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[Display omitted] • Engineered near-infrared carbon dots enhance mitochondrial imaging signal-to-noise ratio by 2–3 folds. • Charge-driven dense blinking of carbon dots enables rapid super-resolution mitochondrial imaging with minimal frames. • Novel graph structure with GNN analysis achieves 98% accuracy in cellular typing and drug toxicity prediction using mitochondrial morphology. • Pioneering interpretability in GNN models elucidates mitochondrial features' impact on predictive outcomes in cellular functions. Mitochondrial morphology is crucial for cell identification and drug toxicity evaluation, yet it is challenged by mitochondrial complexities and limitations in imaging technologies. We develop an ultrasmall (∼1.5 nm) fluorescent carbon dot (CD), specifically designed to target mitochondria in live cells. These CDs exhibit near-infrared fluorescence at 685 nm, enhancing fluorescence imaging's signal-to-noise ratio by 2–3 times. Their dense-blinking behavior enables rapid fluctuation-based super-resolution imaging with as few as 10 frames, thereby allowing for detailed visualization of mitochondrial morphology and dynamics. We further propose a graph-based deep learning framework that integrates multidimensional mitochondrial features, which are updated using a Graph Neural Network (GNN), to achieve precise mitochondria-based cellular typing and drug toxicity analysis with up to 98% accuracy. Additionally, we pioneer the use of interpretability algorithms to elucidate the GNN model, revealing how the depicted mitochondrial features by the CDs drive these predictions. This approach has significant implications in cellular and toxicological research, offering a unique tool for deciphering cellular behaviors and drug interactions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Visible light-driven degradation of CEF was investigated in a flat plate photoreactor. • Fe-N-TiO 2 on PS plate was used as structured photocatalyst. • S-VD light modulation showed 75% of CEF degradation and TOC removal of 70%. • A strong reduction of electric energy consumption was achieved with S-VD modulation. • The photocatalytic treatment can significantly reduce the toxicity of CEF solution. In this paper, the effect of light modulation on photocatalytic ceftriaxone (CEF) degradation in aqueous solution was investigated. The experimental set-up consisted of a fixed bed photocatalytic reactor with a flat plate geometry and visible LEDs for irradiation. Fe-N-codoped TiO 2 photocatalyst was immobilized on a polystyrene plate (PS) by solvent casting method to achieve a structured photocatalyst (Fe-N-TiO 2 /PS), which was loaded in the photoreactor. Raman and UV–Vis diffuse reflectance spectroscopy confirmed the presence of Fe-N-TiO 2 on the PS surface and its uniform distribution on the polymer support. Various LEDs dimming techniques were tested with fixed and variable duty-cycle values. In particular, the following modulations were used: fixed duty-cycle (FD), sinusoidal variable duty-cycle (S-VD), triangular variable duty-cycle (T-VD), square wave variable duty-cycle (SW-VD), saw-tooth variable duty-cycle (ST-VD), pulse variable duty-cycle (P-VD), and pseudo-sinusoidal variable duty-cycle (PS-VD). The optimal light modulation was the S-VD, with an average fed current between 25 and 75 mA and a period of 30 s. Indeed, by using S-VD modulation, the highest value of the apparent CEF degradation kinetic constant (resulting 0.0082 min−1) and the highest total organic carbon (TOC) removal (70 %) were achieved. By comparing the electric energy consumption (E E/O) with S-VD modulation used in this work with those found in other literature studies dealing with the photocatalytic ceftriaxone degradation, a significant decrease of E E/O was evidenced. Moreover, toxicity test showed that the photocatalytic treatment allowed to significantly reduce the toxicity of CEF solution when compared to untreated effluent. [ABSTRACT FROM AUTHOR]

