scholarly journals Nano-TiO2 Phototoxicity in Fresh and Seawater: Daphnia magna and Artemia sp. as Proxies

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 55
Author(s):  
Ana C. Soler de la Vega ◽  
Alberto Cruz-Alcalde ◽  
Carmen Sans Mazón ◽  
Carlos Barata Martí ◽  
M. Silvia Diaz-Cruz
Keyword(s):  
Daphnia Magna ◽  
Uv Radiation ◽  
Engineered Nanoparticles ◽  
Indicator Organisms ◽  
Nano Tio2 ◽  
Micron Size ◽  
Reactive Halogen Species ◽  
Negative Impacts ◽  
Different Characteristics ◽  
Halogen Species

Nowadays, the industry is quite commonly using nanoparticles of titanium dioxide (nTiO2) especially in sunscreens, due to its higher reflective index in comparison to micron size TiO2. Its high demand causes its widespread environmental occurrence, thus damaging the environment. The aquatic ecosystems are the most vulnerable to contamination by nTiO2. Like other engineered nanoparticles, nTiO2 has demonstrated generation of reactive oxygen species (ROS) and reactive halogen species (RHS) in the aquatic environment under UV radiation. This study investigated the toxicity of nTiO2 towards two aquatic indicator organisms, one from freshwater (Daphnia magna) and the other from seawater (Artemia sp.), under simulated solar radiation (SSR). Daphnia magna and Artemia sp. were co-exposed in 16 h SSR and 8 h darkness cycles to different concentrations of nTiO2. The estimated EC50 at 48 h for D. magna was 3.16 mg nTiO2/L, whereas for A. sp. no toxic effects were observed. When we exposed these two organisms simultaneously to 48 h of prolonged SSR using higher nTiO2 concentrations, EC50 values of 7.60 mg/L and 5.59 mg/L nTiO2 for D. magna and A. sp., respectively, were obtained. A complementary bioassay was carried out with A. sp., by exposing this organism to a mixture of nTiO2 and organic UV filters (benzophenone 3 (oxybenzone, BP3), octocrylene (OC), and ethyl 4-aminobenzoate (EtPABA)), and then exposed to SSR. The results suggested that nTiO2 could potentially have negative impacts on these organisms, also this work outlines the different characteristics and interactions that may contribute to the mechanisms of environmental (in salted and freshwater) phototoxicity of nTiO2 and UV radiation, besides their interaction with organic compounds.

Optimization of the Preparation Process of Nano-TiO2/Micro-Cu Composite Particles

2010 ◽  
Vol 105-106 ◽  
pp. 492-494 ◽  
Author(s):  
Bin Wang ◽  
Hai Ping Cui ◽  
Jun Yan ◽  
Shi Guo Du
Keyword(s):  
Particle Morphology ◽  
Oxide Semiconductor ◽  
Photon Absorption ◽  
Composite Particles ◽  
Preparation Process ◽  
Nano Tio2 ◽  
Surface Design ◽  
Acidic Aqueous Solution ◽  
Micron Size ◽  
Hydrolysis Of

Nano-TiO2/micro-Cu composite particles were prepared by hydrolysis of Ti(OBu)4 in abundant acidic aqueous solution and subsequent reflux in the presence of micron size Cu powders. The preparation process was optimized using response surface design with the degradation of TiO2/Cu particles to Methyl orange as target. The particle morphology and composition were characterized by FE-SEM, XPS and XRD. The photon absorption properties of composite particles was investigated by the UV-VIS DRS experiments, and the results show the photoabsorption property of composite particles is intermediate between TiO2 particles and Cu powders, showing cooperative effect by the combination of oxide semiconductor particles with metal substrate.

scholarly journals Chemical interactions between ship-originated air pollutants and ocean-emitted halogens

