Persulfate Activation Research Articles

Benzylic C−H Radical Sulfation by Persulfates

AbstractSulfation is a highly valuable pathological and physiological process, yet it is often underappreciated considering the rather difficult accessibility of organosulfates. O‐sulfonation (O−SO3), a conventional and still common way to make organosulfates, restricts its applicability to hydroxyl compounds and therein lies a major challenge of library construction. Here, we describe a benzylic C−H radical sulfation with persulfates via C−O bond formation. This strategy leverages modular control over the reactivity of persulfates and the stability of sulfate radicals by coutercations. K+/NH4+ stabilized sulfate radicals act as the oxidant to generate carbon‐centered radicals from substrates, and activation of persulfates by n‐NBu4+ provides O−O resource pool to facilitate C−OSO3− bond formation via a bimolecular homolytic substitution (SH2) process.

Solid waste-derived carbonaceous catalysts for environmental and energy applications

AbstractUrbanization and industrialization generate vast amounts of solid waste, posing significant threats to the biotic and abiotic components of the environment. Solid wastes-derived carbonaceous catalysts (SW-CCs) represent an effective strategy for resource utilization, and SW-CCs are gradually applied in environmental remediation and energy fields. However, the effects of the properties of SW-CCs on their catalytic activity remain inadequately understood. A comprehensive review of the applications of SW-CCs in environmental remediation and energy fields is yet to be achieved. It is necessary to systematically review the latest research progress of SW-CCs in environmental remediation and energy fields. First of all, this review summarizes the influences of various factors on the properties of SW-CCs and how these properties affect the catalytic activity. Subsequently, it explores the recent research progress and existing issues in the applications of SW-CCs in environmental remediation (persulfate activation, photocatalysis, and Fenton-like oxidation) and the energy sector (H2 production, biodiesel production, and CO2 conversion). Finally, future research prospects and recommendations are provided to facilitate further development and application of SW-CCs. This review offers new insights into the resource utilization of solid waste and the development of efficient and practical carbonaceous catalysts. Graphical Abstract

NiFe Nanoalloy Electrocatalyst as a Coreaction Accelerator for Enhancing Biomarker Electrochemiluminescence Imaging Detection.

The development of coreaction accelerators with excellent performance is crucial for improving electrochemiluminescence (ECL) performance. In this study, a NiFe nanoalloy electrocatalyst (NiFe-NAEC) was used as a coreaction accelerator to promote persulfate activation, resulting in a 44-fold increase in the ECL intensity of flower-like Zn-3,4,9,10-perylenetetracarboxylate (FL-Zn-PTC). Moreover, the synergistic combination of NiFe-NAEC and silver nanoparticles led to a 134-fold increase in the ECL intensity of FL-Zn-PTC, with a 6275% improvement in the ECL efficiency compared with a reference system containing Ru-bpy/K2S2O8. Consequently, a sensor was constructed for the visual detection of amino-terminal pro-brain natriuretic peptide. This sensor exhibited high sensitivity and provided intuitive results within a linear range from 0.01 to 1000 pg/mL, with a detection limit of 2.1 fg/mL. Overall, this study presents a strategy that integrates an electrocatalytic coreaction accelerator with synergistic enhancement to improve ECL performance. This approach has the potential to expand the range of emitter materials and advance ECL technology.

Mechanochemical Ball Mill Goethite to Activate Sodium Persulfate for the Treatment of Organic Wastewater Containing Tetracycline Hydrochloride

The contamination of aquatic systems by tetracycline hydrochloride (TC) has emerged as an urgent environmental concern necessitating immediate intervention. Herein, a mechanochemical approach was utilized to synthesize a FeOOH@AC nanocomposite through the co-grinding of goethite (FeOOH), hydroxylamine hydrochloride (NH2OH⋅HCl), and activated carbon (AC). The FeOOH@AC nanocomposite acted as a catalyst for the activation of sodium persulfate (PS), producing strong oxidizing radicals for the removal of TC from water. The results demonstrated that the physicochemical properties and crystal structure of FeOOH were altered via ball-milling treatment. The activation of PS-generated sulfate radicals (SO[Formula: see text] and hydroxyl radicals ([Formula: see text]OH) synergistically degraded TC. Additionally, the degradation rate of TC in a 50[Formula: see text]mg/L solution reached 91.26% after the addition of FeOOH@AC and PS. This work offers a theoretical and technical foundation for the mechanochemical ball milling preparation of FeOOH@AC, facilitating PS activation for the degradation of TC in water.

