183 research outputs found

    Cu and Fe oxides dispersed on SBA-15:a Fenton type bimetallic catalyst for N,N-diethyl-p-phenyl diamine degradation

    Get PDF
    A bimetallic oxidation catalyst has been synthesized via wet impregnation of copper and iron over a mesoporous SBA-15 silica support. Physicochemical properties of the resulting material were characterized by XRD, N2 physisorption, DRUVS, FTIR, Raman, SEM and HRTEM, revealing the structural integrity of the parent SBA-15, and presence of highly dispersed Cu and Fe species present as CuO and Fe2O3. The CuFe/SBA-15 bimetallic catalyst was subsequently utilized for the oxidative degradation of N,N-diethyl-p-phenyl diamine (DPD) employing a H2O2 oxidant in aqueous solution

    Characterization and Separation Performance of a Novel Polyethersulfone Membrane Blended with Acacia Gum

    Get PDF
    Novel polyethersulfone (PES) membranes blended with 0.1–3.0 wt. % of Acacia gum (AG) as a pore-former and antifouling agent were fabricated using phase inversion technique. The effect of AG on the pore-size, porosity, surface morphology, surface charge, hydrophilicity, and mechanical properties of PES/AG membranes was studied by scanning electron microscopy (SEM), Raman spectroscopy, contact angle and zeta potential measurements. The antifouling -properties of PES/AG membranes were evaluated using Escherichia coli bacteria and bovine serum albumine (BSA). The use of AG as an additive to PES membranes was found to increase the surface charge, hydrophilicity (by 20%), porosity (by 77%) and permeate flux (by about 130%). Moreover, PES/AG membranes demonstrated higher antifouling and tensile stress (by 31%) when compared to pure PES membranes. It was shown that the prepared PES/AG membranes efficiently removed lead ions from aqueous solutions. Both the sieving mechanism of the membrane and chelation of lead with AG macromolecules incorporated in the membrane matrix contributed to lead removal. The obtained results indicated that AG can be used as a novel pore-former, hydrophilizing and antifouling agent, as well as an enhancer to the mechanical and rejection properties of the PES membranes

    A review of combined advanced oxidation technologies for the removal of organic pollutants from water

    Get PDF
    Water pollution through natural and anthropogenic activities has become a global problem causing short-and long-term impact on human and ecosystems. Substantial quantity of individual or mixtures of organic pollutants enter the surface water via point and nonpoint sources and thus affect the quality of freshwater. These pollutants are known to be toxic and difficult to remove by mere biological treatment. To date, most researches on the removal of organic pollutants from wastewater were based on the exploitation of individual treatment process. This single-treatment technology has inherent challenges and shortcomings with respect to efficiency and economics. Thus, application of two advanced treatment technologies characterized with high efficiency with respect to removal of primary and disinfection by-products in wastewater is desirable. This review article focuses on the application of integrated technologies such as electrohydraulic discharge with heterogeneous photocatalysts or sonophotocatalysis to remove target pollutants. The information gathered from more than 100 published articles, mostly laboratories studies, shows that process integration effectively remove and degrade recalcitrant toxic contaminants in wastewater better than single-technology processing. This review recommends an improvement on this technology (integrated electrohydraulic discharge with heterogeneous photocatalysts) viz-a-vis cost reduction in order to make it accessible and available in the rural and semi-urban settlement. Further recommendation includes development of an economic model to establish the cost implications of the combined technology. Proper monitoring, enforcement of the existing environmental regulations, and upgrading of current wastewater treatment plants with additional treatment steps such as photocatalysis and ozonation will greatly assist in the removal of environmental toxicants

    Vaginal Delivery of Paclitaxel via Nanoparticles with Non-Mucoadhesive Surfaces Suppresses Cervical Tumor Growth

