Synthesis and Photocatalytic Activity of TiO2 on Phenol Degradation

Photocatalysis is a process of accelerating reactions that are assisted by energy from light irradiation. Titanium dioxide (TiO2) is one of the most widely developed photocatalysis materials, and is used because of its high catalytic activity, stability and very affordable. The most commonly used precursors of TiO2 are titanium butoxide (TBOT) and titanium tetraisopropoxide (TTIP). These variations in precursor can lead to phase difference in the formation of TiO2 crystals, which further improves its nature in the activity of photocatalysis. In this study, the sol-gel method was used to synthesize titanium dioxide nanoparticles from variations of TBOT and TTIP. Furthermore, the structure, crystallite size and band gap of TiO2 were determined by X-ray diffraction (XRD) and UV-vis reflectance spectroscopy (DRS). Subsequently, TiO2 photocatalytic activity was evaluated in phenol photodegradation as a contaminant model with UV irradiation. The results showed the structure synthesized from TBOT had a higher amount of anatase, higher crystallinity, smaller crystallite size, larger band gap, and better photocatalytic activity than those from TTIP. Furthermore, it was shown that TiO2 from TBOT had an efficiency of 147% greater than TiO2 P25 Degussa, while TiO2 from TTIP had 66% efficiency compared to TiO2 P25.

Photodegradation of Aquaculture Antibiotics Using Carbon Dots-TiO2 Nanocomposites

In this work, carbon dots (CD) were synthesized and coupled to titanium dioxide (TiO2) to improve the photodegradation of antibiotics in aquaculture effluents under solar irradiation. Oxolinic acid (OXA) and sulfadiazine (SDZ), which are widely used in aquaculture, were used as target antibiotics. To prepare nanocomposites of CD containing TiO2, two modes were used: in-situ (CD@TiO2) and ex-situ (CD/TiO2). For CD synthesis, citric acid and glycerol were used, while for TiO2 synthesis, titanium butoxide was the precursor. In ultrapure water (UW), CD@TiO2 and CD/TiO2 showed the largest photocatalytic effect for SDZ and OXA, respectively. Compared with their absence, the presence of CD@TiO2 increased the photodegradation of SDZ from 23 to 97% (after 4 h irradiation), whereas CD/TiO2 increased the OXA photodegradation from 22 to 59% (after 1 h irradiation). Meanwhile, in synthetic sea salts (SSS, 30‰, simulating marine aquaculture effluents), CD@TiO2 allowed for the reduction of SDZ’s half-life time (t1/2) from 14.5 ± 0.7 h (in absence of photocatalyst) to 0.38 ± 0.04 h. Concerning OXA in SSS, the t1/2 remained the same either in the absence of a photocatalyst or in the presence of CD/TiO2 (3.5 ± 0.3 h and 3.9 ± 0.4 h, respectively). Overall, this study provided novel perspectives on the use of eco-friendly CD-TiO2 nanocomposites for the removal of antibiotics from aquaculture effluents using solar radiation.

How the Ti Precursor is Involved in the Effectiveness of Pt-TiO2 Materials in Photodegrading Methyl Orange

As other studies have demonstrated, improving the effectiveness of TiO2 for environmental remediation requires that the properties of this oxide be modified using different synthesis methods. In the current study, labprepared TiO2 was synthesized using the hydrothermal method and two different Ti precursors (titanium butoxide and titanium isopropoxide). After the synthesis, the obtained titania was also modified using photodeposition by platinum nanoparticles. This study aims to evaluate the effectiveness of the photocatalytic materials prepared in photodegrading methyl orange. The Ti precursors used in the TiO2 synthesis had a slight effect on the physicochemical properties of the oxide obtained. When titanium butoxide was used as a precursor, we observed a change in the bandgap value and some material with the largest surface area. Additionally, the addition of Pt increased the absorption of TiO2 in the visible region of the electromagnetic spectrum and slightly decreased the bandgap value of this oxide. The photocatalyst prepared using titanium isopropoxide as a precursor showed the most remarkable effectiveness in the degradation rate of methyl orange. This is the result of the lower band gap value of this material which leads to easier transport of the photogenerated charges during the photocatalytic reaction. We also observed that the addition of Pt has a detrimental effect on the effectiveness of TiO2 in dye degradation, which may be due to possible obstruction of the dye-photocatalyst interaction on the TiO2 surface because of the Pt nanoparticles observed by tem. The effectiveness of commercial TiO2 in methyl orange degradation is slightly higher than that observed in other evaluated solids.

Effectiveness of Esterification Catalysts in the Synthesis of Poly(Ethylene Vanillate)

Over the last few decades, bio-based polymers have attracted considerable attention from both academic and industrial fields regarding the minimization of the environmental impact arising from the excessive use of petrochemically-based polymeric materials. In this context, poly(ethylene vanillate) (PEV), an alipharomatic polyester prepared from 4-(2-hydroxyethoxy)-3-methoxybenzoic acid, a monomer originating from lignin-derived vanillic acid, has shown promising thermal and mechanical properties. Herein, the effects of three different catalysts, namely titanium butoxide (TBT), titanium isopropoxide (TIS), and antimony trioxide (Sb2O3), on the synthesis of PEV via a two-stage melt polycondensation method are investigated. The progress of the reaction is assessed using various complementary techniques, such as intrinsic viscosity measurement (IV), end group analysis (AV), nuclear magnetic resonance spectroscopy (NMR), Fourier-transformed infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The thermal stability of the produced polyesters is studied by evolved gas analysis mass spectrometry (EGA-MS). Moreover, as the discoloration in polymers affects their applications, color measurement is performed here. Finally, theoretical kinetic studies are carried out to rationalize the experimental observations.