Activation of Persulfate by NiFe-Layered Double Hydroxides Toward Efficient Degradation of Doxycycline in Water

In recent years, the excessive use and improper disposal of antibiotics have led to their pervasive presence in the environment, resulting in significant antibiotic pollution. To address this pressing issue, the present study synthesized nickel–iron-layered double hydroxides (NiFe-LDHs) with varying molar ratios using a hydrothermal method, employing these LDHs as catalysts for the oxidative degradation of doxycycline, with peroxymonosulfate (PMS) serving as the oxidant. X-ray diffraction analysis confirmed that the synthesized NiFe-LDHs exhibited a hexagonal crystal structure characteristic of layered double hydroxides. Experimental results demonstrated that the catalytic efficiency of NiFe-LDHs increased with both the dosage of the catalyst and the concentration of PMS, achieving a high degradation efficiency for doxycycline at a catalyst concentration of 0.5 g/L. Furthermore, the catalytic performance was notably effective across a range of pH conditions, with the highest degradation efficiency being observed at a Ni–Fe molar ratio of 3:1. The activation of PMS by NiFe-LDHs for the catalytic degradation of pollutants primarily occurs through singlet oxygen (1O2), superoxide radicals (O2−·), and sulfate radicals (SO4−·). The study also proposed three potential degradation pathways for doxycycline, indicating that the final degradation products have lower environmental toxicity. This research offers novel approaches and methodologies for the treatment of antibiotic-contaminated wastewater.

Kinetic studies on the sulfathiazole degradation by activated persulfate with ascorbic acid and cysteine

AbstractIn this study, ascorbic acid (AA) and cysteine (Cys) were used as homogeneous potassium persulfate (S2O82−) activators. The efficiency of the S2O82−/AA and S2O82−/Cys systems was investigated to generate sulfate radicals (SO4−•) for the oxidation of sulfathiazole (STZ). The presence of AA and Cys displayed a promoting effect on the activation of S2O82−. The results indicated that the STZ/S2O82− redox reaction followed pseudo‐first order kinetics with respect to STZ concentrations. The oxidative degradation of STZ is accelerated by temperature, dose of S2O82−, AA, Cys, and pH with S2O82−/AA and/or S2O82−/Cys systems. The degradation rates of STZ followed the order S2O82−/AA > S2O82−/Cys > S2O82− under similar experimental conditions. The presence of SO4−• and HO• were tested with two radical scavengers, tertiary butanol (TBA) and ethanol, in which HO• was mainly responsible for STZ degradation at higher pH. In summary, S2O82−/AA and S2O82−/Cys systems might provide a potentially useful technique for remediation of water contaminants.

Improved volatile fatty acid production in anaerobic digestion via simultaneous temperature regulation and persulfate activation by biochar: Chemical and biological response mechanisms

Increasing volatile fatty acid (VFA) production via persulfate activation (i.e., chemical effect) in anaerobic digestion (AD) is an emerging resource utilization method. However, the reaction mechanisms responsible for improving VFA production in AD via simultaneous temperature regulation and persulfate activation by biochar remain unclear. In this study, three PB15 treatment systems of low temperature (15 °C), medium temperature (35 °C) and high temperature (55 °C) were set to explore the relationship between VFAs production and treatment temperature and the influence of temperature on the reaction mechanism. The results show that the improvement of hydrolysis and acidification efficiency of the system in the medium temperature system is the highest. The VFA yield and acid production rate in the treatment group at 35°C were 2.49 and 5.22 times higher than those in the control group, respectively. The chemical effect effectively initiated the anaerobic acid production process and maintained the dominant role of the biological effect. The activity of persulfate is too low at low temperature, and its decomposition is too fast at high temperature. Plenty of free radicals lead to enhanced oxidation of the system, which may kill the fermentation bacteria. The NCM model indicates that microbial stability is reduced in high temperature systems. The SEM model showed that temperature change mainly affected substrate degradation by hydrolytic bacteria and indirectly affected acid production by acid-producing bacteria. This study provides a new strategy for realizing pollutant recycling and increasing VFAs production in cold area.

