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[Display omitted] • The A-Boron/FeIII/PDS system can rapidly and completely degrade BPA for ten cyclic runs. • Fe(IV) and free radicals exhibit substrate-dependent reactivity for oxidizing contaminants. • QSAR study reveals that k obs values of contaminants linearly depend on their E HOMO. • A-Boron can maintain high equilibrium concentration of Fe(II) for fast Fenton-like PDS activation. • Fast dissolution of surface boron oxide enables a reactive surface for long-lasting operations. In this work, amorphous boron (A-Boron) as a metal-free co-catalyst was applied to address the slow kinetics of FeII regeneration and inactive FeIII accumulation in Fenton-like peroxydisulfate (PDS) activation. The A-Boron/FeIII/PDS system can rapidly degrade bisphenol A (BPA) for ten cyclic runs without performance decline. Based on chemical probing, radical quenching and in situ capturing tests, Fe(IV) and radicals (OH and SO 4 −) are identified as the primary reactive species, and the combined ROS can achieve universal pollutants oxidation with high PDS utilization efficiency. QSAR study unveils that the k obs values of pollutants linearly depend on their E HOMO. A-Boron can bind with FeIII species for catalytic reduction, and meanwhile, the semi-metallic surface experiences stepwise transformation. The fast dissolution of inactive surface boron oxide enabled a self-cleaned and reactive boron surface for long-lasting iron circulation. Also, BPA degradation pathways were proposed based on UHPLC-QTOF-MS tests and Fukui index calculation. [ABSTRACT FROM AUTHOR]

• Higher yield, faster extraction rate and shorter time to reach saturation of process. • Priority extraction of pectin was helpful for the reduction of activation energy. • Mass transfer internal resistance of the extraction process was reduced. • Biot number, diffusion and mass transfer coefficient were determined. • Extraction process was shown to be endothermic, irreversible and spontaneous. In the previous research, the multivariate consecutive extraction process of pectin and hesperidin from FAI was completed, and it was found that the extraction efficiency of hesperidin could be significantly improved because of the priority extraction of pectin. The main objective of this paper is to further elucidate the mass transfer mechanism of the extraction process. The kinetics, thermodynamics, activation energy, diffusion coefficients, mass transfer coefficients and Biot number of the multivariate consecutive extraction process as well as the single extraction process of hesperidin in FAI were estimated and compared. It was confirmed that the mass transfer of the process was effectively strengthened because of the priority extraction of pectin from FAI. Its kinetic data was demonstrated to the pseudo-second-order kinetic model, and the activation energy of hesperidin extraction was as low as 2.27 kJ/mol, far lower than that of the single extraction process (16.67 kJ/mol). In particular, the diffusion coefficien and mass transfer coefficient were larger while the Biot number was lower compared with the single extraction process. These results further proved that the priority extraction of pectin from FAI led to the destruction of cell structure and the exposure of hesperidin crystals, which can effectively reduce the internal resistance of the mass transfer and the activation energy of extraction process, therefore accelerating the penetration and wetting of the extractant into the raw material internally, improving the transfer of hesperidin from the inside to the surface of the raw material as well. In addition, the extraction thermodynamics illustrated that the extraction process of hesperidin was endothermic, irreversible and spontaneous. [ABSTRACT FROM AUTHOR]

[Display omitted] • H and OH produced by H 2 O cracking can be produced in ultrasonic agitation coupled system. • H generated in ultrasonic system can strongly reduce Fe(III) into Fe(II). • OH generated in ultrasonic system can be further combined to produce H 2 O 2. • US/A/Fe(III) as an in situ Fenton system can non-selectively oxidize a wide spectrum of pollutants. It has been reported that the ultrasonic agitation coupled system (US/A) has higher oxidation efficiency than the pure ultrasonic system (US), and the atomic hydrogen (H) and hydroxyl radicals (OH) produced by H 2 O cracking and in situ hydrogen peroxide (H 2 O 2) can be significantly detected. In order to utilize the residual H 2 O 2 and explore the role and fate of H, US/A/Fe(III) as an in situ Fenton oxidation system, was constructed in this study. The experimental results proved that the system can generate H 2 O 2 in situ , and adding Fe(III) could significantly promote the oxidation of refractory organic pollutants. Quenching tests, probes experiments and EPR test were performed to successfully monitor the existence of OH. The contribution of H to Fe(III) reduction was speculated and confirmed. In addition, the kinetic model showed the decomposition rate of water molecule and the reduction rate of Fe(III) by H under different ultrasonic power. The effects of the factors (pH, coexisting substance, and actual water environment) on degrading organic pollutants were evaluated. Therefore, this work provides new strategy and mechanistic insight into in situ Fenton technique by coupling ultrasonic agitation and Fe(III) without external oxidants. [ABSTRACT FROM AUTHOR]

