Ecofriendly Green Synthesis of the ZnO-Doped CuO@Alg Bionanocomposite for Efficient Oxidative Degradation of p-Nitrophenol

Abstract

In the present study, ecofriendly green synthesized ZnO/CuO nanorods were prepared by using the stabilizing and reducing characteristics of the alginate biopolymer. The bionanocomposite (BNC) material was characterized by various sophisticated analytical tools such as Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy− energy dispersive X-ray spectroscopy, transmission electron microscopy, UV−visible spectroscopy, differential scanning calorimetry, and the Brunauer−Emmett−Teller (BET) method. The composition of ZnO/CuO@Alg BNC was found to be C (16.16 ± 0.42%), O (42.26 ± 1.87%), Cu (31.96 ± 1.05%), and Zn (9.62 ± 0.48%), which also supports the approximate 3:1 ratio of Cu 2+ and Zn 2+ taken as the precursor. The nanocrystalline spinel ferrite was found to have a BET specific surface area of 19.24 m 2 g −1 with a total pore volume of 0.075 cm 3 g −1 and 1.45 eV as the band gap energy (E g ). Further, the material was applied for the photodegradation of p-nitrophenol (PNP) under the advanced oxidative process (AOP) under visible sunlight irradiation. The visible light radiation was used for the degradation of PNP under pH 2 conditions and resulted in 98.38% of the photocatalytic efficiency of the ZnO/CuO@Alg catalyst within 137 min of irradiation time. The photocatalytic reaction was best defined by the pseudo-first-order kinetics which involves the adsorption of the PNP molecule on the surface of the catalyst, thereby demineralizing it in the presence of advanced active • OH radicals. The values of rate constant for the pseudo-first-order model (k 1 ) were calculated as 0.013, 0.016, 0.019, 0.021, and 0.023 min −1 with half-life periods of 53.31, 43.31, 36.47, 33.00, and 30.13 min for 10−50 mg L −1 PNP concentrations. The presence of t-butyl alcohol decreases the photocatalytic efficiency, which suggests that the degradation of PNP was accomplished by the • OH oxidative radical.

Biodegradable Alginate Films with ZnO Nanoparticles and Citronella Essential Oil—A Novel Antimicrobial Structure

“…In the presence of ZnO the new interactions between –OH moieties and nanoparticles’ surface, induce small shifts in the peak position [ 87 ]. Such shifts were previously reported for alginate–ZnO interactions [ 88 ].…”

“…In the presence of ZnO the new interactions between -OH moieties and nanoparticles' surface, induce small shifts in the peak position [87]. Such shifts were previously reported for alginate-ZnO interactions [88]. The peak from 2921 cm −1 , attributed to C-H symmetric vibration, remains largely unchanged.…”

TiO2 Photocatalysis for the Transformation of Aromatic Water Pollutants into Fuels

“…Nowadays, the photooxidation of organic pollutants based on TiO 2 nanomaterials is still gain huge attention. Several recent studies have shown the effective role of TiO 2 in oxidizing and mineralizing a wide range of hazardous organic contaminants [118,119], such as alcohol [120,121], organic acids [122], aromatic hydrocarbons [104], phenols [123], dyes [124], pharmaceuticals [125,126], and pesticides [126]. The photocatalytic oxidation of organic pollutants proceeds either by the direct attack of the photogenerated holes or via the attack of the highly reactive hydroxyl radicals generated at the surface of the photocatalyst [110].…”

Fabrication of a zinc oxide/alginate (ZnO/Alg) bionanocomposite for enhanced dye degradation and its optimization study

“…The degradation was achieved in 137 min, followed pseudo rst-order kinetics for which cOH oxidative radicals were responsible for achieving the target with 98.32% efficiency. 40 Therefore, this research focuses on two main objectives. The rst is to synthesize ZnO nanostructures with different loading of alginate polymer and study its texture, structure, and optical properties.…”

“…The degradation was achieved in 137 min, followed pseudo first-order kinetics for which ˙OH oxidative radicals were responsible for achieving the target with 98.32% efficiency. 40 …”