Z-scheme heterojunction photocatalyst of LaFeO3@CoS for tetracycline hydrochloride degradation by persulfate activation using visible light

An efficient and stable LaFeO3@CoS Z-scheme heterojunction photocatalyst was prepared through the hydrothermal method (HT). Photocatalytic activity of the LaFeO3@CoS was assessed by activating persulfate under visible light for the degradation of tetracycline (0.1 g/L). Under the condition of 0.06 g/L of KHSO5 (Peroxymonosulfate, PMS), the degradation efficiency of 88.7 % was achieved in 40 min using the 0.02 g/L of developed photocatalyst. The degradation kinetic constants of LaFeO3@CoS were 2.79 and 2.23 times higher than those of LaFeO3 and CoS, respectively. Furthermore, the catalyst exhibited excellent stability over five consecutive degradation cycles. Possible degradation mechanisms and the electron transfer mechanism of the heterojunction formed by the LaFeO3@CoS were investigated by quenching experiments, nitrogen N₂ purging experiments, electron spin resonance (ESR) measurements and corresponding electrochemical analyses. In the LaFeO3@CoS/Vis/PMS system, the Z-scheme charge transfer pathway not only accelerated charge transport efficiency but also effectively spatially separated electrons and holes, enhancing the photocatalytic performance of the photocatalyst. Additionally, the generation of reactive species such as 1O2, O2•−, and SO4• − significantly contributed to the improved degradation efficiency of the present catalyst during the degradation process.

Enhanced mechanism of AO7 degradation by electrochemical activation of persulfate at carbon felt and electrogenerated H2O2 carbon black-modified cathodes in divided cell

Enhanced mechanism of AO7 degradation by electrochemical activation of persulfate at carbon felt and electrogenerated H2O2 carbon black-modified cathodes in divided cell

ZnCo2S4/CuO heterojunction photocatalyst for activation of persulfate to degrade p-nitrophenol

ZnCo2S4/CuO heterojunction photocatalyst for activation of persulfate to degrade p-nitrophenol

Potential of homogeneous persulfate activation as a strategy for the oxidative treatment of tetramethylammonium hydroxide: Superiority of sulfate radical over hydroxyl radical in the oxidation of methylammoniums

Tetramethylammonium hydroxide (TMAH) as the etching and chelating agent exhibits the extreme recalcitrance to advanced oxidation processes utilizing hydroxyl radical (OH). This study showed that based on the relative position of PDS/heat and PDS/UV against H2O2/UV in terms of TMAH degradation efficiency, sulfate radical (SO4−) was superior to OH in oxidizing TMAH. PDS/heat (at 60 °C) and PDS/UV at the initial pH = 7 achieved TMAH degradation efficiency of ∼ 80–90 % within 1 h whereas H2O2/UV barely eliminated TMAH, which contrasted with H2O2/UV decomposing phenol faster than the activated PDS. The high susceptibility of TMAH (in which four methyl groups bonded to nitrogen removed the lone pair of electrons) to oxidation by SO4− aligned with the pH–dependent efficiency of PDS/heat for the treatment of methylamines. PDS/heat effectively degraded methylammoniums (lacking nitrogen lone pair available for electron transfer due to amine protonation) under non–alkaline conditions, whereas acidification caused the efficiency loss of ∼ 90 % for H2O2/UV. Methylammoniums as radical scavengers retarded benzoic acid degradation by PDS/heat to a more pronounced extent than counterparts with deuterated N–methyl groups, which implied that hydrogen–atom abstraction primarily contributed to the SO4−–induced oxidation of methylammoniums. Estimation of the bimolecular reaction rate constants using laser flash photolysis and electron paramagnetic resonance spectroscopic detection of TMAH–derived carbon–centered radical supported the superiority of SO4− over OH in TMAH oxidation. These findings suggested the potential of homogeneous persulfate activation in the pH-insensitive oxidative treatment of alkylamines and quaternary ammonium cations structurally analogous to TMAH.

