Effect of polar and movable (OH or NH2 groups) on the photocatalytic H2 production of alkyl-alkanolamine: a comparative study

Hussein B. Hydrothermal Preparation of Silver Doping Zinc Oxide Nanoparticles: Studys, Characterization and Photocatalytic Activity

In this study , we report the prepared of ZnO nanoparticles and Ag doped ZnO nanostructure via a hydrothermal process. The obtained nanostructures were characterized using different characterization techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) , atomic force microscopy (AFM) ,Fourier transform infrared spectrometry (FTIR)and UV/Visible spectrophotometer.The XRD results showed the wurtzite hexagonal structure of the ZnO Nanoparticles. Furthermore, the morphology of ZnO and Ag-ZnO nanostructures was obtained from SEM and AFM. The photocatalytic degradation of Cibacron Brilliant Yellow 3G-P (CB) dye was studied in presence of visible light using Ag-ZnO nanostructures as a photocatalyst. There are numerous factors which has an effect on the efficiency color removal of this process. Hence a study was conducted on the effect of several parameters on Ag-ZnO like amount of catalyst, CB dye concentration and pH of solution. Results showed Ag doping ZnO with 3% loading shows photocatalytic removal about 65% after 120 min which influenced superior photocatalytic activity than pure ZnO.

The effect of titanium dioxide nanoparticles and UV irradiation on photocatalytic degradation of Imidaclopride

Imidaclopride is an insecticide widely used for pest control in agriculture around the world. It acts on the central nervous system of insects, while posing lower toxicity to mammals. This is an organic material made of Pyridinium, Dihydroimidazol and Nitramide. This structure poses a threat to the environment and humans. Until now, different types of methods have been used for elimination of this organic pollution. Recently, advanced oxidation processes (AOPs) are presented as a proposed method to remove this organic pollution. Photocatalytic degradation is also used as an efficient method for destruction of organic structures. In this study, the effect of titanium dioxide (TiO₂) nanoparticle as a photocatalyst activated by UV irradiation is investigated. The new design of the reactor was prepared with coaxial cylinders in which the inner cylinder is rotated at a constant speed. The reactor worked in two batch and continuous modes. The results show that the UV irradiation is more effective than activated TiO₂ nanoparticle, as the designed reactor with UV irradiation eliminated Imidaclopride in less than 2 hours.

Sonochemical/hydration-dehydration synthesis of Pt-TiO2 NPs/decorated carbon nanotubes with enhanced photocatalytic hydrogen production activity

Modified Pt-TiO₂ NPs/decorated carbon nanotubes were synthesized utilizing sonochemical/hydration-dehydration techniques. Pt was loaded on TiO₂ by a photodeposition method keeping in mind the end goal to achieve electron-hole pair separation and promote the surface reaction. The morphological and basic properties of Pt-TiO₂/fCNTs were investigated by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), powder X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and Raman spectroscopy. The selected area electron diffraction (SAED) patterns of Pt-TiO₂/fCNTs were obtained utilizing TEM-based energy dispersive X-ray spectroscopy (EDXS) analysis. It was found that the TiO₂ nanoparticles were uniformly distributed on the fCNTs, and the Pt particles were decorated on the surface of TiO₂/fCNTs. The photocatalytic hydrogen production activity of the Pt_(0.5%)-TiO₂/fCNTs_(0.5%) nanoparticle composites was investigated using a sacrificial agent methanol solution. Pt-loaded TiO₂ demonstrated a hydrogen evolution rate around 20 times that of TiO₂/fCNTs_(0.5%) (fSWCNTs, fMWCNTs). When compared with platinized TiO₂ in methanol, which was utilized as a control material, Pt-TiO₂/fCNTs demonstrated an almost 2-fold increment in hydrogen generation.

Synthesis, characterization, and photocatalytic activity of sonochemical/hydration-dehydration prepared ZnO rod-like architecture nano/microstructures assisted by a biotemplate

ZnO nanoparticles of rod-like architecture have excellent potential to be used in wastewater treatment as a photocatalyst. They were synthesized by utilizing sonochemical/hydration- dehydration techniques using glutamine as a biotemplate. The effects of calcination temperatures, that is, 300°C, 500°C, and 700°C, on the crystallinity, optical properties, and photocatalytic activity of synthesized zinc oxide nanoparticles were investigated. X-ray diffraction (XRD) results indicated that all calcinated samples have a crystalline hexagonal wurtzite structure. Morphology and elemental compositions were investigated using field emission-scanning electron microscopy with energy-dispersive X-ray spectroscopy. The XRD and Fourier transform infrared (FTIR) spectra revealed that the samples were amorphous at 100°C; however, it changed into a crystalline structure amid the calcination process. Optical properties were determined using a UV-visible reflection spectrophotometer and showed abatement in the band gap with increasing annealing temperature. The progress of the photocatalytic degradation was monitored by a UV-visible spectrophotometer, while the mineralization ability was estimated by total organic carbon tests of ZnO-calcinated samples. The effect of various operational parameters the photocatalytic efficiency and rate of dye degradation was studied. High photocatalytic degradation of maxilon blue dye (GRL) was found at pH 6.3.

Aqueous photocatalytic degradation of selected micropollutants by Pd-modified titanium dioxide in three photoreactor types

The goals of the present study were to synthesise highly efficient Pd-TiO₂ photocatalyst, to characterise its performance in slurry in smaller scale and to investigate its performance in the aqueous photocatalytic oxidation of three antibiotics: doxycycline, sulphamethizole and amoxicillin. The performance of the photocatalyst was evaluated in an open batch slurry reactor equipped with a fluorescent long-wavelength ultraviolet (UVA) lamp (0.2 L). With the fastest degrading doxycycline, experimental research was continued in a fixed-bed continuous flow photoreactor (0.13 L), with the Pd-TiO₂ photocatalyst attached to a glass plate, and a medium laboratory-scale three-phase fluidised-bed reactor (2 L) equipped with four fluorescent UVA lamps, with the photocatalyst attached to the surface of expanded clay granules employed as the bed material. While showing very high activity in the batch slurry reactor, far surpassing P25 Aeroxide, the performance of Pd-TiO₂ with doxycycline was comparable to P25 in the semi-continuous reactors.

Photocatalytic hydrogen production from biomass-derived compounds: a case study of citric acid

Highly crystalline anatase TiO2 nanoparticles with high BET surface area have been synthesized by thermal hydrolysis of titanium(IV) bis(ammoniumlactato) dihydroxide aqueous solutions. The photocatalytic H2 production from aqueous citric acid (CA) solutions over Pt-loaded TiO2 has been investigated under different experimental conditions, that is, different CA concentration, temperature, light intensity, and pH of Pt/TiO2 suspension. For comparison, the photocatalytic dehydrogenation of triethanolamine (TEA) has also been investigated. The highest H2 production rates were obtained at pH 3 and 9 for CA and TEA, respectively. This behavior is readily explained by the adsorption characteristic of the employed reagent on the surface of the charged TiO2. The effect of the photocatalyst loading and the light intensity on the H2 production rate showed the same behavior in the case of CA and TEA evincing that these parameters are catalyst dependent. The apparent activation energies have been determined to be 13.5 ± 1.8 and 14.7 ± 1.6 kJ mol(-1) for CA and TEA, respectively, indicating the existence of an activation energy barrier in a photocatalytic process which can be attributed to the desorption of adsorbed products.