Preparation of the Mn-Fe-Ce/γ-Al2O3 ternary catalyst and its catalytic performance in ozone treatment of dairy farming wastewater

MnCe-based catalysts for removal of organic pollutants in urban wastewater by advanced oxidation processes - A critical review

With Advanced oxidation processes (AOPs) widely promoted, MnCe-based catalysts have received extensive attention under the advantages of high efficiency, stability and economy for refractory organic pollutants present in urban wastewater. Driven by multiple factors such as environmental pollution, technological development, and policy promotion, a systematic review of MnCe-based catalysts is urgently needed in the current research situation. This research provides a critical review of MnCe-based catalysts for removal of organic pollutants in urban wastewater by AOPs. It is found that co-precipitation and sol-gel methods are more appropriate methods for catalyst preparation. Among a host of influence factors, catalyst composition and pH are crucial in the catalytic oxidation processes. The synergistic effect of the free radical pathway and surface catalysis results in better pollutants degradation. It is more valuable to utilize multiple systems for oxidation (e.g., photo-Fenton technology) to improve the catalytic efficiency. This review provides theoretical guidance for MnCe-based catalysts and offers a reference direction for future research in the AOPs of organic pollutants removal from urban wastewater.

The Use of Ozone Technology: An Eco-Friendly Method for the Sanitization of the Dairy Supply Chain

The dairy field has considerable economic relevance in the agri-food system, but also has the need to develop new 'green' supply chain actions to ensure that sustainable products are in line with consumer requirements. In recent years, the dairy farming industry has generally improved in terms of equipment and product performance, but innovation must be linked to traditional product specifications. During cheese ripening, the storage areas and the direct contact of the cheese with the wood must be carefully managed because the proliferation of contaminating microorganisms, parasites, and insects increases significantly and product quality quickly declines, notably from a sensory level. The use of ozone (as gas or as ozonated water) can be effective for sanitizing air, water, and surfaces in contact with food, and its use can also be extended to the treatment of waste and process water. Ozone is easily generated and is eco-sustainable as it tends to disappear in a short time, leaving no residues of ozone. However, its oxidation potential can lead to the peroxidation of cheese polyunsaturated fatty acids. In this review we intend to investigate the use of ozone in the dairy sector, selecting the studies that have been most relevant over the last years.

Hydrophobically modified mesoporous silica supported Pt as a dual-function adsorbent buffer-catalyst for toluene removal under low-temperature

High performance hydrophobic Pt/SiO2 as an adsorbent buffer catalyst for toluene removal.

The degradation of printing and dyeing wastewater by manganese-based catalysts

Printing and dyeing wastewater generally has high pH, high turbidity, poor biodegradability, complex composition, and high chroma, which make it one of the most difficult industrial wastewaters to treat. Herein, heterogeneous ozone oxidation technology is applied to oxidize and degrade printing and dyeing wastewater. A metal oxide catalyst supported on activated carbon (γ-MnO₂/AC) was prepared by hydrothermal synthetic method and shown to enable synergistic catalysis involving MnO₂ metal sites and N/C sites. A simulated methyl orange solution was used to determine the effects of various preparation and operation parameters. The results confirmed that the γ-MnO₂/AC catalyst exhibited good chemical oxygen demand (COD) removal and reusability. Additionally, γ-MnO₂/AC demonstrated excellent degradation of the secondary biochemical effluent of printing and dyeing wastewater (COD removal = 72.45% within 120 min). The γ-MnO₂/AC catalyst was fully characterized, and the mechanism governing its catalytic ozone oxidation process was investigated experimentally.

Ternary catalyst Mn-Fe-Ce/Al2O3 for the ozonation of phenol pollutant: performance and mechanism

In this study, a novel ternary catalyst Mn-Fe-Ce/Al2O3 was synthesized by co-impregnation method, and was characterized by XRD, SEM, XPS, and FTIR. The catalytic performance of this ternary catalyst was evaluated in the heterogeneous catalytic ozonation of phenol pollutants and it improved the removal rate and mineralization degree of phenol pollutants. The changes of dissolved ozone in water and the TBA experiment proved that the ternary catalyst could accelerate the decomposition of ozone into hydroxyl radicals, thus accelerating the oxidation of phenol. Phosphate experiments and surface hydroxyl density measurements proved that surface hydroxyl was the active site of the catalyst. XPS analysis showed that the ternary catalysts accelerated electron transfer through the redox cycles of Mn2+-Mn3+-Mn4+, Fe2+-Fe3+, and Ce3+-Ce4+, which also contributed to the high catalytic activity. Moreover, the catalyst maintained high catalytic activity after five cycles of use. Therefore, the ternary catalyst was considered an efficient and promising catalyst for catalytic ozonation system.

Ce-based catalysts used in advanced oxidation processes for organic wastewater treatment: A review

Refractory organic pollutants in water threaten human health and environmental safety, and advanced oxidation processes (AOPs) are effective for the degradation of these pollutants. Catalysts play vital role in AOPs, and Ce-based catalysts have exhibited excellent performance. Recently, the development and application of Ce-based catalysts in various AOPs have been reported. Our study conducts the first review in this rapid growing field. This paper clarifies the variety and properties of Ce-based catalysts. Their applications in different AOP systems (catalytic ozonation, photodegradation, Fenton-like reactions, sulfate radical-based AOPs, and catalytic sonochemistry) are discussed. Different Ce-based catalysts suit different reaction systems and produce different active radicals. Finally, future research directions of Ce-based catalysts in AOP systems are suggested.