Heterogeneous degradation of oil field additives by <scp>Cu</scp>(<scp>II</scp>) complex‐activated persulfate oxidation

Abstract

Abstract In this work, bentonite‐supported Cu(II) complex (B@Cu(II)L) was prepared by a one‐pot method and used as a heterogeneous catalyst for evaluating its catalytic activity in oxidation degradation of hydroxypropyl guar gum (HPGG) in oilfield wastewater. All of the reaction parameters effected degradation efficiency, such as Na 2 S 2 O 8 concentration, catalyst amount, reaction temperature, and pH value, were investigated in detail. The results showed that the absolute viscosity of HPGG solution can be decreased from 15 to 1.48 mm 2 /s in presence of 15% Na 2 S 2 O 8 (mass ratio to HPGG) and 1.5 g/L B@Cu(II)L at 45°C and pH = 10. It was also found that the chemical oxygen demand of HPGG solution catalyzed by B@Cu(II)L decreased from 4,080 to 584 mg/L after 240 min under the optimum experimental conditions. The catalytic activity of supported bivalent copper complexes over bentonite was gradually decreased due to the loss of the active copper.