scholarly journals Ag-TiO2 Assisted Photocatalytic Degradation of Cytostatic Drug Cyclophosphamide Under UV-VIS Light

2020 ◽  
Vol 71 (4) ◽  
pp. 347-355 ◽  
Author(s):  
Ionut Nicolae Cristea ◽  
Arcadie Sobetkii ◽  
Lucian Alexandru Constantin ◽  
Mirela Alina Constantin ◽  
Ines Nitoi

Cyclophosphamide (CP) is a commonly prescribed cytostatic drug that has cytotoxic, genotoxic, mutagenic, carcinogenic and teratogenic effects on living organisms, which asks for its elimination from any water source. The photocatalytic degradation of CP under UV-VIS irradiation was studied, using non-doped TiO2 and Ag- doped TiO2 (0.5-1.7% wt.). The catalysts were synthesized by vacuum deposition method. The influence of Ag concentration on the degradation performance of CP was investigated and an optimal content of 1.0% Ag was established. Using of this catalyst assures the pollutant degradation with a rate constant kCP = 6.59 x 10-4 s-1 and an efficiency ηCP = 99% after120 min irradiation time. Based on the results of the quenching experiments in the presence of suitable scavengers, a mechanism of photocatalytic degradation of CP has been proposed. This consists in the attack of free hydroxyl radicals and superoxide radicals on the pollutant. Also, the contribution of Ag to inhibition of charge recombination and the additional generation of superoxide radicals, which are responsible for the higher photocatalytic activity of Ag doped TiO2 compared to non-doped TiO2, was emphasised.

Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1243
Author(s):  
Sunday Joseph Olusegun ◽  
Gonzalo Larrea ◽  
Magdalena Osial ◽  
Krystyna Jackowska ◽  
Pawel Krysinski

The challenges associated with the uncontrolled presence of antibiotics such as tetracycline in the environment have necessitated their removal through different techniques. Tetracycline is hard to degrade in living organisms and can even be converted to more toxic substances. In view of this, we synthesized iron oxide nanoparticles with good magnetization (70 emu g−1) and 15 nm particle size for the adsorption and photocatalytic degradation of tetracycline. Characterization carried out on the synthesized iron oxides revealed a bandgap of 1.83 eV and an isoelectric point at pH 6.8. The results also showed that the pH of the solution does not directly influence the adsorption of tetracycline. The adsorption isotherm was consistent with the model proposed by Langmuir, having 97 mg g−1 adsorption capacity. Combined with the superparamagnetic behavior, this capacity is advantageous for the magnetic extraction of tetracycline from wastewater. The mechanisms of adsorption were proposed to be hydrogen bonding and n-π interactions. Photocatalytic degradation studies showed that approximately 40% of tetracycline degraded within 60 min of irradiation time with UV/vis light. The kinetics of photodegradation of tetracycline followed the pseudo-first-order mechanism, proceeding through hydroxyl radicals generated under illumination. Moreover, the photogenerated hydrogen peroxide could lead to heterogeneous photo-Fenton processes on the surface of iron oxide nanoparticles, additionally generating hydroxyl and hydroperoxyl radicals and facilitating photodegradation of tetracycline.


2016 ◽  
Vol 13 (1) ◽  
pp. 110-116 ◽  
Author(s):  
Rani P. Barkul ◽  
Farah-Naaz A. Shaikh ◽  
Sagar D. Delekar ◽  
Meghshyam K. Patil

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
S. Ismat Shah ◽  
Sawsan A. Mahmoud ◽  
Samar H. Bendary ◽  
Ahmed K. Aboulgheit ◽  
A. A. Salem ◽  
...  

AbstractPulsed laser deposition facilitates the epitaxial deposition and growth of TiO2 at low temperature on hot substrate. In this study, nanosized nitrogen-doped TiO2 thin films were deposited on fabricated alumina disc-shaped and glass substrates. Textural properties of the fabricated disc and alumina disc-supported TiO2 were investigated using N2 adsorption–desorption isotherms, field emission scanning electron microscopy (FESEM), X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy. FESEM showed the presence of single crystals of TiO2 on the alumina disc. FTIR showed the presence of octahedral TiO2 and different hydroxyl groups on the surface which is responsible for the photoactivity and also showed the functional groups adsorbed on the catalyst surface after the photocatalytic degradation. The concentration of 2-chlorophenol and the photo-redox intermediate products as a function of irradiation time was determined. The concentration of the produced chloride ion during the photocatalytic degradation was determined by an ion chromatography. The results showed that the photocatalytic activity of the catalyst decreased upon cycling. The obtained results were compared with nanostructured TiO2 supported on glass substrate. Higher efficiency of 100% degradation was achieved for TiO2/Al2O3 catalyst, whereas about 70% degradation of 2-CP was achieved using TiO2/glass. Different photointermediates of 2-CP degradation have been identified for each cycle. The difference of intermediates is supported by the adsorbed fragments on the catalyst surface.


Chemosphere ◽  
2007 ◽  
Vol 66 (11) ◽  
pp. 2142-2151 ◽  
Author(s):  
Wen-Chi Hung ◽  
Ssu-Han Fu ◽  
Jeou-Jen Tseng ◽  
Hsin Chu ◽  
Tzu-Hsing Ko

2011 ◽  
Vol 110-116 ◽  
pp. 3795-3800 ◽  
Author(s):  
Xiao Zhi Wang ◽  
Wei Wei Yong ◽  
Wei Qin Yin ◽  
Ke Feng ◽  
Rong Guo

Expanded perlite (EP) modified titanium dioxide (TiO2) with different loading times were prepared by Sol-Gel method. Photocatalytic degradation kinetics of Rhodamine B (RhB) in polluted water by the materials (EP-nanoTiO2), as well as the effects of different loading times and the initial concentration of RhB on photocatalysis rate were examined. The catalytic activity of the regenerated photocatalyst was also tested. The results showed that photocatalyst modified three times with TiO2had the highest catalytic activity. Degradation ratio of RhB by EP-nanoTiO2(modified three times) under irradiation for 6 h were 98.0%, 75.6% and 63.2% for 10 mg/L, 20 mg/L and 30 mg/L, respectively.The photocatalyst activity has little change after the five times recycling, and the degradation rate of RhB decreased less than 8%. The reaction of photocatalysis for RhB with irradiation time can be expressed as first-order kinetic mode within the initial concentration range of RhB between 10mg/L and 30 mg/L. EP-nanoTiO2photocatalyst has a higher activity and stability to degrade RhB in aqueous solution.


2013 ◽  
Vol 15 (10) ◽  
Author(s):  
Fabrizio Ruggieri ◽  
Daniela Di Camillo ◽  
Livia Maccarone ◽  
Sandro Santucci ◽  
Luca Lozzi

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