Catalytic remediation of phenol contaminated wastewater using Cu–Zn hydroxide nitrate

Abstract

This work highlights an application of Cu–Zn hydroxide nitrate (denoted as 6Cu–Zn) as a highly effective and reusable catalyst for catalytic wet peroxide oxidation of phenol under mild conditions (35 °C). PXRD and XANES experiments were carried out to confirm a single phase of copper hydroxide nitrate in the 6Cu–Zn sample. The catalytic activity of 6Cu–Zn for degrading phenol was reported in terms of the percent phenol conversion, and chemical oxygen demand (COD) removal efficiency. Treatment of 100, 200, and 500 ppm aqueous phenol solutions with H₂O₂/6Cu–Zn resulted in complete phenol degradation within 10 min. The 6Cu–Zn catalyst can be reused for up to five consecutive runs while maintaining complete phenol conversion and COD removal efficiency (greater than 90%) after water washing. This work introduces a simple, mild, energy efficient and effective pretreatment method for highly toxic wastewater which could be applied prior to feeding the pretreated wastewater to subsequent conventional treatment units.