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[Display omitted] • ACF cathode exhibits excellent performance in PAA activation for SMX elimination. • ACF could maintain persistent catalytic ability under a cathodic electric field. • •OH generated from ACF cathode plays the dominant role in organics degradation. • Degradation intermediates of SMX are harmless to the aquatic ecology. Advanced oxidation processes (AOPs) based on peracetic acid (PAA) could generate various radicals with low by-product generation, making them a vital technology in the remediation of organic pollution. Maintaining the activity and continuous operation of catalytic systems in water treatment processes was a highly challenging research topic. Herein, the electrochemical process with an activated carbon fiber (E-ACF) cathode was devised to boost the activation of PAA (E-ACF-PAA) for persistent elimination of organics. Compared to other commonly used electrodes, the ACF cathode displayed superior PAA activation ability and higher sulfamethoxazole (SMX) removal. The applied cathodic electric field could protect ACF from PAA oxidation, maintaining its long-term catalytic ability over 50 cycles. Based on radical quenching studies, the EPR test, and the estimation of radical contribution, the E-ACF-PAA process was identified as a radical dominant system. Importantly, isolated chamber experiments proved that PAA was mainly decomposed on the cathode to produce hydroxyl radicals (OH) for SMX degradation, while the anode played a negligible role. According to toxicity prediction and algae growth tests, the degradation products were harmless to the aquatic ecology. Remarkably, continuous flow experiments over a 24 h and different water matrix tests have also proven applicability in practical scenarios. This work provided novel insights into the electrochemical activation of PAA and further expanded the potential applications of PAA-based AOPs in the remediation of organic pollution. [ABSTRACT FROM AUTHOR]

Activated carbon fiber (ACF) was used to enhance the UV/Electro-Fenton (UV/EF) system to remove nitrobenzene (NB). Comparative removal of NB by ACF adsorption, electrolysis, and UV photolysis was investigated, which indicated ACF can significantly enhance the UV/EF (ACF) system to remove NB. By using ACF cathode, 98% of NB removal was achieved after 20 min, which was much higher than Ti cathode by 60%. The UV/EF (ACF) system was proved to have the feasibility of mineralization of nitrobenzene by the 90% of TOC removal after 5 h. ACF reuse experiments were carried, and the results showed ACF cathode could be reused for successive 4 runs with just 5% declination of NB removal. The impacts of several key influence factors (current intensity, electrolyte, and O 2 flux) were explored. Three different kinds of ACF (ACF 0 : original ACF; ACF N : treated by ammonia; ACF H : treated by nitric acid), methanol, tert-butyl (TBA) alcohol, phenol, and catalase were involved in the system to study the mechanism of the UV/EF (ACF) system. The results showed the combination of ACF and the UV/EF system could significantly improve the H 2 O 2 production and NB removal. Finally, the comparison of the electrical energy per order (EE/O) values between the UV/EF (ACF) and UV/EF (Ti) system showed that ACF can significantly improve the current efficiency of the UV/EF system. [ABSTRACT FROM AUTHOR]

Removal of nitrobenzene (NB), a carcinogenic and refractory pollutant, in aqueous solution by adsorption, ozonation, electrolysis, and electro-peroxone (E-peroxone) with activated carbon fiber (ACF) was investigated, respectively. Kinetic analyses of NB removal by all the processes followed pseudo-first-order kinetics and the K app of E-peroxone-ACF was 14.90 × 10 −2 min −1 , which was much higher than the others. Besides, the K app of E-peroxone-ACF process reduces slightly to 12.18 × 10 −2 min −1 even after 100 times of ACF recycle, showing a sustainable activity. Moreover, according to the pore texture characteristics, surface functional groups, FTIR, and SEM images, E-peroxone process does not considerably alter the ACF surface, whereas ozone alone can cause substantial damage to it. These results suggested that ACF was induced from an initiator/a promoter into an electrocatalyst in ozonation by free electrons injection. Moreover, comparing with titanium cathode, ACF can remarkably improve the removal of NB in E-peroxone due to the synchronous adsorption of pollutants and ozone as well as the enhancement of H 2 O 2 generation. It indicates that the ACF cathode is a promising material for organic pollutants removal in the E-peroxone process. [ABSTRACT FROM AUTHOR]