• Lanthanide metal Nd-evoked valence electronic modulation of Co in Co@NC nanocubes. • Nd-doping induces defect sites and hydrophibicity regulation of Co@NC nanocubes. • Enhanced degradation activity and reusability of Nd/Co@NC-0.2 for 4-NP is obtained. • Radical/non-radical and direct electron transfer pathway are detected in the system. • Toxicity of intermediates and degradation pathways by the system are unveiled. Metallic Co-based materials are widely recognized as benchmark catalysts for the degradation of organic pollutants. However, they still suffer from relatively low stability and reusability, necessitating the development of efficient regulation strategies. In this study, we propose a unique and effective approach using neodymium (Nd)-mediated valence electronic and surface microenvironment regulation to enhance the catalytic properties of Co/N-doped carbon cubes for the degradation of 4-nitrophenol (4-NP) via peroxymonosulfate (PMS) activation. The strong coordination between the negatively charged organic ligands and positively charged Nd and Co metal ions ensures the intense coupling of Nd and Co sites in the synthesized sample through pyrolysis. Notably, the incorporation of Nd not only modulates the valence electronic properties of Co sites but also increases the defect degree, surface hydrophobicity, and conductivity of the resulting material. These enhancements are responsible for the high-performance degradation of 4-NP through PMS activation. The optimal Nd/Co@NC-0.2 catalyst achieves a remarkable degradation efficiency of 95 % within 20 min, while also exhibiting enhanced stability and reusability. Furthermore, our developed system demonstrates good tolerances to different conditions, solution pH and inorganic/organic substances. The degradation system involves both radical/non-radical and direct electron transfer pathways. We also unveil the reaction intermediates, their toxicities and the degradation pathways catalyzed by the Nd/Co@NC-0.2/PMS system. This study presents a novel strategy utilizing lanthanide metal-evoked regulation to enhance capability of Co-based catalysts for PMS activation towards the degradation of harmful organics. [ABSTRACT FROM AUTHOR]

[Display omitted] • TM-mediated electrochemical system showed a good performance in SMX degradation. • The H 2 O 2 can be electro-generated via utilization of O 2 generated on Pt surface. • TM-mediated electrochemical system generated ·OH and ·O 2 – radicals for degrading SMX. • Five SMX degradation pathways were proposed and rationalized by DFT calculation. • ECOSAR analysis and algae test suggested reduction of SMX toxicity after treatment. Antibiotics are emerging contaminants that have become a global concern because of their refractory and toxic characteristics. The treatment of antibiotic contaminants using advanced electrochemical oxidation processes is currently gaining interest. In this study, we constructed a natural iron-mediated electrochemical system for the removal of antibiotics using natural tourmaline (TM) as the heterogeneous iron catalyst, platinum (Pt) as the anode, and nickel foam (NiF) as the cathode. Sulfamethoxazole (SMX) was selected as the target antibiotic. The surface properties and components of TM were characterized using energy-dispersive X-ray spectroscopy, N 2 adsorption–desorption isotherms, X-ray diffraction, and X-ray photoelectron spectroscopy. Compared with the Pt-NiF electrochemical system, the Pt-NiF-TM electrochemical system showed a 23 times enhanced reaction rate constant of SMX degradation under the optimal conditions of current density 4.17 mA/cm2, 200–400 mesh, TM dosage 3 g/L, and initial pH 3, in which SMX was almost completely degraded (removal rate = 99.92 %) after 60 min. The ·OH and ·O 2 – radicals generated in the Pt-NiF-TM electrochemical system were the active species for SMX degradation. Thirteen SMX degradation intermediates were identified and possible SMX degradation pathways were proposed. Density functional theory calculations demonstrated that C3 and N11 are the sites with higher electrophilic reactivity in SMX. Furthermore, toxicity calculations and analysis of SMX and its degradation products showed that after treatment with the Pt-NiF-TM electrochemical system, the toxicity of SMX to the microalgae Oocystis was reduced. Overall, this study provides a novel and environmentally friendly electrochemical system mediated by TM for the highly efficient degradation of antibiotic contaminants. