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a EPR spectra of PMS-based reaction processes; b Effects of different quenchers on the CBZ removal in the process of MoS2/Fe²⁺/PMS; c Eight cycles of the oxidation of CBZ by the process PMS/Fe²⁺/MoS2; d the dissolved Mo⁴⁺ in the solution after 8 cycles of reaction
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Activation of peroxymonosulfate (PMS) by Fe²⁺ is a green oxidation process for degradation of organic contaminants. However, the formation of iron mud and low PMS utilization lead to the decreased oxidation efficiency. In this work, commercial MoS2 particles were used as the catalyst for boosting the Fe²⁺/PMS process for carbamazepine (CBZ) removal...
Citations
... Advanced oxidation processes (SR-AOPs) based on sulfate radicals are receiving more attention due to their high purification efficiency Wang et al., 2021b). Compared to hydroxyl radicals (-OH) (1.8-2.5 V), sulfate radicals have the advantages of higher redox potential (2.5-3.1 V) (Holkar et al., 2016), high selectivity and long half-life (30-40 μs) (Luo et al., 2021;Peng et al., 2022). During the advancement of SR-AOPs research, numerous techniques were explored to activate persulfate (PS). ...
One 3D Cu-based metal–organic frameworks (Cu-MOFs) was prepared by hydrothermal method as a catalyst for activating persulfate to degrade tetracycline. The degradation efficiency of TC was investigated under various conditions including catalyst dosage, pH, and persulfate concentration. The effects of these factors on the degradation efficiency were examined and discussed in detail. Cu-MOFs/PS catalytic systems can degrade 96% of TC under suitable conditions. The quenching experiments showed that there are both free radical and non-free radical pathways in TC degradation, with singlet-line substitution of oxygen playing a major role. The stability of the material structure was explored through cyclic experiments. The degradation pathway of TC was investigated through the analysis of intermediate products. Additionally, the toxicity of these intermediate products was evaluated using toxicity analysis software.
... At pH ¼ 11, the removal efficiency of BPA dropped to 15%, which indicated that the catalyst had no activation effect on PMS at this time. Interestingly, the removal rate of BPA also decreases at low pH, which might result from the formation of (Fe (H 2 O) 6 ) 2þ and (Fe (H 2 O) 6 ) 3þ in extreme acidic conditions (Peng et al. 2022). Fig. S6c shows that the k obs reached its maximum when pH ¼ 7, so neutral conditions Uncorrected Proof were selected as the initial environment for subsequent research. ...
In this paper, molybdenum disulfide was grown on the surface of iron-containing tailings by hydrothermal method, and a series of highly efficient activated persulfate (PMS) iron-based catalysts were successfully prepared. The results show that in the CTM 1–200/PMS system, the additional ratio of tailings and the hydrothermal temperature have important effects on the catalyst. The catalyst prepared under the conditions of CT:MoS2 (molar ratio 1:1) and hydrothermal temperature of 200 °C (CTM 1–200) had the best degradation effect on BPA, and the degradation effect was increased by four times. The reason for the improvement of degradation efficiency is that the introduction of MoS2 accelerates the REDOX cycle between Fe(II)/Fe(III), and the reduction of Fe(III) is mainly related to Mo(IV), while the reduction capacity of S is relatively weak. Molybdenum disulfide/iron tailing composite material provides a way for tailings to solve the problem of water pollution.
... The promising potential of MoS 2 in boosting homogeneous persulfate-based oxidative systems towards practical wastewater treatment and gaseous volatile organic compounds (VOCs) has been widely demonstrated in the literature (Table 1) [43,44,46,[107][108][109][110][111][112][113][115][116][117][118][119][120][121][122][123][124]. Overall, the MoS 2 cocatalyst is primarily in the bulk 2 H phase because bulk material is commercially available and shows good effectiveness. ...
Fenton technology, as a typical advanced oxidation processes (AOPs), can generate reactive oxygen species (ROS) of strong oxidation capacity to degrade organic pollutants, which has attracted wide attention. However, it is accompanied by the slow Fe3+/Fe2+ cycle rate, easy to generate iron sludge and so on. Recently, it has been proven that the inorganic cocatalysts represented by MoS2 can effectively solve the above problems. Meanwhile, MoS2 can accelerate the activation of peroxymonosulfate (PMS) and peroxodisulfate (PDS) by Fe2+. In this paper, MoS2 as the cocatalyst in H2O2 + Fe2+, PMS + Fe2+ and PDS + Fe2+ were comprehensively reviewed. Specially, the cycling processes of Fe3+/Fe2+ in different systems, the cocatalytic effect of MoS2 by the exposed active sites, the ROS generation mechanism as well as the microscopic mechanism during the reaction were elaborated emphatically. The results indicate that the reductive active sites on the surface of MoS2 can promote the regeneration of Fe2+ through the cycle between Fe3+/Fe2+ and Mo4+/Mo5+/Mo6+. Thus, ROS such as ⋅OH, SO4⋅− and 1O2 with strong oxidizing property can be produced to improve the degradation efficiency of organic pollutants. At last, the challenges and developments of MoS2 cocatalysts in AOPs for practical applications were prospected. This review contributes to a deeper understanding of the cocatalytic effect of two-dimensional metal sulfides in AOPs and facilitates their industrial application.
