Application of MIL-53(Fe) metal-organic framework material in catalytic wet oxidation of phenol

In the present study, MIL-53(Fe) metal-organic framework material was applied as catalyst for phenol oxidation reaction in aqueous solution with H2O2 under UV radiation. The materials were characterized using X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FT-IR). The effects of reaction time, initial phenol concentration, and initial pH of the solution on phenol oxidation reactions were investigated. The results indicated that MIL-53(Fe) could work effectively in the wide pH range from 2 to 10. Phenol was quickly oxidized to form simple organic acids, including acetic acid, formic acid and oxalic acid.

Chemical removal of m-cresol: a critical review

m-Cresol containing wastewater has generally become a globally environmental issue due to its refractory and high toxicity towards plants, animals and human being. The development of m-cresol related industries increases the risk of excessive m-cresol discharge, making high efficiency methods to treat m-cresol an urgent topic in both economic and environmental aspects. This review focuses on the chemical treatment methods of m-cresol wastewater, including chemical adsorption, photocatalytic degradation, electrocatalytic degradation and catalytic wet oxidation. The efficiency, cost and process optimization of different methods are discussed in detail. Chemical adsorption is convenient but has relatively low efficiency. Photocatalytic degradation is an easily operated technology with high efficiency, but the selection of catalyst is too limited and the cost of light source is relatively high. Electrocatalytic degradation is time-saving but energy-intensive, and operational difficulty brings a barrier to industrialization. Catalytic wet oxidation (CWO) is highly effective and easily modified, but the performance and stability of catalysts are still very moderate. Following this, the selection and application of different methods regarding the requirement of actual environment are analyzed. Finally, a perspective on the opportunities and development for efficient m-cresol removal method is given.

Optimization of catalytic wet oxidating fulvic acid with zero-valent copper chitosan activated carbon ball as the catalyst

The degradation efficiency of fulvic acid (FA) was investigated in the catalytic wet oxidation process (CWPO) by zero-valent copper chitosan activated carbon ball (ZVC/CTS-ACB). Characterization of ZVC/CTS-ACB shows that zero-valent copper was loaded successfully on the chitosan activated carbon. Plackett–Buiman (PB) design and response surface methodology (RSM) were employed to determine the influence factors and the optimum processing parameters. The model was well fitted to the actual data and the correlation coefficients of R2 and R2-adj were 0.9359 and 0.9039, respectively. Under the obtained optimum conditions for FA degradation: temperature = 94 °C and pH 3.8, the average FA removal by three replicate experiments was 93.02%, which has a high consistency to the RSM optimal target response of 93.86%. The comparison of catalytic performance showed that the addition of catalyst ZVC/CTS-ACS could increase the removal rate of FA, color number (CN) and TOC by 93.6%, 83.5% and 81.9% respectively. The high TOC removal rate indicated the good performance of the catalyst to FA mineralization. Additionally, the ICP analysis of copper ion leaching was only 0.08 mg/l after 5 repeated recycles of the catalyst, demonstrating the high stability of ZVC/CTS-ACB that is beneficial for the actual application.

Catalytic Wet Oxidating Fulvic Acid By Zero-Valent Copper Chitosan Activated Carbon Ball: Plackett-Buiman Design and Response Surface Modeling Optimization

In this paper, the active component zero-valent copper (ZVC) supported by chitosan activated carbon ball (CTS-ACB) (i.e. ZVC/CTS-ACS catalyst) was successfully prepared. The characterization results showed obvious characteristics of activated carbon and zero-valent copper. The catalyst was used to degrade fulvic acid (FA) in catalytic wet oxidation(CWO) system. The two significant factors acidity and temperature were found with the statistical tool Plackett-Buimanhe(PB) in CWO for FA removal. Then the response surface methodology(RSM) model was used to optimize the experimental conditions in order to obtain the optimal FA removal rate. With the optimal experimental parameters, that is, a temperature of 94°C and an acidity of 3.8, the average maximum removal rate of FA was 93.02%, which was in agreement with the expected result of the model 93.86%, indicating that the model is well established. The comparison of catalytic performance showed that the addition of catalyst ZVC / CTS-ACS could increase the removal rate of FA, colour number(CN) and TOC by 93.6%, 83.5% and 81.9% respectively. The utilization of ZVC can greatly increase the mineralization rate of FA , which indicates the high catalytic activity and minerazation of the catalyst.

Research on the Stability of Pd-Based Multi-Component Supported Catalysts

Based on SEM, FT-IR and XRD characterization, the catalyst Pd-Fe-Co-Ce/FSC (ratio 1:1:1:3) was calcined at a temperature of 550°C and a calcination time of 3 h. The catalyst is applied to the catalytic wet oxidation treatment of difficult-to-biodegradable organic waste-water. By the characterization of the catalyst before and after the reuse, it is verified that the SEM morphologis of the catalyst changed little, and the groups contained in the catalyst characterized by FT-IR hardly changed, and the XRD characteristic peaks did not change. From the SEM photos of the catalyst before and after use, the morphology of the catalyst does not change much, and the agglomerated support on the catalyst surface is slightly reduced; the absorption peaks of the FI-IR spectrum of the catalyst before and after use are not significantly different, indicating that the functional groups contained in the catalyst have not changed significantly; After using the catalyst, compared with before use, the characteristic peak shape of each characteristic diffraction did not change significantly. The results show that the catalyst Pd-Fe-Co-Ce/FSC (ratio 1:1:1:3) revealed a stable catalyst performance in the process of CWAO for the treatment of difficult-to-biodegradable organic waste-water.