Removal of contaminants of concern in water using advanced oxidation techniques

2007 ◽  
Vol 55 (12) ◽  
pp. 301-306 ◽  
Author(s):  
H.M. Coleman ◽  
V. Vimonses ◽  
G. Leslie ◽  
R. Amal
Keyword(s):  
Titanium Dioxide ◽  
Solar Radiation ◽  
Sol Gel ◽  
Advanced Oxidation ◽  
Commercial Catalyst ◽  
Titanium Dioxide Photocatalysis ◽  
Uva Light ◽  
Degussa P25 ◽  
Removal Of Contaminants ◽  
Uva Radiation

This research involves the removal of contaminants of concern in water supplies using advanced oxidation technologies, in particular titanium dioxide photocatalysis. Photocatalysis for the removal of 1,4-dioxane and the natural (17β-oestradiol, oestriol) and synthetic (17α-ethynyloestradiol) oestrogens in water was investigated using both UVA and solar radiation. The H2O2/UVC process, solar, UVC and UVA light alone were also investigated and the processes compared. It was found that TiO2 photocatalysis is an effective method for the degradation of the natural (17β-oestradiol and oestriol) and the synthetic (17α-ethynyloestradiol) oestrogens in water in immobilised Degussa P25 and sol-gel spiral reactors with both UVA and solar radiation as the light source. Photocatalysis using the commercial catalyst Degussa P25 as an immobilised reactor with a UVA lamp shows the best performance. Photocatalysis was shown to completely mineralise 1,4-dioxane to CO2 in Degussa P25 suspension and sol-gel reactors using both UVA and solar radiation. The commercial catalyst Degussa P25 in suspension with UVA radiation shows the best performance. Photocatalysis is much more efficient than H2O2/UVC, UVA, UVC and solar radiation alone for all contaminants investigated.

Effect of the calcination temperature on the photocatalytic efficiency of acidic sol–gel synthesized TiO2nanoparticles in the degradation of alprazolam

2017 ◽  
Vol 16 (6) ◽  
pp. 935-945 ◽  
Author(s):  
Andreia Romeiro ◽  
Diana Freitas ◽  
M. Emília Azenha ◽  
Moisés Canle ◽  
Hugh D. Burrows
Keyword(s):  
Aqueous Solution ◽  
Titanium Dioxide ◽  
Calcination Temperature ◽  
Sol Gel ◽  
Psychoactive Drug ◽  
Photocatalytic Efficiency ◽  
Titanium Dioxide Photocatalysis

The benzodiazepine psychoactive drug alprazolam is efficiently photodegraded and mineralized in aqueous solution using titanium dioxide photocatalysis.

scholarly journals TiO2-assisted photodegradation of pharmaceuticals — a review

2012 ◽  
Vol 10 (4) ◽  
pp. 989-1027 ◽  
Author(s):  
Alfred Tong ◽  
Rhiannon Braund ◽  
David Warren ◽  
Barrie Peake
Keyword(s):  
Titanium Dioxide ◽  
Advanced Oxidation Process ◽  
Treatment Time ◽  
Sewage Treatment ◽  
Advanced Oxidation ◽  
Careful Consideration ◽  
Experimental Conditions ◽  
Wastewater Treatment Process ◽  
Titanium Dioxide Photocatalysis ◽  
Degradation Rates

AbstractPharmaceutical compounds have been detected in the environment and potentially arise from the discharge of excreted and improperly disposed medication from sewage treatment facilities. In order to minimize environmental exposure of pharmaceutical residues, a potential technique to remove pharmaceuticals from water is the use of an advanced oxidation process (AOP) involving titanium dioxide (TiO2) photocatalysis. To evaluate the extent UV/TiO2 processes have been studied for pharmaceutical degradation, a literature search using the keywords ‘titanium dioxide’, ‘photocatalysis’, ‘advanced oxidation processes’, ‘pharmaceuticals’ and ‘degradation’ were used in the ISI Web of Knowledge TM, Scopus TM and ScienceDirect TM databases up to and including articles published on 23 November 2011. The degradation rates of pharmaceuticals under UV/TiO2 treatment were dependent on type and amount of TiO2 loading, pharmaceutical concentration, the presence of electron acceptors and pH. Complete mineralization under particular experimental conditions were reported for some pharmaceuticals; however, some experiments reported evolution of toxic intermediates during the photocatalytic process. It is concluded that the UV/TiO2 system is potentially a feasible wastewater treatment process, but careful consideration of the treatment time, the loading and the type of TiO2 (doped vs. undoped) used for a particular pharmaceutical is necessary for a successful application (198 words).

