Carbon-supported Titanium Dioxide Research Articles

Fabrication of a novel superhydrophobic cotton by HDTMS with TiO2 supported activated carbon nanocomposites for photocatalysis and oil/water separation

The strong superhydrophobic and photocatalytic cotton was fabricated by a simple one-step dip rolling technique using activated carbon supported titanium dioxide (TiO2) composite with fluoride-free hexadecyltrimethoxysilane (HDTMS) coupling agent. The experimental result shows that the contact angle of cotton fabric treated with TiO2-AC/HDTMS reaches 158°. More importantly, 0.7 g TiO2-AC provided the same superhydrophobic effect as 5 g TiO2. Moreover, the surface physical morphology and chemical composition of modified cotton fabric were observed via scanning electron microscopy (SEM), atomic force microscope(AFM), X-ray diffractometer(XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) correspondingly. The experimental results show that the micro-/nano-scale rough structure, together with the long side chain alkyl in HDTMS and the siloxane (Si-O-Si) structure generated after hydrolysis and crosslinking, endows the modified cotton fabric with superhydrophobic properties. In addition, the thermogravimetric analysis shows that the modified sample exhibited excellent thermal stability. Besides, the degradation rates of methylene blue (MB) solution was 90 % when photocatalytic performance was tested on the modified fabric under simulated sunlight, and the contact angle still reached 150°. In addition, the modified fabric showed superior oil-water separation ability, with the separation efficiency higher than 98%, separation flux is greater than 1600 Lm−2 s−1, oil absorption is more than twice its own weight and it has excellent recyclability and reusability, because of its superhydrophobic surface, TiO2-AC/HDTMS fabric also showed superior stain resistance and self-cleaning ability. At the same time, the TiO2-AC/HDTMS treated fabric remained hydrophobic in acid and alkali immersion, 25 home washes, and high strength mechanical properties tests. In short, this simple porous nano-composite material combined with non-fluorosilane coupling agent finishing technology has a broad development prospect in the industrial production of multifunctional advanced textiles.

Photocatalytic Degradation of Industrial Printing and Dyeing Wastewater with Rice Husk-Based Porous Carbon Supported Titanium Dioxide

China has become the world’s largest country in the printing and dyeing industry. It is of great practical significance to research and explore effective methods and techniques for treating printing and dyeing wastewater for protecting the water environment and promoting the sustainable development of economy, society and environment. Based on the above background, the purpose of this study is the photocatalytic degradation of industrial printing and dyeing wastewater with rice husk-based porous carbon supported titanium dioxide. In this study, nano-TiO2/AC photocatalyst was prepared by sol-gel method, and the effect and mechanism of removal of methylene blue by TiO2/AC photocatalyst were investigated. The experimental results show that the activated carbon carrier improves the photodegradation efficiency of TiO2. When TiO2 is 0.5 g/L and AC is 0.2 g/L, the photocatalyst has the best photodegradation effect on methylene blue solution; with the initial concentration of methylene blue solution As the temperature rises, the efficiency of catalyst adsorption and photocatalytic degradation decreases. The effect of the three anions on the photocatalytic efficiency is NO3 −>SO4 2->Cl−.

Granular activated carbon-supported titanium dioxide nanoparticles as an amendment for amending copper-contaminated sediments: Effect on the pH in sediments and enzymatic activities