Acetic acid-modified nitrogen-doped biochar loaded Fe-Co bimetal promotes persulfate activation for efficient quinoline removal and its 1O2 and O2•- pathways

Acetic acid-modified nitrogen-doped biochar loaded Fe-Co bimetal promotes persulfate activation for efficient quinoline removal and its 1O2 and O2•- pathways

Revisiting the persulfate activation performance of seaweed derivied biochars: The composition and origin of pollutant degradation activity

A steady increase in seaweed production necessitates effective strategies to manage its post-production waste and its assosicated CO2 emission. Biochar formation stand out as a promising option, offering significant advantage for persulfate-activated water remediation processes. Herein, we investigated and compared the performance of two seaweed-derived biochars, focusing on their physical characteristics, heteroatoms, and chemical composition in activating persulfate (PS). Although, both seaweeds (Capsosiphon fulvescens (CF) and Undaria pinnatifida (SW)) that studied are edible, they exhibit unique catalytic behavior in the degradation of simazine (SMZ). The differences in simazine degradation activity observed in these biochars were primarily attributed to the description of metal active sites rather than the complex composition and specific surface area of the biochars. The identification of these active sites was achieved through various physical characterization tools (XRD, XPS, BET) and by examining the adsorption models and degradation patterns of simazine under different conditions. Our results demonstrate that the biochar derived from CF (100% removal) seaweed having metal active centres is more catalytic than SW (58.4% removal) derived biochar. ROS quantification and electrochemical studies suggest that simazine degradation occurs through different mechanisms in these biochars. Therefore, the CF-derived biochar catalytic system was optimized for simazine oxidation, with studies focusing on its degradation pathway, intermediate toxicity, and catalytic stability. This comprehensive study outlines the significance of selection of seaweed biomass for optimal activity in the persulfate-based oxidative system.

Synthesized CuO-PEI-JE with 3D open-cell structure as an efficient heterogeneous activator of peroxodisulfate for phenol degradation

The core of heterogeneous catalytic systems is to design high-performance heterogeneous catalysts. In the present study, CuO-PEI-JE was synthesized via in situ precipitation of CuO on the 3D structure of PEI-JE prepared by a cross-linking method. It possessed a macro-size and 3D open-cell structure, being easily separated and having super-performance for PDS activation. Compared to PDS alone (0.0017 min-1), the CuO-PEI-JE+PDS+NaHCO3 system increased the kobs (0.3526 min-1) by a factor of 207 with 100% phenol degradation within 20 min and 87% TOC removal at 30 min. It outperformed many other published heterogeneous persulfate systems in phenol degradation. Meanwhile, the developed system displayed a good anti-interference ability in the coexistence of anions or different water matrixes. After five successive cycles, the degradation rate still kept 100%, exhibiting the excellent reusability of CuO-PEI-JE. Furthermore, the preparation of CuO-PEI-JE had the advantages with moderate preparation conditions (60 °C) and readily available raw materials. The activation mechanism was mainly involved in the formation of active PDS and its further decomposition into ·OHads, SO4·-ads, O2·- and 1O2. Surface functional groups and phenol acted as electron donors for active PDS. Phenol was first degraded into hexadienedioic acid, then oxidized to propane diacid and oxalic acid, and finally mineralized into CO2 and H2O. This work provides a new strategy for preparing effective heterogeneous persulfate activators and has high potential for the treatment of phenol-containing wastewater.

Highly dispersed single-atom Fe and Fe3O4 clusters anchored hierarchical-pore carbon as efficient persulfate activation catalyst

The selective removal of Fe particles from carbonized Fe-MOFs presents an intriguing strategy for developing efficient peroxydisulfate (PDS) activators. It is commonly accepted that their outstanding performance is largely attributed to the high specific surface area/pore volume. However, our investigation into the structure–function relationship of these materials has revealed new insights. In this study, a highly dispersed single-atom Fe and Fe3O4 clusters anchored hierarchical-pore carbon (CM88-H) was obtained via post-acid treatment of carbonized MIL-88B (CM88). Various characterizations were comparatively conducted to highlight the beneficial effects of iron dissolution. The CM88-H/PDS system achieved a notable BPA degradation efficiency, with a reaction rate of 0.323 min−1, which is 3.94 times higher than that of the CM88/PDS system. DFT calculations indicate that the Fe3O4 clusters optimize the charge distribution around single-atom Fe, promoting favorable PDS adsorption and facilitating a higher oxidation state of CM88-H. As a result, BPA can be completely degraded within 10 min with 0.1 g/L CM88-H and 0.05 g/L PDS via both radical and non-radical pathways. The CM88-H/PDS/BPA system performs effectively under various conditions, with a general reduction in toxicity. Furthermore, the CM88-H/PDS system shows broad oxidation activity towards BPA substitutes and pollutants with high ionization potential (IP). Notably, the CM88-H sponge-based fixed-bed catalytic reactor demonstrated satisfactory BPA degradation, highlighting the promising application of CM88-H in water purification. This study provides a sustainable solution for water treatment and accelerates the practical application of powdered nanocatalysts to improve water quality.