Preparation and properties of a long time durable superhydrophilic titanium dioxide film obtained by a sol-gel process

2017 ◽  
Vol 59 (1) ◽  
pp. 81-85
Author(s):  
Jianjun Zhang ◽  
Hao Zeng ◽  
Chun Liu ◽  
Chao Li ◽  
Sude Ma ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Sol Gel ◽  
Titanium Dioxide Film ◽  
Sol Gel Process ◽  
Long Time ◽  
Dioxide Film

scholarly journals Effect of Titanium Dioxide Nanoparticles on the Expression of Efflux Pump and Quorum-Sensing Genes in MDR Pseudomonas aeruginosa Isolates

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 625
Author(s):  
Fatma Y. Ahmed ◽  
Usama Farghaly Aly ◽  
Rehab Mahmoud Abd El-Baky ◽  
Nancy G. F. M. Waly
Keyword(s):  
Titanium Dioxide ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Titanium Dioxide Nanoparticles ◽  
Sol Gel ◽  
Efflux Pumps ◽  
Antibiofilm Activity ◽  
The Impact

Most of the infections caused by multi-drug resistant (MDR) P. aeruginosa strains are extremely difficult to be treated with conventional antibiotics. Biofilm formation and efflux pumps are recognized as the major antibiotic resistance mechanisms in MDR P. aeruginosa. Biofilm formation by P. aeruginosa depends mainly on the cell-to-cell communication quorum-sensing (QS) systems. Titanium dioxide nanoparticles (TDN) have been used as antimicrobial agents against several microorganisms but have not been reported as an anti-QS agent. This study aims to evaluate the impact of titanium dioxide nanoparticles (TDN) on QS and efflux pump genes expression in MDR P. aeruginosa isolates. The antimicrobial susceptibility of 25 P. aeruginosa isolates were performed by Kirby–Bauer disc diffusion. Titanium dioxide nanoparticles (TDN) were prepared by the sol gel method and characterized by different techniques (DLS, HR-TEM, XRD, and FTIR). The expression of efflux pumps in the MDR isolates was detected by the determination of MICs of different antibiotics in the presence and absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP). Biofilm formation and the antibiofilm activity of TDN were determined using the tissue culture plate method. The effects of TDN on the expression of QS genes and efflux pump genes were tested using real-time polymerase chain reaction (RT-PCR). The average size of the TDNs was 64.77 nm. It was found that TDN showed a significant reduction in biofilm formation (96%) and represented superior antibacterial activity against P. aeruginosa strains in comparison to titanium dioxide powder. In addition, the use of TDN alone or in combination with antibiotics resulted in significant downregulation of the efflux pump genes (MexY, MexB, MexA) and QS-regulated genes (lasR, lasI, rhll, rhlR, pqsA, pqsR) in comparison to the untreated isolate. TDN can increase the therapeutic efficacy of traditional antibiotics by affecting efflux pump expression and quorum-sensing genes controlling biofilm production.

scholarly journals Suitability of Different Titanium Dioxide Nanotube Morphologies for Photocatalytic Water Treatment

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 708
Author(s):  
Clayton Farrugia ◽  
Alessandro Di Mauro ◽  
Frederick Lia ◽  
Edwin Zammit ◽  
Alex Rizzo ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Titanium Dioxide ◽  
Water Treatment ◽  
Environmental Remediation ◽  
Survival Rates ◽  
Bacterial Survival ◽  
Nanotubular Structure ◽  
Excellent Activity ◽  
Uva Light ◽  
High Degree

Photocatalysis has long been touted as one of the most promising technologies for environmental remediation. The ability of photocatalysts to degrade a host of different pollutants, especially recalcitrant molecules, is certainly appealing. Titanium dioxide (TiO2) has been used extensively for this purpose. Anodic oxidation allows for the synthesis of a highly ordered nanotubular structure with a high degree of tunability. In this study, a series of TiO2 arrays were synthesised using different electrolytes and different potentials. Mixed anatase-rutile photocatalysts with excellent wettability were achieved with all the experimental iterations. Under UVA light, all the materials showed significant photoactivity towards different organic pollutants. The nanotubes synthesised in the ethylene glycol-based electrolyte exhibited the best performance, with near complete degradation of all the pollutants. The antibacterial activity of this same material was similarly high, with extremely low bacterial survival rates. Increasing the voltage resulted in wider and longer nanotubes, characteristics which increase the level of photocatalytic activity. The ease of synthesis coupled with the excellent activity makes this a viable material that can be used in flat-plate reactors and that is suitable for photocatalytic water treatment.

