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Cobalt (Co) co-doped TiO2 photo-catalysis were synthesized, characterized and tested toward solar photocatalytic oxidation of toluene (TOL). A multi-technique approach was used to characterize and relate the photo-catalytic property to photo-oxidation performance. Adding Co to TiO2 significantly changed crystal size and surface morphology (surface area, pore-volume, and pore size), reduced the bandgap energy of TiO2 and improved the solar photo-oxidation of TOL. Up to 96.5% of TOL conversion (%TNconv) was achieved by using Co–TiO2 compared with 28.5% with naked TiO2. The maximum %TNconv was achieved at high hydraulic retention time (HRT) ≥ 100 s, Co content in the photo-catalyst of 5 wt% and relative humidity (%RH) of 50%. The mechanism of TOL solar oxidation was related to the concentration of OH• and radicals produced from the generated electrons and holes on the surface of Co–TiO2. The products formed during the photo-catalytic oxidation of TOL were mainly CO2 and water, and minor concentration of benzene and benzaldehyde. Overall, the Co–TiO2 could be used as a potential photo-catalyst for the oxidation of toluene in gas-phase streams on an industrial scale. Scopus

This paper reports the thermochemical splitting of CO2 using Ce0.9Ln0.05Ag0.05O2-d materials, which are prepared by using the co-precipitation method. The phase composition and the morphology of the derived materials was analyzed using powder X-ray diffractometer and scanning electron microscope. The thermal reduction and CO2 splitting reactions were conducted by using a high temperature TGA operated in the range of 1000 to 1400 C. Qatar Foundation;Qatar National Research Fund Scopus

In this paper, the thermal reduction and CO2splitting ability of Ce0.9Cr0.102-δare investigated by performing multiple thermochemical cycles using a thermogravimetric analyzer. The Ce0.9Cr0.102-δmaterial is successfully derived via co-precipitation method and analyzed via powder X-ray diffraction (PXRD). The Ce0.9Cr0.102-δderived is further tested towards its O2releasing and CO production capacity by performing three thermochemical CO2splitting cycles (regarding weight loss and gain) Qatar Foundation;Qatar National Research Fund Scopus

[No abstract available] This publication was made possible by NPRP grant (NPRP8-509-2-209) from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the author(s). Scopus

In this study, a Co ferrite/ZrO2 ceramic nanornixture was synthesized by the propylene-oxide-assisted sol-gel method. Cobalt, iron, and zirconium nitrate salts were used as the metal precursors, and ethanol and propylene oxide were used as the solvent and gelation agent, respectively. The prepared gels were aged, dried, and annealed at 1000°C for different dwell times. The annealed Co ferrite/ZrO2 powder was analyzed by powder X-ray diffraction (PXRD), Brunauer-Emmett-Teller surface area analysis (BET), and energy-dispersive spectroscopy (EDS). The characterization results are reported in detail. Scopus

The treatment of effluent wastewater containing pharmaceutical by solar advanced oxidation processes were studied in a pilot plant. The removal efficiency of four groups of pharmaceuticals (antibiotics, estrogens, acidic, and neutral), commonly detected as emerging contaminants, were tested by different solar-driven photochemical processes including solar-photolysis, solar-photocatalytic oxidation using Fe(III) or TiO2 and solar based photo-Fenton reaction. Results showed that Solar-photolysis is not effective for the complete removal of the selected contaminants, on other hand solar-photocatalytic oxidation using TiO2, solar based photo-Fenton reaction showed significant removal efficiencies and high mineralization. Solar photo-catalytic systems produced a final solution with lower toxicity if compared with original solution. This publication was made possible by the NPRP grant (NPRP No.: 6-1436-2-581) from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of authors. The authors gratefully acknowledge the support provided by the Qatar University to do this work. Scopus

In this study, a Co ferrite/ZrO2 ceramic nanomixture was synthesized by the propylene-oxide-assisted sol-gel method. Cobalt, iron, and zirconium nitrate salts were used as the metal precursors, and ethanol and propylene oxide were used as the solvent and gelation agent, respectively. The prepared gels were aged, dried, and annealed at 1000�C for different dwell times. The annealed Co ferrite/ZrO2 powder was analyzed by powder X-ray diffraction (PXRD), Brunauer-Emmett-Teller surface area analysis (BET), and energy-dispersive spectroscopy (EDS),. The characterization results are reported in detail. Copyright This publication was made possible by the NPRP grant (NPRP8-370-2-154) from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of author(s). Scopus

