Catalytic Oxidation of Polymers Remained in Oilfield by Transition Metal-Ethylenediamine Complex

This work is intended to seek for an efficient Fe-based Fenton reagent for clean oxidation of waste fracturing fluid containing hydroxypropyl guar gum (HGG) and other polymers in wide pH range. A series of complex was prepared with transition metal and ethylenediamine (L) by the coordination. The catalytic performance of the complexes were evaluated in the degradation of HGG, and the reaction conditions were optimized. The kinetics of HGG degradation was evaluated by means of the chemical oxygen demand (COD) and the viscosity. The results show that Fe(II)L exhibits high catalytic performance for the degradation of hydroxypropyl guar gum in a wide pH range of 7.0–11.0, the COD removal can reach to 86.4%. Under the optimum experimental conditions, the relative viscosity of hydroxypropyl guar gum solution can be reduced effectively to 7.99 from 247 with 10.0% H2O2 in presence of 5.0% Fe(II)L. Besides, under the optimized condition, three typical polymers used in oilfield can be degradated effectively.