The problem of heavy metal pollution in sediments attracts increasing attention with the process of industrialization. In this study, a novel sediments amendment granular activated carbon (GAC)-supported titanium dioxide nanoparticles (GATN) was synthesized to amend copper (Cu)-contaminated sediments. The effect of the amendments on the potential mobility and bioavailability of Cu was evaluated by the concentration of Cu in the overlying water and the chemical speciations of Cu in sediments. After 35 days of incubation, GATN and GAC were separated from the GATN-amended sediments and the GAC-amended sediments. The European Community Bureau of Reference (BCR) sequence extraction procedure was performed on the separated sediments. Compared with the control group, the addition of 20% GATN amended sediments for 35 days, the Cu concentration in the overlying water decreased by 90.75%. Compared with original sediments, the exchangeable fraction and reducible fraction of Cu decreased from 42.30% to 17.36%–3.63% and 6.57%, respectively, and the oxidizable fraction and residual fraction of Cu increased from 13.57% to 26.77%–33.21% and 56.58%, respectively. The potential mobility and bioavailability of Cu were significantly reduced. According to the BCR sequence extraction results of the remaining sediments after the separation of the GATN, the Cu adsorbed on the GATN surface is mainly an oxidizable fraction, which is generated by the complexation reaction of hydroxyl (-OH) and Cu2+. Meanwhile, the present of GATN also can enhance the remediation capacity of sediments, which plays an important role during the amendment process. The pH was measured after GATN-amended sediments adding. Results showed that GATN improved their remediation capacity of sediments by optimizing the pH in sediments. The enzyme activity-experiment indicated that GATN effectively reduces the biological toxicity of Cu in Cu-contaminated sediments. Results verified that GATN, as a sediments amendment, has good application potential.

Remediation of copper contaminated sediments by granular activated carbon-supported titanium dioxide nanoparticles: Mechanism study and effect on enzyme activities

After much effort, the remediation of heavy metal contaminated sediments still remains physically hard and technically challenging issue to resolve. In this study, granular activated carbon-supported titanium dioxide nanoparticles (GAC-TiO2 NPs) are synthesized to remedy heavy metal copper (Cu) contaminated sediments. The concentration and chemical speciation of Cu in overlying water, interstitial water and contaminated sediments are fully assessed to examine the remediation effect of GAC-TiO2 NPs. The GAC-TiO2 NPs are separated from GAC-TiO2 NPs-remedied sediments and characterized by X-ray photoelectron spectra (XPS), which reveals the mechanism of GAC-TiO2 NPs remedy Cu Contaminated sediments. The results show that after 35 days adding 20% GAC-TiO2 NPs to contaminated sediments, the Cu concentration in the overlying water and interstitial water decreases 89.47% and 83.52%, respectively, and the exchangeable fraction (F-1) of Cu in sediments decreases from 43.91% to 7.49%. The percentage of residual fraction (F-4) increases sharply from 42.79% to 80.30%. XPS results show that hydroxyl (–OH) plays an important role in the remediation process. The synergistic effects of pH, phosphorus concentration and organic matter (OM) content on the remediation effect are explored. When the pH value is 8, phosphorus concentration is 0.32 mg/L and OM content is 151.2 g/kg, adding 20% GAC-TiO2 NPs achieves the best remediation effect on Cu contaminated sediment. Biological enzyme-activity experiments prove that GAC-TiO2 NPs not only reduce the bioavailability and biotoxicity of Cu, but also effectively suppress the negative effects of granular activated carbon (GAC) on enzyme activities. All these results indicate that GAC-TiO2 NPs is an environmentally friendly remediation material for Cu contaminated sediments with high-potential applications.

In situcarbon-supported titanium dioxide (ICS-TiO2) as an electrode material for high performance supercapacitors

Supercapacitors have attracted significant attention in the last few years as they have the capability to fulfill the demand for both power and energy density in many energy storage applications. In this study, an in situ carbon-supported titanium oxide (ICS-TiO2) electrode has been prepared using sucrose and TiO2 powder. The ICS-TiO2 powder was prepared by slipcasting, followed by the annealing of the TiO2 slurry. Sucrose was added to the TiO2 slurry as a soluble carbon source, and was converted into carbon at 600 °C then coated on the TiO2 particles. The morphological and structural evolution of the electrode was investigated by FEG-SEM, FEG-TEM, XRD, BET, FTIR, XPS and Raman spectroscopy. The electrochemical characterization of ICS-TiO2 demonstrated that this material exhibits an efficient value of specific capacitance (277.72 F g−1 at 25 mV s−1) for charge storage. ISC-TiO2 also exhibits a specific capacitance of 180 F g−1 at 2 A g−1 in a 1 M Na2SO4 aqueous electrolyte. The results suggest that ICS-TiO2 can be utilized as a high-performance electrode material for supercapacitors with desirable electrochemical properties.

