Metal-oxide nanotubes functional material tailored for membrane water/wastewater treatment

Titanium Dioxide Nano-Tubes (TNTs) synthesized by hydrothermal method were used to prepare new polysulfone thin film nanocomposite (TFN) membranes. The TFN membranes contained different TNTs proportions (0.1, 0.3 and 0.5 wt. %). A polyamide selective layer was formed on top of the TFN membrane surface using interfacial polymerization (IP). Nanofiltration experiments were performed using NaCl and MgSO4 salts solutions. The water flux was found to increase with increased TNT loading in the membrane due to high porosity of embedded nanoparticles and the formation of enlarged pores. The antifouling behaviour of the membrane was tested by bovine serum albumin (BSA) solution and found to improve with increased TNT content in the membrane. - 2019 IOP Publishing Ltd. All rights reserved.This paper was made possible by an NPRP10-0127-170270 and NPRP8-1115-2-473 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

Development of novel thin film composite reverse osmosis membranes for desalination

Microporous Polyetherimide (PEI) membranes were prepared by wet phase inversion at different temperatures. The thin film composites (TFC) of polyamide on microporous PEI were prepared using meta-Phenylenediamine (MPD) and 1,3,5-Benzenetricarbonyl chloride (BTC). The ATR FTIR characterization showed the formation of polyamide (PA) on microporous PEI membrane, whereas scanning electron microscopy (SEM) revealed that a thin film of polyamide is formed on microporous PEI. The cross-sectional SEM of PEI prepared at 60 °C, showed finger like morphology and sparingly distributed balloon like morphology for PEI synthesized at 80 °C. The performance of PEI membranes and PA TFCs were ascertained by studying permeation of water and rejection of sodium chloride by reverse osmosis. The polyamide TFC with hydrophobic PEI support structures exhibited permeation of 28 to 50 lm-2h-1, with 98 – 95 % 2000 ppm NaCl rejection at 60 bar pressure

Corrosion Study of Carbon Steel in CO2 Loaded Amine-Amino Acid Solutions-Case of Mixtures of NMethyldiethanolamine and L-Arginine

© Published under licence by IOP Publishing Ltd. This research presents an electrochemical corrosion investigation to quantify the corrosiveness of carbon steel in blends of methyldiethanolamine (MDEA) and arginine (Arg) at two molar concentration and different solvent proportions. The selected temperatures range varied from 20 °C to 50 °C and the CO2 partial pressure was in the range of 49-100 kPa. The obtained data showed increased corrosion rate with increased CO2 partial pressure and increased the temperature of the solution. However, when added to MDEA, arginine was found to act as an inhibitor, the higher Arginine proportion in the mixture, the more inhibition effect was observed.This paper was made possible by an NPRP Grant # 7-1154-2-433 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors

Reaction kinetics of carbon dioxide in aqueous blends of N-methyldiethanolamine and L-arginine using the stopped-flow technique

Reduction of carbon dioxide emission from natural and industrial flue gases is paramount to help mitigate its effect on global warming. Efforts are continuously deployed worldwide to develop efficient technologies for CO 2 capture. The use of environment friendly amino acids as rate promoters in the present amine systems has attracted the attention of many researchers recently. In this work, the reaction kinetics of carbon dioxide with blends of N-methyldiethanolamine and L-Arginine was investigated using stopped flow technique. The experiments were performed over a temperature range of 293 to 313 K and solution concentration up to one molar of different amino acid/amine ratios. The overall reaction rate constant (k ov ) was found to increase with increasing temperature and amine concentration as well as with increased proportion of L-Arginine concentration in the mixture. The experimental data were fitted to the zwitterion and termolecular mechanisms using a nonlinear regression technique with an average absolute deviation (AAD) of 7.6% and 8.0%, respectively. A comparative study of the promoting effect of L-Arginine with that of the effect of Glycine and DEA in MDEA blends showed that MDEA-Arginine blend exhibits faster reaction rate with CO 2 with respect to MDEA-DEA blend, while the case was converse when compared to the MDEA-Glycine blend.The authors thank Ahmed Soliman and Dan Jerry Cortes for providing laboratory support This paper was made possible by an NPRP Grant # 7-1154-2-433 from the Qatar National Research Fund (a member of Qatar Foundation)

