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Query: KEGG:D01931 (TiO2)
 11,320 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A metallic condensing cone that concentrates microwave radiation (equivalent to an optical lens) has been developed and used as part of a system to activate a microwave discharge electrodeless lamp (MDEL) in the oxidative treatment of wastewaters by aiding the novel self-ignition of the lamp on irradiation at low microwave power levels. This approach to self-ignition can potentially lead to considerable energy savings in such treatments. System performance was examined for the ignition power of microwaves of such MDEL devices in water, whose usefulness was assessed by investigating the photolytic transformation of aqueous solutions of representatives of three classes of contaminants: chlorinated phenols, herbicides and endocrine disruptors, specifically 4-chlorophenol (4-CP), 2,4-dichlorophenoxyacetic acid (2,4-D) and 4,4'-isopropylidenediphenol (bisphenol-A; BPA), respectively, taken as model wastewaters in air-equilibrated, in oxygen-saturated and in TiO2-containing aqueous media. The results are discussed in terms of the dynamics of the photo-induced degradation processes.
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PMID:Microwave discharge electrodeless lamps (MDEL). Part IV. Novel self-ignition system incorporating metallic microwave condensing cones to activate MDELs in photochemical reactions. 1986 22

This paper describes the fabrication of two different 3D mesoporous TiO2 microspheres via one-step solvothermal process without templates using different titanium sources. The resulting materials were characterized by XRD, FESEM, TEM, and nitrogen adsorption techniques. Their photodegradation of bisphenol A [2,2-bis(4-hydroxyphenyl)propane, BPA] in aqueous suspension was investigated under UV irradiation. The experimental results revealed that the photocatalytic effect of the two 3D mesoporous TiO2 microspheres was superior to the commercial P25 TiO2, and as-prepared samples as catalysts demonstrated that the smaller pore size it is, the higher the effective degradation for BPA is. Particular attention was paid to the identification of intermediates and analysis of photocatalytic degradation mechanism of BPA by HPLC-MS and HPLC-MS-MS. Five main intermediates were formed during photocatalytic degradation, and their evolution was discussed. On the basis of the evidence of oxidative intermediate formation, a detailed degradation pathway of BPA degradation by two mesoporous TiO2 microspheres photocatalysts are proposed.
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PMID:Directed synthesis of mesoporous TiO2 microspheres: catalysts and their photocatalysis for bisphenol A degradation. 1992 97

The removal of micropollutant in wastewater treatment has become a key environmental challenge for many industrialized countries. One approach is to use enzymes such as laccase for the degradation of micropollutants such as bisphenol-A. In this work, laccase was covalently immobilized on APTES modified TiO2 nanoparticles, and the effects of particle modification on the bio-catalytic performance were examined and optimized. These bio-catalytic particles were then suspended in a hybrid membrane reactor for BPA removal with good BPA degradation efficiency observed. Substantial improvement in laccase stability was achieved in the hybrid system compared with free laccase under simulated harsh industrial wastewater treatment conditions (such as a wide range of pH and presence of inhibitors). Kinetic study provided insight of the effect of immobilization on the bio-degradation reaction.
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PMID:Hybrid membrane with TiO2 based bio-catalytic nanoparticle suspension system for the degradation of bisphenol-A. 2508 46

Seeking an efficient treatment method for bisphenol A ( BPA), a representative endocrine disrupting compound, is important for environmental remediation and human health. Herein, the degradation of BPA by means of photoelectrocatalysis was investigated. Fe doped-TiO2 nanotube arrays ( Fe/TNA ) served as the photoanode, and a xenon lamp simulated the solar light source. First, undoped TiO2 nanotube arrays (TNA) and a series of Fe/TNA were characterized by field emission scanning electron microscopy, X-ray diffraction and UV-Vis diffuse reflectance spectroscopy. The UV-Vis absorption spectra of Fe/TNA showed a red-shift and an enhancement of the absorption in the visible-light region compared to TNA. Then, experimental conditions including Fe doping content, current intensity and aeration rate were varied to demonstrate their effects on the elimination of BPA. It was observed that the degradation of BPA could be fitted to the quasi-first-order equation. Under the following conditions: Fe/TNA prepared by 0.9 mol x L(-1) Fe(NO3)3 solution dip-coating as photoanode, titanium foil as cathode, current intensity of 1.15 mA x cm(-2) and initial BPA concentration of 10 mg x L(-1), 72.3% BPA was decomposed during 4 h reaction, with a rate constant of 5.32 x 10(-3) min(-1). Aeration enhanced the removal rate of BPA to 82.7% and 94.1% with an aerating rate of 1.0 L x min(-1) using titanium foil as cathode and an aerating rate of 0.2 L x min(-1) using carbon cloth as cathode, respectively, and the corresponding rate constants were 7.20 x 10(-3) min(-1) and 11.6 x 10(-3) min(-1), respectively.
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PMID:[Photoelectrocatalytic degradation of bisphenol A in water by Fe doped-TiO2 nanotube arrays under simulated solar light irradiation]. 2603 Oct 84

Experiments were carried out, the aim of which was to determine the leaching rates for bisphenol A (4,4'-(propane-2,2-diyl)diphenol - BPA), 4-tert-octylphenol (OP), 4-nonylphenol (NP) from polycarbonate and recycled tyre granules into the seawater. Additionally biodegradation, sorption on marine suspended particulate matter and sorption on various types of nano-TiO2 of BPA, OP, NP were studied. Experiments were carried out on plastics at various stages of degradation. The conducted experiment confirmed the flux of BPA, OP and NP from the studied plastics into seawater. The initial photodegradation of the plastic had a significant influence on the amount of the studied components released into water. During the first days of the experiment leaching was weaker from aged materials. After 60 days leaching of BPA and OP was higher for aged plastic compared to unaged. On average, suspension adsorbed OP, BPA and NP from seawater at respective levels of 37%, 75% and 100%. On the other hand, during biodegradation on average 25%, 9% and 2% of OP, BPA and NP respectively are removed from water. Nano-TiO2 of 21 nm pore size diameter adsorbed all the compounds more strongly than nano-TiO2 of 15 nm pores sized coated with Al and stearic acid. The strongest sorption (100%) on different types of nano-TiO2 was that of the most hydrophobic and more linear structured NP with just one phenol group. The weakest sorption was observed in the case of BPA, which is the least hydrophobic, and characterized by higher compared to NP and OP steric hindrance and electrostatic repulsion.
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PMID:The fate of bisphenol A, 4-tert-octylphenol and 4-nonylphenol leached from plastic debris into marine water--experimental studies on biodegradation and sorption on suspended particulate matter and nano-TiO2. 2670 57