An Effective Heterogeneous Ozone-Based Advanced Oxidation Process in Acidic Solution— Ti-MCM-41/H2O2/O3

A useful ozone-based advanced oxidation process in acidic solution- Ti-MCM-41/H₂O₂/O₃ was studied, and acetic acid (HAc) was selected to be degraded because it is a hydroxyl radical-probe compound in ozonation. The results showed that only Ti-MCM-41/H₂O₂/O₃ could effectively degrade HAc at initial pH 3.0, and that other oxidative processes such as O₃, H₂O₂/O₃ Ti-MCM-41/O₃ and MCM-41/H₂O₂/O₃, all could not, indicating the coexistence of Ti-MCM-41 and H₂O₂ was necessary for the generation of hydroxyl radicals under the experimental conditions. The optimization of parameters indicated that the rate of generation of hydroxyl radicals could be regulated by the amount of Ti-MCM-41, and that the amount of hydroxyl radicals could be controlled by the concentration of H₂O₂. The preceding results are of significance for effective treatment of acidic refractory wastewater.     

Treatability of Organic Constituents in the Paşaköy Wastewater Treatment Plant Effluent by O3 and O3/H2O2

Effluent from the Pa?aköy Wastewater Treatment Plant was oxidized by using O₃ and O₃/H₂O₂. DOC, COD, UV₂₅₄, total coliform, dissolved ozone and some endocrine disrupting compounds were monitored during oxidation. Results showed that O₃ provided superior disinfection, however, lower reductions in DOC, COD and endocrine disrupting compounds were exhibited compared to O₃/H₂O_2. The highest removal efficiency of DOC, COD and endocrine disrupting compounds were achieved at 0.5 molar ratio of O₃/H₂O_2. The benefit of H₂O₂ addition for advanced oxidation reduced significantly when the mole ratio was increased to 2. Therefore, the mole ratio of H₂O₂ to O₃ is a critical parameter for the design of wastewater oxidation by O₃/H₂O₂.     

A Separation Technology of H2/CO in the Process of Kailuan ＇ s Synthetic Process of Ethanediol

开滦在鄂尔多斯新建的煤制乙二醇项目中,要求对H2/CO混合气进行分离。生产中采用了深冷分离和H2提浓的联合技术进行分离,最终使得H2的回收率为80%～90%之间,H2纯度可达99%,CO纯度〉99%,为乙二醇的合成提供了合格、优质的原料气。     

On the Promotion of Ag/γ-Al2O3 by Cs for the SCR of NO by C3H6

The promotion of Ag/-Al₂O₃ by adding alkali metals (Li, Na, K, Cs) for selective catalytic reduction of NO with C₃H₆ was studied in this work. The activity of NO reduction was enhanced by addition of Cs to Ag/-Al₂O₃ in the presence of excess oxygen and SO₂. The stability and growth of silver oxide particles were promoted and the dispersion of silver particles on -Al₂O₃ was improved by the addition of 0.5 wt% Cs and 1 wt% Cs to 2 wt% Ag/-Al₂O₃, respectively. The results were confirmed by H₂ TPR, UV-Vis DRS, TEM, and XPS.     

Application of the Solvothermal Process in the Synthesis of High-performance Ag/γ-Al2O3 Catalysts

Ag/γ-Al2O3 is a kind of promising catalyst with the relatively lower cost compared with those using noble metals,good resistance against catalytic poisoning and excellent behaviour for NOx removal. In the present study, Ag/γ-Al2O3 catalysts were synthesized by the solvothermal process and characterized by XRD, TG-DTA, TEM, UV-Vis and FT-IR. It was found that high-performance Ag/γ-Al2O3 catalysts could be synthesized by properly selecting starting materials,controlling the composition of solvent and other reaction conditions. The microstructure evolution of the catalysts was also discussed.     

Comparative Study of Reactive Dyes Oxidation by H2O2/UV,H2O2/UV/Fe2+ and H2O2/UV/Fe° Processes

The decolorization and mineralization of two reactive dyes C.I. Reactive Blue 4 (RB 4) and C.I. Reactive Blue 268 (RB 268) were studied using various advanced oxidation processes (AOPs) such as H₂O₂/UV, H₂O₂/UV/Fe²⁺, and the H₂O₂/UV/Fe°. All processes were performed within a laboratory-scale photo-reactor setup. The experimental results were assessed in terms of absorbance (A) and total organic carbon (TOC) reduction. The main degradation products were identified by high resolution gas chromatography/high resolution mass spectrometry analyses. The results of our study demonstrated that the additions of moderate concentrations of H₂O₂ and Fe catalyst during the AOPs evidently increased the decolorization efficiencies within the first few minutes of the processing time (5–10 min) for both tested dyes, and prolonged irradiation does not necessarily significantly improve decolorization. On contrary, TOC removal rate increased with the processing time and with the addition of the catalyst from 40–50% up to 70–80% at defined experimental conditions. All the tested AOPs were very successful methods for RB 268 decolorization, having very complex structure and much higher molecular weight compared to the dye RB 4. This is important from both economic and ecological points of view.     

