121 research outputs found

    Optimization Of Palm Oil Mill Effluent Treatment By Applying RSM And ANN

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    AbstractThe optimization of the COD removal from palm oil mill effluent (POME) has done. The correlation of concentration and pH of POME, and Trans membrane pressure (TMP) of Reverse Osmosis (RO) membrane was optimized by response surface method using a second order polynomial model with Box Behken design consist of 17 runs. To determine whether the model was adequate for representing the experimental data; it was indicated by the ANNOVA table (p-value, lack of fit and R2 values).  The main factor influenced the COD removal was concentration and pH of POME.  The optimum conditions were determined from 3D response surface and 2D contour graphs i.e. 28.30% of POME concentration at pH 10.75 and TMP 0.69 kPa to yield 24.1372 mg/L of COD value. The results demonstrate that the response surface method effective to minimize the number of experiment. Keywords: POME; RO membrane; RSM; ANN; CO

    Application of Response Surface Method in Reverse Osmosis Membrane to Optimize BOD, COD and Colour Removal from Palm Oil Mill Effluent

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    Palm oil mill effluent (POME) is typically non-biodegradable and has high concentration of organic matter that represented as COD, BOD and Colour values. The correlation of concentration and pH of POME, and Trans membrane pressure (TMP) of Reverse Osmosis (RO) membrane was optimized by response surface method using a second order polynomial model with central composite design (CCD) which is a part model of response surface method (RSM) in Design-Expert® software. The main limits that influenced the parameters removal i.e. concentration of POME, pH of solution and transmembrane pressure were empirically determined at laboratory level and successfully optimized using RSM. The best conditions were determined from 3D response surface and 2D contour graphs i.e. 10.05% of POME concentration at pH 3.0 and TMP 0.50 kPa to yield the last values of COD, BOD and Colour i.e. 24.1372 mg/L,  24.33 mg/L and 11.76 PtCo, respectively.  The results show that the response surface method effective to reduce the number of experiment

    Retinal Architecture in ​\u3cem\u3eRGS9-\u3c/em\u3e and ​\u3cem\u3eR9AP\u3c/em\u3e-Associated Retinal Dysfunction (Bradyopsia)

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    Purpose To characterize photoreceptor structure and mosaic integrity in subjects with RGS9- and R9AP-associated retinal dysfunction (bradyopsia) and compare to previous observations in other cone dysfunction disorders such as oligocone trichromacy. Design Observational case series. Methods setting: Moorfields Eye Hospital (United Kingdom) and Medical College Wisconsin (USA). study population: Six eyes of 3 subjects with disease-causing variants in RGS9 or R9AP. main outcome measures: Detailed retinal imaging using spectral-domain optical coherence tomography and confocal adaptive-optics scanning light ophthalmoscopy. Results Cone density at 100 μm from foveal center ranged from 123 132 cones/mm2to 140 013 cones/mm2. Cone density ranged from 30 573 to 34 876 cones/mm2 by 600 μm from center and from 15 987 to 16,253 cones/mm2 by 1400 μm from center, in keeping with data from normal subjects. Adaptive-optics imaging identified a small, focal hyporeflective lesion at the foveal center in both eyes of the subject with RGS9-associated disease, corresponding to a discrete outer retinal defect also observed on spectral-domain optical coherence tomography; however, the photoreceptor mosaic remained intact at all other observed eccentricities. Conclusions Bradyopsia and oligocone trichromacy share common clinical symptoms and cannot be discerned on standard clinical findings alone. Adaptive-optics imaging previously demonstrated a sparse mosaic of normal wave-guiding cones remaining at the fovea, with no visible structure outside the central fovea in oligocone trichromacy. In contrast, the subjects presented in this study with molecularly confirmed bradyopsia had a relatively intact and structurally normal photoreceptor mosaic, allowing the distinction between these disorders based on the cellular phenotype and suggesting different pathomechanisms

