[Synergistic Reaction Mechanism of Cu0@Fe3O4 Activated PMS for Degradation of p-nitrophenol].

A Cu0/PMS system mainly relies on the leaching of copper ions to degrade the pollutants and adapt to the narrow pH range (<7). To solve this defect, we studied the properties and reaction mechanism of Cu0@Fe3O4 magnetic core-shell material, which was successfully prepared using co-precipitation method, taking PNP as the target pollutant. The results showed that: ① a degradation rate of 96% can be achieved within 60 min for 5 mg ·L-1 PNP, 200 mg ·L-1 Cu0@Fe3O4, and 0.5 mmol ·L-1 PMS at a natural pH value (5.65); ② the Cu0@Fe3O4/PMS system can be regarded as a heterogeneous reaction system because TCu, TCu+, and iron leaching were almost negligible; ③ on comparing the performance of the Cu0@Fe3O4/PMS system and Cu0/PMS system in the pH range of 3 to 11, it was discovered that the method by which Cu0 activates the PMS to degrade the PNP was successfully changed by coating a layer of Fe3O4. The Cu0@Fe3O4/PMS system has a good degradation performance towards PNP in the pH range of 5-9; ④ SO-4 · and HO · existed in the reaction system, and their contribution rates to the reaction system were 34% and 60% ; HO · was the dominant free radical; ⑤ A bimetallic synergy exists between Fe and Cu. The presence of Cu(Ⅰ) can promote the reduction of Fe(Ⅲ) to Fe(Ⅱ), thereby forming a good redox cycle and improving the durability of the reaction system.

Photocatalytic removal of phenanthrene and algae by a novel Ca-Ag3PO4 composite under visible light: Reactivity and coexisting effect.

In this study, the feasibility of a novel Ca-Ag3PO4 composite with visible light irradiation for the phenanthrene (PHE) degradation and algae inactivation in artificial seawater was firstly investigated. The experimental findings revealed that Ag3PO4 phase was sucessfully formed on the Ca-based material, and the presence of Ca-based material could effectively keep Ag3PO4 particles stable. An excellent performance on PHE degradation or algae inactivation was observed from Ca-Ag3PO4 composite under visible light irradiation. The degradation of PHE or inactivation of algae not only could be efficiently achieved in the single mode, but also could be successfully achieved in the coexisting mode. Above 96% of PHE and algae were simultaneously removed within 12 h in the Ca-Ag3PO4/visible light system. It was further observed that the degradation of PHE and/or inactivation of algae increased with the increase of Ca-Ag3PO4 dosage. HO was the primary radical responsible for PHE degradation, whereas HO and Ag+ released from Ca-Ag3PO4 mainly contributed to the algae inactivation. A possible mechanism involving the catalytic removal of PHE and algae by Ca-Ag3PO4 under visible light irradiation was proposed. This study provides helpful guide for the simultaneous removal of various pollutants in real seawater.

Insights on the nitrate reduction and norfloxacin oxidation over a novel nanoscale zero valent iron particle: Reactivity, products, and mechanism.

Herein, the application of a novel acid mine drainage-based nanoscale zero valent iron (AMD-based nZVI) for the remediation of nitrate and norfloxacin (NOR) was studied. Experimental results indicated that the catalytic reactivity of AMD-based nZVI toward nitrate reduction was superior to that of iron salt-based nanoscale zero valent iron (Iron salt-based nZVI). The presence of ultrasound irradiation could significantly enhance the reactivity toward both the nitrate reduction and NOR oxidation processes. The optimal efficiencies of nitrate and NOR by AMD-based nZVI/US process could be kept 96 and 94% within 120 min, respectively. Ammonia was identified as a major product in nitrate reduction process, while three oxidation products were observed in NOR degradation process. Both reduction reaction of nitrate from AMD-based nZVI and oxidation reaction of NOR from US-assisted Fenton system might be involved in AMD-based nZVI/US process. The AMD-based nZVI/US process showed a better performance on the removal of NOR compared with that of nitrate. The findings of the present work could be as a guide and show that AMD-based nZVI/US process is feasible for the remediation of both nitrate and NOR in real wastewater.

Preparation and application of a novel bioflocculant by two strains of Rhizopus sp. using potato starch wastewater as nutrilite.

A complex bioflocculant MBF917 was prepared by Rhizopus sp. M9 and M17 using potato starch wastewater (PSW) as nutrilite, and its flocculation characteristics of treating PSW were studied. Culture conditions of the two strains were optimized, and flocculating conditions of the bioflocculant for treating PSW were also investigated. The optimal and economical culture conditions were determined as COD of about 1600 mg/L, 0.3 g/L urea and 0.04 g/L potassium dihydrogen phosphate, with no need of adding carbon sources or adjusting pH. When the bioflocculant was used to flocculate PSW, the optimal dosage was 0.1 mL/L with addition of 5 mL/L 10% CaCl2 as coagulant aid, and there was no need to adjust pH. After flocculation, COD and turbidity removal rates of the PSW could reach 54.09% and 92.11%, respectively, and 1.1g/L proteic substance was recycled from the PSW as a byproduct that could be used for animal feed.