Alternative for the Treatment of Leachates Generated in a Landfill of Norte de Santander–Colombia,by Means of the Coupling of a Photocatalytic and Biological Aerobic Process

In the present study, the use of heterogeneous photocatalysis TiO2/UV coupled to an activated sludge reactor was evaluated as an alternative treatment for the leachate coming from a Landfill, located in Cucuta (Colombia). TiO₂ (Degussa P-25) between 100 and 600 mg.L^?1 was used as a catalyst, semi-continuous type reactors for the photocatalysis, a batch for the biological stage, UV light with accumulated energies from 20 to 60 kJ.L^?1 were also used, a constant concentration of H₂O₂ was used as an adjuvant in all tests. The research consisted of four main phases: leachate characterization, biological treatment, optimization of photocatalytic and AOP-biological coupling. For the optimization of the photocatalytic step, an experimental design was carried out through the statistical program Statgraphics Centurion XV of factorial type 3^2 (3 levels 2 variables), modeling the results by means of a response surface, the variables of the pH and the concentration of the catalyst were included, having this as input for the response of interest the percentage (%) of DOC removal. The biological process itself provided a removal of 38 and 24% for COD and DOC, respectively. The AOP-biological coupling provided a removal of 68 and 76% in terms of COD and DOC, respectively. Thus, the coupling significantly improves the overall efficiency of the process by more than 50%, which represents a promising improvement compared to the removal of organic matter for the treatment of the same type of water using only the biological process. The results show a viable alternative for the treatment of leachate because higher removal levels are achieved in residence times, which are considered shorter than the ones in conventional processes.

     

Degradation of surfactant used in iron mining by oxidation technique: Fenton,photo-Fenton,and H2O2/UV—A comparative study

Reuse of water in mining helps reduce the volume of tailings directed to dams, avoiding overloads and ruptures, as occurred in Brumadinho, Brazil. Water reuse in mining requires treatment mainly for removing the surfactant substances used. Photo-Fenton and UV/H₂O₂ showed 96% to 98% degradation results of anionic surfactants within 5 minutes, suggesting this technique is faster than biological systems that can take days. This paper aims to study the degradation of a surfactant used in the flotation process by UV/H₂O₂, Fenton, and photo-Fenton oxidation techniques. The compound was characterized by FTIR and MALDI-TOF. In degradation experiments, the variation in reactants concentrations was evaluated with hydrogen peroxide, iron sulphate heptahydrate, and oxalic acid. We used a synthetic solution of surfactant in the reverse flotation of ore with 180 mg/L. The reaction was monitored with TOC analysis and a spectrophotometer throughout the reaction. The UV/H₂O₂ and Fenton system were studied by varying peroxide and iron concentrations, with 120 minute tests. Additionally, photo-Fenton concentrations, the pH variation (1.5-8.0), temperature (15°C, 21°C, and 60°C), and time were evaluated. The results showed the most efficient degradation was that using photo-Fenton, which achieved total TOC removal using 4500 mg/L of peroxide and 364 mg/L of iron for 330 minutes, while the UV/H₂O₂ system achieved 29% and 49% TOC removal of the Fenton. It is verified that the oxidative processes can be applied to degrade the surfactants present in the water recovered from the flotation processes.     

Exosomes in the Treatment of Pancreatic Cancer: A Moonshot to PDAC Treatment?

Pancreatic Ductal Adenocarcinoma (PDAC) constitutes a leading cause of cancer death globally. Its mortality remains unaltered despite the considerable scientific progress made in the fields of diagnostics and treatment. Exosomes comprise of small extracellular vesicles secreted by nearly all cells; their cargo contains a vast array of biomolecules, such as proteins and microRNAs. It is currently established that their role as messengers is central to a plethora of both physiologic and pathologic processes. Accumulating data have shed light on their contributions to carcinogenesis, metastasis, and immunological response. Meanwhile, the advancement of personalized targeted therapies into everyday clinical practice necessitates the development of cost-efficient treatment approaches. The role of exosomes is currently being extensively investigated towards this direction. This review aims to summarize the current pre-clinical and clinical evidence regarding the effects of exosomal applications in the timely diagnosis, prognosis, and therapeutic management of pancreatic cancer.     

