Photocatalytic Activity of ZnO–SnO₂ Ceramic Nanofibers for RhB Dye Degradation: Experimental Design, Modeling, and Process Optimization

Abstract

Photocatalytic degradation of rhodamine B (RhB) dye in aqueous solution is evaluated using ZnO−SnO2 nanofibers under visible‐ and UV‐light irradiation. The ceramic nanofibers are characterized by X‐ray diffractometry (XRD) and TEM technique. The results of XRD disclose the wurtzite phase for the inorganic structures. In turn, the microscopy analysis by TEM reveals the formation of the ultrathin ceramic fibers with 500 nm in diameter. The influence of the irradiation time, temperature, and pH on the color removal efficiency is investigated. UV–vis spectral analysis is used to measure the photocatalytic activity of metal oxide composites. The optimal conditions for the efficient RhB dye degradation under visible‐light are found to be: irradiation time *t = 13.3 h; temperature *T = 42 °C, and *pH = 9.5. In these conditions, a color removal efficiency of 94.20% is observed under visible‐light irradiation. In addition, a photocatalytic test under UV‐light irradiation is performed revealing a pseudo‐first‐order rate constant of 0.0166 min−1 and a color removal efficiency of 99.35%.

ZnO–SnO2–Sn nanocomposite as photocatalyst in ultraviolet and visible light

“…By increasing the process temperature to 42 °C and pH to 9.5, the authors obtained an efficiency of 94.20% under visible light and 99.35% under UV light. Increasing the degradation time from 240 to 810 min allowed to increase the efficiency of photodegradation from 40% to over 94% (Pascariu et al 2019) (Table 5).…”

Facile Preparation of Magnetically Separable Fe3O4/ZnO Nanocomposite with Enhanced Photocatalytic Activity for Degradation of Rhodamine B

“…As an efficient photocatalyst, ZnO has also demonstrated many intriguing qualities, including chemical and physical stability, strong oxidation strength, environmental friendliness, and low price [ 21 , 22 , 23 ]. However, the utilization of ZnO was not fulfilled due to its higher bandgap of ~3.3 eV [ 24 , 25 ], resulting in ZnO only absorbing 5% of the solar energy in UV light and exhibiting low degradation activity for organic pollutants [ 1 ], which limited its practical applications [ 26 , 27 ]. To overcome this drawback and improve the catalytic efficiency, an effective strategy is to utilize metal oxide particles including metal doping, constructing heterojunctions, or nanocomposites to tune the electronic structure of the host, thereby reducing the band gap [ 8 , 10 , 11 , 28 , 29 ].…”

Photocatalytic activity of electrospun Fe‐doped ZnO nanofibers: Synthesis, characterization and applications

“…Recently, ZnO nanostructures have been extensively explored owing to their potential application in various applications 33–35 . Such as ZnO nanostructured materials are potentially candidates for detecting gas leakage and sensing, 36–40 application in photocatalytic degradation organic pollutions, 31,41,42 heavy metal polluted wastewater 43 areas due to its excellent properties 28,41,44 …”