Lymphomes malins non-hodgkiniens primitifs des amygdales palatines

Introduction: The most predominant localization for extranodal  non-hodgkinien lymphoma (NHL) in the head and neck region is the tonsil. The vast majority of NHL at this site is B-cell lymphomas.Materials and methods: The authors presented three cases of primary Non Hodgkin's Lymphoma of the tonsil, treated between 1995 and 2007Results: we report the cases of three men aged respectively 15, 42 and 72 years. They complained of a persistent odynophagia during three months ago. Clinical examination detected unilateral enlarged tonsil with ulcerated surface. All of them have bilateral tonsillectomy. The histopathologic examination concluded at a NHL with a B phenotype. The treatment consisted on chemotherapy for two patients and on radio and  chemotherapy for the third patient. We have noted one death for our three patients.Conclusion: Primary NHL of the tonsil is rare. An advanced diagnosis is often difficult. Both histopathologic identification of the tumor and evaluation of the patient are essentiel for the therapeutic decision. Prognostic depends on the stage of the lymphoma.Keywords: Non Hodgkin lymphoma, Oral cavity, Radiotherapy, Chemotherapy, antineoplastic agent, malignant hemopathy, Oral cavity disease

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

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

Molecular diagnostics for verification of pleural tuberculosis in Morocco

Pleural tuberculosis (pTB) is a very common form of extrapulmonary tuberculosis (TB). pTB diagnostics represents a major burning challenge worldwide due to the limitations of available conventional diagnostic tools. These latter include microscopic examination of the pleural fluid for acid-fast bacilli, mycobacterial culture of pleural fluid in solid or liquid media, sputum or pleural tissue, and histopathological examination of pleural tissue; these tests have recognized limitations for clinical use. Hence, to overcome these limitations, attention has been devoted to new nucleic acid amplification (NAA) diagnostic tests such as the polymerase chain reaction (PCR) and real-time PCR (RT-PCR), owing to their accuracy, rapidity, high sensitivity and specificity. Within this context, this prospective study was conducted to evaluate the performance of molecular diagnosis methods for differentiation between tuberculosis and non-tuberculosis pleural effusions. Fifty patients with pleural effusion were enrolled in this prospective study in Rabat, Morocco. The efficacy of conventional polymerase chain reaction (PCR) in the diagnostics of tuberculous pleurisy by targeting IS6110 and mycobacterial internal transcribed spacer (MYITS) was evaluated compared to histopathologic examination and culture data. Our results showed that IS6110 PCR could “rule in” pTB, the sensitivity and specificity being 41.6% and 85.7%, respectively. Therefore, the findings confirmed that molecular tests exert a relatively high specificity in EPTB but lower sensitivity, thus a positive test is considered as a pTB case whereas negative one cannot exclude the disease. Although the study was limited by a small sample size, it adds to the body of evidence of usefulness of molecular testing as adjuncts to histopathologic examination for accurate diagnosis of pTB, to treat timely and to avoid the emergence and spread of drug resistant pTB. However, further efforts should be made to increase the sensitivity of NAA methods and to identify the best molecular targets to be useful in clinical practice

Mechanical Behavior of a Novel Nanocomposite Polysulphone - Carbon Nanotubes Membrane for Water Treatment

