•The kinetics of CAP degradation by O3/PMS were investigated.•The relative contribution of various reactive species on CAP removal was evaluated.•The transformation degradations of CAP by O3/PMS, in ...compared with other O3-based AOPs were identified.•The effects of several AOP pre-treatments on the DCAcAm generation were investigated.
The frequent detection of chloramphenicol (CAP) in wastewater and surface water gives rise to concerns on its fatal myelosuppression and aplastic anemia. Recently, the combination of ozone and peroxymonosulfate (O3/PMS) has received wide attention in removing pollutants due to the multiple oxidants (i.e., O3, hydroxyl radicals (OH) and sulfate radicals (SO4−)) existed therein. This study showed that O3/PMS could effectively degrade CAP under various conditions. The second-order rate constant of CAP with O3, OH and SO4− was 0.291±0.005, 2.27(±0.03)×109 and 1.02±0.02×108M-1s-1, respectively. The degradation efficiency of CAP was significantly enhanced as PMS concentration or pH increased. Bicarbonate (HCO3−) at concentration of 5 mM slightly inhibited CAP degradation at pH 7. Chloride (Cl−) at concentration of 0.5 mM enhanced CAP removal at pH 7, while this enhancement gradually weakened as Cl− concentration further increased. The degradation efficiency of CAP first increased with increasing natural organic matter (NOM) concentrations (0.1–0.3 mg/L), while it was completely suppressed at higher NOM concentrations (0.5 mg/L). Four degradation products in total of CAP were identified in O3-based processes (i.e., O3, O3/TBA, O3/H2O2, O3/PMS and O3/PMS/tert-butyl alcohol (TBA) systems. Besides, these transformation products by OH, SO4− and/or O3 were also distinguished. Finally, the impact of O3/PMS pre-oxidation on the formation of dichloroacetamide (DCAcAm) from CAP during post-chlorination process was investigated. Compared with the traditional O3 and O3/H2O2 processes, O3/PMS pre-oxidation generally led to the least generation of DCAcAm under similar conditions, where SO4− rather than OH was conducive to relieve the formation of DCAcAm. Moreover, the presence of NOM obviously alleviated the formation of DCAcAm by O3/PMS pre-oxidation.
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Current research focused on developing multiple active species in peroxymonosulfate (PMS) system to degrade contaminants, but deepening concern lacks over why cooperation of those ...active species facilitated a faster degradation. Here, we employed Co3O4, rGO and Co3O4@rGO composite to activate PMS for tetracycline (TC) degradation, and detected crucial factors toward highest performance of Co3O4@rGO/PMS system. Batch experiments exhibited a satisfactory TC degradation efficiency under Co3O4@rGO/PMS, complete degraded 50 mg/L TC within 20 min. Analytical tests discovered that radical active species generated by Co3O4/PMS and non-radical species by rGO/PMS were successfully co-existed in Co3O4@rGO/PMS system, significantly improving the performance of TC removal. Subsequently, a combination of density functional theory (DFT) calculation and intermediates analysis revealed that, in Co3O4@rGO/PMS system, the cooperation rather than independent effect of radical and non-radical active species expanded TC degradation pathways, enhancing the degradation performance. Furthermore, decent adaptability, stability, and recyclability toward affecting factors variation of Co3O4@rGO/PMS demonstrated it as a potent and economical system to degrade TC. Overall, this study developed a novel Co3O4@rGO/PMS system with a cooperative oxidation pathway for highly efficient TC removal, and managed to clarify why this oxidation pathway achieved high efficiency through a combination of theoretical and experimental method.
•Cooperative oxidation pathways were developed in Co3O4@rGO/PMS system.•The advantages of Co3O4@rGO/PMS system were verified by calculations and experiments.•Optimal Co3O4@rGO showed an excellent catalytic performance.•Co3O4@rGO/PMS system has a satisfactory adaptability, stability, and recyclability.
