An effective catalytic process that is responsible for treating textile organic wastewater was investigated in the current study. The original (photo) Fenton reaction can only be used in the pH range of 3 - 4, though most organic contaminated wastewater has a natural pH around 7, thus, the reaction is often restricted in industrial application. Cu⁺, as a catalyst in helping generating hydroxyl radicals with H₂O₂, is much less pH sensitive and, therefore, becoming a possible solution. However, when coating copper onto porous solid such as clay to obtain a heterogeneous catalyst, the leaching problem of copper is much more serious than that of iron. The current study has seen that a pretreatment step by acid, referred to as acid activation of clay, can significantly reduce the leaching p...[ Read more ]

An effective catalytic process that is responsible for treating textile organic wastewater was investigated in the current study. The original (photo) Fenton reaction can only be used in the pH range of 3 - 4, though most organic contaminated wastewater has a natural pH around 7, thus, the reaction is often restricted in industrial application. Cu⁺, as a catalyst in helping generating hydroxyl radicals with H₂O₂, is much less pH sensitive and, therefore, becoming a possible solution. However, when coating copper onto porous solid such as clay to obtain a heterogeneous catalyst, the leaching problem of copper is much more serious than that of iron. The current study has seen that a pretreatment step by acid, referred to as acid activation of clay, can significantly reduce the leaching problem and improve the catalytic activity. This helps the catalyst recovery and prevents the secondary pollutants (metal ions). The Cu catalyst supported by acid-activated clay is better than Fe/clay at pH higher than 5 and has a comparable activity as Fe/clay at pH 3. The effects of temperature, pH, loading of catalyst, H₂O₂ and pollutant concentration on the catalytic performance of the Cu/clay catalyst are investigated.

The current investigation has successfully elucidated that the bimetallic catalyst consisting of deposited Cu and Fe simultaneously onto the clay support has extraordinary efficient catalytic activity at pH ranging from acidic to alkaline. The metal leaching has been continuously kept in a low level by the acid activation of clay, which further substantiates the applicability of the catalyst.

With the current investigated process, the photo-oxidation of organic pollutants can be done at ambient temperature with the presence of UV light, H₂O₂ and Cu/clay or Cu/Fe/clay catalyst. Therefore, the equipment used for this reaction is simple. As a result, the developed catalytic process is recommended for organic removal in water, particularly in textile industry.