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Photolysis and ZnIn 2 S 4 photocatalysis of fluvastatin under UV–Vis were compared. • O 2 − and OH were involved in the photocatalytic process. • Photolytic pathway and photocatalytic pathway were comparatively studied. • The photolytic samples were more toxic than the photocatalytic samples. • Photocatalysis was a more effective way for removing fluvastatin than photolysis. Abstract Fluvastatin, a commonly used cholesterol-lowering drug, has attracted considerable attention because of its adverse effects on human beings. Photolysis and ZnIn 2 S 4 photocatalysis of fluvastatin under UV–Vis irradiation were compared based on analysis of reactive oxygen species (ROS), degradation pathways, and toxicity evaluation. The removal rates of fluvastatin by photolysis and photocatalysis were 71.07% and 99.79%, respectively. Photolytic degradation of fluvastatin was conducted in the absence of ROS, whereas O 2 − played a vital role and OH played an auxiliary role during the photocatalytic process. The photolytic degradation of fluvastatin was achieved through cleavage of the C C, C N, and C C bonds. Because of the limited photon energy, photolytic products with stable structure did not decompose easily, which resulted in chemical oxygen demand (COD) removal rate of the photolytic system only 15.62%. The photocatalytic degradation of fluvastatin was achieved through direct cleavage of the chemical bonds under the synergistic oxidation of O 2 − and OH, and the hydroxylation reaction under OH attack. The COD removal rate of the photocatalytic system reached 43.05%. The photocatalytic samples were slightly less toxic than fluvastatin, whereas the photolytic samples were more toxic than fluvastatin. Therefore, the toxicity of the photolytic samples was significantly higher than that of the photocatalytic samples. Photocatalysis was an effective way for mitigation and elimination of harm of statins to the environment than photolysis. [ABSTRACT FROM AUTHOR]

Phenicol antibiotics (PABs) degradation by UV/H 2 O 2 is important because we need to determine the reduction in toxicity and disinfection byproducts for post-chlorine. In this study, the degradation of PABs, including florfenicol (FLO), chloramphenicol (CAP) and thiamphenicol (THA), was examined. The pseudo-first order degradation rate constants of PABs were 3 times higher in ultrapure water (UW) than that in synthetic wastewater (SW) for these conditions: [PABs] 0  = 1 μM, [H 2 O 2 ] = 0.1 mM, and I 0  = 1.985 × 10 −6  E L −1  s −1 . Fulvic acid (FA) and HCO 3 – inhibited PABs degradation, Cl − and NO 3 – concentrations of up to 5 mM and 10 mM had a negligible impact. The impact of water matrix on PABs degradation was successfully predicted using pseudo-steady-state kinetic model. The degradation of PABs was triggered via hydroxylation and/or hydrogen abstraction. The treatment of PABs via UV/H 2 O 2 could decrease their antimicrobial properties, while the byproducts of FLO and THA showed higher acute toxicity in Vibrio fischeri . In addition, two identification products (TP-276 and TP-354) of FLO had higher ecotoxicity toxicity (using ECOSAR) in fish, daphnid and green algae. The trichloromethane formation potential (TCMFP) for PABs with post-chlorination in UW and SW can be reduced after UV/H 2 O 2 compared to UV, and is related to the corresponding decrease of dissolved organic carbon (DOC). [ABSTRACT FROM AUTHOR]

Recently, lincomycin has been detected frequently in aquatic environment, especially in the effluent of pharmaceutical wastewater treatment plants. Public concerns have been raised due to its adverse bio-effect and potential of inducing resistance genes. In this study, hydrothermal treatment (HT) was applied to remove lincomycin from high-concentrated pharmaceutical waste water. Influence factors (e.g., temperature, initial concentration and pH) were investigated from kinetics perspective. Meanwhile, degradation byproducts were identified using liquid chromatography–mass spectrometry (LC–MS), based on that transformation pathways were proposed. Finally, the toxicity of lincomycin degradation intermediates were evaluated by Microcystis cells. The results showed that lincomycin was eliminated efficiently via HT and an obvious lag time existed in its degradation process. An autocatalytic model was developed successfully based on the degradation kinetics analysis. The model showed good fitness with experiments data (R 2  > 0.99). Observed reaction constant ( k ) increased when reaction temperature varied from 110 to 160 °C; it decreased from 0.034 to 0.015 min −1 as pH ranged from 2.0 to 6.0. Additionally, increasing initial concentration of lincomycin promoted its degradation, while it showed a different trend once the concentration exceeded 300 mg L −1 . A total of 7 major intermediates were identified, based on which hydrolysis, hydroxylation and desulfuration were inferred as the mainly evolution processes. Finally, toxicity evaluation indicated that both lincomycin and its degradation byproducts have no inhibition on algal strains. Thus, it is concluded that HT is an efficient method for removing lincomycin. [ABSTRACT FROM AUTHOR]