Carcinogenic N, N-Dimethylnitrosamine (NDMA) has been reported to generate significantly during ozonation of fuel additive unsymmetrical dimethylhydrazine (UDMH), the combined ...ozone/Peroxy-Monosulfate (O3/PMS) technology was tried for reducing its formation in this study. The influence of PMS dosages, ozone concentrations, pH, Br- and humic acid (HA) on NDMA formation from UDMH were investigated. In addition, the reduction mechanisms were explored by intermediates identification and Gaussian calculation. The results demonstrated that O3/PMS technology was effective on NDMA reduction, reaching an efficiency of 81% with 80 μM PMS. Higher NDMA reduction rates were achieved by O3/PMS with increasing pH within the scope of research (from 5 to 9), achieving a maximum of 69.9% at pH 9. The presence of bromide ion facilitated NDMA generation during ozonation, but the reduction efficiency by O3/PMS slightly improved from 66.3% to 70.6%. The presence of HA reduced NDMA formation in O3/PMS system. The contribution of SO4•− on NDMA reduction accounted for ~64%, which was higher than that of •OH (41.4%); however, its promotion role on conversing UDMH to NDMA was lower than O3. Therefore, the technology could reduce NDMA formation effectively. In addition, the results of Gaussian calculation manifested that the N atom in -NH2 group of UDMH was easily attacked not only by •OH but also by O3, so it is the key path that determines final NDMA formation. This study would provide reference for reducing NDMA formation during ozonation of UDMH-containing water matrixes.
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•The O3/PMS technology could significantly reduce NDMA formation from UDMH during ozonation.•The NDMA reduction efficiency in O3/PMS system lessened at the presence of HA.•The contribution of SO4•− on NDMA reduction was higher than that of •OH, which accounted for ~64%.•The formed SO4•− played roles on conversing UDMH to NDMA, but its promotion role was lower than O3.•N atom in the -NH2 group of UDMH was the key site that promoted the formation of NDMA.
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•A synergistic effect of TiO2 nanotubes arrays and PMS in visible light for BPA degradation was achieved.•A PMS-TiO2 complex was formed and contributed to the radicals ...generation.•Visible light excited the electron of PMS-TiO2 complex to theconduction band of TiO2.•TiO2 nano-tubes arrays/Ti plate exhibited excellent stability and separability.
TiO2 photocatalysis and peroxymonosulfate (PMS) oxidation can exhibit a good performance in ultraviolet light but a less activity in visible light (VL). Herein, the TiO2 nano-tubes arrays (TiO2NTAs) and PMS were combined to degrade bisphenol A (BPA) under VL irradiation. Surprisingly, about 94.6% of BPA was removed in TiO2NTAs/PMS/VL system within 30 min, which was much higher than that of TiO2NTAs/VL (20.1%) and PMS/VL (9.4%) systems. A series of spectroscopic characterizations and photoelectrochemical measurements confirmed the formation of PMS-TiO2 complex with VL response, which can be excited by VL to transfer electrons to theconductionband (CB) of TiO2 for activating PMS. The quenching tests and electron spin resonance (ESR) spectra indicated that SO4•− and ·OH were responsible for BPA degradation, and then the possible degradation pathways of BPA were proposed. Humic acid (HA) and chloride ions (Cl−) significantly enhanced the BPA degradation, while bicarbonate (HCO3–) and phosphate (H2PO4−) exhibited an inhibition effect. Moreover, TiO2NTAs/PMS/VL system displayed an enhanced BPA degradation in tap water and drinking water compared with deionized water, and as an immobilization catalyst which fabricated on Ti plate, TiO2NTAs exhibited excellent stability and separability without complex catalyst separation/recovery processes. We believe this work will provide a new insight of the VL-induced photocatalytic PMS activation in practical water treatment.
