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• Co 1.1 Mn 1.9 O 4 exhibited excellent activity to activate PAA for SMX degradation. • CH 3 C(O)OO● was evidenced as the dominant reactive oxidizing species. • Significant role of Mn in intensifying the activity of Co sites was revealed. • Co 1.1 Mn 1.9 O 4 /PAA process had great potential in high-salinity wastewater treatment. Activation of peracetic acid (PAA) to generate powerful oxidizing species has become a promising advanced oxidation processes (AOPs) in wastewater treatment, yet the development of low-cost and high-performance activators is still a primary challenge. Herein, a range of Co–Mn spinel oxides (Co 3-x Mn x O 4) with varying levels of Co and Mn were successfully elaborated, in which Co 1.1 Mn 1.9 O 4 exhibited remarkable performance in PAA activation, outperforming most reported heterogeneous catalysts. Extensive quenching experiments and electron spin resonance (ESR) analysis indicated that acetylperoxyl radical (CH 3 C(O)OO●) was the predominated oxidizing species responsible for sulfamethoxazole (SMX) degradation. Density functional theory (DFT) calculations revealed that doping with Mn not only promoted the electron transfer and accelerated reduction of Co(III) to Co(II), but also lowered the energy barrier for PAA activation. Moreover, the prominent chemisorption and activation of PAA with Co 1.1 Mn 1.9 O 4 was also benefitted from the significant role of Mn in optimizing the distribution of bonding and antibonding states on Co 3d orbitals. Unexpectedly, high levels of Cl−greatly facilitated SMX degradation due to the mass production of HOCl from the chain reactions of various radicals with Cl−. This work provides new insights into bimetallic activation of PAA, and the knowledge obtained will further advance the application of PAA-based AOPs. [Display omitted] [ABSTRACT FROM AUTHOR]

• nCuO exhibited the highest reactivity in PAA activation among nMOPs. • High reactivity of Cu(I) in PAA activation was unveiled. • A new scavenging experiment was developed to distinguish CH 3 C(O)OO●. • Co-existing H 2 O 2 played a significant role in Cu(II)/Cu(I) conversion. • The nCuO/PAA process is promising in real wastewater decontamination. Peracetic acid (PAA)-based advanced oxidation processes (AOPs) has attracted increasing attentions towards contaminant degradation in the wastewater treatment. Herein, we report the efficient activation of PAA by nano-CuO (nCuO/PAA) to degrade carbamazepine (CBZ) for the first time. Rapid degradation of CBZ was observed in the nCuO/PAA system at neutral initial pH. A new scavenging experiment with Mn2+ as a specific scavenger was developed to distinguish the dominant role of CH 3 C(O)OO● for CBZ degradation in the nCuO/PAA process. The oxidation of CBZ by CH 3 C(O)OO● was verified to proceed via the electrons transfer, and the acute and chronic toxicity of the transformation products was significantly reduced. The efficient activation of PAA by nCuO was found to be realized through continuous conversion of Cu(II) to Cu(I), which was significantly boosted by co-existing H 2 O 2. The nCuO/PAA process was slightly affected by the water matrices, and maintained high efficiency in real water samples. The findings obtained in this study provide new insights into the catalytic formation of CH 3 C(O)OO● from PAA and facilitate the development and application of PAA-based AOPs in wastewater treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

• Cu2+ can synergistically activate PDS with magnetite to generate radicals. • Synergistic activation of PDS is effective to degrade contaminants in groundwater. • The adsorbed Cu2+ is reduced by the structural Fe(II) to generate Cu+. • Stability of Cu+ is enhanced on magnetite surface at pH 7 and higher. • The generated Cu+ on magnetite surface contributes to PDS activation. Magnetite is known to exhibit high catalytic reactivity in Fenton-like reactions merely at low pH conditions. Here we report the association of Cu2+ ion can significantly enhance peroxydisulfate (PDS) activation with magnetite under environmental aquatic conditions (near neutral pH). Cu2+ is able to synergistically activate PDS with magnetite to generate radicals, e.g., SO 4 ·−, at neutral or slightly alkaline pH, and such synergistic activation of PDS is promising to degrade various contaminants in groundwater. In-depth study reveals Cu2+ ion adsorbed on magnetite plays a crucial role in PDS activation. The adsorbed Cu2+ is labile to be reduced by the structural Fe(II) on magnetite to generate Cu+, which is relatively stable in the presence of magnetite at neutral or alkaline pH, but extremely unstable at acidic pH. The generated Cu+ on magnetite surface, rather than Cu2+, contributes to PDS activation in the reaction system, and the recycling of Cu+/Cu2+ sustains continuous activation of PDS. This study is among the first to report the synergistic activation of PDS by magnetite and Cu2+ ion at neutral pH, and unambiguously discern the role of Cu+ in PDS activation. The new mechanistic knowledge provides a more accurate understanding of PDS activation by natural minerals in environmental remediation. [ABSTRACT FROM AUTHOR]