[Display omitted] • NDMA formation during PMS oxidation was decreased in the presence of Br−. • The formed HOBr accelerated the reaction and inhibited the NDMA formation. • The reaction sites were predicted by DFT calculations. • The intermediates and mechanisms were compared in the absence and presence of Br−. • The presence of Br− reduced the theoretical and overall toxicity of the oxidation products. In this study, bromide ion (Br−) was found to accelerate the degradation of N , N -dimethylhydrazine compounds in peroxymonosulfate (PMS) oxidation and synchronously reduce their N -Nitrosodimethylamine (NDMA) formation. Hexamethylenebis (1,1-dimethylsemicarbazide) (HDMS) and daminozide (DMZ) were selected as the model compounds to clarify the mechanisms in the presence or absence of Br− for the PMS batch oxidation experiments. In the absence of Br−, the degradation of the model compounds accompanied by the formation of NDMA was induced by the electron transfer between PMS/singlet oxygen (1O 2) and the (CH 3) 2 N-N- groups of the model compounds. In the presence of Br−, the generated hypobromous acid (HOBr) was verified to account for the acceleration of the reaction. The difference in NDMA formation in PMS oxidation and PMS/Br− oxidation was related to the changes in degradation paths. The electron-withdrawing substituents Br or O of PMS or HOBr substituted the N atoms of the model compounds, generating brominated or oxidation products that were hard to be further oxidized, thus decreasing NDMA formation. Moreover, the toxicity of the products in PMS/Br− oxidation was significantly lower than in alone PMS oxidation. This work provides new insight into the unique advantage of Br− during PMS oxidation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Excessive BC and TiO 2 @BC inhibited the growth and energy metabolism of strain LH-1. • OH and ·O 2 – played an important role in bacterial damage. • Appropriate amounts of BC and TiO 2 @BC enhanced the biodegradation of PAHs. • Appropriate amounts of BC and TiO 2 @BC increased the microbial diversity in the SBR. • Appropriate amounts of BC and TiO 2 @BC promoted the C and N cycles in the SBR system. Biochar (BC) and its composites have been widely used for pollutant treatment upon their adsorption and photocatalytic efficiency, but their toxicity and ecological effects have received little attention. In this study, BC was prepared and modified with nano-titanium dioxide to obtain BC composite (TiO 2 @BC), then the biotoxicity and ecological effects were investigated from two dimensions (single bacteria and microflora). In detailed, the effects of different dosage of BC and TiO 2 @BC on the degradation function, growth characteristics and toxicity mechanism of the strain Achromobacter sp. LH-1 were comprehensively studied. It was found that when the dosage of BC and TiO 2 @BC was less than or equal to 0.5 g/L, the degradation function of LH-1 was enhanced, but the effect on growth was negligible. However, when the dose exceeded 0.5 g/L, a large amount of ROS accumulated, which inhibited the cell respiratory chain and destroyed the cell wall. In another word, ·OH and ·O 2 – generated by BC and TiO 2 @BC played important roles in the inactivation of LH-1. Furthermore, a laboratory scale bioreactor (SBR) was built and applied to study the ecological effects of BC and TiO 2 @BC, and it was found that proper amount (0.5 g/L) of BC and TiO 2 @BC can not only effectively remove polycyclic aromatic hydrocarbons (PAHs) pollutants, but also increase the diversity of microbial communities, and promote the carbon and nitrogen cycle in the sewage system. This study analyzes the ecotoxicity risk of BC and TiO 2 @BC under photocatalysis in detail, which has important reference value for future practical applications in ecosystems. [ABSTRACT FROM AUTHOR]

[Display omitted] • UVA-LED/CFO-rGO/PMS system was highly effective for BPA degradation. • The effect of reaction parameters for BPA degradation was completely studied. • Degradation intermediates were determined and degradation pathway was proposed. • CFO-rGO had high stability and low metal leaching. • Ecotoxicity of BPA and intermediates were evaluated by ECOSAR. In this work, CoFe 2 O 4 -reduced graphene oxide (CFO-rGO) nanocomposite was synthesized to activate peroxymonosulfate (PMS) under UVA-LED irradiation. Bisphenol A (BPA) was selected as an emerging pollutant to evaluate the performance of the UVA-LED/CFO-rGO/PMS system. CFO-rGO was characterized by several advanced methods including XRD, FTIR, FESEM, EDX-mapping, TEM, XPS, BET-BJH, Raman spectrometry, VSM, PL, and