In this work, a comparative study of efficient degradation of Rhodamine B (RhB) in CoFe2O4/H2O2 and CoFe2O4/PMS systems was performed. Batch experiments indicated that the RhB degradation rate of ...CoFe2O4/H2O2 system reached 95.5% at 90 min under the condition of 0.5 g L−1 of CoFe2O4 dosage, 10 mM of H2O2 concentration and 3.0 of initial pH. At certain conditions of initial pH = 7.0, 0.3 g L−1 of CoFe2O4 dosage, 7 mM of PMS concentration, CoFe2O4/PMS system could completely degrade RhB within 90 min. EPR and quenching experiments indicated that •OH was the main active species of CoFe2O4/H2O2 system, and •OH, SO4•-, •O2− and 1O2 participated in RhB degradation of CoFe2O4/PMS system. The circulate of Co(II)/Co(III) and Fe(II)/Fe(III) on the CoFe2O4 surface promoted the formation of free radical species in the two system. In CoFe2O4/PMS system, the formed •O2− and SO5•- realized the generation of non-free radical species (1O2). The LC-MS results indicated that N-de-ethylation, chromophore cleavage, opening rings and mineralization were the main steps for the RhB degradation of the two systems. After five cycles of degradation experiment, the CoFe2O4/H2O2 and CoFe2O4/PMS systems still maintained the high degradation rate (85.2% and 92.4%) and low mass loss (2.7% and 3.09%). In addition, CoFe2O4/PMS system had better potential value for the actual water and multi-pollutant degradation than CoFe2O4/H2O2 system. Finally, the toxicity analysis and cost assessment of the two oxidation systems were preliminarily evaluated.
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•Possible degradation mechanism and pathway of CoFe2O4/H2O2 and CoFe2O4/PMS systems were proposed.•Two oxidation systems effectively reduced the toxicity of pollutants and presented the low costs.•CoFe2O4/PMS system presented a strong adaptability to actual water and multi pollutant degradation.•CoFe2O4/PMS system showed the better degradation ability, stability and reuse than CoFe2O4/H2O2 system.
•Enhanced PMS utilization efficiency with boosting e−1 transfer in Co+2/Co+3 cycle.•Treatment system LaCoO3/PMS provided very low treatment cost 27.87$/m3 of aqueous solution.•In-situ generated ...reactive species SO4•– and •OH both play major role on degradation.•Six plausible degradation pathways for ofloxacin were proposed with PMS activation mechanism.•Phytotoxicity of pharmaceutical wastewater on various plant species.
This study aims to investigate the detoxification of real pharmaceutical manufacturing wastewater by PMS activated with perovskite LaMO3 (M = Cu, Co, Fe), synthesized by citric sol–gel method. The textural properties of synthesized perovskite were monitored by BET, FESEM/EDS, TEM, XRD, FTIR, and XPS techniques. The effects of key parameters (PMS dose, catalyst, pH and reaction temperature) on ofloxacin degradation along with PMS utilization efficiency as well as PMS consumption were evaluated in detail. Catalyst LaCoO3 exhibited the excellent catalytic activity and stability towards the degradation of ofloxacin (97.11 %) and COD (79.41 %) at optimum operating conditions. Removal of ofloxacin and COD were suppressed by 7 % and 9 % over the fourth cycle, along with minor leaching of Co were observed. Quenching experiments and EPR results demonstrated that both ROS species (SO4•− and •OH) were dominant species for ofloxacin degradation in LaCoO3/PMS system. The treatment cost for ofloxacin degradation in LaCoO3/PMS system was estimated to be 40.78$/m3 of real pharmaceutical wastewater. Six plausible degradation pathways of ofloxacin were proposed based on intermediate compounds identified by GC-MS and reported literature.
In this paper, we use the concept of an intuitionistic fuzzy set to PMS-ideals in PMS-algebras. We discuss the notion of intuitionistic fuzzy PMS-ideals under homomorphism and Cartesian product and ...investigate several related properties. The homomorphism of an intuitionistic fuzzy PMS-ideal of a PMS-algebra is studied, and its homomorphic image and inverse image are investigated. The Cartesian product of any two intuitionistic fuzzy PMS-ideals is discussed, and some related results are obtained. The Cartesian product of the intuitionistic fuzzy PMS-ideals is characterized in terms of their level sets. Finally, we discuss the concept of the strongest intuitionistic fuzzy relations on an intuitionistic fuzzy PMS-ideal of a PMS-algebra and investigate the relationships between the strongest intuitionistic fuzzy relations and the intuitionistic fuzzy PMS-ideals.
