Search

Sulfur (S)-doped α-Fe2O3 has been regarded as an excellent catalyst for eliminating organic pollutants in the photo-Fenton-like reaction. Yet, the synthetic complexity and extremely low activity in the dark Fenton-like reaction still need to be solved. In this study, magnetic α-Fe2O3 with sulfide was successfully fabricated via hydrothermal and calcination processes, for the first time, where thiourea acted as both S source and reducing agent, and then, it was applied for activating peroxydisulfate (PDS) to degrade organic contaminants. Important influencing factors were systemically investigated, and the results showed that this catalyst activating PDS was highly effective in the removal of organic pollutants in dark- and photo-Fenton-like reactions. In addition, the catalyst possessed good stability and recyclable ability. The structure of catalyst was analyzed by several characterizations, such as XRD and XPS. The results revealed that sulfide had an important effect on the structure and performance of α-Fe2O3. The detected mechanism indicated that the main reactive oxygen species were altered after switching from darkness to LED illumination. This work offered a promising method to rationally design for S/α-Fe2O3 in the environmental remediation. [ABSTRACT FROM AUTHOR]

Fe-modified graphite carbon nitride (denoted as Fe/g-C3N4) in the photo-Fenton-like reaction was greatly paid attention in the past few years but it principally involved H2O2 and peroxymonosulfate, and it was little about the activation of peroxydisulfate. In this work, Fe/g-C3N4 was synthesized by a simple heat treatment and then was used to activate peroxydisulfate under LED illumination. Several characteristic techniques including XRD, EPR, FT-IR, N2-physisorption, XPS, UV-Vis, and PL were employed to reveal the structure of catalysts. The characterized results unveiled that Fe modification altered the structure of g-C3N4 nanosheets to remarkably inhibit the combination of photogenerated holes and electrons. Important influencing factors were systematically investigated. The results demonstrated that Fe/g-C3N4 activated peroxydisulfate driven from LED illumination could significantly remove Rhodamine B (RhB), and the catalytic system had a wide pH range. The scavenging and EPR experiments confirmed that SO4•−, •OH, and 1O2 were the main reactive oxygen species in this reaction. This finding offered a novel treating process for eliminating organic pollutants in wastewater. [ABSTRACT FROM AUTHOR]

The post-treated ZSM-5 was an effective catalyst for the synthesis of pyridine bases and therefore selecting suitable post-synthetic method was very crucial. In this work, a series of Mg-modified ZSM-5 with different forms was directly treated by HF-NH4F mixture solution, and then they acting as catalysts were for the first time employed for the reaction of acrolein dimethyl acetal, water and ammonia toward 3-picoline. The catalysts were characterized by means of XRD, SEM, EDX, FT-IR, 27Al MAS NMR, N2-physisorption, NH3-TPD and Py-IR techniques. The characterization results revealed that the fluorination had a great influence on the pore structure and acidity of catalysts, deriving from the simultaneous desilication and dealumination. These factors resulted in large changes on the catalytic activities toward the modified catalysts than the corresponding to parent ones. [ABSTRACT FROM AUTHOR]

A Ni-based catalyst modified with copper and vanadium (5Cu–20V/30Ni/SiO2) was synthesized and employed in the hydrogenation of 3-hydroxypropanal (3-HPA) to 1,3-propanediol (1,3-PDO). Catalysts were systematically characterized via XRD, TEM, HRTEM, SAED, H2-TPD, N2 physisorption, H2-TPR, and XPS. It was indicated that the addition of Cu and V not only promoted the reduction of Ni2+ species and the generation of active hydrogen species, but also increased the dispersion of Ni species and the interaction between Ni particles and SiO2. The catalytic performance evaluation showed that the (5Cu–20V/30Ni/SiO2) could provide the largest yield of 1,3-PDO (above 76.8%) and highest TOF (4.32 × 103 s−1). The structure–activity relationship was clarified according to the characterization results. The optimized reaction conditions over the 5Cu–20V/30Ni/SiO2 catalyst were obtained as the reaction temperature of 80 °C, a H2 pressure of 2.0 MPa (H2), and an LHSV of 0.4 h−1. The employment of non-noble metals, the relatively low pressure of H2, and the relatively high yield of 1,3-PDO make 5Cu–20V/30Ni/SiO2 an efficient and economic catalyst that may have potential applications in industry. [ABSTRACT FROM AUTHOR]