EIS analyses. The operating factors, the determination of reactive species, and the mechanism were studied and discussed. During 30 min reaction time, more than 99% of BPA was removed by 150 mg/L PMS and 400 mg/L CFO-rGO under mild conditions (pH = 3–9). Bicarbonate ions could inhibit the BPA degradation by scavenging the free radicals. The trapping experiments exhibited that sulfate ( SO 4 • - ) and hydroxyl (•OH) radicals were prevailing agents for BPA degradation. Humic acid (HA) and sodium dodecyl sulfate (SDS) had a hindering effect on BPA degradation. CFO-rGO showed a high potential for recyclability up to six cycles. Moreover, the leaching of metals was approximately null for CFO-rGO, indicating that the current nanocomposite is highly stable. We also examined UVA-LED/CFO-rGO/PMS system on other pollutants, as well as real conditions. The results showed high efficiency for all conditions. The UVA-LED/CFO-rGO/PMS process could mineralize 67% of BPA during 80 min reaction time. Intermediates of BPA degradation were identified and their toxicity was also estimated. This work enlightened the ferrite catalysts' importance in activating PMS under UVA-LED irradiation for emerging pollutants wastewater remediation. [ABSTRACT FROM AUTHOR]

Raw leachate and a biological effluent coming from the same raw leachate that has been biologically treated in a new type of biological reactor, were electrochemically treated. A batch-type electrolytic cell using two patented DSA® electrodes was employed. Raw leachate, treated for 240 min at a current density of 200 mA/cm 2 , falls within the sewer discharge limits set by Italian legislation for the COD. Instead, effluent obtained through combined biological and electro-oxidation treatment (by using 83 mA/cm 2 and 133 mA/cm 2 ) has a COD such that could be discharged into the sewer and, after applying a current density equal to 200 mA/cm 2 after 240 min, has a COD value such that can even discharged into receiving water bodies. The electrochemical oxidation carried out is only effective on nitrogen ammonia through indirect electro-oxidation; it is not effective on other nitrogen-containing species. In any case, where ammonia is present (i.e., in the raw leachate), 82% is removed by the end of the test (i.e., after 240 min of electrolysis) at 200 mA/cm 2 . Also, for the raw leachate, chloramine formation is most marked at low current densities. Nevertheless, the toxicity does not appear to be affected; in fact, decrease regardless of the applied current density. [ABSTRACT FROM AUTHOR]

[Display omitted] • MoS 2 /GDY with high piezoelectric catalytic performance was prepared by ball milling. • The influence factor on the degradation efficiency of tetracycline were investigated. • The free radicals of the catalytic process and degradation mechanism were analyzed. • Possible degradation paths and toxicity evaluation were explored. A new strategy for the degradation of tetracycline in water by the piezo-catalysis of MoS 2 doped with graphdiyne was proposed. The optimally doped MoS 2 /GDY-3 had a few and thin layer structure, and PFM characterization showed that the piezoelectric response of MoS 2 /GDY-3 was 35.29% higher than that of MoS 2. MoS 2 /GDY-3 exhibited excellent catalytic activity, and the degradation rate of tetracycline reached 92.15% after 40 min by ball milling to trigger piezoelectric catalysis. After 5 cycles, the degradation rate reached 87.15%, which demonstrates the stability of the material. The influence of the MoS 2 /GDY-3 dosage, ball milling speed, TC concentration, pH, inorganic anions and water source on the degradation efficiency were investigated. ESR characterization showed that ∙OH and ∙O 2 – were the main active radicals of the piezoelectric catalysis. By analyzing the intermediate products, the possible degradation path of tetracycline was further analyzed, and a suitable mechanism of piezoelectric catalysis was proposed. The toxicity of intermediate products was evaluated to explore the toxicity changes in the degradation process. This work provides a new approach for changing the morphology of MoS 2 to enhance its piezocatalytic performance and effectively degrade tetracycline in water. [ABSTRACT FROM AUTHOR]