Preliminary Study on Effect of Hydrothermal Temperature during TiO2 Synthesis on the Biodiesel Production from Waste Cooking Oil

In the present work, effect of hydrothermal temperature from 120 to 160 °C on TiO2 physicochemical properties as well as its photocatalytic activity towards biodiesel production using waste cooking oil (WCO) was investigated. TiO2was synthesized via hydrothermal method using Titanium butoxide, Ti(OBu)4 as the precursor and nitric acid, HNO3 as the peptizing agent. Next, the synthesized photocatalyst was dried at 60 °C for 24 h and later calcined at 400 °Cfor 2 h. The synthesized TiO2 was characterized using X-ray diffraction (XRD) and Burnauer- Emmet- Teller (BET) to determine their crystallinity and textural properties. Results showed that all synthesized TiO2 have a mixture of anatase and rutile phase and N2 adsorption- desorption isotherm for all catalyst possess Type IV isotherm according to IUPACclassification with hysteresis loop of type H1. Then, all the synthesized catalysts were tested for biodiesel production using esterified waste cooking oil under visible light irradiation for 1 h and 10 min. Percentage of fatty acid methyl ester (FAMEs) present in the synthesized biodiesel was determined using gas chromatography with flame ionization detector (GC-FID). The synthesized catalyst (T24_160) showed a good photocatalytic activity as the percentage of biodiesel yield was higher (3.41%) compared to the other catalyst.

The Effect of Titanium Tetra-Butoxide Catalyst on the Olefin Polymerization

The purpose of this study was to assess the ability of titanium Ti(IV) alkyloxy compounds supported by organic polymer polyvinyl chloride (PVC) to polymerize ethylene by feeding triethylaluminium (TEA) as a cocatalyst. Additionally, the impacts of the molar ratio of [Al]/[Ti] on the catalytic activities in ethylene’s polymerization and of the comonomer through utilization of diverse quantities of comonomers on a similar or identical activity were studied. The optimal molar ratio of [Al]/[Ti] was 773:1, and the prepared catalyst had an initial activity of up to 2.3 kg PE/mol Ti. h. when the copolymer was incorporated with 64 mmol of 1-octene. The average molecular weight (Mw) of the copolymer produced with the catalysts was between 97 kg/mol and 326 kg/mol. A significant decrease in the Mw was observed, and PDI broadened with increasing concentration of 1-hexene because of the comonomer’s stronger chain transfer capacity. The quick deactivation of titanium butoxide Ti(OBu)4 on the polymers was found to be associated with increasing oxidation when supported by the catalyst. The presence of Ti (III) after reduction with the aluminum alkyls cleaves the carbon-chlorine bonds of the polymer, producing an inactive polymeric Ti(IV) complex. The results show that synergistic effects play an important role in enhancing the observed rate of reaction, as illustrated by evidence from scanning electron microscopy (SEM). The diffusion of cocatalysts within catalytic precursor particles may also explain the progression of cobweb structures in the polymer particles.

Effect of titanium source and sol-gel TiO2 thin film formation parameters on its morphology and photocatalytic activity

TiO2 thin films with different surface structure have been prepared from alkoxide solutions by the sol-gel method using different cationic precursors and heat treatment techniques. The effect of using titanium isopropoxide as well as titanium butoxide as a titanium source on the surface structure and photocatalytic activity of the resultant thin films was studied. Significant differences in the rate of hydrolysis and condensation reactions during the sol-gel synthesis were observed for these titanium precursors. This had a direct influence on the morphology of the as-prepared TiO2 films. Higher quality oxide coatings were obtained from titanium isopropoxide. They were characterized by a smaller grain size, improved surface roughness and uniform coverage of the glass substrate. A beneficial effect of calcination process after each sol application cycle in contrast to single step calcination after all dip-coating cycles was observed. Photocatalytic degradation tests showed that methyl orange was decolorized in the presence of all prepared TiO2 films by exposing their aqueous solutions to UV light (λ = 254 nm). The highest photocatalytic activity had the TiO2 layer produced using titanium isopropoxide.

Removal of the antimicrobial activity from fortified effluents with fluoroquinolones by photocatalytic processes: a comparative study of differently synthesized TiO2-N

This study presents a comparison of three methods for TiO2-N synthesis that were applied in the photocatalytic oxidation of the fluoroquinolones (FQs) ciprofloxacin, ofloxacin, and lomefloxacin in aqueous solution. The TiO2-N bandgap is small enough to allow the use of solar energy in the photocatalytic oxidation (PCO) reactions. The TiO2 doped by a sol-gel method with titanium butoxide (TiO2–N–BUT) and titanium isopropoxide (TiO2–N–PROP) as the precursor were effective as the TiO2 (P25) impregnation with urea (TiO2-N-P25) to degrade the FQs. The FQ degradation was higher by 74, 65, and 91%, respectively for TiO2–N–BUT, TiO2–N–PROP, and TiO2-N (load 50 mg L−1, 20 min of reaction under 28 W UV-ASolar). The TiO2-P25 with urea showed the best performance in FQ degradation. The reaction intermediates might present modifications in their acceptor groups by PCO and, because of that the antimicrobial activity dropped as the reaction time increased. Reactions with TiO2-N-P25 (100 mg L−1) and TiO2-N-BUT (100 mg L−1) achieved ≥ 80% of antimicrobial activity removal from the mixed FQ solution (Cciprofloxacin = 100 μg L−1; Cofloxacin = 100 μg L−1; Clomefloxacin = 100 μg L−1) after 40 min of reaction, for both for Escherichia coli and Bacillus subtilis.