Preconcentration and Determination of Trace Palladium with 1, 5-Diphenylcarbazone- Naphthalene as Adsorbent by Atomic Absorption Spectrometry

ABSTRACT|A highly selective, sensitive, rapid and simple atomic absorption spectrometric method has been developed for the determination of trace amounts of palladium in synthetic and real samples. Palladium can be adsorbed on naphthalene-1, 5-diphenyl-carbazone (DPCO) as adsorbent from the large volume of its aqueous solutions in the pH range 2.0 to 0. After filtration, the metal ion was desorbed with 5ml of 0.25M thiourea solution, and determined by AAS.

Alternatively, palladium can be adsorbed on this adsorbent packed in a column and determined similarly. The detection limit is 0.5 μg (signal to noise ratio=2) and the linearity is maintained in concentration range of 1.5-50μg of Pd with a correlation coefficient of 0.9992. Seven replicate determinations on samples containing 2.5 and 20μg of palladium gave the relative standard deviations of 3.6% and 0.81%, respectively. Various parameters such as effect of pH, volume of aqueous phase, shaking time and interference of number of ions on the determination of Pd have been studied in detail to optimize the conditions for its estimation in various synthetic and real samples.     

Sample and Sorbent Integrity During Combustion Source Sampling

Abstract

A research program was initiated to evaluate the stability of selected organic compounds collected on porous polymer sorbents during combustion source sampling. This type of study is necessary to determine if destruction and removal of hazardous materials waste has occurred during incineration and not as a result of the sampling and analytical approach used. Two compounds, hexachlorobenzene and toluene diisocyanate, were selected for study. Due to difficulties encountered in preliminary work, studies on toluene diisocyanate were discontinued. Hexachlorobenzene sorbed onto XAD-2 resin at the 1 μg level was exposed to the following conditions intended to simulate hazardous waste incineration stack samplin: moist air, moist air in combination with HCl (two concentrations), and warm air. Recoveries following exposure were determined for each of three trials. The results indicate that hexachlorobenzene sorbed onto XAD-2 is stable with respect to the conditions routinely encountered during incineration stack sampling.     

氨基酸在固/液界面的吸附作用

本文介绍了氨基酸在固/液界面吸附等温线的特点,氨基酸液相吸附热力学和活性炭、硅胶、二氧化钛、氧化铝、蒙脱土等自水中吸附氨基酸的机制。     

Investigations on the adsorbents for uremic middle molecular toxins (II)

Chitosan resins, which clinically served as adsorbents in hemo perfusion therapy, were prepared with reversed-phase suspension methodology using three differently structured crosslinking agents, methanal, glyoxal and glutaraldehyde. And the glyoxal and glutaraldehyde crosslinked chitosan resins were reduced with NaBH₄ afterwards. By analyzing the results from FTIR and SEM, it was found that the reduction treatment to the adsorbents efficiently improved the chemical stability of these chitosan resins, and the shifts in crosslinking agents exerted influences over the morphologies of the adsorbents obviously. After being put to use in the adsorption tests upon some model uremic middle molecular toxins and BSA in vitro, all three adsorbents demonstrated a fairly realistic adsorption capability to the model toxins but little to BSA. And the adsorption process reached the equilibrium in a clinically qualified short time. But the adsorption capacities of these adsorbents to the model toxins were quite different. It had been found that with the growing of fatty chain length of crosslinking agent, these adsorbents showed a gradually increased adsorption capacity to the model toxins, and the glutaraldehyde crosslinked chitosan resin behaved best.     

Adsorption of carbon dioxide on microporous carbon adsorbent PAU-10

Carbon dioxide adsorption on the microporous carbon adsorbent PAU-10 within the 177.8—423 K temperature and 0.1—5.13·10⁶ Pa pressure intervals was studied. The isosteres of absolute adsorption are well approximated by straight lines, which do not change their slope on going to temperatures higher than the critical temperature of CO₂. An increase in the differential molar isosteric heat of adsorption (q _st) at 0 < a < 1 mmol g^–1 is explained by the influence of the endothermic effect of adsorption expansion of the adsorbent. In the region of high pressures and nonideal gas phase, q _st is temperature-dependent.     

