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Preparation and swelling properties of a starch-g-poly(acrylic acid)/organo-mordenite hydrogel composite

Yan Zhang,Pingqiang Gao,Lin Zhao,Yizhong Chen

《化学科学与工程前沿（英文）》 2016年第10卷第1期页码 147-161 doi: 10.1007/s11705-015-1546-y

摘要： A novel hydrogel composite was prepared via inverse suspension polymerization using starch, acrylic acid and organo-mordenite micropowder with the crosslinker, , ′-methylenebisacrylamide and the initiator, potassium persulfate. Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, scanning electron microscopy, and energy dispersive spectroscopy confirmed that the acrylic acid was grafted onto the backbone of the corn starch, that the organo-mordenite participated in the polymerization, and that the addition of organo-mordenite improved the surface morphology of the hydrogel composite. The swelling capacity of the hydrogel composite was evaluated in distilled water, and solutions with different pH values, and various salt solutions. It was found that the incorporation of 10 wt-% organo-mordenite enhanced the water absorbency by 144% (from 268 to 655 g·g ) and swelling was extremely sensitive to the pH values, the concentration of the salt solution and cation type. Swelling kinetics and water diffusion mechanism of the hydrogel composite in distilled water were also discussed. Moreover, the hydrogel composite showed excellent reversibility of water absorption even after five repetitive cycles and the hydrogel composite exhibited significant environmental-responsiveness by changing the swelling medium from distilled water to 0.1 mol·L NaCl solution. In addition, the loading and release of urea by the hydrogel composite were tested and the nutrient-slow-release capability of this material was found to be suitable for many potential applications.

关键词： hydrogel composite environmental-responsiveness organo-mordenite starch acrylic acid

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Removal of copper ions from aqueous solution by adsorption using LABORATORIES-modified bentonite (organo-bentonite

Sandy, Velycia MARAMIS, Alfin KURNIAWAN, Aning AYUCITRA, Jaka SUNARSO, Suryadi ISMADJI

《化学科学与工程前沿（英文）》 2012年第6卷第1期页码 58-66 doi: 10.1007/s11705-011-1160-6

摘要： Equilibrium, kinetic and thermodynamic aspects of the adsorption of copper ions from an aqueous solution using linear alkylbenzene sulfonate (LABORATORIES) modified bentonite (organo-bentonite) are reported. Modification of bentonite was performed via microwave heating with a concentration of LABORATORIES surfactant equivalent to 1.5 times that of the cation exchange capacity (CEC) of the raw bentonite. Experimental parameters affecting the adsorption process such as pH, contact time and temperature were studied. Several adsorption equations (e.g., Langmuir, Freundlich, Sips and Toth) with temperature dependency were used to correlate the equilibrium data. These models were evaluated based on the theoretical justifications of each isotherm parameter. The Sips model had the best fit for the adsorption of copper ions onto organo-bentonite. For the kinetic data, the pseudo-second order model was superior to the pseudo-first order model. Thermodynamically, the adsorption of copper ions occurs via chemisorption and the process is endothermic (Δ >0), irreversible (Δ >0) and nonspontaneous (Δ >0).

关键词： heavy metal copper adsorption organo-bentonite temperature dependent

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Halide-free carbonylation of methanol with H-MOR supported CuCeO

Chaoli Tong, Jiachang Zuo, Danlu Wen, Weikun Chen, Linmin Ye, Youzhu Yuan

《化学科学与工程前沿（英文）》 2021年第15卷第5期页码 1075-1087 doi: 10.1007/s11705-020-2019-5

摘要： Heterogeneous halide-free carbonylation of methanol to acetates, including methyl acetate (MA) and acetic acid, using non-precious metal catalysts has been a topic of interest for decades. The key issue is that the water produced by methanol dehydration inhibits the formation of acetyl species and reduces the MA selectivity. Here, we report that CuCeO /H-mordenite (H-MOR) catalyst can nearly eliminate the inhibiting effect of water on carbonylation by a water-gas shift reaction (WGSR) on-site, and can thus achieve 96.5% methanol conversion with 87.4% MA selectivity for the halide-free carbonylation of methanol. The results of powder X-ray diffraction, transmission electron microscopy, and scanning electron microscopy show that the Cu and Ce species are highly dispersed on H-MOR even when the CuCeO contents are as high as 29 wt-%. Fourier transform infrared spectroscopy and CO chemisorption analysis reveal that a small portion of Cu species can migrate into the channel of H-MOR when CuCeO /H-MOR is calcined at 500 °C and these Cu species are converted into Cu sites upon reduction. The Cu sites facilitate the WGSR and are also active sites for methanol carbonylation. The introduction of Ce benefits the inhibition of coke deposits and thus enhances the catalyst stability.

关键词： methanol carbonylation halide-free methyl acetate H-mordenite copper and cerium oxide