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Comparison of Catalytic Properties of Cu/13X Catalyst in the Wet Peroxide Oxidation of 4-(2- Hydroxyethyl)phenol in Batch and Fixed Bed Reactor

4-(2-Hydroxyethyl)phenol is one of the phenolic compounds commonly found in olive oil mill wastewater (OOMW) – the liquid waste generated in the olive oil production process. This wastewater represents a special challenge for treatment because it contains a number of harmful organic contaminants such as lignin, tannins and polyphenolic compounds whose proven toxicity towards the microorganisms used in the aerobic biological processes make direct conventional biological treatment inapplicable [1]. Its high polluting charges are measured in BOD5 and COD levels up to 35 g dm-3 as well as the presence of phenols and polyphenols that can constitute up to 20 wt. % of total organic content. Therefore, the current research focuses investigation on developing viable treatment processes that will reduce or eliminate toxic content of the OOMW and improve its biodegradability. Catalytic wet peroxide oxidation (CWPO) is simple, cost effective and environmentally friendly process that is based on non selective oxidation of organic compounds by hydroxyl radicals that are formed upon the decomposition of hydrogen peroxide over a suitable catalyst. Finding a suitable catalyst has become a focal point of most studies [2]. This study deals with investigation of applicability of zeolite based catalyst for such purposes. Zeolites have been widely used as catalysts in a number of different oxidation reactions yielding excellent catalytic properties because of what they were selected for evaluation in this process [3, 4]. Cu/ 13X zeolite catalyst (dP= 0.4 - 0.6 mm) was prepared, characterized, thermally stabilized by high temperature calcination in air and used in the catalytic screening in wet peroxide oxidation of model wastewater (tyrosol aqueous solutions) to evaluate its catalytic properties. The experiments were performed in a suspension batch and adiabatic continuous fixed bed reactors under mild reaction conditions with low energy consumption (T = 323-343 K, 500 mg dm-3 organic compound(s), stoichiometric oxidant amount, 1.25 g of catalyst). It was found that the prepared catalyst showed promising activity in both reactor systems yielding over 50 % conversions of targeted organic contaminants at with no significant leaching of active metal component of the catalyst.

Zeolites ; Catalysis: Synthesis ; Reactions ; Application

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