Synthesis and application of perovskite-based photocatalysts in environmental remediation: A review

Research progresses on the application of perovskite in adsorption and photocatalytic removal of water pollutants.

Adsorbents are attracting growing interest due to their potential applications in various research areas like the sorption of toxic dyes from aqueous environments. This paper describes the sorptive removal of malachite green (MG) on activated charcoal (AC) from the aqueous solutions. Various sorption parameters such as adsorption capacity, the influence of pH, equilibration time, and initial dye concentration were systematically investigated. Experimental results that the maximum uptake of the dye onto the sorbent was 27 ​mg/g and the equilibrium was reached in about 45 ​min. The MG uptake by AC is strongly favored in an acidic environment. An abrupt decrease in adsorption was seen for pH values greater than 5. Different adsorption isotherms including Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) were tested to validate the sorption data. The kinetics reveals that the adsorption of MG on AC was a second-order kinetic process. The intraparticle diffusion rate, Kid, was 1.82 ​mmol ​g−1 min−1/2. Thermodynamic studies showed that the adsorption of MC on AC was exothermic and spontaneous. In short, powder activated charcoal can be used as a potential adsorbent for the removal of various effluents particularly dyes drained into the water systems.

Sorptive removal of malachite green dye by activated charcoal: Process optimization, kinetic, and thermodynamic evaluation

The degradation of this dye has been studied by many researchers. H. Ayoub et al.6 carried out photodegradation of the dye (BTB) using TiO2 as a catalyst. In their work, L. Cao et al.7 and M. S. E. Farida et al.8 studied the adsorption of BTB on QCF (quaternized cellulose fibres) and on bentonite carbon composite, respectively. M. Ghaedi et al.9 and H.Tavakkoli et al.10 used gold nanoparticle-loaded activated carbon (Au-NP-AC) and nanoparticles of perovskite type for the elimination of BTB. Y. Zheng et al.11 studied the photocatalytic performance of MgO in the degradation of BTB. A. Ameri et al.12 carried out a photocatalytic bleaching of BTB using biogenic selenium nanoparticles.

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Adsorption of Bromothymol Blue (BTB) Dye Using Four Zeolites as Adsorbent

Nanoparticles of perovskite-type Gd0.5Y0.5CrO3 were prepared by the sol–gel method and tested for dye removal from aqueous media. The structure and morphology of Gd0.5Y0.5CrO3 nanopowders were characterised using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, the Brunauer–Emmett–Teller technique, thermal gravimetric analysis-differential thermal analysis and infrared spectroscopy. The ability of calcined nanoparticles to remove bromothymol blue (BTB) dye from aqueous solution was assessed. Adsorption experiments were carried out systematically by batch experiments to investigate the influence of different factors, such as contact time, initial concentration of dye, various adsorbent doses and pH of the solutions. The dye removal efficiency was found to be decreased with an increase in initial pH of the dye solution and Gd0.5Y0.5CrO3 nanoparticles exhibited good dye removal efficiency at acidic pH, optimized at pH 2. Kinetic adsorption data were studied using three m...

Gd0.5Y0.5CrO3 Perovskite-Type Oxide Nanopowder: A Novel Adsorbent to Remove Organic Dye from Aqueous Media:

Nanoparticles of perovskite-type Gd0.5Ca0.5CrO3 was investigated for its ability to perform as a suitable sorbent for anionic dye from aqueous solution. The nanoperovskite were characterized using X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The effects of various experimental factors; adsorbent dose, contact time, pH and dye concentration were studied by using the batch technique. Experimental results indicate that the prepared Gd0.5Ca0.5CrO3 nanopowder can remove 91.38% of BTB dye under optimum operational conditions of a dosage of 0.02 g, pH 2, contact time of 25 min and initial dye concentration of 50mg/L. Adsorption isotherms have been modeled by Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R). The Langmuir model displayed the best fit for the isothermal data. The maximum predicted adsorption capacities were 300 mg/g for Bromo Thymol Blue (BTB) dye. The results showed that the sorption kinetics of BTB removal from aqueous solutions onto nanopowder fitted well with the pseudo-secondorder model.

Zohreh Zaman

Papers

Gd0.5Y0.5CrO3 Perovskite-Type Oxide Nanopowder: A Novel Adsorbent to Remove Organic Dye from Aqueous Media:

Fabrication of perovskite-type oxide nanopowders as a novel adsorbent in removal of Bromo Thymol Blue dye from aqueous solutions