[Display omitted] • Anatase/rutile homojunction QDs anchored on g-C 3 N 4 is obtained by template method. • A formation process of A-R QDs/g-C 3 N 4 (TCN-150) is performed. • TCN-150 shows coupled adsorption-photocatalysis activity to OTC removal in seawater. • Toxicity of OTC and its photocatalytic intermediates are evaluated. • Adsorption-photocatalysis synergistic mechanism of TCN-150 is proposed. In this work, a facile two-step approach involving a templated solvothermal reaction and post-pyrolysis was developed for fabrication of ternary heterojunctions of anatase/rutile quantum dots (QDs)/g-C 3 N 4 (TCN-150), which shows well coupled adsorption and photocatalytic activity. The encapsulation of hydrolyzed titanium precursors by P123 polymer on the surface of exfoliated g-C 3 N 4 nanosheets produced anatase/rutile homojunction QDs (7–8 nm)/g-C 3 N 4 heterostructural lamellas, while the subsequent pyrolysis resulted in amorphous carbon layers stacking on g-C 3 N 4. The adsorption occurs on the carbon layers, while the photocatalysis proceeds on the conduction band of g-C 3 N 4 and valence band of anatase, which gave free radicals of ∙O 2 − and ∙OH for antibiotics decomposition, respectively. Formation of mixed anatase/rutile phases and amorphous carbon in the composite promoted the oxytetracycline (OTC) removal in dynamic flow conditions, with efficiencies about 46.8 and 3.8 times than that of g-C 3 N 4 and TiO 2 respectively, owing to facilitated photogenerated charge separation and transfer, as well as the synergy between adsorption and photocatalysis. The toxicity evaluation of detected final intermediates in the proposed OTC degradation pathways showed decreased acute toxicity of LD 50 and reduced mutagenicity, confirming weaken toxicities of intermediate solutions after visible-light irradiation for 120 min, and this demonstrated a huge potential of TCN-150 as an eco-friendly photocatalyst for practical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Mesoporous g-C 3 N 4 nano-clusters with nitrogen defects were synthesized. • Reverse replica of silica clusters as hard template confined g-C 3 N 4 planes' growth. • Complete photodegradation of TC and RhB was achieved in a short time. • O 2 −, h+ were the main active species involved in the degradation process. • The toxicity of produced intermediates of TC was lower in compared to TC. Constructing high-performance visible-light responsive photocatalyst to remediate organic pollutants from wastewater is of great challenge in recent years. In this study, by using SiO 2 clusters as a template, mesoporous graphitic carbon nitride nano-clusters (NC MCN) were fabricated as a high-activity photocatalyst. The confined growth of carbon nitride in the presence of SiO 2 clusters introduced extra structural defects to the carbon nitride framework including nitrogen vacancies and cyano groups, which was confirmed by employing different characterization analyses. These structural defects created midgap states below the conduction band, which improved light-harvesting efficiency and suppressed electron-hole recombination. Thus, NC MCN showed high photocatalytic activity toward degradation of both tetracycline and rhodamine B under visible light irradiation. Complete degradation of 15 mL solution of 15 ppm tetracycline was achieved in 30 min compared to the bulk catalyst (taking more than 3 h). Furthermore, NC MCN demonstrated high stability after reusing for 8 consecutive photodegradation cycles. The total organic carbon concentration at different reaction time showed a rising and falling trend, which illustrate photodegradation process, i.e. adsorption, photodegradation, and mineralization. By liquid chromatography-mass spectroscopy analysis, the produced intermediates during the tetracycline degradation were proposed, which showed the formation of smaller molecules in just 15 min. The toxicity of the intermediates was analyzed using quantitative structure–activity relationship estimation and the outcomes exhibited that the toxicity of the solution reduced as the reaction time increased. This comprehensive study from photodegradation process to mineralization of TC demonstrated NC MCN as a promising photocatalyst for sustainable treatment of wastewater. [ABSTRACT FROM AUTHOR]

