Catalyst For Persulfate Activation Research Articles

Synthesis, characterization, and application of Cu-substituted LaNiO3 perovskites as photocatalysts and/or catalysts for persulfate activation towards pollutant removal

The presence of emerging contaminants in environmental aqueous matrices is an ever-growing problem, since conventional wastewater treatment methods fail to adequately remove them. Therefore, the application of non-conventional methodologies such as advanced oxidation processes is of great importance to tackle this modern problem. Photocatalysis as well as catalytic activation of persulfates are promising techniques in this field as they are capable of eliminating various emerging contaminants, and current research aims to develop new materials that can be utilized for both processes. In this light, the present study focused on the use of a simple sol-gel-combustion methodology to synthesize Cu-substituted LaNiO3 perovskite materials in an attempt to improve the photocatalytic and catalytic performance of pure LaNiO3, using molar ratios of Cu:Ni that have not been previously reported in the literature. The morphological, structural, and optical features of the synthesized materials were characterized by a series of analytical techniques (e.g., X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, diffuse reflectance spectroscopy, etc.). Also, their performance as photocatalysts, persulfate anion activators and simultaneously as photocatalysts/persulfate anion activators (hybrid) was evaluated by conducting laboratory-scale experiments using phenol (phenolics) as a model emerging contaminant. Interestingly, the results revealed that LaCu0.25Ni0.75O3 exhibited the best efficiency in all the applied processes, which was mainly attributed to the introduction of oxygen vacancies in the structure of the substituted material. The contribution of selected reactive species in the hybrid photocatalytic/catalytic experiments utilizing LaCu0.25Ni0.75O3 as a (photo)catalyst was investigated using appropriate scavengers, and the results suggested that singlet oxygen is the most dominant. Additionally, the stability of all synthesized perovskites was assessed by monitoring the concentration of the leached Cu and/or Ni cations at the end of every applied process. Finally, the reusability of LaCu0.25Ni0.75O3 was evaluated in three consecutive catalytic cycles using the hybrid experiment methodology, as this process demonstrated the best efficiency in terms of phenolics removal, and the results were rather promising.

A Review on N-Doped Biochar for Oxidative Degradation of Organic Contaminants in Wastewater by Persulfate Activation.

The Persulfate-based advanced oxidation process is the most efficient and commonly used technology to remove organic contaminants in wastewater. Due to the large surface area, unique electronic properties, abundant N functional groups, cost-effectiveness, and environmental friendliness, N-doped biochars (NBCs) are widely used as catalysts for persulfate activation. This review focuses on the NBC for oxidative degradation of organics-contaminated wastewater. Firstly, the preparation and modification methods of NBCs were reviewed. Then the catalytic performance of NBCs and modified NBCs on the oxidation degradation of organic contaminants were discussed with an emphasis on the degradation mechanism. We further summarized the detection technologies of activation mechanisms and the structures of NBCs affecting the PS activation, followed by the specific role of the N configuration of the NBC on its catalytic capacity. Finally, several challenges in the treatment of organics-contaminated wastewater by a persulfate-based advanced oxidation process were put forward and the recommendations for future research were proposed for further understanding of the advanced oxidation process activated by the NBC.

Utilization of Waste Znmn-Battery Cathode Material Directly as a Catalyst for Persulfate Activation in Efficient Degradation of Dye in Wastewater

Utilization of Waste Znmn-Battery Cathode Material Directly as a Catalyst for Persulfate Activation in Efficient Degradation of Dye in Wastewater

In-situ formed N-doped bamboo-like carbon nanotubes encapsulated with Fe nanoparticles supported by biochar as highly efficient catalyst for activation of persulfate (PS) toward degradation of organic pollutants

In this study, N-doped bamboo-like carbon nanotubes encapsulated with Fe nanoparticles (Fe NPs) on the surface of soybean dregs-derived biochar (Fe@NCNT − BC) was synthesized via a low-cost and facile strategy. The unique composites behaved as efficient catalysts for the degradation of various organic pollutants by the activation of persulfate (PS). Under the conditions of [PS] = 5 mM, [RhB] = 20 mg/L, [Fe@NCNT-BC-800] = 1.0 g/L, pH = 7.0, the RhB degradation rate was very fast reaching up to 100% within 10 min. The system also exhibited significant high activity in a broad pH window (3.0–11.0). Meanwhile, the recycling experiments and Fe leaching tests further demonstrated the stability of Fe@NCNT − BC during the activation of PS. Most interestingly, the Fe nanoparticles played a key role in promoting the degree of graphitization and the formation of bamboo-like N-doped carbon nanotubes. Besides, the introduction of biochar significantly improved the dispersion ability to the Fe@NCNT − BC. The competitive radical quenching tests and electron paramagnetic resonance measurements (ESR) illustrated that instead of the traditional radicals (sulfate radicals and hydroxyl radicals), the non-radical singlet oxygen (1O2) was the dominant reactive oxidative species (ROS) in the Fe@NCNT-BC/PS system. A mechanistic study suggested that pyridinic N, graphitic N, sp2-hybridized carbon structure and C = O bond in the Fe@NCNT − BC − 800 promoted the generation of the ROS. This study successfully provides an economic and feasible method for synthesis of a novel catalyst as an eco-friendly and efficient material for the degradation of organic pollutants in the environment.