An efficient catalytic process for the treatment of genotoxic aniline wastewater using a new granular activated carbon-supported titanium dioxide composite

This work presents an efficient catalytic ozonation process for the treatment of aniline wastewater as a model pollutant. The process uses a granular activated carbon-supported titanium dioxide catalyst with environmentally-friendly and sustainable characteristics. Titanium dioxide composites were prepared by precipitation of alcoholic titanium tetrachloride solutions on two different carbon supports: Norit® GAC 1240 Plus and Norit® ROX 0.8. This method is an improvement on other composite preparation methods such as hydrothermal and impregnation by immersion techniques, which were also carried out for comparison. It characterised our composites by Brunauer–Emmett–Teller analysis, scanning electron microscopy-energy dispersive X-ray spectroscopy and Fourier-transform infrared spectroscopy to assess the influence of the carbon support. Composites synthesised via this novel precipitation method presented a 25% increase in their initial specific surface area and a 9.1% increase in titanium dioxide loading. It compared the catalytic activity of the different titanium dioxide composites on different aniline solutions, and studied the optimal pH and ozone dose. Norit® GAC 1240 Plus-supported titanium dioxide composite prepared by the precipitation method gave the highest removal yield with 80.24% mineralisation of total organic carbon in 45 min. With respect to the costs associated with the treatment, the composite achieved a removal yield of 26.8 mg ozone/mg total organic carbon.

Adsorption Properties of Granular Activated Carbon-Supported Titanium Dioxide Particles for Dyes and Copper Ions

In the present paper, granular activated carbon (GAC) supported titanium dioxide (TiO2@GAC) particles were prepared by sol-gel process. Their performance in simultaneous adsorption of dye and Cu2+ from wastewater was studied. X-ray diffraction (XRD) indicated that TiO2 of the TiO2@GAC microsphere is anatase type, and Fourier transform infrared spectroscopy (FT-IR) showed that the samples have obvious characteristic peaks in 400–800 cm−1, which indicated that there are Ti-O-Ti bonds. The experimental results showed that the adsorption of TiO2@GAC for Methylene blue (MB) and Cu2+ were favorable under acidity condition, the adsorption of Methyl orange (MO) was favorable under alkalecent condition. The reaction kinetics of TiO2@GAC for MO, MB and Cu2+ were well described as pseudo-second-order kinetic model; The reaction isotherms for MO, MB and Cu2+ were well fitted by Langmuir model. The maximum adsorption capacity of TiO2@GAC for MO, MB and Cu2+ in the single systems were 32.36 mg/g, 25.32 mg/g and 23.42 mg/g, respectively. As for adsorption, Cu2+ had a suppression effect on MB, and a promotion effect on MO, however, the impact of MO and MB on Cu2+ were negligible.

Carbofuran removal in continuous-photocatalytic reactor: Reactor optimization, rate-constant determination and carbofuran degradation pathway analysis

ABSTRACTCarbofuran (CBF) removal in a continuous-flow photocatalytic reactor with granular activated carbon supported titanium dioxide (GAC-TiO2) catalyst was investigated. The effects of feed flow rate, TiO2 concentration and addition of supplementary oxidants on CBF removal were investigated. The central composite design (CCD) was used to design the experiments and to estimate the effects of feed flow rate and TiO2 concentration on CBF removal. The outcome of CCD experiments demonstrated that reactor performance was influenced mainly by feed flow rate compared to TiO2 concentration. A second-order polynomial model developed based on CCD experiments fitted the experimental data with good correlation (R2 ∼ 0.964). The addition of 1 mL min−1 hydrogen peroxide has shown complete CBF degradation and 76% chemical oxygen demand removal under the following operating conditions of CBF ∼50 mg L−1, TiO2 ∼5 mg L−1 and feed flow rate ∼82.5 mL min−1. Rate constant of the photodegradation process was also calculated by applying the kinetic data in pseudo-first-order kinetics. Four major degradation intermediates of CBF were identified using GC-MS analysis. As a whole, the reactor system and GAC-TiO2 catalyst used could be constructive in cost-effective CBF removal with no impact to receiving environment through getaway of photocatalyst.

