Synthesis of Nano-Flakes Ag•ZnO•Activated Carbon Composite from Rice Husk as A Photocatalyst under Solar Light

Abstract

This study aimed to synthesize Ag•ZnO•Activated carbon (Ag•ZnO•AC ) composite from rice husk for degradation of dyes. The deposition of Ag and ZnO on AC led to decreasing the surface area and pore volume of Ag•ZnO•AC composite. In addition, when Ag and ZnO were dispersed on activated carbon, the Ag•ZnO flakes became denser and tighter, but the particle size of Ag became smaller from 5 to 7 nm. The photocatalytic ability of Ag•ZnO•AC composite was evaluated by degradation of Janus Green B (JGB) and compared with that of AC, ZnO, Ag•ZnO, and ZnO•AC samples. The effects of catalyst dosages, pH values, and initial dye concentrations on photocatalytic degradation were investigated in detail. The Ag•ZnO•AC composite had a high degradation efficiency of 100% in 60 min, showing the reaction rate of 0.120 min-1 and degradation capacity of 17.8 mg/g within 20 min. The photocatalytic performance of the Ag•ZnO•AC composite was also evaluated by cyclic test and the degradation of other persistent dyes such as Methylene Blue, Tartrazine, Congo Red, and organic compounds (Caffeine and Bisphenol A). Based on the experimental results, the possible destruction route of JGB by the as-synthesized Ag•ZnO•AC composite was suggested. Copyright © 2020 BCREC Group. All rights reserved

Study on Method of Doping Au Nanoparticles on ZnO Stratified Microstructure to Enhance Photocatalytic Ability and Antibacterial Activity

“…The concentrations of organic pollutants at each time interval were monitored by the UV-Vis spectrophotometer (Agilent 8453 instrument). The rate constant was calculated by using the pseudo-first-order model, equation (1) [31]. The degradation efficiency (DE) degradation capacity (DC) of the pollutant was determined by Equations ( 2) and (3) [31].…”

“…The rate constant was calculated by using the pseudo-first-order model, equation (1) [31]. The degradation efficiency (DE) degradation capacity (DC) of the pollutant was determined by Equations ( 2) and (3) [31]. The crystal sizes samples were determined through equation ( 4) [32].…”

“…Clearly, it revealed that many pore structures in the size range of 20÷50 nm were formed on the ZnO surface, which was an important contributor to photocatalytic processes Figure 3(ab). By virtue of these pore structures, ZnO nanoparticles (ZnO NPs) have the significant abil-ity to diffuse light as well as efficiently transport hydroxyl radicals in photochemical reactions, leading to enhancing their photocatalytic performance of them [31,33]. By comparison, after doping Au NPs into ZnO, the holes tended to be narrower on the petals, it was not as smooth as that of the original ZnO.…”

“…The crystal wurtzite ZnO phase was revealed by XRD pattern in Figure 4(a), which showed the (100), ( 002), ( 101), ( 102), ( 110), ( 103), (112), and (201) planes at 2θ of 31.7, 34.4, 36.2, 47.5, 56.6, 62.8, and 67.9º, respectively (JCPDS card No. 36-1451) [31]. In addition, the other diffraction peaks at 38.2, 44.4, and 64.5º were specified to the (111), (200), and (220) crystal planes of crystal Au particles [34], in the Au/ZnO-Hg lamp sample.…”

Preparation of Au/ZnO/Fe3O4 Composite for Degradation of Tartrazine under Visible Light

“…There are several types of research on doping precious metals into ZnO to reduce band gap energy, increase visible light absorption, and lower electron and hole recombination. To solve this problem, the proposed solution is to dope an appropriate amount of precious metals such as Au, Ag, Pt, and Pb, which enhances sunlight absorption and reduces electron-hole recombination, resulting in increased decomposition of organic substances [7][8][9][10][11][12][13][14][15].…”