    Get PDF
    Local delivery of chemotherapeutics in the cervicovaginal tract using nanoparticles may reduce adverse side effects associated with systemic chemotherapy, while improving outcomes for early stage cervical cancer. We hypothesize drug-loaded nanoparticles must rapidly penetrate cervicovaginal mucus (CVM) lining the female reproductive tract to effectively deliver their payload to underlying diseased tissues in a uniform and sustained manner. We develop paclitaxel-loaded nanoparticles, composed entirely of polymers used in FDA-approved products, which rapidly penetrate human CVM and provide sustained drug release with minimal burst effect. We further employ a mouse model with aggressive cervical tumors established in the cervicovaginal tract to compare paclitaxel-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (conventional particles , or CP) and similar particles coated with Pluronic® F127 (mucus-penetrating particles , or MPP). CP are mucoadhesive and, thus, aggregated in mucus, while MPP achieve more uniform distribution and close proximity to cervical tumors. Paclitaxel-MPP suppress tumor growth more effectively and prolong median survival of mice compared to free paclitaxel or paclitaxel-CP. Histopathological studies demonstrate minimal toxicity to the cervicovaginal epithelia, suggesting paclitaxel-MPP may be safe for intravaginal use. These results demonstrate for the first time the in vivo advantages of polymer-based MPP for treatment of tumors localized to a mucosal surface

    Expert Consensus on Microtransplant for Acute Myeloid Leukemia in Elderly Patients -Report From the International Microtransplant Interest Group

    Get PDF
    Recent studies have shown that microtransplant (MST) could improve outcome of patients with elderly acute myeloid leukemia (EAML). To further standardize the MST therapy and improve outcomes in EAML patients, based on analysis of the literature on MST, especially MST with EAML from January 1st, 2011 to November 30th, 2022, the International Microtransplant Interest Group provides recommendations and considerations for MST in the treatment of EAML. Four major issues related to MST for treating EAML were addressed: therapeutic principle of MST (1), candidates for MST (2), induction chemotherapy regimens (3), and post-remission therapy based on MST (4). Others included donor screening, infusion of donor cells, laboratory examinations, and complications of treatment

    An Optimized Design Method and Experimental Study of Belt-Type Ultra-High-Pressure Dies

    No full text
    In this study, various structures are designed to improve the bearing capacity of belt-type ultra-high-pressure dies. Via theoretical analysis, numerical simulation, and destructive experiments, the stress distribution, bearing capacity, and failure principle of various dies are analyzed. The results demonstrate that the positive and negative values of the third invariant of the deviatoric stress tensor J3′ determine the deformation mode of the cylinder; when J3′ > 0, the cylinder is in the tensile deformation state, and when J3′ J3′ > 0, which causes tensile failure and rupture due to excessive circumferential stress. The use of a split cylinder can significantly reduce the circumferential stress, thus effectively reducing the maximum shear stress and von Mises stress and improving the pressure capacity of the cavity. However, when J3′ > 0 for the split cylinder, the pressure capacity is affected and the cylinder experiences tensile failure. A tangential split cylinder has a compressive deformation of J3′ < 0, which can fully utilize the properties of hard alloy materials and significantly improve the pressure-bearing capacity of the cylinder. This article provides an effective optimization design theory for belt-type dies, and the effectiveness of this method is proven through experiments

    Investigation on the effects of fabrication parameters on the structure and properties of surface-modified membranes using response surface methodology

    Get PDF
    Surface Modifying Macromolecules (SMM) were used to alter the hydrophobicity of polyetherimide (PEI) hollow fiber membranes and the effects of three fabrication parameters, which are the mass fraction of PEI and SMM in the casting dope and air gap, on the properties of fabricated membranes were investigated by application of Response Surface Methodology (RSM). The fabricated membranes were characterized in terms of mean pore size (r P,m), permeation rate of helium gas at 1 bar transmembrane pressure difference, membrane porosity, and contact angle of water with inner and outer surfaces of membrane. The regression models obtained for mean pore size and permeation rate have good statistical parameters and are accurate. The model for r P,m predicts that plot of r P,m versus air gap has a minimum point, whereas the plots of r P,m versus PEI (wt %) and SMM (wt %) have maximum points. The regression model developed for membrane porosity predicts that membrane porosity decreases when air gap increases. Since water was used as bore fluid, the model developed for inner surface contact angle has low accuracy but the model developed for outer surface contact angle predicts that contact angle increases with SMM concentration in dope solution but there is a maximum point versus air gap
    • …
    corecore