2021 ◽  
Author(s):  
Qinyi Li ◽  
Alba Badia ◽  
Rafael P. Fernandez ◽  
Anoop S. Mahajan ◽  
Ana Isabel López-Noreña ◽  
...  
Keyword(s):  
Air Pollutants ◽  
Atmospheric Composition ◽  
Chemical Transformations ◽  
Chemical Interactions ◽  
China Sea ◽  
Reactive Halogen Species ◽  
The Impact ◽  
Surface Increase ◽  
Halogen Species

<p>Ocean-going ships supply products from one region to another and contribute to the world’s economy. Ship exhaust contains many air pollutants and results in significant changes in marine atmospheric composition. The role of Reactive Halogen Species (RHS) in the troposphere has received increasing recognition and oceans are the largest contributors to their atmospheric burden. However, the impact of shipping emissions on RHS and that of RHS on ship-originated air pollutants have not been studied in detail. Here, an updated WRF-Chem model is utilized to explore the chemical interactions between ship emissions and oceanic RHS over the East Asia seas in summer. The emissions and resulting chemical transformations from shipping activities increase the level of NO and NO<sub>2</sub> at the surface, increase O<sub>3</sub> in the South China Sea, but decrease O<sub>3</sub> in the East China Sea. Such changes in pollutants result in remarkable changes in the levels of RHS as well as in their partitioning. The abundant RHS, in turn, reshape the loadings of air pollutants and those of the oxidants with marked patterns along the ship tracks. We, therefore, suggest that these important chemical interactions of ship-originated emissions with RHS should be considered in the environmental policy assessments of the role of shipping emissions in air quality and climate.</p>

Insights into the uptake, distribution, and efflux of arsenite associated with nano-TiO2 in determining its toxicity on Daphnia magna

2020 ◽  
Vol 7 (4) ◽  
pp. 1194-1204
Author(s):  
Zhuanxi Luo ◽  
Zhenhong Wang ◽  
Baoshan Xing
Keyword(s):  
Daphnia Magna ◽  
Trojan Horse ◽  
Nano Tio2

This study provides new insights into the “Trojan horse” effects of nano-TiO2 on arsenite (As(iii)) bioaccumulation in Daphnia magna.

Two-generational effects and recovery of arsenic and arsenate on Daphnia magna in the presence of nano-TiO2

2019 ◽  
Vol 172 ◽  
pp. 136-143 ◽  
Author(s):  
Wenhong Fan ◽  
Dingyuan Liang ◽  
Xiangrui Wang ◽  
JinQian Ren ◽  
Shengtao Xiao ◽  
...  
Keyword(s):  
Daphnia Magna ◽  
Nano Tio2 ◽  
Generational Effects

scholarly journals Waterproof Aerated Bricks from Stone Powder Waste through Nano-TiO2 Structured Hydrophobic Surface Modification

2019 ◽  
Vol 9 (13) ◽  
pp. 2619 ◽  
Author(s):  
Tao Li ◽  
Shaopeng Zeng ◽  
Yaxiong Ji ◽  
Boxu Shen ◽  
Zhuangmiao Wang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Large Scale ◽  
Aqueous Suspension ◽  
Hydrophobic Surface ◽  
Great Promise ◽  
Mold Growth ◽  
Nano Tio2 ◽  
Hydrothermal Reactions ◽  
Negative Impacts ◽  
Water Proofing

To eliminate the negative impacts of waste stone powder that arises from stone processing, the waste was recycled into aerated bricks with a porous structure that exhibited exceptional properties when applied in buildings. However, the pores easily absorb rainwater and dust, causing performance degradation and mold growth inside. In this paper, we have developed through hydrothermal reactions an environmentally friendly aqueous suspension, containing homemade highly dispersive TiO2 nanoparticles modified with super-hydrophobic groups on the surface. The suspension was coated onto the aerated bricks, creating a super-hydrophobic surface with a highly textured hierarchical structure. A large contact angle of 146° tested on the surface and negligible water absorption for 24 h immersion demonstrate the excellent water proofing performance, holding a great promise for large scale applications in construction and buildings.

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