“…On the contrary, at high pH, electrostatic repulsion may occur between the dye anions and the negatively charged photocatalyst surface, resulting in negligible adsorption. A similar result has been reported by Bagheri et al [27]. In acidic condition, MO-, CR-, and DB38-containing sulfonic groups can be easily ionized to form anionic dyes, thereby enhancing the adsorption of dye anions on the ZnO surface.…”
Section: Resultssupporting
confidence: 87%
“…Furthermore, the photons were blocked before reaching the photocatalyst surface; hence, the adsorption of photons was decreased by the photocatalyst. Accordingly, the removal rate reduced at high initial dye concentrations [3, 27]. Fig.…”
Zinc oxide (ZnO) photocatalysts were synthesized by sol–gel method using zinc acetate as precursor for degradation of azo dyes under UV irradiation. The resultant samples were characterized by different techniques, such as XRD, SEM, and EDX. The influence of preparation conditions such as calcination temperature and composite ratio on the degradation of methyl orange (MO) was investigated. ZnO prepared with a composite ratio of 4:1 and calcination temperature of 400 °C exhibited 99.70% removal rate for MO. The effect of operation parameters on the degradation was also studied. Results showed that the removal rate of azo dyes increased with the increased dosage of catalyst and decreased initial concentration of azo dyes and the acidic condition is favorable for degradation. Furthermore, the kinetics and scavengers of the reactive species during the degradation were also investigated. It was found that the degradation of azo dyes fitted the first-order kinetics and superoxide ions were the main species. The proposed photocatalyst can efficiently and rapidly degrade azo dyes; thus, this economical and environment-friendly photocatalyst can be applied to the treatment of wastewater contaminated with synthetic dyes.
“…On the contrary, at high pH, electrostatic repulsion may occur between the dye anions and the negatively charged photocatalyst surface, resulting in negligible adsorption. A similar result has been reported by Bagheri et al [27]. In acidic condition, MO-, CR-, and DB38-containing sulfonic groups can be easily ionized to form anionic dyes, thereby enhancing the adsorption of dye anions on the ZnO surface.…”
Section: Resultssupporting
confidence: 87%
“…Furthermore, the photons were blocked before reaching the photocatalyst surface; hence, the adsorption of photons was decreased by the photocatalyst. Accordingly, the removal rate reduced at high initial dye concentrations [3, 27]. Fig.…”
Zinc oxide (ZnO) photocatalysts were synthesized by sol–gel method using zinc acetate as precursor for degradation of azo dyes under UV irradiation. The resultant samples were characterized by different techniques, such as XRD, SEM, and EDX. The influence of preparation conditions such as calcination temperature and composite ratio on the degradation of methyl orange (MO) was investigated. ZnO prepared with a composite ratio of 4:1 and calcination temperature of 400 °C exhibited 99.70% removal rate for MO. The effect of operation parameters on the degradation was also studied. Results showed that the removal rate of azo dyes increased with the increased dosage of catalyst and decreased initial concentration of azo dyes and the acidic condition is favorable for degradation. Furthermore, the kinetics and scavengers of the reactive species during the degradation were also investigated. It was found that the degradation of azo dyes fitted the first-order kinetics and superoxide ions were the main species. The proposed photocatalyst can efficiently and rapidly degrade azo dyes; thus, this economical and environment-friendly photocatalyst can be applied to the treatment of wastewater contaminated with synthetic dyes.
“…These observations suggest that the gallia acts as a crystallite growth inhibitor for In 2 O 3 nanoparticles. Similar behavior has been observed in other reports[34][35][36][37]. On the other hand, the intense peaks in the pure In 2 O 3 pattern indicate the excellent crystal quality of c-In 2 O 3 nanostructures.It should be noted that In 2 O 3 has two major phases: c-In 2 O 3 and rh-In 2 O 3 .…”
“…Congo red (CR) (sodium 3,3 0 -(1E,1 0 E)-biphenyl-4,4 0 -di ylbis(diazene-2,1-diyl)bis(4-aminonaphthalene-1-sulfonate)) is a benzidine-based anionic diazo dye prepared by coupling tetrazotised benzidine with two molecules of napthionic acid. Benzidine is a toxic metabolite of congo red, and is a known human carcinogen substance [1][2][3].…”
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