Lanthanum-modified bentonite (LMB) is a widely used phosphorus-inactivating agent in lakes. However, dissolved organic carbon (DOC) exists ubiquitously in lakes, and its influence on phosphate binding is still not adequately understood. Our results showed that both phosphate and DOC can be adsorbed by LMB. The Langmuir adsorption maxima of phosphate and DOC were 9.06 mg P/g and 5.31 mg C/g, respectively, generating a C/P molar ratio ∼1.5. When phosphate and DOC coexisted at this ratio, the adsorption of phosphate was not influenced by DOC and vice versa. However, the phosphate capture by LMB was significantly reduced by raising the ratio above ∼9, and the reduction was increased with increasing the ratio. Once adsorbed by LMB, phosphate was essentially not desorbed by DOC, while adsorbed DOC can be mostly liberated by phosphate. It is deemed that phosphate can interact preferentially with La on LMB. However, DOC can still be adsorbed by LMB, even after LMB was saturated with phosphate, which was attributed to (i) the high coordination capacity of La; (ii) the interaction of DOC with the hydroxyl group(s) of the adsorbed phosphate via hydrogen bonding; and (iii) the interaction of DOC with the La sites unoccupied by phosphate. We proposed that LMB can be applied in the season (time) when the DOC/P ratio in lakes is low enough to facilitate the adsorption of phosphate, which will no longer be released into water, even after the C/P ratio is raised later. Image 1 • Both phosphate and DOC can be adsorbed by lanthanum-modified bentonite (LMB). • Influence of DOC on P capture became significant when C/P molar ratio exceeding ∼9. • P adsorbed on LMB can not be desorbed by DOC. • DOC adsorbed on LMB can be mostly released by P. • We proposed a strategy that LMB can be applied when C/P ratio in lakes is low. [ABSTRACT FROM AUTHOR]

• Toxicity of aged PVC MPs is greater than that of virgin PVC MPs. • MPs affect the growth and intracellular components of C. pyrenoidosa. • MPs promote nitrate uptake and inhibit photosynthesis of C. pyrenoidosa. • Extracellular polymeric substances increase during exposure to aged MPs. • The toxicity of MPs was associated with intercellular oxidative stress levels. The toxicity of microplastics (MPs) on freshwater plants has been widely studied, yet the influence of aged MPs remains largely unexplored. Herein, we investigated the influence of polyvinyl chloride (PVC) MPs, both before and after aging, at different environmentally relevant concentrations on Chlorella pyrenoidosa , a freshwater microalgae species widely recognized as a valuable biomass resource. During a 96-h period, both virgin and aged MPs hindered the growth of C. pyrenoidosa. The maximum growth inhibition rates were 32.40 % for virgin PVC at 250 mg/L and 44.72 % for aged PVC at 100 mg/L, respectively. Microalgae intracellular materials, i.e., protein and carbohydrate contents, consistently decreased after MP exposure, with more pronounced inhibition observed with aged PVC. Meanwhile, the MP aging significantly promoted the nitrogen uptake of C. pyrenoidosa , i.e., 1693.45 ± 42.29 mg/L (p < 0.01), contributing to the production of humic acid-like substances. Additionally, aged PVC induced lower chlorophyll a and Fv/Fm when compared to virgin PVC, suggesting a more serious inhibition of the photosynthesis process of microalgae. The toxicity of MPs to C. pyrenoidosa was strongly associated with intercellular oxidative stress levels. The results indicate that MP aging exacerbates the damage to photosynthetic performance and bioenergy production in microalgae, providing critical insights into the toxicity analysis of micro(nano)plastics on freshwater plants. [Display omitted] [ABSTRACT FROM AUTHOR]

• Human manure (HM) is an ideal waste biomass for the production of P fertilizer. • Hydrothermal carbonation was used to recover high-bioavailable P from HM directly. • C and P were preserved in the derived P-rich hydrochars (PHCs) well. • The derived PHCs has a promising application potential. Phosphorus (P) recovery from human manure (HM) is critical for food production security. For the first time, a one-step hydrothermal carbonation (HTC) treatment of HM was proposed in this study for the targeted high-bioavailable P recovery from P-rich hydrochars (PHCs) for direct soil application. Furthermore, the mechanism for the transformation of P speciation in the derived PHCs was also studied at the molecular level. A high portion of P (80.1∼89.3%) was retained in the solid phase after HTC treatment (120∼240°C) due to high metal contents. The decomposition of organophosphorus (OP) into high-bioavailable orthophosphate (Ortho-P) was accelerated when the HTC temperature was increased, reaching ∼97.1% at 210°C. In addition, due to the high content of Ca (40.45±2.37 g/kg) in HM, the HTC process promoted the conversion of low-bioavailable non-apatite inorganic (NAIP) into high-bioavailable apatite inorganic P (AP). In pot experiments with pea seedling growth, the application of newly obtained PHCs significantly promoted plant growth, including average wet/dry weight and plant height. Producing 1 ton of PHCs (210°C) with the same effective P content as agricultural-type calcium superphosphate could result in a net return of $58.69. More importantly, this pathway for P recovery is predicted to meet ∼38% of the current agricultural demand. [Display omitted] [ABSTRACT FROM AUTHOR]