Natural Vanadium–Titanium Magnetite Activated Peroxydisulfate and Peroxymonosulfate for Acid Orange II Degradation: Different Activation Mechanisms and Influencing Factors

Persulfate-based advanced oxidation processes have emerged as a promising approach for the degradation of organic pollutants in aqueous environments due to their ability to generate sulfate radicals (SO4−·) within catalytic systems. In this study, peroxydisulfate (PDS) and peroxymonosulfate (PMS) were investigated with the natural vanadium–titanium magnetite (VTM) as the activator for the degradation of acid orange II. The degradation efficiency increased with higher dosages of VTM or persulfate (both PDS and PMS) at lower concentrations (below 10 mM). However, excessive PMS (higher than 10 mM) in the PMS/VTM system led to the self-consumption of free radicals, significantly inhibiting the degradation of acid orange II. The VTM-activated PDS or PMS maintained an effective degradation of acid orange II in a wide pH range (3~11), suggesting remarkable pH stability. The SO4−· was the main active species in the PDS/VTM system, while hydroxyl radical (·OH) also contributed significantly to the PMS/VTM system. In addition, PMS exhibited better thermal stability during VTM activation. Coexisting ions in an aqueous environment such as bicarbonate (HCO3–), carbonate (CO32–), and hydrogen phosphate (HPO42–) had obvious effects on persulfate activation. Our study systematically investigated the different activation processes and influencing factors associated with PDS and PMS when the natural VTM was used as a catalyst, thereby providing new insights into the persulfate-mediated degradation of organic pollutants in aqueous environments.

Recent Advances in Photocatalytic Degradation of Tetracycline Antibiotics

China is a significant global producer and consumer of pesticides and antibiotics, with their excessive use leading to substantial water pollution that poses challenges for subsequent treatment. Photocatalytic degradation, leveraging renewable solar energy, presents an effective approach for decomposing organic pollutants and reducing residual contaminant levels in water bodies. This approach represents one effective way for addressing environmental challenges. This paper classifies representative photocatalytic materials by structural design and degradation principles including MOFs (Metal–Organic Frameworks), metal- and nonmetal-doped, mesoporous material-loaded, carbon quantum dot-modified, floatation-based, and heterojunction photocatalysts. We also discuss research on degradation pathways and reaction mechanisms for antibiotics. Of particular importance are several key factors influencing degradation efficiency, which are summarized within this work. These include the separation and charge transfer rate of catalyst surface carriers, and the wide-spectrum response capabilities of photocatalysts, as well as persulfate activation efficiency. Furthermore, emphasis is placed on the significant role played by intrinsic driving forces such as built-in electric fields within catalytic systems. Moreover, this paper introduces several promising composite-structure photocatalytic technologies from both composite-structure perspectives (e.g., Aerogel-based composites) and composite-method perspectives (e.g., the molecularly imprinted synthesis method). We also discuss their latest development status, along with future prospects, presenting valuable insights for pollutant degradation targets. This work aims to facilitate the design of efficient photocatalytic materials, while providing valuable theoretical references for environmental governance technologies.