In this paper computational thermodynamics modeling of the solar H2 production via twostep thermochemical manganese oxide - manganese sulfate (MnO-MnS) water splitting cycle is reported. In this cycle, the first step corresponds to the exothermic oxidation of manganese oxide via SO2 and H2O producing MnSO4 and H2 and second step is related to the endothermic reduction of MnSO4 into MnO, SO2, and O2. The MnO and SO2 produced in the second step can be recycled to the step 1 and hence, reutilized for the production of H2 via water splitting reaction. The equilibrium compositions for the MnSO4 thermal reduction and water splitting steps were determined by performing thermodynamic analysis and are reported here. Furthermore, exergy analysis was performed to determine the cycle efficiency and solar to fuel energy conversion efficiency attainable without heat recuperation. Scopus

This paper reports the thermodynamic analysis of Sm2O3 based solar thermochemical CH4 reforming process. Thermodynamic equilibrium compositions of the syngas production via CH4 reforming via Sm2O3 reduction as a function of reaction temperature were determined. Second law thermodynamic analysis was performed to determine the cycle efficiency and solar to fuel energy conversion efficiency attainable without heat recuperation. Qatar University Scopus

In this paper, we investigate the reaction mechanism followed during the solution combustion synthesis of transition metals (Cu, Ni and Co) and their alloys. Metal nitrates were mixed with a choice of fuel (glycine, and urea) and mixed in deionized water to get a homogeneous mixture of solution with uniform properties. The solution thus obtained is heated to initiate the highly exothermic combustion reaction resulting in the synthesis of metals/metal-oxides. TGA-DTA analysis of the reactants (metal-nitrates, fuel, and cellulose) along with the XRD of the final products obtained helped in deducing the reaction mechanism. Scopus

This paper reports the thermodynamic feasibility of the production of solar fuel via GeO2/GeO Thermochemical H2O and CO2 Splitting Cycle. This is a two-step process in which the first step is solar thermal dissociation of GeO2 into GeO and the second step is non-solar splitting of H2O and CO2 via oxidation of GeO into GeO2. Computational thermodynamic HSC Chemistry software and databases were used for the thermodynamic modeling of this process. This paper includes chemical thermodynamic equibrium analysis and second law thermodynamic modeling of the GeO2/GeO based thermochemical CO2 splitting process. Results obtained via the computational thermodynamic modeling are presented. Scopus

In this paper computational thermodynamic modeling of solar syngas production via ferrite based (Fe3 O4 /FeO) thermochemical H2O and/or CO2 splitting cycle. This two-step cycle involves solar thermal reduction of Fe3O4 into FeO and O2 and non-solar splitting of H2O and CO2 via exothermic oxidation of FeO into Fe3O4. Solar syngas produced will be used for the production of solar liquid transportation fuels by catalytic Fischer Tropsch process. This paper reports the solar reactor efficiency analysis for the iron oxide based solar syngas production process. Second-law thermodynamic analysis is applied to determine the cycle efficiencies attainable with and without heat recuperation. Also, the energy required for the inert Ar heating during the solar thermal reduction step was included during the efficiency calculation. Thermodynamic analysis has been performed and the analysis shows that solar syngas production via the Iron Oxide redox cycle is a promising approach for CO2/H2O conversion into alternative fuels. Qatar University Scopus

In this paper thermodynamic feasibility of the production of solar fuel via SnO2/SnO based thermochemical CO2 splitting redox reactions was investigated. The first step is the thermal dissociation of SnO2 into SnO where concentrated solar energy is the source of this high temperature process heat. The second step which is a non-solar exothermic stage is the reaction of SnO with CO2 to produce CO together with SnO2 that is recycled back to the first step. Commercially available HSC Chemistry software and databases were used for the thermodynamic modeling of this process. Thermodynamic analysis was performed in two sections, namely, a) equilibrium thermodynamic calculations, and b) second law thermodynamic modeling of the SnO2/SnO based thermochemical CO2 splitting process. Results obtained via the computational thermodynamic modeling are presented. Acknowledgments The authors gratefully acknowledge the financial support provided by the Qatar University Internal Grants QUUG-CENG-CHE-13/14-4 and QUUG-CENG-CHE-14\15-10. Scopus