The FeMoS 2 catalyst for activating peroxymonosulfate (PMS) is a promising pathway for removing organic pollutants in wastewater, however, the dominant FeS 2 phases and sulfur (S) vacancies in it are little involved. Herein, for the first time, novel bimetallic FeMoS 2 microparticles were synthesized by a simple method and then applied for PMS activation for degrading organic pollutants. The catalysts were characterized by several techniques, including X-ray diffraction and X-ray photoelectron spectroscopies. The results revealed that new FeMoS 2 microparticles containing S vacancies in the main FeS 2 phases were obtained. FeS 2 and S vacancies were found to play important roles for activating PMS by radical and nonradical pathways. More Fe 2+ and Mo 4+ were formed in the presence of S vacancies, which offered a new strategy for exploring novel heterogeneous catalysts in the activation of PMS for environmental remediation., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The enhancement of vacancies in catalysts involving Fenton-like reactions is a promising way to remove organic pollutants in wastewater, but sulfur vacancies are rarely involved. In this work, MoS 2 containing defect sites were synthesized by a simple high-temperature treatment and then applied for activating peroxymonosulfate to eliminate organic pollutants in wastewater. The structure was characterized by several techniques such as XRD, BET, and XPS. Important influencing factors were systemically investigated. The results indicated that MoS 2 with sulfur vacancies possessed a higher catalytic activity than that of the parent MoS 2 . The annealing temperature of the catalyst had a great effect on the removal of organic pollutants. Besides, the catalytic system had a wide pH range. Quenching and electron paramagnetic resonance (EPR) experiments indicated that the reaction system contained radical and non-radical species. The characterization results revealed that the defect sites in catalysts mainly strengthened the activity of catalysts. This study offers a new heterogeneous catalyst for the removal of organic pollutants via the peroxymonosulfate-based Fenton-like reactions., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The development of novel wastewater treatment processes that use heterogeneous catalysts to activate hydrogen peroxide (H 2 O 2 ) with bicarbonate (HCO 3 - ) has been a subject of great interest in recent years; however, significant challenges remain, despite research into numerous metal-based catalysts. The work presented herein employed oxygen-doped graphitic carbon nitride (O/g-C 3 N 4 ) as a non-metal catalyst for activating H 2 O 2 in the presence of HCO 3 - , and this method represented the first system capable of removing organic pollutants in the dark, to our knowledge. The catalysts were characterized using several microscopic imaging, spectroscopic, electrochemical, and crystallographic techniques, as well as N 2 -physorption procedures. Analysis of the results revealed that the O/g-C 3 N 4 catalyst possessed a high specific surface area and many defect sites. Various operational parameters, including the relative amounts of HCO 3 - , H 2 O 2 , and O/g-C 3 N 4 , were systemically investigated. A clear performance enhancement was observed in the degradation of organic contaminants when subjected to the HCO 3 - -H 2 O 2 -O/g-C 3 N 4 system, and this result was ascribed to the synchronous adsorption and chemical oxidation processes. The novel system presented herein represented a new water treatment technology that was effective for removing organic contaminants., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

This study presents a TiO 2 /C hybrid material with biomimetic channels fabricated using a wood template. Repeated impregnations of pretreated wood chips in a Ti precursor were conducted, followed by calcination at 400-600 °C for 4 hours under a nitrogen atmosphere. The generated TiO 2 nanocrystals were homogenously distributed inside a porous carbon framework. With an extremely low Pt catalyst loading (0.04-0.1 wt%), the obtained porous catalyst could effectively oxidize formaldehyde to CO 2 and H 2 O even under room temperature (conv. ∼100%). Wood acted as both a structural template and reduction agent for Pt catalyst generation in sintering. Therefore, no post H 2 reduction treatment for catalyst activation was required. The hierarchal channel structures, including 2-10 nm mesopores and 20 μm diameter channels, could be controlled by calcination temperature and atmosphere, which was confirmed by SEM and BET characterizations. Based on the abundant availability of wood templates and reduced cost for low Pt loading, this preparation method shows great potential for large-scale applications., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)