[Display omitted] • The facilitation of AB on Fe(VI) oxidation outperformed that of CNTs, GO, G, ND, and BC. • Fe(IV)/Fe(V) were identified as predominant reactive species in the Fe(VI)−CMs systems. • The reduction behavior of AB dominates Fe(VI) activation with C = O as electron-donating sites. • The Fe(VI)−AB system performed well in cyclic tests and real waters. carbonaceous materials (CMs) have attracted broad concern as catalysts in wastewater remediation due to their excellent physicochemical and structural properties. Here, the decontamination ability of ferrate (Fe(VI)) was evaluated in the presence of various CMs and Fe(IV)/Fe(V) was determined as predominant species. Acetylene black (AB), a kind of carbon black widely used in the modification of electrode materials, showed the best activation effect on Fe(VI) decontamination. Ozone pre-oxidation combined with characterization analyses revealed the critical role of ketonic (C O) groups on AB as reductive sites. The promoting effect of Fe(III) and H 2 O 2 indicated the involvement of Fe(VI) decay products in the activation process. Additionally, the decontamination efficiency above 90% in cyclic tests and actual waters reflected the advantages of nonradical oxidation in the heterogeneous Fe(VI)−AB system, indicating its great potential in practical application for wastewater remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • μZVW can strongly accelerate the redox cycles of Fe(III)/Fe(II). • Fe(II) and μZVW can synergistically activate PDS to produce reactive oxygen species. • Fe(III)/PDS enhanced the μZVW corrosion to release the low valence tungsten species. • •OH,SO 4 •−, and Fe(Ⅳ) were produced in μZVW/Fe(III)/PDS system to oxidize CBZ. The slow conversion of the Fe(III)/Fe(II) redox couple arising from Fe(III) accumulation strongly restricts the ongoing generation for reactive oxygen species (ROS) in Fenton/Fenton-like systems. Hereby, micron zero-valent tungsten (μZVW) was applied as a co-catalyst to boost Fe(III) reduction for promoting the Fenton-like activation of peroxydisulfate (PDS), and the oxidation capacity and reaction mechanism of μZVW/Fe(III)/PDS system are investigated with carbamazepine (CBZ) as the target pollutant. The results show that CBZ can be completely degraded by the μZVW/Fe(III)/PDS system within 30 min, μZVW exhibits exceptionally high stability for long-lasting CBZ oxidation during 10 cycling tests. According to a mechanistic analysis, the main ROS responsible for CBZ oxidation include high-valent iron (Fe(IV)), hydroxyl radicals, and sulfate radicals, meanwhile, μZVW can rapidly reduce Fe(III) into Fe(II) and further boost Fenton-like activation of PDS. Fe(III) and PDS can speed up the stepwise oxidation of μZVW to steadily release low-valence tungsten species, which can induce reduction of dissolved oxygen to produce H 2 O 2 and donate electrons to cleave peroxide O-O bonds of H 2 O 2 and PDS to produce ROS. In addition, the self-cleaning function of μZVW makes it efficient to remove CBZ was discovered. Therefore, the finding of this study proposes a novel co-catalyst to boost Fenton-like activation of PDS, which can promote the scientific advances in enhanced Fenton-like oxidation towards realistic use in water remediation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Polyimide based aerogel was synthesized through a facile and eco-friendly way. • The aerogel exhibits lightweight, outstanding compressibility, and hydrophobicity. • Optimized sample (PI/CAC-3) shows excellent absorption capacity and separation flux. • The aerogel can be used for rapid, efficient, and continuous oil/water separation. The frequent oil spill accidents have created increasingly environmental and ecological problems. Therefore, the development of effective oil-cleaning materials is of great importance. In this study, we prepared superhydrophobic polyimide/cattail-derived active carbon composite (PI/CAC) aerogels for efficient oil/water separation through a facile approach based on freeze-drying and thermal imidization. The resultant aerogel shows ultralight weight (29.7 mg/cm3), superhydrophobicity (water contact angle = 151.3°), excellent compressibility, and ideal chemical stability, which are conducive to the oil sorption and extrusion at various harsh conditions including acidic, alkaline, and saline solutions, as well as oil-in-water emulsions. Typically, the optimized sample PI/CAC-3 aerogel could achieve saturation within 5–20 s, delivering a high oil sorption capacity of 25.1–71.0 g/g for various oils. When used for continuous oil/water separation, high flux of 4.47 × 104 L m-2 h−1 and separation efficiency of 98.3% were achieved for chloroform/water mixture by gravity-driven separation method. Furthermore, due to the high compressibility, the aerogel can be used for cycling separation through sorption-extrusion process with less than 3% decrease in separation efficiency after 10 cycles. These advantages make it a potential candidate for the treatment of wastewater polluted by various oils and/or organic solvents. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel nitrogen, sulfur co-doped nanocarbon materials were synthesized to enhance Fe(III)/H 2 O 2 system. • The structure and functional groups of NSC which conduct effective catalysis were revealed. • Two Fe(III)/Fe(II) cycling pathways were verified in NSC/Fe(III)/H 2 O 2 process. • Intermediate and possible degradation pathways ofa SMX were proposed. Fenton-like technology has been widely used in the field of water treatment as an advanced oxidation processes (AOPs), and a multitude of non-homogeneous catalysts have been reported effectively to enhance it. Herein, nitrogen and sulfur co-doped nanocarbon materials (NSC) was designed and synthesized, which formed a unique mesoporous structure and abundant functional groups on the surface. It exhibits superior catalytic performance to enhance the Fe(III)/H 2 O 2 system for sulfamethoxazole (SMX) degradation, k obs is 18 times higher than Fe(III)/H 2 O 2 system after the introduction of NSC under the same experimental conditions. Also, the working pH of Fe(III)/H 2 O 2 system was broadened by NSC. Quenching and probe experiments demonstrate that hydroxyl radical (∙OH) was the dominant active species. Both dissociative and surface-bound iron species were observed, which indicates direct reduction and in-situ binding of Fe(III), respectively. Further investigation found nitrogen and sulfur co-doped attribute to the formation of abundant functional groups, the C O bond and C S C bond on the surface of NSC result in the directly reduce of Fe(III), while –COOH contributes to the in-situ binding. The intermediates and possible degradation pathway of SMX degradation were proposed based on the results of liquid chromatography-quadrupole time of flight-mass spectrometer (LC-QTOF-MS). The results of cycling and co-existing ions experiments demonstrate that NSC has outstanding potential for application. This work provides a novel insight into the sustained removal of micropollutants from the aqueous environment based on the nanocarbon materials enhancing the Fenton-like oxidation. [ABSTRACT FROM AUTHOR]