    Recent advances on the treatment of oil fields produced water by adsorption and advanced oxidation processes

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    The handling and treatment of produced water (PW) generated during oil and gas extraction has continued to be a serious dilemma due to its large quantities and complex composition with variety of pollutants. In this review article, the treatment of PW using adsorption and advanced oxidation processes (AOP) and their integrated processes is analyzed and discussed, where the PW sources studied were both real and artificially contaminated PW. The role of different reaction parameters and their effect on the performance of these processes is critically evaluated. Furthermore, the existing research gaps were identified where it was found that there are insufficient studies on the integration of adsorption and advanced oxidation processes, but with the available literature, it was shown that integrated adsorption-advanced oxidation processes could be effectively used to treat produced water. It was deduced that further studies should target continuous columns (packed bed) rather than batch systems. Moreover, cost analysis and comparison should be carried out to see the feasibility of these systems. Also, innovative integrated technologies and efficient methods for the regeneration and reuse of these systems should be studied for their upscaling to industrial-scale applications.- Qatar National Library - open access fund. - Qatar University - grant no. (IRCC-2021-014; CL/SQU-QU/CESR/21/01). - Sultan Qaboos University - grant no. CL/SQU-QU/CESR/21/01, IRCC-2021-014

    Processing and Properties of Bar-Shaped Single-Seeded and Multi-Seeded YBCO Bulk Superconductors by a Top-Seeded Melt Growth Technique

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    © 2016 The Author(s)The fabrication of (RE)-Ba-Cu-O bulk superconductors, where RE is a rare-earth element such as Y, Gd and Sm, is both time consuming and expensive due to the complexity of the melt process and the slow growth rate of large, single grains. In this study, different approaches to the fabrication of bar-shaped, bulk YBCO superconductors are investigated and compared using single- and multiple-seeding techniques via top-seeded melt growth (TSMG). Both the microstructural and superconducting properties of the bulk samples are investigated, including trapped field, critical current density, critical temperature and levitation force. The results of this study indicate that, in general, the superconducting properties of YBCO fabricated by a single-seeded process are significantly better than those of samples fabricated by a four-seeded process for non-bridge seeds. The differences between the samples are less pronounced in the levitation force measurements, however. In this paper, we attempt to explain the reasons for the similarities and differences observed between bulk samples fabricated by the different single- and multi-seeded processes.This work was supported by the King Abdulaziz City for Science and Technology (KACST)

    Adsorption of organic water pollutants by clays and clay minerals composites: A comprehensive review

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    Clays and clay minerals are inexpensive, non-toxic, and naturally occurring minerals that have been utilized in water remediation as adsorbents. However, clays and clay minerals and those modified with heat, surfactants, acids, or organic-inorganic modifiers exhibit low adsorption capacity and re-generation ability towards organic water pollutants. The development of clays and clay minerals composites has gained considerable attention in recent years due to their enhanced adsorption capacity, ease of recovery from aqueous solution and improved physiochemical properties relative to raw and modified clays and clay minerals. This review aims to assess recent literature on clays and clay minerals composites including bentonite, montmorillonite and kaolinite intercalated with carbonaceous, metals, metal oxides, chitosan and polymeric materials and appraise their adsorption performance towards organic water pollutants. The review examines the effect of the composites' physicochemical properties on the adsorption performance and evaluates the adsorption mechanism as well as regeneration methods. The review also attempts to highlight the current progress in this area by assessing the outcomes of recently published articles and outline the research gaps for future research.This publication was made possible by an Award [GSRA6-2-0516-19029] from Qatar National Research Fund (a member of Qatar Foundation). The contents herein are solely the responsibility of the author[s]. Open access funding is provided by the Qatar National Library.Scopu

    Adsorption of 4-Nitrophenol onto Iron Oxide Bentonite Nanocomposite: Process Optimization, Kinetics, Isotherms and Mechanism