Photocatalytic degradation of poultry wastewater using activated carbon-supported titanium dioxide

Photocatalytic degradation of real-time poultry wastewater was investigated in a lab-scale batch reactor equipped with low-pressure submergible UV lamp(s). The experiments were conducted using slurry TiO2 (Slurry-TiO2) and activated carbon (AC)- supported TiO2 (granular and powdered), i.e. GAC–TiO2 and PAC–TiO2. The TiO2 coatings on the GAC and PAC surfaces were confirmed by using scanning electron microscopy coupled with energy dispersive spectroscopy.Among the systems investigated, GAC–TiO2 and PAC–TiO2 photocatalytic systems produced 100% total solids, total volatile solids and biochemical oxygen demand (BOD) removals under 14W and 56W UV irradiation within 180 min of reaction. In contrast, complete destruction of organics was not achieved in the photolytic experiments conducted with 56W UV irradiation even after 240 min of reaction. The first-order reaction kinetics was adopted to estimate and compare the rate of BOD removal in the systems. A maximum BOD removal rate constant of 0.987 min−1 and a maximum BOD removal rate of 320 mg/L/min were observed in 56W GAC–TiO2 system. The BOD removal rate observed in 14W GAC–TiO2 (227 mg/L/min) and PAC–TiO2 (247 mg/L/min) systems were comparable; however, GAC–TiO2 was recovered effectively compared to PAC–TiO2. At the same time, photocatalytically treated poultry wastewater using both GAC–TiO2 and PAC–TiO2 was found to be free from coliforms.

Adsorption and Photocatalytic Degradation of Reactive Brilliant Red K-2BP by TiO2/AC in Bubbling Fluidized Bed Photocatalytic Reactor

An activated carbon-supported titanium dioxide photocatalyst (TiO2/AC) was prepared by a spinning coating method and applied in a designed bubbling fluidized bed photocatalytic reactor (BFBPR). Ads...

Investigation into NanoTiO2/ACSPCR for Decomposition of Aqueous Hydroquinone

The suspended TiO2 powder enjoys free contact with pollutant molecule in a photocatalytic reactor; it can generally achieve better efficiency than the immobilized TiO2 catalysts. However, the separation and reuse of this catalyst powder from treated water often limit its application in practice. An adsorptive activated carbon-supported titanium dioxide photocatalyst TiO2/AC was prepared using nanosized titanium dioxide (anatase) immobilized on activated carbon powder by a novel preparation technique with polyacrylic ester emulsion. Meanwhile, the heterogeneous photocatalytic decomposition of aqueous hydroquinone over the ultraviolet irradiated TiO2/AC photocatalyst was carried out with high decomposition efficiencies in a slurry photocatalytic reactor (SPCR), which provided the effective contact of TiO2/AC photocatalyst and reactant. The pH value, the ratio of TiO2/hydroquinone, the aerating, and the concentration of H2O2 on photocatalytic decomposition of hydroquinone were discussed in detail. Experimental results showed that not only did the photocatalyst have a high adsorption performance and a good photocatalytic activity for hydroquinone but also the catalyst was easily separated from SPCR and recycled as well. Moreover, it was found that the reaction kinetic fixed the pseudo-first-order kinetic equation, which provided a detailed kinetic understanding of photocatalytic degradation of hydroquinone in SPCR.