Activation of persulfate by heterogeneous catalyst Zn[Co.sub.2][O.sub.4]-RGO for efficient degradation of bisphenol A

A nanocomposite, reduced graphene oxide (RGO) modified Zn[Co.sub.2][O.sub.4] (Zn[Co.sub.2][O.sub.4]-RGO) was synthesized via one-step solvothermal method for activating persulfate (PS) to degrade bisphenol A (BPA). The morphology and structure of the nanocomposite were identified by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. RGO provides nucleation sites for Zn[Co.sub.2][O.sub.4] to grow and inhibits the agglomeration of the nanoparticles. The influence of different reaction conditions on the oxidation of BPA catalyzed by Zn[Co.sub.2][O.sub.4]-RGO was investigated, including the content of RGO, the dosage of catalyst, the concentration of humic acid (HA), anions in the environment, the reaction temperature, and pH. BPA can be totally degraded within 20 min under optimized reaction conditions. The presence of HA, [Cl.sup.-], and N[O.sub.3.sup.-] only has a slight effect on the oxidation of BPA, whereas the presence of either [H.sub.2]P[O.sub.4.sup.-] or HC[O.sub.3.sup.-] can greatly inhibit the reaction. Zn[Co.sub.2][O.sub.4]-RGO shows good cycling stability and practical application potential. A reaction mechanism of the degradation of BPA was also explored. Key words: graphene based nanocomposite, heterogeneous activation, persulfate, advanced oxidation processes, bisphenol A. Nous avons synthetise un nanocomposite de Zn[Co.sub.2][O.sub.4] modifie par l'oxyde de graphene reduit (rGO), le Zn[Co.sub.2][O.sub.4]-rGO, par une methode sovothermale en une etape permettant d'activer le persulfate afin de degrader le bisphenol A (BPA). Nous avons caracterise la morphologie et la structure du nanocomposite par diffraction des rayons X, spectroscopie infrarouge a transformee de Fourier, spectroscopie de photoelectrons X, microscopie electronique a balayage et microscopie electronique en transmission. Le rGO offre des sites de nucleation permettant la croissance des cristaux de Zn[Co.sub.2][O.sub.4] et inhibe l'agglomeration des nanoparticules. Nous avons etudie l'influence de differentes conditions de reaction sur l'oxydation du BPA catalysee par le Zn[Co.sub.2][O.sub.4]-rGO, a savoir la teneur en rGO, la quantite de catalyseur, la concentration d'acide humique (AH), la presence d'anions dans le milieu, la temperature de reaction et le pH. En conditions de reaction optimisees, le BPA peut etre totalement degrade en moins de 20 minutes. La presence d'AH et d'ions [Cl.sup.-] et N[O.sub.3.sup.-] n'ont qu'un leger effet sur l'oxydation du BPA, tandis que la presence d'ions [H.sub.2]P[O.sub.4.sup.-] ou d'ions HC[O.sub.3.sup.-] peut inhiber grandement la reaction. Le Zn[Co.sub.2][O.sub.4]-rGO presente une bonne stabilite au cours des cycles successifs et offre des possibilites d'applications pratiques. Nous avons egalement explore un mecanisme de reaction de la degradation du BPA. [Traduit par la Redaction] Mots-cles : nanocomposite a base de graphene, activation heterogene, persulfate, procedes d'oxydation avances, bisphenol A.
Introduction Bisphenol A (BPA) is commonly used for producing polycarbonate plastics and epikotes (1) and can also be utilized as an additive in flame retardants, brake fluid, and thermal papers. [...]