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•PMS and PAA can be directly introduced in high-salinity water for organic removal.•Both systems tend to degrade electron-rich phenolics under investigations.•Both systems present ...certain resistance towards water interferences.
Phenolic pollutants are highly toxic and can affect the growth and reproduction of aquatic organisms, as well as contaminate drinking water resources, posing a significant threat to both ecological and human health. However, conventional biological treatment processes are constrained in treating high salinity organic wastewaters due to the potentially lethal effects of high concentrations of dissolved salts on microorganisms. While advanced oxidation processes have shown promise in removing phenolic contaminants from high-saline wastewater, their widespread application is always limited by the high costs associated with energy and chemical usage. In this study, we explored the potential application of directly introducing peroxymonosulfate (PMS) and peracetic acid (PAA) to high-salinity water for the removal of nine phenolic contaminants. By establishing a correlation between the degradation rate constants in the PMS/Cl– (kPMS) and PAA/Cl– (kPAA) systems and various molecule descriptors, two multiple linear regression models were developed to predict the degradation rate constants under investigation. Additionally, we selected bisphenol A (BPA) as the target contaminant and investigated the impact of common ions found in natural water, such as HCO3–, NO3–, and humic acid, on the removal of BPA using two systems. Finally, we conducted experiments using tap water and sewage water to demonstrate the practical application and performance of the two systems. These experiments aimed to provide valuable insights into the influence of background chloride on PMS and PAA activation, as well as the potential of direct PMS/PAA introduction for eliminating phenolic micropollutants from high-saline wastewaters.
•O3/PMS-BAC was developed to reduce the AMR caused by BAC treatment.•The effluent water quality of O3/PMS-BAC was better than that from O3-BAC and BAC.•The O3/PMS removed 32 %−54 % more antibiotics ...than O3.•The ARB in the effluent of O3/PMS-BAC was only 0.01–0.03 times that of BAC.•O3/PMS-BAC removed 1.76 %−62.83 % more of the targeted ARGs in the effluent than BAC.
Biological activated carbon (BAC) is one of the important treatment processes in wastewater and advanced water treatment. However, the BAC process has been reported to have antimicrobial resistance (AMR) risks. In this study, a new BAC-related treatment process was developed to reduce AMR caused by BAC treatment: ozone/peroxymonosulfate-BAC (O3/PMS-BAC). The O3/PMS-BAC showed better treatment performance on the targeted five antibiotics and dissolved organic matter removal than O3-BAC and BAC treatments. The O3/PMS-BAC process had better control over the AMR than the O3-BAC and BAC processes. Specifically, the amount of targeted antibiotic-resistant bacteria in the effluent and biofilm of O3/PMS-BAC was only 0.01–0.03 and 0.11–0.26 times that of the BAC process, respectively. Additionally, the O3/PMS-BAC process removed 1.76 %–62.83 % and 38.14 %–99.27 % more of the targeted ARGs in the effluent and biofilm than the BAC process. The total relative abundance of the targeted 12 ARGs in the O3/PMS-BAC effluent was decreased by 86 % compared to the effluent after BAC treatment. In addition, Proteobacteria and Bacteroidetes were probably the main hosts for transmitting ARGs in this study, and their relative abundance decreased by 9.6 % and 6.0 % in the effluent of the O3/PMS-BAC treatment compared to that in BAC treatment. The relationship analysis revealed that controlling antibiotic discharge was crucial for managing AMR, as antibiotics were closely related to both ARGs and bacteria associated with their emergence. The results showed that the newly developed treatment process could reduce AMR caused by BAC treatment while ensuring effluent quality. Therefore, O3/PMS-BAC is a promising alternative to BAC treatment for future applications.
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