In this work we report the synthesis of copper oxide nanoparticles using solution combustion synthesis. These nanopowders are used as catalyst in ethanol decomposition reaction for hydrogen production. In situ study of ethanol decomposition has been conducted in FTIR using DRIFTS reactor at temperature of 50°C and 400°C over the reduced catalyst obtained after passing H2 at 300°C for one hour. XRD, SEM and TEM analysis were conducted to identify the phase and morphology of catalyst before and after reaction. Qatar Foundation;Qatar National Research Fund;Qatar University Scopus

This paper reports the thermodynamic analysis of the production of solar syngas (a mixture of H2 and CO with molar ratio equal to 2: 1) via ZnO/Zn based thermochemical H2O and/or CO2 splitting redox reactions. Solar syngas production from CO2 and H2O that is considered in a two-step thermochemical cycle via Zn/ZnO redox reactions, encompassing: 1) the ZnO thermolysis to Zn and O2 using concentrated solar radiation as the source of process heat, and 2) Zn reacting with mixtures of H2O and CO2 yielding high-quality syngas and ZnO. The ZnO is recycled to the first, solar step. Syngas is further processed to liquid hydrocarbon fuels via FischereTropsch or other catalytic processes. Second-law thermodynamic analysis is applied to determine the cycle efficiencies attainable with and without heat recuperation for varying the thermal reduction temperature (TR) in the range 1700-1950 K. Furthermore, the effect of various TR on molar flow rate of inert Ar has been presented. Considered is the energy penalty of using Ar dilution in the solar step below 2235 K for shifting the equilibrium to favor Zn production. Thermodynamic analysis has been performed and the analysis shows that solar syngas production via the Zinc Oxide redox cycle is a promising approach for CO2/H2O conversion into alternative fuels. Qatar University Scopus

This study assesses the potential use of mixed Indigenous Microalgae (MIMA) for carbon capture from flue gases in a photo-bioreactor. The effect of inlet CO2 concentration on the carbon biofixation rate was investigated. The PBR wasoperated under ambient conditions of solar irradiation and temperature for 3-months. Under the conditions studied, MIMA showed a significant carbon bio-fixation rates in order of 0.34 gC.L?1.d?1 suggesting that Microalgae with fast growth rate and naturally grown in the water system can be a sustainable and effective technology for CO2 uptake. Copyright (2018) by AIChE. All Rights Reserved. Scopus

This study evaluated the use of green algae Spirulina microalgae as a C02 capturing technology at different temperatures. The growth of Spirulina at 25 and 30◦C were studied in synthetic wastewater and its performance in removing nutrient were determined. Significant differences between the growth patterns of Spirulina were observed at different C02 dosage rate and different operational temperature. Spirulina showed the highest growth at 30 C and with a C02 injection dosage of 10%. Limited growth was observed for the systems injected with 5 and 15 % of C02 with respect to blank solution. Ammonia and phosphorus removals for Spirulina were 69%, 75%, and 83%, and 20%, 45% and 75 % for the media injected with 0, 5 and 10% C02. The results of this study show that simple and cost-effective microalgae-based wastewater treatment systems can be successfully employed at different temperatures as a successful C02 capturing technology even with the small probability of inhibition at high temperatures. Scopus

This paper reports the investigation of effect of temperature on physico-chemical properties of formulated solvent (comprises on ethylaminoethanol, N-methyl-2-pyrollidone, and K2CO3/KHCO3) and reaction kinetics of the absorption of CO2 in this formulated solvent. The physico-chemical properties were estimated by using a specific gravity bottle (density), an Ostwald's capillary viscometer (viscosity), and a stirred cell reactor (diffusivity and solubility of CO2 in formulated solvent). Similarly, a stirred cell reactor was used for the investigation of CO2 absorption kinetics by following a novel fall in CO2 pressure technique. Qatar University Scopus