Photocatalytic degradation of azo dye using core@shell nano-TiO2 particles to reduce toxicity

Abstract

Clean and safe water is fundamental for human and environmental health. Traditional remediation of textile dye-polluted water with chemical, physical, and biological processes has many disadvantages. Due to this, nano-engineered materials are drawing more attention to this area. However, the widespread use of nano-particles for this purpose may lead to photocatalytic degradation of xenobiotics, while increasing the risk of nano-particle-induced ecotoxicity. Therefore, we comparatively evaluated the toxicity of novel synthesized core@shell TiO and SiO nano-particles to embryonic stages of Danio rerio and Xenopus laevis. The ability of photocatalytic destruction of the synthesized nano-particles was tested using toxic azo dye, disperse red 65, and the effects of reducing the toxicity were evaluated. The reflux process was used to synthesize catalysts in the study. The samples were characterized by scanning electron microscopy, X-ray fluorescence spectroscopy, X-ray diffractometry, BET surface area, and UV-vis-diffuse reflectance spectra. It was determined that the synthesized nano-particles had no significant toxic effect on D. rerio and X. laevis embryos. On the other hand, photocatalytic degradation of the dye significantly reduced lethal effects on embryonic stages of the organisms. Therefore, we suggest that specific nano-particles may be useful for water remediation to prevent human health and environmental impact. However, further risk assessment should be conducted for the ecotoxicological risks of nano-particles spilled in aquatic environments and the relationship of photocatalytic interaction with nano-particles and xenobiotics.

Fabrication, functionalization and performance of doped photocatalysts for dye degradation and mineralization: a review

“…This is because each study is 'unique' in itself with respect to the scale of the assessment, the dye tested, the photocatalytic dye degradation conditions, the extents of degradation of the dye and degree of mineralization reached, the test subject(s) used to assess the toxicity levels and the specific architecture and chemical composition of the photocatalytic materials used (de Sousa Filho et al 2020;Serrà et al 2020). For example, recently, Ozmen et al (2018) reported several interesting findings when studying the photodegradation of disperse red 65 using core@shell nano-TiO 2 particles. Amongst the complete set of observations made in Ozmen et al (2018), the highlights comprised the following: (1) even at the maximum test concentration of core@shell NPs of 250 mg L −1 , there was little mortality in comparison with the control groups in Danio rerio and Xenopus laevis embryos, (2) the lower concentrations of NPs had not caused lethality to the embryos of the D. rerio and X. laevis species, (3) the prepared core@shell NPs had not brought about developmental abnormalities in the embryos, (4) however, an exposure to the photocatalytic degradation products of disperse red 65 obtained after 1 h of photodegradation led to 100% mortality in both test species after a 96-h exposure, (5) a photocatalytic degradation reaction lasting 2 h could partially lessen the lethal effect for X. laevis embryos, (6) 3 h of photocatalytic degradation of disperse red 65 had not led to mortality in the X. laevis embryos, viand in the case of D. rerio embryos, a 3-h photocatalytic degradation of disperse red 65 using the synthesized TiO 2 and SiO 2 @ TiO 2 catalysts had eliminated the lethal effects of disperse red 65 on the zebrafish embryos.…”

“…For example, recently, Ozmen et al (2018) reported several interesting findings when studying the photodegradation of disperse red 65 using core@shell nano-TiO 2 particles. Amongst the complete set of observations made in Ozmen et al (2018), the highlights comprised the following: (1) even at the maximum test concentration of core@shell NPs of 250 mg L −1 , there was little mortality in comparison with the control groups in Danio rerio and Xenopus laevis embryos, (2) the lower concentrations of NPs had not caused lethality to the embryos of the D. rerio and X. laevis species, (3) the prepared core@shell NPs had not brought about developmental abnormalities in the embryos, (4) however, an exposure to the photocatalytic degradation products of disperse red 65 obtained after 1 h of photodegradation led to 100% mortality in both test species after a 96-h exposure, (5) a photocatalytic degradation reaction lasting 2 h could partially lessen the lethal effect for X. laevis embryos, (6) 3 h of photocatalytic degradation of disperse red 65 had not led to mortality in the X. laevis embryos, viand in the case of D. rerio embryos, a 3-h photocatalytic degradation of disperse red 65 using the synthesized TiO 2 and SiO 2 @ TiO 2 catalysts had eliminated the lethal effects of disperse red 65 on the zebrafish embryos. Serrà et al (2020) recently reported a significant enhancement in algal viability when using supported ZnO@ZnS core@shell micro/nanoferns after noting that the corresponding ecotoxicity after a 96-h light exposure was considerably lower in comparison with the ZnO films, ZnO NPs, ZnO micro/nanoferns or ZnO@ ZnS NPs at concentrations ranging from 25 to 400 mg L −1 .…”

Progress in Hybridization of Covalent Organic Frameworks and Metal–Organic Frameworks

“…[178][179][180][181][182][183][184] Many chemical industry dyes were especially toxic and were known to increase the risk of illness. [185][186][187][188][189][190][191][192] Adsorption has been considered to be a green method in removing these pollutants due to the high efficiency, easy operation, and low cost. [193][194][195][196][197] COFs and MOFs as well-known porous materials have been applied in the field of pollutant adsorption.…”

Visible-Light-Driven AO7 Photocatalytic Degradation and Toxicity Removal at Bi-Doped SrTiO3

“…Photocatalysis is a promising, clean process that can be applied in the degradation of persistent organic pollutants, such as organic dyes [ 1 , 2 , 3 , 4 , 5 , 6 ]. This process initiates with the irradiation of a suitable catalyst’s surface with a type of radiation, i.e., UV, visible, or solar, with energy equal to or higher than the bang gap energy (E g ) value.…”