Photocatalytic activity of transition metal ions-loaded activated carbon: Degradation of crystal violet dye under solar radiation

Abstract

In this work, activated carbon (AC) was prepared from date palm stone by chemical activation method. Its properties were investigated, the surface of the AC was found to be acidic (pHpzc of 3.95), Brunauer-Emmet-Teller (BET) surface area of 12.7 m2/g, with meso and microporous structures. The prepared AC was loaded with Zn(II), Cd(II), Cu(II), and Pb(II) metal ions by adsorption and ion exchange. Scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) were used to elucidate the morphology, composition, and bonding of loaded metal ions to the functional group on carbon surface. The prepared AC and its loaded metal ions showed significant catalytic activity for the degradation of crystal violet (CV) under solar radiation. The highest photocatalytic degradation rate was obtained using Zn(II)-loaded AC with 80% mineralization in 40 h. The Zn(II)-loaded AC was used for many cycles of photocatalytic degradation of CV without loss in its catalytic efficiency. The highest degradation rate was obtained at pH 6.5. The degradation rate was found to be inversely proportional to the CV concentration and mesh size of the catalyst. The degradation of the CV was found to take place via OH attack.