrane displayed good stability and high efficiency. The analysis of the mechanism showed that adding MoS 2 to FeOCl can promote the reduction of Fe 3+ to Fe 2+ through the oxidation of Mo 4+ to Mo 6+ . The active species in this system were identified as SO 4 - •, •OH, O 2 - •, and 1 O 2 . SO 4 - • and 1 O 2 were dominant. This research provides a new strategy for the development and application of membrane separation technology.
The traditional Electro-Fenton (EF) is an efficient technology for wastewater treatment but suffers from the acidic condition requirement and external catalyst addition. To overcome these challenges, a GF@MoS 2 @FeOCl cathode was fabricated using a facile method. The as-prepared GF@MoS 2 @FeOCl cathode showed excellent performance for ciprofloxacin (CIP) degradation in EF process with RuO 2 /Ti electrode as the anode. H 2 O 2 was electro-generated and activated on-site at the cathode at mild pH without adding Fe 2+ . CIP was 100% removed with 74.4% of mineralization in 90 min at pH 6. The GF@MoS 2 @FeOCl cathode exhibited good reusability after consecutive runs of degradation. The degradation intermediates were investigated, and the possible mechanism was proposed. This work demonstrated that the prepared GF@MoS 2 @FeOCl cathode is a promising candidate for contaminants treatment in an EF system.