Oxidation of ß-SiC at high temperature in Ar/O2, Ar/CO2, Ar/H2O gas mixtures: Kinetic study of the silica growth in the passive regime

The kinetics of silica growth during passive oxidation of SiC was studied using an original interferometric method carried out in a reactor specifically designed for that purpose. The influence of various oxidant species, O₂, H₂O, CO₂ as well as their mixtures was investigated in a high temperature domain ranging from 1550 °C to 1850 °C at atmospheric pressure. This method is an efficient way to measure the various oxidation regimes usually described by the Deal-Grove model. Both the linear and parabolic rate constants are found to be independent of gas phase composition above 1700 °C, and to increase with oxygen partial pressure below 1700?°C for P_O2?>?20?kPa. In the parabolic growth regime, we observed a transition from a low temperature interstitial-dominant to a high temperature network-dominant oxygen transport in the silica scale. The present results suggest the existence of a similar transition in the linear growth regime.     

Rh–Sr/Al2O3 Catalyst for N2O Decomposition in the Presence of O2

The improving effect of Sr in the catalytic activity of Rh for N₂O decomposition has been studied under 1,000 ppm N₂O/He and 1,000 ppm N₂O/5% O₂/He (GHSV = 10,000 h^?1). Different techniques have been used for catalysts characterization: TEM, SEM-EDX, XRD, N₂ adsorption at ?196 °C and in situ XPS. Sr favours the Rh dispersion and reduction under reaction conditions, and allows the low temperature removal of N₂O in the presence of O₂ (100% decomposition at 350 °C).     

Promotional effect of H2O on the activity of In2O3‐doped Ga2O3–Al2O3 for the selective reduction of nitrogen monoxide

Effect of metal oxide additives on the catalytic performance of Ga₂O₃–Al₂O₃ prepared by the sol–gel method for the selective reduction of NO with propene in the presence of oxygen was studied. Of several metal oxide additives, the addition of In₂O₃ enhanced drastically the activity of Ga₂O₃–Al₂O₃ for NO reduction by propene in the presence of H₂O. In addition, the activity of In₂O₃‐doped Ga₂O₃–Al₂O₃ catalyst was extremely intensified by the presence of H₂O below 350°C. The promotional effect of H₂O was interpreted by the suppression of undesirable propene oxidation and the removal of carbonaceous materials deposited on the catalyst surface. We also found that close interaction of In₂O₃ and Ga₂O₃ is necessary for the enhancement of activity by H₂O. A lot of hydrocarbons except methane and oxygenated compounds served as good reducing agents, among which propene and 2‐propanol were the most efficient ones. In₂O₃‐doped Ga₂O₃–Al₂O₃ catalyst was capable of reducing NO into N₂ quite efficiently in the presence of H₂O at a very high space velocity. This revised version was published online in July 2006 with corrections to the Cover Date.     

Kinetics of the Steady-State Acetylene Oxidation by Oxygen over a Pt/Rh/CeO2/γ-Al2O3 Three-Way Catalyst

The steady-state kinetics of acetylene oxidation has been studied in the framework of automotive exhaust gas catalysis over a commercially available three-way catalyst. Experiments under cold-start conditions have been carried out in a laboratory fixed-bed reactor, which can adequately be described by the developed elementary step model and rate parameters.     

A Sol–Gel Derived CuOx/Al2O3–ZrO2 Catalyst for the Selective Reduction of NO by Propane in the Presence of Excess Oxygen

Copper catalysts supported on alumina-doped zirconia were prepared by sol–gel processing followed by supercritical drying or aging in the mother solution at 100°C. After drying and calcination, the catalyst supports were impregnated with a copper(II) nitrate aqueous solution by the incipient wetness method to achieve a Cu loading of about 2%. The samples showed 90% NO conversion at 350–400°C. The catalytic performance of these systems appears to be determined by the degree of clustering of copper cations as probed by FTIR spectroscopy of adsorbed CO.     

Promising Antioxidant Activity of Erythrina Genus: An Alternative Treatment for Inflammatory Pain?

The negative impact that oxidative stress has on health is currently known. The complex mechanism of free radicals initiates a series of chain reactions that contribute to the evolution or development of different degenerative disorders. Likewise, these disorders are usually accompanied by inflammatory processes and, therefore, pain. In this sense, reactive oxygen species (ROS) have been shown to promote the nociceptive process, but effective treatment of pain and inflammation still represents a challenge. Over time, it has been learned that there is no single way to relieve pain, and as long as there are no other alternatives, the trend will continue to apply multidisciplinary management, such as promote the traditional use of the Erythrina genus to manage pain and inflammation. In this sense, the Erythrina genus produces a wide range of secondary metabolites, including flavanones, isoflavones, isoflavones, and pterocarpans; these compounds are characterized by their antioxidant activity. Phenolic compounds have demonstrated their ability to suppress pro-oxidants and inhibit inflammatory signaling pathways such as MAPK, AP1, and NFκB. Although there is preclinical evidence supporting its use, the pharmacological effect mechanisms are not entirely clear. Nowadays, there is a fast advancement in knowledge of the disciplines related to drug discovery, but most of nature’s medicinal potential has not yet been harnessed. This review analyzes the decisive role that the Erythrina genus could play in managing inflammatory pain mediated by its compounds and its uses as an antioxidant.