To address the disadvantage of poor degradation effect of Fe²⁺/peroxydisulfate (PDS) system, a co-catalyst was introduced in this study to construct a molybdenum (Mo)/Fe²⁺/PDS system for the degradation of Acid Orange 7 (AO7), and the degradation rate could reach 95.67%. The effects of different parameters (initial pH, Fe²⁺ concentration, etc.) on the degradation effect of AO7 in this system were investigated, and the optimal degradation conditions were obtained by combining cost analysis. Cycling experiments showed that Mo had good stability. The co-catalytic mechanism of Mo powder was determined using X-Ray Diffraction, Scanning Electron Microscope, and X-ray Photoelectron Spectroscopy. The effects of different inorganic anions on AO7 were discussed: Cl⁻ and NO3⁻ had little effect on degradation, while SO4²⁻ and HCO3⁻ both inhibited the removal of AO7 from the system to different degrees, with HCO3⁻ showing a greater inhibition than SO4²⁻. The main active radicals were identified as sulfate radical (SO4·−) and hydroxyl radical (·OH). In addition, intermediates were identified, and the attack sites were determined by combining the highest occupied molecular orbital/lowest unoccupied molecular orbital energy levels and the Fukui index to hypothesize the degradation pathways. Toxicity indicators such as the mutagenicity of AO7 and intermediates were evaluated, and the overall trend of toxicity was decreasing. This study is expected to provide an efficient treatment process for dye wastewater.
In this study, a new cobalt-based metal-organic framework (JLNU-500), [Co2(OH)(PBA)(AIP)]·3DMA·0.75H2O (4-(pyridin-4-yl) benzoic acid (HPBA), 5-aminoisophthalic acid (H2AIP) and N,N-dimethylacetamide (DMA)), was fabricated using a solvothermal method. JLNU-500 has 3D network architecture with 1D nanopore channels. The prepared JLNU-500 can activate peroxymonosulfate (PMS) for Rhodamine B (RhB) dye decolorization. Interestingly, catalyst JLNU-500 exhibited high efficiency for PMS activation, and nearly 100% (above 99.8%) removal of RhB with a high concentration (50.0 mg L-1, 100 mL) was achieved within 6 min. The reaction rate constant of the JLNU-500/PMS system was 1.02 min-1 calculated based on the pseudo-first-order kinetics, which is higher than that of the other reported catalysts. Furthermore, the factors, which could influence PMS activation were also investigated, such as PMS dosage, catalyst dosage, pollutant RhB concentration, reaction temperature and solution pH. More importantly, the radical trapping experiments ferreted out that sulfate (SO4˙-) and hydroxyl (˙OH) radicals were the dominating oxidants in the removal of RhB. Moreover, the possible degradation mechanism was elucidated. This study provides new prospects for fabricating new MOFs that can potentially be employed for high-efficiency catalytic oxidation as heterogeneous catalysts.
The discharge of colored textile printing and dyeing wastewater causes environmental pollution. The fading of wastewater efficiently, simply and with low consumption is a problem to be considered. Herein, a catalytic method for rapid decolorization of organic dyes was devised employing terpyridine iron complex to activate oxidized permonosulfate (PMS). CI Acid Red 1 (AR1) was used as the simulated pollutant, the influences of operating parameters on the fading effects of wastewater were explored. According to the results, the produced catalytic system exhibits a universal catalytic effect. Even when the dye concentration reaches 76.4 mg/L, the dyeing wastewater may be effectively decolorized. In addition, when anions (HCO 3 ⁻ , SO 4 ²⁻ , Cl ⁻ ) were present in the solution, the degradation effect of AR1 was still effective. Interestingly, active species such as sulfate radicals and singlet oxygen were detected in the catalytic degradation system by radical capture experiments. The total organic carbon (TOC) can reach a removal rate of 26.22% at 2 h. This research provides a unique enzyme‐like catalytic system for the rapid breakdown of dye contaminants.
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