Performance of Dye-Containing Wastewater Treatment Using MnxOy-Catalyzed Persulfate Oxidation

Dye wastewater is characterized by high salinity, intense coloration, difficulty in degradation, and complex organic compositions, posing significant environmental risks. Manganese oxide (MnxOy)-based materials have been widely used for the removal of recalcitrant organic pollutants in water environments. In this study, various MnxOy polymorphs were prepared, and their catalytic activities for persulfate (PS) activation were evaluated using Orange II (AO7) as a model molecule. After 50 min treatment, the degradation efficiency of AO7 ranked as α-MnO2/PS > γ-MnO2/PS > β-MnO2/PS > Mn2O3/PS, with α-MnO2/PS achieving the highest efficiency of 98.6%. XPS, XRD, and electrochemical analyses indicated that α-MnO2 exhibited an exceptional crystal structure and performance. The α-MnO2/PS system exhibited a strong pH adaptability across a wide pH range of 3.0–9.0. The presence of coexisting anions at 0.1 mM, including Cl−, NO3−, CO32−, and SO42−, slightly reduced the degradation rate of AO7. The reactive oxygen species, mainly SO4•− and 1O2, predominantly destroyed the naphthalene ring structure of AO7. Furthermore, α-MnO2 exhibited an excellent stability, allowing for multiple reuse cycles without interference from common anions in water, highlighting its strong potential for practical applications. These results provided insights into the environmental fates of AO7 in the α-MnO2/PS system.

Atomically Dispersed Cobalt Anchored on Hollow Tubular Carbon Nitride Mediates Direct Electron Transfer and Oxygen-Related Active Species Path for Activation of Permonosulfate.

Atomically dispersed catalysts anchored on nitrogen-rich substrates present promising application potential for the persulfate-based advanced oxidation process. Nevertheless, efficient activation efficiency and a clear activated mechanism of persulfate remain challenging in carbon nitride-based single-atom catalysts (SACs). To these, combined with the regulation strategy of metal-ligand section and carrier's architecture, an atomically dispersed Co single-atom catalyst anchored on regular hollow tubular carbon nitride (Co/TCN SAC) herein was devised and utilized to activate permonosulfate. As a result, Co/TCN SACs show excellent catalytic performance for the degradation of common antibiotics. Combined with X-ray absorption fine structure and theory calculation, it is confirmed that superficially anchored CoO3 sites of the Co2N2O2-CoO3 unit are the catalytic active center for peroxymonosulfate (PMS) activation. The electrochemical test and in situ electron paramagnetic resonance results demonstrate radical (SO4•- and •OH) and nonradical (electron transfer process and 1O2) paths contributing to the superior catalytic performance. In addition, the catalyst exhibits high reaction efficiency and structural stability considering water quality parameters. Finally, a continuous and efficient device was operated on a laboratory scale, which exhibited satisfactory efficiency in continuously removing electron-rich antibiotics such as tetracycline. This work reveals the atomic-level modulation of cobalt atomic sites on hollow tubular carbon nitride and their structure-activity relationship with persulfate activation.

Iron–Cobalt Bimetallic Metal–Organic Framework-Derived Carbon Materials Activate PMS to Degrade Tetracycline Hydrochloride in Water

Organic pollutants entering water bodies lead to severe water pollution, posing a threat to human health. The activation of persulfate advanced oxidation processes using carbon materials derived from MOFs as substrates can efficiently treat wastewater contaminated with organic pollutants. This research uses NH2-MIL-101(Fe) as a substrate, doped with Fe2+ and Co2+, to prepare Fe/Co-CNs through a one-step carbonization method. The surface morphology, pore structure, and chemical composition of Fe/Co-CNs were investigated using characterization techniques such as XRD, SEM, TEM, XPS, FT-IR, BET, and Raman. A comparative study was conducted on the performance of catalysts with different Fe/Co ratios in activating PMS for the degradation of organic pollutants, as well as the effects of various influencing factors (the dosage of Fe/Co-CNs, the amount of peroxymonosulfate (PMS), the initial pH of the solution, the TC concentration, and inorganic anions) on the catalyst’s activation of persulfate for TC degradation. Through radical quenching experiments and post-degradation XPS analysis, the active radicals in the FeCo-CNs/PMS system were investigated to explain the possible mechanism of TC degradation in the Fe/Co-CNs/PMS system. The results indicate that Fe/Co-CNs-2 (with a Co2+ doping amount of 20%) achieves a degradation rate of 93.34% for TC (tetracycline hydrochloride) within 30 min when activating PMS, outperforming other Co2+ doping amounts. In addition, singlet oxygen (1O2) is the main reactive species in the reaction system.