Abstract:
Objective The aim was to explore the feasibility of removing organic matter in high saline and refractory shale gas flowback water through oxidation by alkaline activated sodium persulfate (NaOH/PS).
Methods Single-factor analysis of PS dosage, initial pH value and PS dosage were performed, while the kinetic equations of TOC removal rate and the reaction mechanism of NaOH/PS system were investigated.
Results The Results showed that the optimal reaction conditions of NaOH/PS oxidation shale gas flowback water are as follows: PS concentration at 1 500 mg/L, initial pH value at 12, PS added four times; and organic matter degradation could be described by quasi-second-order reaction kinetics. EPR and quench experiments showed that the active substances in NaOH/PS oxidation system were SO4-· and OH·.
Conclusions This study could serve as the reference for the design and operation of organic matter removal units in the shale gas flowback water treatment process.