Effect of the agglomeration of TiO2 nanoparticles on their photocatalytic performance in the aqueous phase

Li, Gang; Lv, Lu; Fan, Huiqing; Ma, Junyan; Li, Yanqiang; Wan, Yong; Xin, Zhao

doi:10.1016/j.jcis.2010.04.045

Cited by 142 publications

(62 citation statements)

References 26 publications

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“…Recent efforts to enhance the photocatalytic activity of NTO include the synthesis of mesoporous TiO 2 [62][63][64][65][66][67][68][69][70][71][72], the use of different TiO 2 morphologies (nanowires, nanotubes, and nanospheres) [73][74][75][76], reducing the agglomeration in NTO powders [77][78][79], and surface treatments of NTO [80][81][82][83]. Synthesis of mesoporous NTO is a means to achieve TiO 2 photocatalysts with improved photocatalytic activities.…”

Section: Activity Enhancementmentioning

confidence: 99%

“…The agglomeration of TiO 2 can be minimized by changing the pH of the reaction mixture [78], adsorbing polyallylamine hydrochloride on the TiO 2 surface [78], adopting a flame hydrolysis synthesis route [79], or ball milling of the TiO 2 powder [77]. All attempts were successful in reducing the agglomeration of NTO in aqueous suspensions, but the photocatalytic activities were found to depend not only on agglomeration but also on several other factors.…”

Section: Activity Enhancementmentioning

confidence: 99%

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Photocatalytic Water Treatment by Titanium Dioxide: Recent Updates

Varghese²,

2012

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Photocatalytic water treatment using nanocrystalline titanium dioxide (NTO) is a well-known advanced oxidation process (AOP) for environmental remediation. With the in situ generation of electron-hole pairs upon irradiation with light, NTO can mineralize a wide range of organic compounds into harmless end products such as carbon dioxide, water, and inorganic ions. Photocatalytic degradation kinetics of pollutants by NTO is a topic of debate and the mostly reporting Langmuir-Hinshelwood kinetics must accompanied with proper experimental evidences. Different NTO morphologies or surface treatments on NTO can increase the photocatalytic efficiency in degradation reactions. Wisely designed photocatalytic reactors can decrease energy consumption or can avoid post-separation stages in photocatalytic water treatment processes. Doping NTO with metals or non-metals can reduce the band gap of the doped catalyst, enabling light absorption in the visible region. Coupling NTO photocatalysis with other water-treatment technologies can be more beneficial, especially in large-scale treatments. This review describes recent developments in the field of photocatalytic water treatment using NTO.

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Section: Activity Enhancementmentioning

confidence: 99%

Section: Activity Enhancementmentioning

confidence: 99%

Photocatalytic Water Treatment by Titanium Dioxide: Recent Updates

Varghese²,

2012

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“…Promotion of the photocatalytic activity of TiO 2 including the synthesis of mesoporous TiO 2 (Joo et al 2012;Nakata and Fujishima 2012), the use of various TiO 2 morphologies (nanowires, nanotubes, and nanospheres; Sun et al 2012), reduction of the agglomeration in TiO 2 powders (Li et al 2010;Farbod and Khademalrasool 2011) and surface treatments of TiO 2 (Monllor-Satoca et al 2011). Various TiO 2 morphologies or surface treatments on TiO 2 can be increased the photocatalytic degradation efficiency.…”

Section: Influence Of Water Matrix On Tc Degradationmentioning

confidence: 99%

Photocatalytic degradation of tetracycline using nanosized titanium dioxide in aqueous solution

Safari

Hoseini

Seyedsalehi

et al. 2014

Int. J. Environ. Sci. Technol.