Nowadays, global fresh water shortage is becoming the most serious problem affecting the economic and social development. Water treatment including seawater desalination and wastewater treatment is the main technology for producing fresh water. Membrane technology is favored over other approaches for water treatment due to its promising high efficiency, ease of operation, chemicals free, energy and space saving. Membrane filtration for water treatment has increased significantly in the past few decades with the enhanced membrane quality and decreased membrane costs. In addition to high permeate flux and high contaminant rejection, membranes for water treatment require good mechanical durability and good chemical and fouling resistances. Thus, investigation of the mechanical behavior of water treatment membranes with underlying deformation mechanisms is critical not only for membrane structure design but also for their reliability and lifetime prediction. Compared to ceramic and metallic membranes, polymer membranes with smaller pore size and higher efficiency for particle removal are widely used in seawater desalination with a high applied pressure. However, polymer membranes are mechanically weaker and have lower thermal and chemical stability compared to inorganic membranes. Blending of polymers with inorganic fillers is an effective method to introduce advanced properties to polymer based membranes to meet the requirements of many practical applications. The reinforced polymeric membranes with inorganic fillers can provide desirable mechanical strength as well as mechanical stability. Carbon nanotubes (CNTs) have received considerable attention from academic and industries over the last twenty years. In addition to their excellent electrical and thermal properties, CNTs exhibit outstanding mechanical characteristics due to its instinct mechanical strength and high aspect ratio. For the application of water treatment membranes, CNTs could be the excellent channels for water to go through and therefore, CNTs have proven to be excellent fillers in polymer membranes improving the permeability and rejection properties. In literature, it is reported that the mechanical strength of the polymer membranes was improved with the embedding of CNTs due to reinforcement effect of the more rigid CNTs. The mechanical responses of polymer_CNTs composites depended on the interfacial adhesion between the CNTs and the membrane-based polymer as well as the dispersion and distribution of the CNTs within the polymer matrix. In this study, a vertical chemical vapor deposition reactor was designed in order to synthesize CNTs of high aspect ratio using continues injection atomization. Bundles of high purity (99%) and high quality CNTs were produced by this system. The produced CNTs had diameters ranging from 20 to 50 nm and lengths ranging from 300 to 500 micron (corresponded aspect ratios ranging from 6000 to 25000). A novel polysulphone (PSF) based nanocomposite membrane incorporated with the produced high aspect ratio CNTs was then casted via phase inversion method, at a wide range of CNTs loading (0-5 wt. %), in polysulphone-dimethylformamide solutions using the Philos casting system. The poly(vinylpyrrolidone) was used as pore-forming additive. To demonstrate the effect of nanocomposite morphology on the mechanical behavior of the prepared membranes, a set of control samples consisted of PSF membranes embedded with commercial CNTs at the same CNTs loading, were casted at the same conditions. The commercial CNTs had a lengths of 1 ?m to 10 ?m and outer diameters of 10 nm to 20 nm (corresponded aspect ratios ranging from 50 to 1000), with purity >95% and BET surface area of 156 m2/g. The effects of CNTs content and aspect ratio on morphological, water transport and mechanical properties of the prepared PSF-based porous membranes were investigated. The surface and cross-section morphologies of PSF/CNTs porous membranes were examined using scanning electron microscopy (SEM). The orientation, dispersion and distribution of CNTs within polymer membranes were evaluated for the membrane samples with different CNTs content and CNTs aspect ratio. The average membrane pore size was evaluated by using SEM image analysis software. Uniaxial tensile behavior of the membranes was characterized by means of a universal material testing machine under different testing conditions. Wet specimens were carefully cut from the casted membranes by using a razor blade. Elastic, plastic and failure behaviors of the membranes are analyzed with the impacts of CNTs content and aspect ratio. The macroscopic mechanical behaviors of the membranes are correlated with their strain induced microstructure evolution by using SEM. In this, pore shape evolution, pore and CNTs orientations, neighboring pore interaction, interface between the CNTs and PSF matrix and the failure behavior of the deformed porous membranes were analyzed. The macroscopic stress-strain responses of the membranes were correlated with the microstructure of the studied nanocomposites membranes to provide a better understanding of materials' processing-microstructure-properties relationship.qscienc

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

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

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

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