Abstract
Objective: This study aims to degrade the organic dyes in aqueous medium and low UV intensity by nano-rod ZnO. Methodology: The ZnO was prepared by a facile and fast method, as-synthesized ZnO was characterized by SEM,XRD, N2 adsorption/desorption isotherm, and diffuse reflectance UV-vis. The composition of samples before and after calcination steps was analyzed by XRD. The catalytic performance of ZnO was evaluated by the degradation of dyes in aqueous solution under a low UV light irradiation. Finding: the precursor was completely transformed to ZnO at 400 ◦C. The ZnO was nanorod structure with the crystalline phase of hexagonal wurtzite. The degradation efficiency of ZnO for Janus Green B in 10 min was 96.8%, it was 95.8% in 40 min for Congo Red. The reaction kinetic of photodegradation of dyes was followed by the first-order kinetic model and the photodegradation mechanism of ZnO for dyes was proposed. Application/Improvement: The facile and fast method was developed for the synthesis of nano-rod ZnO, it could be applied for practical application in wastewater treatment. Keywords: ZnO; dyes; photocatalyst; first-order kinetic; Nano-rod
Highlights
Today, the rapid development of industry leads to the release of large amounts of pollutants into the environment
It was reported that the photocatalytic ability of Zinc oxide (ZnO) was strongly depended on the morphology and surface area in which the synthesis method played an important role $(3–5) Nanosize ZnO synthesized by facile and fast method showed the highly effective degradation of tartrazine under UV light[6]
ZnO was observed as a spherical aggregation with 2-3 μm in size ( Figure 1(a) and (b)), it was assembled from many hexagonal rods, approximately width of
Summary
The rapid development of industry leads to the release of large amounts of pollutants into the environment. It was reported that the photocatalytic ability of ZnO was strongly depended on the morphology and surface area in which the synthesis method played an important role $(3–5) Nanosize ZnO synthesized by facile and fast method showed the highly effective degradation of tartrazine under UV light[6]. The degradation efficiency of acid red 57 was 90.03% within 200 min at a calcination temperature of 400 ◦C and catalyst dosage of 2.5 g/L(8). ZnO nanorods with an average length and diameter of 186 and 20 nm, respectively, prepared by hydrothermal method could degrade orange II at 10 mg/L, the catalyst dosage of 1 g/L and the degradation efficiency of 100% in 150 min[9]. RGO/ZnO/ZnFe2O4 composite prepared by a two-step method could degrade methylene blue at degradation efficiency was 100% in 60 min[12].
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