• PAA was effective in inactivating AR E. coli and preventing their regrowth. • PAA could induce antibiotic resistant E. coli into viable but nonculturable state. • Amino acids containing thiol, thioether and imidazole groups are inactivation sites. • PAA was poorly reactive with plasmid strands and bases. • PAA-treated plasmid remained high-efficient transformation functionality. The occurrence of a viable but nonculturable (VBNC) state in antibiotic-resistant E. coli (AR E. coli) and inefficient degradation of their antibiotic resistance genes (ARGs) may cause potential health risks during disinfection. Peracetic acid (PAA) is an alternative disinfectant for replacing chlorine-based oxidants in wastewater treatment, and the potential of PAA to induce a VBNC state in AR E. coli and to remove the transformation functionality of ARGs were investigated for the first time. Results show that PAA exhibits excellent performance in inactivating AR E. coli (over 7.0-logs) and persistently inhibiting its regeneration. After PAA disinfection, insignificant changes in the ratio of living to dead cells (∼4%) and the level of cell metabolism, indicating that AR E. coli were induced into VBNC states. Unexpectedly, PAA was found to induce AR E. coli into VBNC state by destroying the proteins containing reactive amino acids at thiol, thioether and imidazole groups, rather than the result of membrane damage, oxidative stress, lipid destruction and DNA disruption in the conventional disinfection processes. Moreover, the result of poor reactivity between PAA and plasmid strands and bases confirmed that PAA hardly reduced the abundance of ARGs and damaged the plasmid's integrity. Transformation assays and real environment validation indicated that PAA-treated AR E. coli could release large abundance of naked ARGs with high-efficiency transformation functionality (∼5.4 × 10–4 - ∼8.3 × 10–6) into the environment. This study has significant environmental implications for assessing the transmission of antimicrobial resistance during PAA disinfection. [Display omitted] [ABSTRACT FROM AUTHOR]

• PMS exhibits specific and high reactivity towards HRAs. • HRAs oxidation by PMS proceeds via a non-radical process. • PMS-promoted HRAs degradation is unaffected by water matrices. • Thioether sulfur in HRAs (except RXTD) is oxidized to sulfoxide product. • Ecotoxicity of HRAs is remarkably reduced after PMS oxidation. Peroxymonosulfate (PMS) is an appealing oxidant for organic contaminant destruction relying on radical generation after activation. Herein, we report PMS-promoted rapid degradation of histamine H 2 -receptor antagonists (HRAs) through non-radical process for the first time. Five commonly used HRAs, i.e., ranitidine (RNTD), cimetidine (CMTD), famotidine (FMTD), nizatidine (NZTD) and roxatidine (RXTD), were examined their reactivity towards PMS. Results show that HRAs (except RXTD) exhibit high reactivity towards PMS, with apparent second-order rate constants from 403 to 872 M−1s−1 at pH 7.0. Radical scavenging experiments excluded the contribution of radicals to PMS-promoted degradation of HRAs, and this non-radical process was unaffected by the real water matrices. Structure-activity assessment and theoretical calculation indicated that the thioether sulfur in HRAs (except RXTD) was the main reactive site for PMS oxidation. Transformation product analysis further elucidated oxidation of the thioether sulfur to sulfoxide product through an oxygen atom transfer process. Moreover, the thioether sulfur on the straight chain was more susceptible to oxygen transfer with PMS than that on the thiazole ring of HRAs. Toxicity evaluation indicated the ecotoxicity of HRAs could be remarkably reduced after PMS oxidation. Hence, this work provides a promising strategy to rapidly remove HRAs and significantly reduce their toxicity in water treatment. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Nickel phosphide (Ni 2 P) is an emerging efficient catalyst for the hydrogen evolution and water splitting. Herein, we report that Ni 2 P is also a promising catalyst for enhancing electrochemical dechlorination of chlorinated disinfection byproducts (DBPs). Amorphous Ni 2 P (ANP) mini-nanorod arrays were in-situ fabricated on nickel foam (NF) via a facile phosphidation process, and then used as a binder-free cathode for electrochemical dechlorination of trichloroacetic acid (TCAA). Results showed that ANP exhibited superior performance on electrochemical dechlorination of TCAA than other metal cathodes (e.g., NF and Pd/C). Scavenging experiments and electron spin resonance (ESR) technique indicated that atomic H* was generated from water reduction through ANP catalysis, and primarily contributed to TCAA dechlorination. Indeed, the superhydrophilic surface of ANP favored electrocatalyst/electrolyte contact, and its low impedance further afforded rapid electron transport from the electrode to water or protons for atomic H* generation. The kinetic modelling and mass balance evaluation revealed the transformation mechanism of TCAA dechlorination. This study is among the first to develop ANP as a binder-free cathode for electrochemical dechlorination, and have important implications for eliminating chlorinated DBPs in water. Image 1 • ANP, a noble metal-free cathode, exhibited superior efficiency than Pd/C. • The atomic H* was primarily responsible for TCAA dechlorination. • Superhydrophilic surface of ANP accelerated H* formation in a wide pH range. • Stepwise and concerted pathway accomplished dechlorination of TCAA to AA. • ANP showed high reusability for dechlorination. [ABSTRACT FROM AUTHOR]