Mechanistic and structure investigation of the KOH activation ZIF-8 derived porous carbon as metal-free for unprecedented peroxymonosulfate activation degradation of bisphenol A.

The high-performance and free secondary pollution of the catalysts are the most critical issues in the peroxymonosulfate-based advanced oxidation processes (PMS-AOPs). In this research, the KOH was used to activate ZIF-8 derived carbon materials to synthesize the NC-KOH-x (x = 700, 800, 900 °C), which was an effective metal-free PMS activator. As-prepared NC-KOH-x showed significant improvement not only pore structure and BET surface area but also CO groups, and graphite N content, which were beneficial for the adsorptive and oxidative reaction. The NC-KOH-900 as an excellent metal-free carbon-catalyst exhibited considerable reactivity for bisphenol A (BPA) removal in broad pH ranges. Almost 100% of BPA was eliminated using 9 mg NC-KOH-900, 0.5 mM PMS within 60 min. Interestingly, It was found that the BPA removal efficiency by adding PMS after saturated adsorption of NC-KOH-x was better than that by adding NC-KOH-x and PMS simultaneously. Electronic paramagnetic resonance (EPR) and quenching experiments results demonstrated that the BPA degradation relied mainly on the nonradical (1O2) pathways and the defects (ID/IG), graphitic nitrogen, pyridinic nitrogen, and CO were verified as leading catalytic sites for BPA degradation via PMS activation. Finally, degradation pathways of BPA were proposed and the Toxicity Estimation Software Tool (T.E.S.T.) result implicated that the intermediates of BPA were environmentally friendly to the microorganism and recycled in the ecosystem. The outcomes of this study illustrated the NC-KOH-x owned many merits of state-of-the-art, eco-friendly, and high-performance for great potential practical application value.

Activation of peroxymonosulfate by ZIFs derived Fe/Cu encapsulated N-doped carbon for bisphenol A degradation: The role of N doping.

Bisphenol A (BPA) is a typical kind of endocrine disruption chemical, which has a negative effect on human health, and thus it is necessary to remove BPA from water. Herein, activation of peroxymonosulfate (PMS) by Fe, Cu-Coordinated ZIF-Derived Carbon Framework bifunctional catalyst (Fe/Cu@NC-x) fabricated via hydrothermal-calcination method for BPA removal. The physicochemical properties of Fe/Cu@NC-x were studied by X-ray diffraction, Transmission electron microscopy, Scanning electron microscopy, Raman Spectroscopy, Brunauer-Emmett Teller, and X-ray photoelectron spectroscopy. The effects of the Fe/Cu@NC-900 dosage and PMS concentration, initial pH, and co-existing anions on BPA degradation were evaluated. Under optimized factors (pH unadjusted, Fe/Cu@NC-900 = 0.2 g/L, and PMS = 0.75 g/L), the degradation efficiency of BPA can reach 98% after 30 min. In addition, the BPA degradation efficiency was different extents restrain by inorganic anions (SO42- > Cl- > HCO3- > NO3-). Furthermore, the free radicals (SO4-·, ·OH, and O2-·) and non-radical (1O2) contribute to rapid BPA degradation in Fe/Cu@NC-900/PMS system. This study presents a novel material with significant performance for the removal of organic pollutants.