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    Despite its importance in chemical industry, 4-Nitrophenol (4-NP) is a persistent organic pollutant that has serious effects on the ecosystem. In the present study, Box–Behnken design in response surface methodology was used to optimize the adsorption process parameters for the maximum 4-NP removal at 30 ℃ using Fe3O4/Bt NC. The regression model results suggested that the optimum adsorbent dosage, initial concentration, pH and contact time were 0.3182 g, 85 mg/L, 11 and 137.2 min, respectively. The regression model showed an optimum removal of 100%, while 99.5% removal was obtained from batch experiments at the optimum conditions suggested by the regression model, which confirm the model validity. The adsorption data best fitted to Freundlich isotherm model and Pseudo second-order kinetic model suggesting the existence of physical and chemical interaction between the fabricated composite and 4-NP. FTIR analysis suggested that the adsorption mechanism included an electrostatic attraction and the formation of new chemical bonds. Obtained results suggest that Fe3O4/Bt NC can be an effective adsorbent for complete 4-NP removal at the indicated optimum conditions.This research was made possible by an NPRP Grant # 10-0127-170270 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. The author Dina Ewis acknowledged the financial support of QNRF through the Graduate Sponsorship Research Award (GSRA) number GSRA#6-2-0516-19029.Scopu

    Electrochemical reduction of CO2 into formate/formic acid: A review of cell design and operation

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    The release of carbon dioxide (CO2) into the atmosphere is threatening the environment and ecosystems, resulting in major challenges to sustainable development for modern industry. In this context, CO2 electrochemical reduction (CO2 ECR) is one of the most promising technologies to mitigate the effects of high CO2 content in the atmosphere. Electrochemical technology can convert CO2 into value-added chemicals including methanol, ethanol and formate. In this review, different mechanisms of CO2 electrochemical reduction into formate/formic acid are reviewed, highlighting the different cell designs. Also, the effect of cell design and operating parameters on the electrochemical reduction process are discussed. The review aims to highlight recent developments in the CO2 electrochemical cell design for formate production and provide guidelines for future advancements. Challenges of large-scale production and research gaps are also provided. 2023 The AuthorsThe authors would like to acknowledge the support of Qatar National Research Fund (a member of Qatar Foundation) through Grant # NPRP 12 C-33923-SP-102 (NPRP12 C-0821-190017). The findings achieved herein are solely the responsibility of the authors. Open Access funding provided by the Qatar National Library.Scopu

    Effective Heterogeneous Fenton-Like degradation of Malachite Green Dye Using the Core-Shell Fe3O4@SiO2 Nano-Catalyst

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    In this study, the application of the core-shell Fe3O4@SiO2 nano-catalysts for fenton-like degradation of malachite green dye has been presented. The nano-catalysts were prepared using a combination of solvothermal and sol-gel techniques and characterized using XRD, FTIR, SEM/EDX, TEM and VSM techniques. The effects of various reaction parameters on the degradation of malachite green dye using the prepared nano-catalysts were investigated. The optimal condition for pH, catalyst dosage and H2O2 amount were found to be at 6.7, 15 mg and 50 μL, respectively. Under the optimized conditions, a degradation efficiency of 96.18 % for malachite green dye was achieved using the catalyst within 30 minutes at 303 K with a pseudo first order rate constant of 0.1102 min−1. The plausible mechanism for MG degradation was determined to be the combination of adsorption and simultaneous decomposition via formation of hydroxyl radicals. The performance of the nano-catalyst was compared with other fenton-like catalysts reported in the literature. Finally, the magnetic properties of the Fe3O4@SiO2 catalysts was utilized for its successful recovery and application in multiple degradation cycles.This research was made possible by an NPRP Grant#10-0127-170270 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. The authors would like to acknowledge the help Centre for Advanced Materials (CAM) at Qatar University and Mr. Abdullah Al Ashraf for providing XRD test data. SEM/EDX tests was accomplished in the Central Laboratories unit, Qatar University.Scopu
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