Comparison between Solar and Artificial Photocatalytic Decolorization of Textile Industrial Wastewater

The photocatalytic decolorization of industrial wastewater was investigated by using TiO2 and ZnO photocatalysts. Heterogeneous photocatalytic processes applied under natural weathering conditions, in the presence of solar radiation show a promising degradation capability. The complete removal of color could be achieved in a relatively short time of about 20 minutes, when ZnO was used and about 100 minutes when TiO2 was used under solar irradiation. However, in the presence of artificial UV-light, complete decolorization of textile industrial wastewater was obtained after less than one hour of irradiation when ZnO was used and in less than two hours, when TiO2 was used at the same temperature. The results indicate that the degree of photocatalytic decolorization of textile industrial wastewater was obviously affected by different parameters. These parameters include catalyst mass, type of catalyst, type of reactor, type of dye, dye concentration, and temperature. The procedure used in this research can be used as an efficient technology for solar photocatalytic decolorization of the colored wastewater discharged from the textile industry under the climatic conditions of most countries

Photocatalytic dehydrogenation of liquid alcohols by platinized anatase and other catalysts

The work described in this thesis was undertaken at the University of Nottingham between October 1981 and November 1984, under the supervision of Dr. R. Rudham. Except where indicated by reference, it is the original work of the author and has not been submitted for any other degree. The photocatalytic dehydrogenation of liquid alcohols (methanol, ethanol, propan-1-ol and propan-2-ol) by suspensions of platinum and other metals supported on anatase have been investigated by following carbonyl compound formation under a nitrogen atmosphere. Measurements were made over the temperature range 278-303 K using filtered 366 nm U.V. radiation. Reaction on photodeposited catalysts was consistently associated with an activation energy of 20 + 1 kJ mol-1 , although the activity fell in the sequence: PT/TiO2 > Pd/TiO2 > Rh/TiO2 > Au/TiO2 – O for catalysts with a metal content of 0.5 wt%. The activation energy is identical to that for photoreaction on the anatase support in the presence of oxygen and is believed to be associated with the transport of photoelectrons through the anatase to either metal particles or adsorbed oxygen. Activities and activation energies for carbonyl compound formation from the photocatalytic dehydrogenation of the individual alcohols were effectively identical on the same catalyst, indicating that the photocatalytic dehydrogenation reaction is not governed by the physical or chemical properties of the reactant alcohol. With platinized anatase prepared by hydrogen reduction there was an appreciable dark reaction, which was absent with catalysts prepared by photodeposition. It is believed that reduction in hydrogen at elevated temperature renders the anatase support non-stoichiometric, a process favoured by spillover of hydrogen atoms from the platinum particles. The low activation energy for photocatalysis on hydrogen reduced catalyst is considered to be associated with the non-stoichiometric nature of the anatase, which presumably provides an energetically favourable mechanism for photoelectron transport to the metal particles and negates the photoelectron traps responsible for an activation energy of 20 ± 1 kJ mol-1 on the non-reduced catalysts. A radical mechanism for photocatalytic dehydrogenation is proposed. This mechanism predicts a l1m1 ting quantum yield of one half, which is in good agreement with the value obtained from experiments at different light intensities

Photocatalytic dehydrogenation of liquid alcohols by platinized anatase and other catalysts

The work described in this thesis was undertaken at the University of Nottingham between October 1981 and November 1984, under the supervision of Dr. R. Rudham. Except where indicated by reference, it is the original work of the author and has not been submitted for any other degree. The photocatalytic dehydrogenation of liquid alcohols (methanol, ethanol, propan-1-ol and propan-2-ol) by suspensions of platinum and other metals supported on anatase have been investigated by following carbonyl compound formation under a nitrogen atmosphere. Measurements were made over the temperature range 278-303 K using filtered 366 nm U.V. radiation. Reaction on photodeposited catalysts was consistently associated with an activation energy of 20 + 1 kJ mol-1 , although the activity fell in the sequence: PT/TiO2 > Pd/TiO2 > Rh/TiO2 > Au/TiO2 – O for catalysts with a metal content of 0.5 wt%. The activation energy is identical to that for photoreaction on the anatase support in the presence of oxygen and is believed to be associated with the transport of photoelectrons through the anatase to either metal particles or adsorbed oxygen. Activities and activation energies for carbonyl compound formation from the photocatalytic dehydrogenation of the individual alcohols were effectively identical on the same catalyst, indicating that the photocatalytic dehydrogenation reaction is not governed by the physical or chemical properties of the reactant alcohol. With platinized anatase prepared by hydrogen reduction there was an appreciable dark reaction, which was absent with catalysts prepared by photodeposition. It is believed that reduction in hydrogen at elevated temperature renders the anatase support non-stoichiometric, a process favoured by spillover of hydrogen atoms from the platinum particles. The low activation energy for photocatalysis on hydrogen reduced catalyst is considered to be associated with the non-stoichiometric nature of the anatase, which presumably provides an energetically favourable mechanism for photoelectron transport to the metal particles and negates the photoelectron traps responsible for an activation energy of 20 ± 1 kJ mol-1 on the non-reduced catalysts. A radical mechanism for photocatalytic dehydrogenation is proposed. This mechanism predicts a l1m1 ting quantum yield of one half, which is in good agreement with the value obtained from experiments at different light intensities

Preparation, Characterization, and Photocatalytic Applications of MWCNTs/TiO2 Composite

The multiwall carbon nanotubes (MWCNTs)/titanium dioxide (P25) composite in different ratios was prepared using simple evaporation and drying process. The composite was characterized by Raman spectroscopy, X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy, and scanning electron microscopy (SEM). The photocatalytic activity of this composite was investigated using degradation of the Bismarck brown R dye (BBR). An optimal MWCNTs/TiO2 ratio of 0.5% (w/w) was found to achieve the maximum rate of BBR degradation. It was observed that the composite exhibits enhanced photocatalytic activity compared with TiO2. The enhancement in photocatalytic activity performance of the MWCNTs/P25 composite is explained in terms of recombination of photogenerated electron-hole pairs. In addition, MWCNTs act as a dispersing support to control the morphology of TiO2 particles in the MWCNTs/TiO2 composite

Effect of chemical and physical properties of river water in Shatt AlHilla on phytoplankton communities.

