Comparative procedure of photodegradation of methylene blue using N doped activated carbon loaded with hollow 3D flower like ZnS in two synergic phases of adsorption and catalytic

摘要

In the present work, 3D flower like ZnS was synthesized by a sonochemical-solvothermal process and loaded on Nitrogen doped activated carbon (NAC-ZnS). photocatalytic degradation of methylene blue (MB) onto NAC-ZnS investigated in aqueous solution at room-temperature. The whole method was studied in two different processes of adsorption and photodegradation in detail separately with a synergic perspective. Influence of various operational parameters such as pH, composite dose, and contact time for adsorption process, and also pH, composite dose, and degradation time for catalytic process were examined in multivariate method through response surface methodology (RSM) based upon the central composite design (CCD) by design expert7 software. In addition, initial MB concentration as well as calculations of adsorption kinetic and isotherm and catalytic kinetic were done. In NAC-ZnS photodegradation process the mechanism of electron-hole pairs generation was fully studied. MB was successfully photo reduced by NAC-ZnS nanocomposite and investigated in two periodic phases of 110?min and 10?h of irradiation to decay all secondary pollutants resulted from first phase. The products (secondary pollutants) produced from first phase were identified by liquid chromatography–mass spectrometry (LC–MS/MS). Moreover, the NAC-ZnS morphological studies including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), Thermo gravimetric analysis (TGA), and energy dispersion spectroscopy (EDS) were performed.