Flower-like MnO 2 decorated activated multihole carbon (AMC) was fabricated by a simple but effective strategy. Such unique MnO 2 @AMC nanocomposite exhibited the optimized pseudocapacitance performance, revealing a specific capacitance (297.8 F g −1 ) with excellent rate ability. An asymmetric supercapacitor with nanocomposite as the positive electrode and activated graphene (AG) as the negative electrode yielded an energy density of 18.04 W h kg −1 and a maximum power density of 8.97 kW kg −1 . And thus, this facile synthetic strategy could be useful to design high-performance electrode for supercapacitors. [ABSTRACT FROM AUTHOR]

• MnFe 2 O 4 magnetic activated carbon adsorbent was prepared by co-precipitation method. • Maximum adsorption capacity of MnFe 2 O 4 -PAC was 2–3 times that of original PAC-2. • Stronger magnetic properties of magnetic PAC have better adsorption performance. • MnFe 2 O 4 -PAC after regeneration still had good magnetic properties and adsorption capacity. In this study, co-precipitation was used to prepare Fe 3 O 4 magnetic powder activated carbon (PAC) (Fe 3 O4-PAC) and MnFe 2 O 4 magnetic PAC (MnFe 2 O 4 -PAC) for the in-depth treatment of glyphosate pesticide wastewater. Magnetic adsorbent characterization results indicate that MnFe 2 O 4 was successfully loaded on the activated carbon powder. Adsorption experiment results show that the maximum adsorption capacity of MnFe 2 O 4 -PAC for glyphosate is two to three times that of the original PAC. The adsorption of glyphosate by using magnetic PAC conforms to the Langmuir adsorption isotherm, and the adsorption kinetics is consistent with the quasi-second adsorption kinetic model. The adsorption capacity of Fe 3 O 4 -PAC and MnFe 2 O 4 -PAC showed the same trend effect with the change in pH, temperature, and adsorbent dosage. The adsorption capacity of Fe 3 O 4 -PAC and MnFe 2 O 4 -PAC for glyphosate decreased with the increase in pH and magnetic PAC and rises with temperature. Regeneration experiment results showed that the order of the regeneration method of MnFe 2 O 4 -PAC is: microwave combined Fenton reagent regeneration > wet microwave regeneration > microwave combined hydrogen peroxide regeneration. MnFe 2 O 4 -PAC after regeneration still exhibited good magnetic properties and adsorption capacity. [ABSTRACT FROM AUTHOR]

Electrolysis and permanganate (PM) oxidation are two commonly used technologies for water treatment. However, they are often handicapped by their slow reaction rates. To improve the removal efficiency of refractory contaminants, we combined electrolysis with PM using an activated carbon fiber (ACF) as cathode (E-ACF-PM) for the first time to treat diclofenac (DCF) in aqueous solution. Up to 90% DCF was removed in 5 min by E-ACF-PM process. In comparison, only 3.95 and 27.35% of DCF was removed by individual electrolysis and PM oxidation at the same time, respectively. Acidic condition was more conducive to DCF removal. Surprisingly, soluble Mn(III) (aq) formed on the surface of ACF was demonstrated as the principal oxidizing agent in E-ACF-PM process. Further studies showed that all three components (electrolysis + ACF + PM) were necessary to facilitate the heterogeneous generation of reactive Mn(III) (aq). Moreover, SEM images and XPS spectra of ACF before and after treatment revealed that the morphologies and elemental compositions of reacted ACF were nearly unchanged during the E-ACF-PM process. ACF can be remained active and utilized to the rapid degradation of DCF in E-ACF-PM process even after reused for 20 times. Therefore, the E-ACF-PM process may provide a novel and effective alternative on the generation of reactive Mn(III) (aq) in situ for water treatment by green electrochemical reactions. Image 1 • A novel synergistic technology coupling electrolysis and permanganate (PM) was developed. • DCF can be rapidly removed in E-ACF-PM process from raw water. • Mn(III) formed on the ACF cathode played a key role in DCF degradation. • All three components (electrolysis + ACF + PM) were necessary to facilitate the heterogeneous generation of reactive Mn(III). • The recycled ACF for 20 times in E-ACF-PM process still had a satisfactory efficiency. [ABSTRACT FROM AUTHOR]