Abstract: This paper aims to study the chemical and physical properties in the ecological system of Shatt Al-Hilla in Babylon Governorate in Iraq and its effect on phytoplankton population. In this context, several limnological parameters were evaluated during the period from December 2003 through November 2004 from four sampling stations sited along Shatt Al-Hilla. The physical parameters included: temperature, turbidity and electrical conductivity. The chemical parameters included: pH, alkalinity dissolved oxygen, total hardness and the concentrations of nitrite, nitrate, phosphate and sulphate. A total of 154 species were recorded. Ninety-seven species of the total belong to Bacillariophyceae, 37 species belong to Chlorophyceae, 13 species to Cyanophyceae, 5 species to Chrysophyceae, and 2 species to Euglenophyceae. Bimodal variation of phytoplankton was observed. Five genus of phytoplankton were the highest number of species ( Nitzschia, Navicula, Gomphonema, Cymbella and Scendesmus). Some species was occurred continuously during study period such as, Cyclotella ocellata, Cyclotella meneghiniana, Aulacoseria distans, and Gomphonema abbreviatum. The phytoplankton communities at all sampling sites showed a clear seasonal variation in phytoplankton cell number. However, no significant correlation between total cell number of phytoplankton and nutrient concentration was observed. The study was revealed the city sewage discharge, agriculture and urban run-off were affecting the water quality of Shatt Al-Hilla

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

Adult Normal Value and Deficiency Percentage of Serum Zinc in both Sexes Iraqi Healthy Population, using Atomic Absorption spectrophotometer (AAS)

The essential trace elements were very significant for the life of humans, and the imbalance in blood serum lead to so serious diseases. In this study, zinc (Zn) has been measured in the serum of  2005 samples (1305 male and 700 female) apparently healthy Iraqi persons aged 20-70 years using a flame atomic absorption spectrophotometer (FAAS). The mean concentration of Zn was (0.96 – 1.12 mg ml-1) in males and slightly lower (0.8 – 1.02 mg ml-1) in females. The concentration of Zinc was slightly increased by age, especially in the groups of 31-40 years, and slightly reduced in the group of 51-61 years. The concentration of zinc in all groups of the study seems to be stable. The study showed that there is a deficiency in Zn value (Zn concentration below 0.5 mg ml-1) in the male and females healthy populations by 22.9% and 18.85%, respectively

Application of the ANOVA method in the optimization of a thermoelectric cooler-based dehumidification system

© 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).In recent studies, Thermo-Electric Coolers (TEC) have been utilized for dehumidification purposes, which is mainly based on the extraction of moisture from humid atmospheric air. The reviewed literature showed that the rate of water collection from the TEC-based system can be affected by various parameters such as the module’s input voltage, the heat sink orientation, and tilt angles. In this research, the analysis of variance (ANOVA) was used to examine the significance of these factors and their interaction within the system on the TEC-based dehumidification system. Four levels were investigated for both, the Peltier’s input voltage and the rotation angle, and three levels for the tilt angle. This study indicated the significance of the studied factors and their interactions within the dehumidification system along with performing an overall numerical optimization. The experiments were conducted under the same working conditions in an enclosed environment to minimize errors. According to the overall numerical optimization, which was validated experimentally, the optimum system performance was predicted to be obtained at approximately 6.8V Peltier input volt, 65° rotation angle, and 90° tilt angles, with predicted optimum productivities of 0.32278 L/kWh and 13.03 mL/hr. For the same set of parameters, the variation between the experiment and the numerical optimization was less than 4%. The experiments show that when optimizing water collection rates for thermoelectric cooling heat sinks​ under high humidity conditions, the orientation of the heat sink should be considered.Peer reviewe

Thermohydraulic analysis of covalent and noncovalent functionalized graphene nanoplatelets in circular tube fitted with turbulators

© The Author(s) 2022. This article is licensed under a Creative Commons Attribution 4.0 International. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.Covalent and non-covalent nanofluids were tested inside a circular tube fitted with twisted tape inserts with 45° and 90° helix angles. Reynolds number was 7000 ≤ Re ≤ 17,000, and thermophysical properties were assessed at 308 K. The physical model was solved numerically via a two-equation eddy-viscosity model (SST k-omega turbulence). GNPs-SDBS@DW and GNPs-COOH@DW nanofluids with concentrations (0.025 wt.%, 0.05 wt.% and 0.1 wt.%) were considered in this study. The twisted pipes' walls were heated under a constant temperature of 330 K. The current study considered six parameters: outlet temperature, heat transfer coefficient, average Nusselt number, friction factor, pressure loss, and performance evaluation criterion. In both cases (45° and 90° helix angles), GNPs-SDBS@DW nanofluids presented higher thermohydraulic performance than GNPs-COOH@DW and increased by increasing the mass fractions such as 1.17 for 0.025 wt.%, 1.19 for 0.05 wt.% and 1.26 for 0.1 wt.%. Meanwhile, in both cases (45° and 90° helix angles), the value of thermohydraulic performance using GNPs-COOH@DW was 1.02 for 0.025 wt.%, 1.05 for 0.05 wt.% and 1.02 for 0.1 wt.%.Peer reviewe