238

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The aim of the study was to investigate the degradation kinetics of tetracycline antibiotic by nanosized titanium dioxide under ultraviolet irradiation. Enhancement of photocatalysis by addition of Hydrogen peroxide was also evaluated. Various experimental parameters such as initial tetracycline concentrations, initial titanium dioxide concentration, initial pH, reaction times, initial Hydrogen peroxide concentrations, as well as water matrix using ultrapure water, drinking water and secondary effluent were investigated. The initial rate of photocatalytic degradation of tetracycline well fitted the Langmuir-Hinshelwood kinetic model (R 2 = 0.9926) with a reaction rate constant of 1.4 mg/L min. The degradation rate depended on initial tetracycline concentration and initial pH. The degradation rate also increased with higher titanium dioxide density and reached a plateau at titanium dioxide concentration of 1.0 g/L. The tetracycline degradation rate was higher in drinking water compared to ultrapure water. The addition of Hydrogen peroxide to titanium dioxide suspension significantly enhanced the tetracycline degradation rate and substantially reduced the time required to degrade 100 % of tetracycline. Changes of chemical oxygen demand values during photolysis indicated that tetracycline transformed into intermediate products without complete mineralization. The ultraviolet visible spectra obtained before and after ultraviolet irradiation in the presence of titanium dioxide can indicate the formation of 4a,12a-anhydro-4-oxo-4-dimethylaminotetracycline.

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“…To the best of our knowledge, no information regarding the pKa constants of TP1/TP2 is available, thus not allowing any direct conclusion regarding the role of electro-static attraction between TiO2 particles and TP1/TP2 molecules. For that reason, all the matrices were acidified (5.5) prior to photocatalytic treatment to take advantage of the positive effect of increased catalyst surface when smaller TiO2 particle size is favoured under pH values lower than the Point of Zero Charge of Degussa P25 (pHPZC = 6.7 (Malato et al, 2009)), as recommended by Li et al (2010).…”

Section: Tio2/uv Photocatalysis Step Performancementioning

confidence: 99%

Solar photocatalytic oxidation of recalcitrant natural metabolic by-products of amoxicillin biodegradation

et al. 2014

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The contamination of the aquatic environment by non-metabolized and metabolized antibiotic residues has brought the necessity of alternative treatment steps to current water decontamination technologies. This work assessed the feasibility of using a multistage treatment system for amoxicillin (AMX) spiked solutions combining: i) a biological treatment process using an enriched culture to metabolize AMX, with ii) a solar photocatalytic system to achieve the removal of the metabolized transformation products (TPs) identified via LC-MS, recalcitrant to further biological degradation. Firstly, a mixed culture (MC) was obtained through the enrichment of an activated sludge sample collected in an urban wastewater treatment plant (WWTP). Secondly, different aqueous matrices spiked with AMX were treated with the MC and the metabolic transformation products were identified. Thirdly, the efficiency of two solar assisted photocatalytic processes (TiO2/UV or Fe 3+ /Oxalate/H2O2/UV-Vis) was assessed in the degradation of the obtained TPs using a lab-scale prototype photoreactor equipped with a compound parabolic collector (CPC). Highest AMX specific biodegradation rates were obtained in buffer and urban wastewater (WW) media (0.10 ± 0.01 and 0.13 ± 0.07 gAMX gbiomass -1 h -1 , respectively). The resulting TPs, which no longer presented antibacterial activity, were identified as amoxicilloic acid (m/ z = 384). The performance of the Fe /Oxalate/H2O2/UV-Vis system in the 2 removal of the TPs from WW medium was superior to the TiO2/UV process (TPs no longer detected after 40 min (QUV = 2.6 kJ L -1 ), against incomplete TPs removal after 240 min (QUV = 14.9 kJ L -1 ), respectively).

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Effect of the agglomeration of TiO2 nanoparticles on their photocatalytic performance in the aqueous phase

Cited by 142 publications

References 26 publications

Photocatalytic Water Treatment by Titanium Dioxide: Recent Updates

Photocatalytic Water Treatment by Titanium Dioxide: Recent Updates

Photocatalytic degradation of tetracycline using nanosized titanium dioxide in aqueous solution

Solar photocatalytic oxidation of recalcitrant natural metabolic by-products of amoxicillin biodegradation

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