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101.
Adsorption of different aromatic compounds (two of them are electrolytes) onto an untreated activated carbon (F100) is investigated. The experimental isotherms are fitted into Langmuir homogenous and heterogeneous Model. Theoretical maximum adsorption capacities that are based on the BET surface area of the adsorbent cannot be close to the real value. The affinity and the heterogeneity of the adsorption system observed to be related to the pKa of the solutes. The maximum adsorption capacity (Q
max) of activated carbon for each solute dependent on the molecular area as well as the type of functional group attached on the aromatic compound and also pH of solution. The arrangement of the molecules on the carbon surface is not face down. Furthermore, it is illustrated that the packing arrangement is most likely edge to face (sorbate-sorbent) with various tilt angles.For characterization of the carbon, the N2 and CO2 adsorption were used. X-ray Photoelectron Spectroscopy (XPS) measurement was used to surface elemental analysis of activated carbon. 相似文献
102.
Hassan Sereshti Saba Semnani Jazani Nina Nouri Mohammad Hossein Shojaee AliAbadi 《Journal of separation science》2022,45(5):1106-1115
A new green miniaturized quick, easy, cheap, effective, rugged, and safe approach was developed and used for the extraction of multiclass 16 pesticides in milk before gas chromatography analysis. The miniaturization of method reduced the consumption of chemical reagents and samples. Magnetic three-dimensional graphene was used as sorbent in the clean-up step. Choline chloride:lactic acid (1:2) natural deep eutectic solvent was used as desorption solvent. Temperature-assisted solidification of floating menthol drop was executed for preconcentration of analytes. The method parameters including sorbent, desorption solvent, sorption and desorption times, menthol amount, pH, and ionic strength were optimized. The limit of quantification and linear range were 0.03–0.38 and 0.03–250 μg/kg, respectively. The accuracy was assessed by recovery evaluation at the spike levels of 50 and 100 μg/kg, in the range of 61–119%, with relative standard deviations within 2.1–18.2%. The method was applied to the analysis of pasteurized low and high-fat bovine milk, and various pesticide residues were detected in the concentrations range of 1.24–4.68 μg/kg. Finally, the greenness of the procedure was evaluated using the Analytical Eco-Scale. This work represents the first application of hybrid miniaturized extraction/preconcentration using a natural deep eutectic solvent and menthol to analyze pesticides. 相似文献
103.
Parallel solution phase methods for the preparation of a 72-membered 3-aryl-4,5-dihydroisoxazole-5-carboxamide library is reported. The reaction order (nitrile oxide 1,3-dipolar cycloaddition followed by amide formation, or vice versa) was investigated both experimentally and computationally to determine which route would result in the highest yields, minimize purification efforts, and give higher 1,3-dipolar cycloaddition regioselectivity. Automated preparative HPLC was used to purify the final products to >or=90% purity on a 10+ mg scale. 相似文献
104.
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106.
A series of binary and ternary blends composed of polylactic acid (PLA), low-density polyethylene (LDPE), and chitosan (CS) were prepared and characterized in terms of their morphological and mechanical properties. The mechanical properties of the prepared blends, including tensile properties and impact strength, were compared with neat PLA. In addition, the effect of incorporation of maleic anhydride-grafted linear low-density polyethylene (LLDPE-g-MA) as a compatibilizing agent, and the order of mixing on the mechanical and morphological properties of the ternary blends were also studied. It was observed that addition of CS enhanced the stiffness of PLA/LDPE blends while it decreased the toughness and tensile strength. It was demonstrated that addition of LLDPE-g-MA, up to 10 wt%, had no significant compatibilizing effect. However, the mechanical results indicated that when 15 wt% of LLDPE-g-MA was loaded, it started to play a compatibilizing role and caused an improvement in the toughness properties of ternary blend. 相似文献
107.
For a stationary nonlinear Boltzmann equation in a slab with a particular truncation in the collision operator, the Milne problem for the boundary layer together with a weak type of hydrodynamic behavior in the interior of the slab are studied by nonperturbative methods in the small-mean-free-path limit. 相似文献
108.
Boundary conditions for multidimensional scalar conservation laws are obtained in the context of hydrodynamic limits from a kinetic point of view. The initial boundary value kinetic problem is well posed since inward and outward characteristics of the domain can be distinguished. The convergence of the first momentum of the distribution function to an entropy solution of the conservation law is established. Boundary conditions are obtained. The equivalence with the Bardos, Leroux, and Nedelec conditions is studied. 相似文献
109.
L. Arkeryd R. Esposito R. Marra A. Nouri 《Archive for Rational Mechanics and Analysis》2010,198(1):125-187
We consider the Boltzmann equation for a gas in a horizontal slab, subject to a gravitational force. The boundary conditions
are of diffusive type, specifying the wall temperatures, so that the top temperature is lower than the bottom one (Benard
setup). We consider a 2-dimensional convective stationary solution, which for small Knudsen numbers is close to the convective
stationary solution of the Oberbeck–Boussinesq equations, near and above the bifurcation point, and prove its stability under
2-d small perturbations, for Rayleigh numbers above and close to the bifurcation point and for small Knudsen numbers. 相似文献
110.
Kheirollah Nouri Mitra Ghassemzadeh Farshid Mohsenzadeh Maryam Afsharpour 《应用有机金属化学》2020,34(9):e5771
Fuberidazole has been successfully immobilized onto nano-Fe3O4 supported (3-chloropropyl)trimethoxysilane (3-CPTS) leading to a novel functionalized magnetic nanoparticle (FB/MNP). The Pd(0) complex, Pd-FB/MNP, was prepared by grafting Pd (OAc)2 on FB/MNP and subsequent reduction of a synthesized Pd (II) complex using NaBH4. Pd-FB/MNP has been characterized by FT-IR, SEM, TGA, XRD, ICP, EDS, BET and VSM. The Pd(0) complex proved to be an efficient phosphine- and halide-free recyclable heterogeneous catalyst for Suzuki as well as for Stille C-C coupling reactions showing high catalytic activity (up to 98%). Its catalytic activity in both reactions has been studied in PEG-400 as a green solvent. Besides, the selectivity of aryl iodide and aryl bromide over aryl chloride is observed during the C-C coupling reaction. The catalyst could be recovered easily from the reaction mixture using an external magnet device and recycled several times without considerable loss in activity. Additionally, the results of a palladium leaching test of the nano-catalyst demonstrate that no leaching of Pd took place during the C-C coupling process making the procedure environmentally friendly. 相似文献