[Display omitted] • V 2 O 3 stands out among many common metallic/nonmetallic activators of PMS. • The contributions of SO 4 •− and •OH for MNZ oxidation were quantitively analyzed. • The stepwise electron transfer from transient-state vanadium species to PMS can produce radicals. • MNZ degradation pathways were proposed involving two stages based on Fukui function and LC-MS. In this study, vanadium trioxide (V 2 O 3) was adopted to activate PMS via a Fenton-like reaction to degrade metronidazole (MNZ). The V 2 O 3 -PMS system can almost completely degrade MNZ at 30 min with 42.4% TOC removal. Comparative tests reveal that V 2 O 3 stands out among a variety of heterogeneous catalysts, including metallic oxides and carbon materials. Sulfate radicals (SO 4 •−) and hydroxyl radicals (•OH) derived from PMS decomposition are major reactive oxygen species, based on quenching tests, electron spin resonance (ESR) analysis, the steady-state concentrations of radicals ([SO 4 •−] ss = 5.1 × 10-13 M and [•OH] ss = 4.0 × 10-14 M), and kinetics model. The process of stepwise electron transfer from vanadium species to PMS to produce reactive radicals was proved by small-molecule simulation experiments and pickling experiments of vanadium oxides. Possible pathways of MNZ degradation were proposed based on the results of LC-MS and Fukui function, including two stages of the hydroxylation and bond cleavage of nitro and the subsequent ring-opening. This study reveals the high reusability and practicability of the V 2 O 3 -PMS system over a relatively wide pH range, which puts forward a new vision on V 2 O 3 induced Fenton-like reactions and a new reference method for the removal of medical organic contaminants in water. [ABSTRACT FROM AUTHOR]

[Display omitted] • A heterogeneous catalytic system of NaBiO 3 for PMS without light irradiation was investigated. • Both radical (SO 4 −• and •OH) and non-radical (1O 2) were contributed to BPAF degradation. • The contribution rate of 1O 2 , · SO- 4, and · OH was calculated as 80.4%, 8.7%, and 9.9%, respectively. It has been shown previously that the NaBiO 3 (NBO) could efficiently photocatalytically degrade organic contaminants because of its excellent photocatalytic property. In this study, we proposed a heterogeneous catalytic system of NBO for peroxymonosulfate (PMS) without light irradiation. The results showed that NBO/PMS exhibited excellent performance toward bisphenol AF (BPAF) degradation and mineralization. The effectiveness of the NBO/PMS system was also investigated in different multicomponent systems. The effects of initial pH, NBO dosages, and PMS concentration for BPAF degradation were also investigated. Radical quenching experiments combined with electron spin resonance analysis indicated that singlet oxygen (1O 2) was the main reactive oxygen species, and · SO 4 - and · OH– radicals participated in the process. X-ray photoelectron spectroscopy revealed the main catalytic mechanism: lattice oxygen (O vac) was extruded during the transformation of Bi(V) to Bi(III) to form and activate oxygen (O*), and the generated O* between the [BiO 6 ] regular octahedral layers reacted with PMS on the NBO surface to form 1O 2. Based on the results of the Bi element, it is suggested that the activation process proceeded through electron transfer from NBO to PMS. The stability of NBO and applicability of the NBO/PMS system in a natural water environment were explored. This work provides a novel approach to PMS activation and the potential use of NBO for the decontamination of organic pollutants. [ABSTRACT FROM AUTHOR]