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In this study, the fabrication of ZnAl2O4/reduced graphene oxide nanocomposites is reported for the initial time. Two nanocomposites, ZnAl2O4/reduced graphene oxide‐50 and ZnAl2O4/reduced graphene oxide‐100, with different reduced graphene oxide contents (50 mg/ml and 100 mg/ml initial graphene oxide concentration respectively) were synthesized via a hydrothermal route; and characterized with the aid of suitable characterization and analytical techniques. For comparative purposes, two pure ZnAl2O4 samples were fabricated by citrate sol‐gel and urea combustion methods. The photocatalytic activity of the synthesized pure nanospinels and nanocomposites was studied for the degradation of rhodamine B dye under ultraviolet–A light irradiation. Compared to pure ZnAl2O4 nanoparticles, ZnAl2O4/reduced graphene oxide nanocomposites exhibited superior photocatalytic activity. The highest efficiency was observed for ZnAl2O4/reduced graphene oxide‐100 composite, where; full degradation of rhodamine B occurred after 45 min. The enhancements of the photocatalytic performance of ZnAl2O4/reduced graphene oxide composites were mainly attributed to unique electronic and surface properties of reduced graphene oxide. [ABSTRACT FROM AUTHOR]

ZnAl2O4 spinel was synthesized by co-precipitation using ammonia as precipitating agent, followed by thermal treatment at 750 ºC. The structural properties of particles were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), differential thermal analysis (DTA), and N2 adsorption/desorption isotherms (BET) techniques. The photocatalytic activity was evaluated in the degradation of organic pollutant in aqueous solution under sunlight. The results showed that the ZnAl2O4 particles exhibited a mesoporous structure, and a promising photocatalytic activity for the degradation of pollutant molecules.

In this study, ZnAl 2 O 4 and sulfur-doped g-C 3 N 4 (SCN) S -Scheme heterojunctions were successfully prepared by in situ self-assembly method for the efficient removal of malachite green (MG). The composite structure was formed by loading ZnAl 2 O 4 nanoscale particles onto SCN nanosheets. The results showed that the 30 wt% ZnAl 2 O 4 /SCN composite exhibited the best photocatalytic properties. The degradation of malachite green (MG) by 30 wt% ZnAl 2 O 4 /SCN composite reached 98.3% after 120 min of simulated solar illumination. Photo-induced •O 2 − was regarded as the primary active substance in the MG photodegradation. This study is expected to provide new possible strategies for the removal of contaminants MG in water. • The ZnAl 2 O 4 and SCN S -Scheme heterojunctions were successfully prepared. • The 30 wt% ZnAl 2 O 4 /SCN showed strong photocatalytic performance. • The mechanism of ZnAl 2 O 4 /SCN photodegradation was well discussed. [ABSTRACT FROM AUTHOR]

Abstract: Ternary zinc spinel oxides such as Zn2SnO4, ZnAl2O4 and ZnFe2O4 were synthesized and characterized, and their activities in the photodegradation of phenol molecules were investigated. Zn2SnO4, ZnAl2O4 and ZnFe2O4 powders were synthesized by hydrothermal, metal–chitosan complexation and solvothermal routes, respectively. The face-centered cubic spinel structure of each material was confirmed by powder X-ray diffractometry (XRD) and its porous structure by N2 adsorption–desorption isotherms. The characterization of spinels was complemented with Fourier transform infrared spectroscopy (FTIR) and X-rays fluorescence (XRF), revealing the formation of spinel structures with high purity. The photocatalytic activity in the degradation of phenol was observed only with Zn2SnO4 oxide. Mineralization degree of phenol molecules by Zn2SnO4 photocatalyst determined by total organic carbon analysis (TOC) reached 80% at 360min under sunlight. [Copyright &y& Elsevier]

Abstract: ZnAl2O4 nanocrystals were successfully synthesized by three different methods, which were co-precipitation, hydrothermal, and microwave-hydrothermal. The structural properties of the powders were investigated by X-ray diffraction (XRD) and N2 adsorption/desorption isotherms (BET) and its photocatalytic activity was comparatively evaluated in the degradation of the textile dye, Reactive Red 141, in aqueous solution under sunlight. The results indicated that the pore size of the catalyst particles strongly influence the efficiency of the photocatalytic process. The results also indicated that the sample obtained by the co-precipitation method exhibited higher photocatalytic activity due to its larger pore size. The kinetics of dye photodegradation for all the obtained samples follows a zero-order kinetic. Therefore, the ZnAl2O4 nanocrystals were able to be employed for the removal of dyes from wastewater under sunlight. [Copyright &y& Elsevier]