Activation of persulfate by graphite supported CeO2 for isoniazid degradation

Graphite felt (GF) supported cerium oxide (CeO2) composite was prepared by the impregnation method and used to active persulfate (PS) for degradation of isoniazid (INH). The structure and morphology of the catalyst were characterized by X-ray diffraction, X-ray photoelectron spectrum and scanning electron microscope. The effects of some key parameters including initial PS concentration, initial pH value, catalyst dosage, reaction temperature and inorganic ions on INH degradation were investigated in CeO2/GF/PS system. It was found that 94.39% of INH and 89.9% of TOC could be removed within 10 min under the controlled conditions (1.2 g/L CeO2/GF, 0.25 g/L PS, initial pH at 6.8 and temperature at 25 ℃). The degradation intermediates of INH were identified by liquid chromatography-mass spectrometry and ion chromatography, and the possible degradation pathway was also proposed. The radical competition tests indicated that hydroxyl radical (OH), sulfate radical (SO4−), superoxide (O2−) and singlet oxygen (1O2) coexisted in CeO2/GF/PS system, in which OH was the predominated one. The recycling experiment showed the CeO2/GF was an excellently stable catalyst for activation of PS.

Carbon-based magnetic nanocomposite as catalyst for persulfate activation: a critical review.

The activation of persulfate to produce active radicals has been attracting wide attention in environmental remediation fields. Among various catalysts, non-metal carbocatalysts and carbon-based composites have shown attractive prospects given that they are environmental-friendly, highly efficient, abundant, and diverse. In this paper, the use of carbon-based magnetic nanocomposites as catalysts for persulfate activation was reviewed and discussed. The preparation methods of carbon-based magnetic nanocomposites were first briefly summarized. Subsequently, the use of activated carbon, carbon nanotubes, graphene oxide, biochar, and nanodiamond-based magnetic composites to activate persulfate was discussed, respectively. A synergetic effect between carbon materials and magnetic nanoparticles facilitated the activation process because of the increased electron transfer capacity, good dispersity of magnetic nanoparticles, and good repeatability and separability. Both radical and non-radical pathways were detected in the activation processes, but the specific mechanisms were greatly influenced by the components of the catalyst and solution conditions. And fundamental studies were needed to clarify the inner mechanisms of the process. In the end, strategies for enhancing the catalytic performances of carbon-based magnetic nanocomposites were suggested. It is expected that this review will provide some inspirations for developing highly efficient and green catalyst, as well as sulfate radical-based advanced oxidation technology for the remediation water environment.

Improving the degradation of atrazine in the three-dimensional (3D) electrochemical process using CuFe2O4 as both particle electrode and catalyst for persulfate activation

In this study, CuFe2O4 (CFO) magnetic nanoparticles are used as both particle electrode and catalyst for persulfate (PS), applying in the three-dimensional (3D) electrochemical process for atrazine (ATZ) degradation. We studied the effects of operating parameters (i.e., CFO dosage, PS concentration, initial pH, and current density) on ATZ degradation. The optimum ATZ degradation efficiency (>99%) and TOC removal (22.1%) were achieved after 35 min treatment with CFO dosage of 3.0 g/L, PS concentration of 4.0 mM, current density of 4 mA/cm2, and initial pH of 6.3. Several comparative studies of control experiments were carried out, confirming the superior performance of EC/CFO/PS system for ATZ degradation. CFO magnetic nanoparticle electrodes (MNPEs) exhibited a favorable stability during the five runs under optimal conditions. Quenching experiments and electron paramagnetic resonance (EPR) study proved that ATZ was destroyed by free radicals. Meanwhile, the monitored sulfate radical and hydroxyl radical concentration in EC/CFO/PS system revealed that sulfate radical was the dominant reactive radical in ATZ degradation process. Based on the detected intermediates by LC-MS, the pathways of ATZ degradation in the EC/CFO/PS system were proposed. Finally, the study proposed the reaction mechanism of EC/CFO/PS three-dimensional electrochemical process. In brief, EC/CFO/PS 3D electrochemical process was found to be a reliable technology for the remediation of surface water and groundwater contaminated by atrazine.

Ultra-sustainable Fe78Si9B13 metallic glass as a catalyst for activation of persulfate on methylene blue degradation under UV-Vis light.

Stability and reusability are important characteristics of advanced catalysts for wastewater treatment. In this work, for the first time, sulfate radicals (SO4∙−) with a high oxidative potential (Eo = 2.5–3.1 V) were successfully activated from persulfate by a Fe78Si9B13 metallic glass. This alloy exhibited a superior surface stability and reusability while activating persulfate as indicated by it being used for 30 times while maintaining an acceptable methylene blue (MB) degradation rate. The produced SiO2 layer on the ribbon surface expanded strongly from the fresh use to the 20th use, providing stable protection of the buried Fe. MB degradation and kinetic study revealed 100% of the dye degradation with a kinetic rate k = 0.640 within 20 min under rational parameter control. The dominant reactive species for dye molecule decomposition in the first 10 min of the reaction was hydroxyl radicals (∙OH, Eo = 2.7 V) and in the last 10 min was sulfate radicals (SO4∙−), respectively. Empirical operating variables for dye degradation in this work were under catalyst dosage 0.5 g/L, light irradiation 7.7 μW/cm2, and persulfate concentration 1.0 mmol/L. The amorphous Fe78Si9B13 alloy in this work will open a new gate for wastewater remediation.