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Nahomi Sakaguchi Keiji Yamada Shuji Matsuo Taku Matsuo Hisanobu Wakita 《Research on Chemical Intermediates》2006,32(2):171-182
Surface modification of TiO2 powders with lanthanide salts (EuCl3 or YbCl3) enhanced photocatalytic decomposition of ATP. In comparison with the unmodified catalyst, a 3-fold increase in the ATP decay
rate was observed with TiO2 powders as prepared in 5 mM EuCl3 (or YbCl3) solution. The reason was ascribed to enrichment of ATP to TiO2 powder with the lanthanide ions. Evidence was obtained by adsorption experiments where ATP concentration was monitored after
dispersing TiO2 powders into the solution. The ATP molecules adsorbed faster to TiO2 powder and strongly stabilized there in the presence of Yb3+ than otherwise. 相似文献
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THERMODYNAMIC STUDY OF ADSORPTION OF PHENOLIC COMPOUNDS FROM AQUEOUS SOLUTION BY A WATER-COMPATIBLE HYPERCROSSLINKED POLYMERIC ADSORBENT 总被引:2,自引:0,他引:2
Ai-minLi Hai-suoWu Quan-xingZhang Gen-chengZhang ChaoLong Zheng-haoFei Fu-qiangLiu Jin-longChen 《高分子科学》2004,(3):259-267
Equilibrium data for the adsorption of phenolic compounds, i.e., phenol, p-cresol, p-chlorophenol and p-nitrophenol from aqueous solutions by a water-compatible hypercrosslinked polymeric adsorbent (NJ-8) within temperature range of 283-323 K were obtained and correlated with a Freundlich-type of isotherm equation, so that equilibrium constants KF and n were obtained. The capacities of equilibrium adsorption for all the four phenolic compounds on the NJ-8 from aqueous solutions are around 2 times as high as those of Amberlite XAD-4, which may be attributed to the unusual micropore structure and the partial polarity on the network. The values of the enthalpy (always negative) are indicative of an exothermic process, which manifests the adsorption of all the four phenolic compounds on the two polymeric adsorbents to be a process of physical adsorption. The negative values of free energy change show that the solute is more concentrated on the adsorbent than in the bulk solution. The absolute free energy values of adsorption for NJ-8 are always higher than those for Amberlite XAD-4, which indicates that phenolic compounds are preferentially adsorbed on NJ-8. The negative values of the adsorption entropy are consistent with the restricted mobilities of adsorbed molecules of phenolic compounds as compared with the molecules in solution. The adsorption entropy values of phenolic compounds for NJ-8 are lower than those for Amberlite XAD-4, which means the micropores of NJ-8 require more orderly arranged adsorbate. 相似文献
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本文对固态青蒿素的FT-Raman光谱和普通Raman光谱以及低浓度(1×10^-^5mol/L)青蒿素水溶液的表面增强Raman散射(SERS)光谱进行了检测, 着重观察了1756cm^-^1六元内酯环振动谱带, 发现其在FT-Raman和普通Raman光谱中表现为强振动, 而在SERS光谱中此振动谱带消失, 说明分子内酯环发生了破裂。根据1756cm^-^1谱带的变化以及724cm^-^1过氧基团振动频率的位移, 对青蒿素在银表面上的吸附取向进行了研究。还研究了青蒿素与氯高铁血红素的作用情况, 发现两者作用后, 明显改变了青蒿素在银表面上的吸附。 相似文献
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ADSORPTION OF 2,4-D ON MODIFIED HYPERCROSSLINKED POLYSTYRENE (NDA-99) AND XAD-4 RESIN 总被引:1,自引:0,他引:1
The adsorption behavior of pesticide 2,4-dichlorophenoxyacetic acid (2,4-D) in aqueous solution has been investigated using a hypercrosslinked polystyrene adsorbent (NDA-99) modified by dimethylamine group as well as a nonionic macroporous adsorbent (XAD-4). The Langmuir and Freundlich isotherm models were employed to fit the experimental data to describe adsorption mechanism. It shows that NDA-99 resin exhibits an adsorption affinity for 2,4-D higher than XAD-4 resin owing to its exceptional micropore structure and the amine group of the hypercrosslinked matrix.Further studies indicate that the hydrogen bonding interaction and the stronger π-π conjugation play a significant role in the course of the adsorption of 2,4-D on NDA-99 resin, which is in agreement with the IR spectroscopic results and the △E values of HOMO (the highest occupied molecular orbit) of adsorbent and LUMO (the lowest unoccupied molecular orbit) of adsorbate calculated from the MINDO/3 model. 相似文献
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用计量置换吸附模型研究液-固色谱中的溶质保留机理 总被引:3,自引:0,他引:3
本文以表面物理化学吸附模式为基础, 推导出液-固色谱中溶质计量置换保留模型. 与其他模型进行比较的结果证明本模型为最佳. 提出用参数j作为区别反相色谱和液-固色谱的判据. 相似文献
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《Composite Interfaces》2013,20(2):205-212
We investigate the adsorption behavior of methyl orange (MO) on composite xerogels. Mesoporous TiO2-SiO2 and TiO2-SiO2-Al2O3 xerogels are prepared by hydrolysis of tetraethyl orthosilicate (TEOS), tetrabutyl orthotitanate (TBOT), and AlCl3 ·6H2O using HCl as a catalyst and cetyltrimethylammonium bromide (CTAB) as a templating agent. The corresponding microporous xerogels are also prepared without addition of CTAB. These xerogels are then characterized by XRD, FTIR, and BET.We find that MO is adsorbed by the mesoporous xerogels in acidic solutions, showing Langmuir type adsorption isotherms. We also find that the adsorption decreases with increasing temperature. It is suggested that adsorption exhibits a sieve effect and that MO is adsorbed through electrostatic attraction and hydrogen bonding between MO and the xerogels. 相似文献
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