Abstract: Layered double hydroxides (LDH) containing zinc and aluminium within the brucite-like layers and carbonate as the interlayer anion have been used as precursors for the preparation of mixed metal oxides by calcination. Zinc oxide and the ZnAl2O4 spinel were formed with different degree of crystallinity depending of two parameters, i.e., the Zn2+/Al3+ molar ratio and the calcination temperature (500–800°C) of the LDH precursor. A pure spinel phase was obtained to remove ZnO upon a basic post-treatment in NaOH solution of the samples calcined at 800°C. All the samples were tested for the photodegradation of 2-propanol in gas–solid regime. All the samples resulted active as heterogeneous photocatalysts. The photocatalytic activity increased by increasing the Zn2+/Al3+ molar ratio and the calcination temperature of the solids. [Copyright &y& Elsevier]

• The lychee peel biomass was used as a precursor in ibuprofen degradation. • Biochar from lychee peel was used as carbonaceous support and facilitator for the free radical generation process. • Adsorption/photocatalysis to ibuprofen was examined by RSM-CCF and practical tests. • The composite showed superior photocatalytic efficiency due to the presence of functional groups present on the biochar surface. • The biochar is essential for better efficiency in composite photocatalysis. In this study, composites of biochar-ZnAl 2 O 4 produced by the pyrolysis of the lychee waste biomass were synthesized. The composites were characterized by XRD, FTIR, SEM, BET, and BJH. The biochar-ZnAl 2 O 4 composite was successfully formed and the efficiency was tested in adsorption and photocatalysis experiments. The adsorption equilibrium was obtained with a contact time of 60 min. Data on modeling and optimization of ibuprofen removal by statistical approach were fitted to quadratic equations using multiple regressions and analysis of variance (ANOVA). An RSM-CCF has been proposed for the enhanced removal of ibuprofen by adsorption followed by photocatalysis. The composite reached 100% efficiency of degradation of ibuprofen (20 mg L−1) in 120 min, under conditions of pH = 6.5, 25 °C, 1 g L−1 of composite. The ZnAl 2 O 4 supported significantly increased the composite adsorption performance and factors such as specific surface area (111.69 m2 g−1), pore volume and pore size (mesoporous region) of the biochar synergistically promoted the photocatalytic activity of ZnAl 2 O 4 , with k = 0.0093 min−1. The adsorption and photocatalytic efficiencies were confirmed to contribute to the degradation of the ibuprofen aqueous solution by the radicals •OH and O 2 -• in lower molecular weight by-products. The composite developed in this work showed that the support of ZnAl 2 O 4 in the biochar is essential to increase photoactivity, therefore, it has shown to be a promising material for adsorption and degradation of emerging pollutants such as the ibuprofen, avoiding transfer of pollution to another environmental medium. [Display omitted] [ABSTRACT FROM AUTHOR]

ZnAl 2 O 4 /CuS nanocomposite micro-flakes were prepared using a hydrothermal method. The as-prepared catalyst was investigated using X-ray diffraction, Fourier transform infrared spectra, scanning electron microscopy and UV–vis diffusive reflectance spectroscopy. X-ray diffraction analysis revealed the presence of CuS phase as a major phase (70%) in the prepared catalyst. The results indicated that the combination of ZnAl 2 O 4 with CuS ameliorate potentially its photocatalytic efficiency during the degradation of acid red 1 (95% within 150 min) under ultraviolet illumination compared to ZnAl 2 O 4 or CuS alone. The effect of catalyst mass, dye concentration and pH solution were investigated using ZnAl 2 O 4 /CuS. On the other hand, the reuse tests of ZnAl 2 O 4 /CuS displayed high-performance stability after five cycles. Additionally, the activity of hydroxyl radicals (OH. ) and superoxide ions (O 2 ·-) as the spices responsible for AR1 dye degradation was confirmed by the free radicals scavenging tests. [Display omitted] • Synthesis and characterization of the nanocomposite ZnAl 2 O 4 /CuS. • Effect of the addition of CuS on photocatalysis degradation of acid red 1. • Effect of the specific surface area, crystallite size, phase percentage on the efficiency of the photocatalyst. • High degradation efficiency of acid red 1 was achieved using ZnAl 2 O 4 /CuS than ZnAl 2 O 4 or CuS alone. • The photo-degradation of Acid Red 1 using ZnAl 2 O 4 /CuS is dominant by the OH. and O 2 -. radicals. [ABSTRACT FROM AUTHOR]