Efficient activation of persulfate by Nickel-supported cherry core biochar composite for removal of bisphenol A

In this study, low-cost and easily obtained biochar was chosen to prepare nickel-modified biochar materials (Ni/BC) through a one-step activation pyrolysis method. Characterization with X-ray diffraction, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy proved the existence of Ni⁰ and NiO nanocrystals in Ni/BC catalyst. The optimal Ni_0.5/BC exhibited excellent peroxymonosulfate (PMS) and peroxydisulfate (PDS) activation efficiency toward bisphenol A (BPA) degradation. The Ni_0.5/BC (0.03 g) reacted with 1.0 g L^-1 PMS or PDS could completely remove 20 mg L^-1 BPA in 10 min with the first-order kinetic constants (k₁) of 0.322 min^-1 (PMS) and 0.336 min^-1 (PDS). More importantly, the composite has better structural and functional attributes for the BPA degradation with universal applicability at wide pH and temperature range, proving as a better degradation mediator with high adaptation for numerous organic pollutants. Catalytic activity decreased slightly even after 4 cycles. Based on the quenching experiment and electron paramagnetic resonance, it was found that SO₄^•-, •OH and ¹O₂ were the dominant active species in BPA degradation process. Therefore, this work not only supplies a promising catalyst for the removal of organic contaminants, but also is beneficial for the further development of alternative catalysts for sulfate radical based advanced oxidation processes.