Article

Heterogeneous catalytic degradation of phenolic substrates: Catalysts activity

Istituto per Lo Studio dei Materiali Nanostrutturati (ISMN)-CNR via Ugo La Malfa, 153, 90146 Palermo, Italy.
Journal of Hazardous Materials (Impact Factor: 4.53). 06/2008; 162(2-3):588-606. DOI: 10.1016/j.jhazmat.2008.05.115
Source: PubMed

ABSTRACT

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.

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    • "Priority organic pollutants are refractory to biological degradation or even toxic to the microorganisms, if the processes proceed at low rates. Among organic pollutants, phenol and phenol derivates, used as raw materials in chemical, petrochemical, and pharmaceutical industries have received increased attention in the last years due their toxicity (Guo & Al-Dahlan, 2003; Liotta et al., 2009). These compounds represent common organic pollutants in water discharged by several industries, and have particularities that make them valuable as a model pollutants, such as: toxicity even at low concentrations, formation of substituted compounds during disinfection and oxidation processes (such as those used currently for the treatment of natural surface water for drinking purposes), phytotoxicity and ability to bioaccumulate in organisms, that have similarities with persistent organic pollutants (POPs) (Catrinescu & Teodosiu, 2007; Busca et al., 2008). "

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    • "The efficiencies of these treatments were diverse, as expected, because the process is substrate-dependent. Several reviews focus on comparing the efficiency of different treatments for the degradation of phenol as a Bmodel^ contaminant (Esplugas et al. 2002; Liotta et al. 2009; Grabowska et al. 2012). However, no reports were found about the influence of cerium doping of TiO 2 on the photodegradation of phenol. "
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    • "These pollutants have an important impact on the environment and human health. Significant efforts have been made to reduce pollutant discharges by promoting clean technologies in industrial sectors and by cleaning up waste gas and waste water before discharging them into the environment [1]. The latest advances in water treatment have been achieved in the oxidation of organic compounds [2] [3] including phenolic compounds which are harmful to the environment and to human health [4] [5]. "
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    ABSTRACT: A clay catalyst (montmorillonite and kaolinite) was prepared and used to degrade three phenolic compounds: hydroquinone, resorcinol and catechol obtained from the treatment the Olive Mill Wastewater (OMW) generated in the production of olive oil. The operating conditions of the degradation of these compounds are optimized by the response surface methodology (RSM) which is an experimental design used in process optimization studies. The results obtained by the catalytic tests and analyses performed by different techniques showed that the modified montmorillonites have very interesting catalytic, structural and textural properties; they are more effective for the catalytic phenolic compound degradation, they present the highest specific surface and they may support iron ions. We also determined the optimal degradation conditions by tracing the response surfaces of each compound; for example, for the catechol, the optimal conditions of degradation at pH 4 are obtained after 120 min at a concentration of H2O2 equal to 0.3 M. Of the three phenolic compounds, the kinetic degradation study revealed that the hydroquinone is the most degraded compound in the least amount of time. Finally, the rate of the catalyst iron ions release in the reaction is lower when the Fe-modified montmorillonites are used.
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