Hierarchical α-Ni(OH)2 with tunable by interlayer anion exchange for degradation of hydroxypropyl guar gum synergistic H2O2

Hydraulic fracturing for oil and gas production generates a substantial amount of wastewater, and photocatalysis is a potential method for treating fracture flowback fluids due to its low cost and efficiency. This study utilized the hydrothermal method to synthesize layered α-Ni(OH)₂ with a controllable microstructure by substituting various nickel sources, including Cl⁻, SO₄²⁻, OAc⁻, and NO₃⁻ interlayer ions, to focus on the photocatalytic degradation of hydroxypropyl guanidine gum, the primary constituent of fracturing fluid. The results indicate that α-Ni(OH)₂/OAc⁻ exhibits the most effective photocatalytic activity under optimal experimental conditions. The stability of the catalyst was confirmed through cycling studies. Possible degradation mechanisms were hypothesized based on DFT adsorption energy calculations and capture tests. The field performance of the application demonstrates that this work offers novel perspectives on the photocatalytic degradation of fracturing fluids.