[Display omitted] • PMS/PDS activation by various heterogeneous Fe-based materials were provided. • Hybrid PMS/PDS activation systems with assisted external energy were introduced. • Primary reactive oxygen species generated during reaction process were discussed. • Toxicity evaluation of catalysts and degradation intermediate were carried out. • Challenges and prospect were proposed in the future research and applications. Fe-based heterogeneous materials have been the most used transition metal catalysts for advanced oxidation processes (AOPs) due to their versatility, flexibility, high efficiency, and environmental friendliness. Herein, we primarily review the latest progress in various heterogeneous Fe-based catalysts such as single zero-valent iron, monometallic iron (hydr)oxides, bimetallic iron oxides (e.g., ferrospinel, perovskite, layered double (hydr)oxide, and metal–organic frameworks), Fe-based sulfide/carbide/nitride, and other Fe-based materials for peroxymonosulfate (PMS) and peroxydisulfate (PDS) activation. Meanwhile, the hybrid activation systems assisted with light, electric field, ultrasound, microwave, and magnetic field have been made a detailed introduction. In addition to the special attention paid to the activation mechanism, main reactive oxygen species (ROS) existed in the radical (e.g., sulfate radicals (SO 4 −), hydroxyl radical (HO), and superoxide radical (O 2 −)) and nonradical (e.g., singlet oxygen (1O 2) and high-valent iron-oxo species) activation processes have been summarized. In addition, toxicity evaluation of catalysts and degradation intermediate through two common methods (i.e., predictive models and toxicity tests) were introduced. Finally, we highlight the great potential of PMS/PDS activation using Fe-based heterogeneous materials for organic pollutants removal and put forward the challenges that may be faced in future research and practical applications. [ABSTRACT FROM AUTHOR]

• Solution pH significantly influenced ATZ degradation by the Fe0/PMS process. • SO 4 −, OH and Fe(IV) simultaneously existed in the Fe0/PMS system. • Activation mechanism involving Fe(IV) and degradation pathways were proposed. • The toxicity of reaction solution after the Fe0/PMS process finally decreased. In this study, the catalytic degradation of atrazine (ATZ) by peroxymonosulfate (PMS) activated with commercial Fe0 was investigated under different pH conditions. The degradation process was pH dependent, among which acidic and neutral conditions favored Fe0 corrosion and PMS decomposition. Electron spin resonance (ESR) tests and alcohol quenching experiments confirmed the simultaneous presence of sulfate radical (SO 4 −) and hydroxyl radical (OH) in the Fe0/PMS system, both of which were quantified via indirect monitoring of the generation of benzoquinone (BQ) and p -hydroxybenzoic acid (HBA), respectively. In addition, ferryl ion (Fe(IV)) was identified to be involved in the Fe0/PMS system based on the selective transformation from methyl phenyl sulfoxide (PMSO) to methyl phenyl sulfone (PMSO 2). Coupled with SEM and XPS results, the activation mechanism of the Fe0/PMS system was thought to be that Fe(II) released from Fe0 corrosion decomposed PMS into SO 4 − and OH or reacted with PMS to yield Fe(IV), accompanied by the final conversion of Fe(II) to Fe(III). Furthermore, possible degradation pathways were proposed according to intermediates detected by LC-MS, and dechlorinated and dealkylated byproducts were quantitatively analyzed. Ultimately, toxicity tests based on luminescent bacteria Vibrio qinghaiensis sp.-Q67 suggested the detoxification of ATZ by the Fe0/PMS system. [ABSTRACT FROM AUTHOR]

• Investigation of process conditions for the degradation of sulfamethoxazole. • Identification of degradation products for elucidation of the degradation mechanism. • Elucidation of pH influence on formation of degradation products. In this article, heat-activated persulfate oxidation was investigated as a promising technique for the removal of sulfamethoxazole from an aqueous environment. It was found that the degradation efficiency of sulfamethoxazole increases with increasing persulfate concentration due to the increased SO 4 − production. As suggested by the Arrhenius equation, the sulfamethoxazole degradation rate constant increased with increasing temperature. An activation energy of 103 kJ/mol was determined. Furthermore, the initial pH of the reaction mixture had a large influence on the degradation of sulfamethoxazole. At higher initial pH values, the degradation of sulfamethoxazole increased. The main cause for this increase is a difference in sulfamethoxazole distribution: at higher pH, the deprotonated form of sulfamethoxazole is present and found to be more susceptible to degradation. A second reason was found to be the formation of OH at higher initial pH values, although this contribution was smaller. To elucidate the degradation process, six intermediates were identified, and the difference in formation of these compounds at different initial pH values was revealed. Through ECOSAR modeling, some degradation products were found to be of main interest when monitoring the toxicity of the degradation mixture. [ABSTRACT FROM AUTHOR]