scholarly journals Photocatalytic Activity Enhancement of Low-pressure Cold-Sprayed TiO2 Coatings Induced by Long-term Water Vapor Exposure

2021 ◽  
Author(s):  
Seremak Wioletta ◽  
Baszczuk Agnieszka ◽  
Jasiorski Marek ◽  
Gibas Anna ◽  
Winnicki Marcin
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Water Vapor ◽  
Sol Gel ◽  
Low Pressure ◽  
Oxygen Depletion ◽  
Amorphous Structure ◽  
Industrial Applications ◽  
Additional Parameter

AbstractThis work shows that the titanium dioxide coatings obtained by low-pressure cold gas spraying with the use of the sol–gel amorphous TiO2 powder are characterized by photocatalytic activity despite their partial amorphous content. Moreover, the research outcome suggests that the decomposition rate of organic pollutants is enhanced after long-term exposure to moisture. The condensation humidity test is not detrimental to the continuity and integrity of the coating, but the phase composition of coatings changes—with the exposure to water vapor, the portion of the amorphous phase crystallizes into brookite. The mechanism responsible for the conversion of amorphous TiO2 into brookite is attributed to the water-driven dissolution and reprecipitation of TiO6 octahedra. It has been shown that an additional parameter necessary for the stabilization of the brookite is the oxygen depletion of the amorphous structure of titanium dioxide. Considering the results presented in this paper and the advantages of a portable, low-pressure cold spray system for industrial applications, it is expected that TiO2 coatings produced from a sol–gel feedstock powder can be further developed and tested as efficient photocatalysts.

ChemInform Abstract: Titanium Dioxide Tubes from Sol-Gel Coating of Electrospun Polymer Fibers.

ChemInform ◽  
2010 ◽  
Vol 32 (51) ◽  
pp. no-no
Author(s):  
Rachel A. Caruso ◽  
Jan H. Schattka ◽  
Andreas Greiner
Keyword(s):  
Titanium Dioxide ◽  
Sol Gel ◽  
Polymer Fibers

Synthesis of Cu Loaded TiO2 Nanoparticles for the Improved Photocatalytic Degradation of Rhodamine B

2016 ◽  
Vol 15 (05n06) ◽  
pp. 1660002 ◽  
Author(s):  
V. Kavitha ◽  
P. S. Ramesh ◽  
D. Geetha
Keyword(s):  
Titanium Dioxide ◽  
Rhodamine B ◽  
Sol Gel ◽  
Average Particle Size ◽  
Visible Spectrum ◽  
Xrd Analysis ◽  
Bandgap Energy ◽  
Average Particle ◽  
Titanium Tetraisopropoxide ◽  
Photoexcited Electron

Copper doped Titanium dioxide TiO2 nanoparticles were synthesized by sol–gel method using titanium tetraisopropoxide and copper sulfate as precursors. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), UV-Visible spectroscopy (UV-Vis), Photoluminesce spectroscopy (PL) and atomic force microscopy (AFM). XRD analysis confirms the formation of anatase titanium dioxide and average particle size was 35[Formula: see text]nm. Cu– TiO2 exhibits a shift in the absorption edge toward visible spectrum. The rate of recombination and transfer behavior of the photoexcited electron–hole pairs in the semiconductors was recorded by photoluminescence. From SEM spherical shaped nanoparticles was observed. Comparing with pure TiO2 nanoparticles, Cu doped TiO2 photocatalyst exhibited enhanced photocatalytic activity under natural sunlight irradiation in the decomposition of rhodamine B aqueous solution. The maximum 97% of degradation efficiency of Rhodamine B was observed at 0.6% Cu–TiO2 within 180[Formula: see text]min. The photocatalytic efficiency of Rhodamine B of Cu doped TiO2 nanoparticle was higher than the pure TiO2, which could be attributed to the small crystallinity intense light absorption in Sunlight and narrow bandgap energy of Copper.

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