Catalytic wet oxidation of acetic acid using platinum on alumina monolith catalyst

A New Route for Low Pressure and Temperature CWAO: A PtRu/MoS2_Hyper-Crosslinked Nanocomposite

PtRu/MoS₂ nanoparticles (NPs) (PtRu alloy partially coated by one-layer MoS₂ nanosheets) were prepared through a ‘wet chemistry’ approach. The obtained NPs were directly embedded, at 5 parts per hundred resin/rubber (phr) loading, in a poly (divinylbenzene-co-vinyl benzyl chloride) hyper-crosslinked (HCL) resin, synthesized via bulk polymerization of the resin precursors, followed by conventional FeCl₃ post-crosslinking. The obtained HCL nanocomposites were characterized to evaluate the effect of the NPs. It shows a high degree of crosslinking, a good dispersion of NPs and a surface area up to 1870 ± 20 m²/g. The catalytic activity of the HCL nanocomposite on phenol wet air oxidation was tested at low air pressure (P_air = 0.3 MPa) and temperature (T = 95 °C), and at different phenol concentrations. At the lower phenol concentration, the nanocomposite gives a total organic carbon (TOC) conversion of 97.1%, with a mineralization degree of 96.8%. At higher phenol concentrations, a phenol removal of 99.9%, after 420 min, was achieved, indicating a quasi-complete depletion of phenol, with a TOC conversion of 86.5%, corresponding to a mineralization degree of 84.2%. Catalyst fouling was evaluated, showing good reusability of the obtained nanocomposite.

Heterogeneous catalytic degradation of phenolic substrates: catalysts activity

This review article explored the catalytic degradation of phenol and some phenols derivates by means of advanced oxidation processes (AOPs). Among them, only the heterogeneous catalyzed processes based on catalytic wet peroxide oxidation, catalytic ozonation and catalytic wet oxidation were reviewed. Also selected recent examples about heterogeneous photocatalytic AOPs will be presented. In details, the present review contains: (i) data concerning catalytic wet peroxide oxidation of phenolic compounds over metal-exchanged zeolites, hydrotalcites, metal-exchanged clays and resins. (ii) Use of cobalt-based catalysts, hydrotalcite-like compounds, active carbons in the catalytic ozonation process. (iii) Activity of transition metal oxides, active carbons and supported noble metals catalysts in the catalytic wet oxidation of phenol and acetic acid. The most relevant results in terms of catalytic activity for each class of catalysts were reported.

Chemistry of alumina, reactions in aqueous solution and its application in water treatment

Due to the presence and significance of alumina in the natural aquatic environment and its increasing application in drinking and wastewater purification, the knowledge of the structure of alumina and its possible interactions with organic and inorganic compounds in water are of great importance. This is of particular importance in both the understanding of natural aquatic environment processes and efficient industrial applications. The chemistry of alumina reactions in water is complex. The adsorption ability of alumina towards organic and inorganic compounds might be influenced by several factors such as: surface characteristics of the adsorbent (surface area, density, pore volume, porosity, pore size distribution, pH(PZC) as well as mechanical strength and purity), pH of the solution, ionic strength, composition of water and the physicochemical properties of adsorbates. The aim of this paper is to give a brief review of the properties of alumina and its reactivity with organic and inorganic compounds present in aqueous solutions. It also summarises the usage of alumina and alumina supported phases in water treatment technology.

Heterogeneous water phase catalysis as an environmental application: a review

Catalytic water phase processes as an environmental application is a relatively novel subject with tremendous potential in the near future. This review of 120 references presents the wide scale of heterogeneous water phase applications studied mainly within past five years. Both oxidation and hydrogenation processes are included as well as TiO2 assisted photocatalysis. According to the references, heterogeneous catalysis is developing rapidly. New bimetallic catalysts and supports with higher surface area have improved catalytic efficiency in both oxidation and hydrogenation processes. It also seems that study on use of some waste materials such as red mud as catalyst is a very progressive field. On the whole, the chemical aspects are pretty well known, but the catalyst durability, and in many cases activity as well, has to be improved.