Polytrimethylsilylpropyne as adsorbent for separation of gases

Polytrimethylpropyne supported on a solid substrate was proposed as a chromatographic adsorbent for the separation of hydrocarbon gases. The heats of adsorption of hydrocarbon gases were determined. The efficiency of application of this sorbent for the selective separation of C₁--C₄ hydrocarbon gases in packed columns was demonstrated.     

ADSORPTION OF DINITROPHENOLS ONTO POLYMERIC ADSORBENTS AND ITS MECHANISM

1 INTRODUCTIONPhenol and many substitUted phenols, such as nitrophenols, chlorophenols and aminophenolset al, are the common organic pollutantS existing in wane water of many chemical plants.Treatment of the wastewater containing phenols is an important project for environmentprotection and has been studied by various methods, such as dialysis ['l, microbial degradation ['1,oxidation l'l, extracting with solvents I4] and adsorption with polymeric adsorbents IS]. Theadsorption method is v…     

新型磁性亲和吸附剂的制备及其在尿激酶纯化中的应用研究

合成了磁性聚乙烯醇和磁性聚甲基丙烯酸甲酯微球,并以它们为基质,用环氧氯丙烷、羰基二咪唑或溴化氰活化后,分别键合氨基乙酸、6-氨基己酸、乙二胺或己二胺为间隔臂,用1-乙基-3-(3-二甲基氨丙基)碳二亚胺盐酸盐或羰基二咪唑为偶联试剂,分别偶联对氨基苯甲脒、L-精氨酸甲酯、胍基乙酸或胍基己酸配体,合成了17种磁性亲和吸附剂,并用于尿激酶粗品的纯化.与前文制备的8种磁性亲和吸附剂作对照,研究了基质、活化试剂、间隔臂分子、偶联试剂及配体等因素对尿激酶纯化效果的影响.这些磁性亲和吸附剂在尿激酶的纯化中取得了较好的效果,大多数磁性亲和吸附剂的活性回收率在40%～70%之间,纯化倍数为15～40,吸附容量为0.08～0.2mg/mL.     

Synthesis,Characterization and Application of Amine-Functionalized Hierarchically Micro-Mesoporous Silicon Composites for CO2 Capture in Flue Gas

An efficient CO₂ adsorbent with a hierarchically micro-mesoporous structure and a large number of amine groups was fabricated by a two-step synthesis technique. Its structural properties, surface groups, thermal stability and CO₂ adsorption performance were fully investigated. The analysis results show that the prepared CO₂ adsorbent has a specific hierarchically micro-mesoporous structure and highly uniformly dispersed amine groups that are favorable for the adsorption of CO₂. At the same time, the CO₂ adsorption capacity of the prepared adsorbent can reach a maximum of 3.32 mmol-CO₂/g-adsorbent in the actual flue gas temperature range of 303–343 K. In addition, the kinetic analysis results indicate that both the adsorption process and the desorption process have rapid adsorption/desorption rates. Finally, the fitting of the CO₂ adsorption/desorption experimental data by Avrami’s fractional kinetic model shows that the CO₂ adsorption rate is mainly controlled by the intra-particle diffusion rate, and the temperature has little effect on the adsorption rate.     

用大孔氨甲基聚苯乙烯树脂选择性吸附分离茶多酚和咖啡因

3种市售树脂ADS-5、ADS-8和ADS-17对茶多酚和咖啡因的混合物水溶液的吸附表明,具有弱极性的ADS-8对茶多酚的吸附量最大.随着树脂极性的增加(ADS-5＜ADS-8＜ADS-17),从混合物中对茶多酚的选择性吸附作用增加,表明对茶多酚的吸附可能包含疏水作用和氢键,而对咖啡因的吸附为疏水作用.在此基础上,合成了不同交联度(8%～26%DVB)的大孔氨甲基聚苯乙烯树脂,这些树脂具有疏水基质和可与酚类化合物形成较强氢键的氨基.对茶多酚和咖啡因的混合物溶液的吸附表明,这些树脂对茶多酚具有高吸附量和高吸附选择性.交联度为10%的大孔氨甲基聚苯乙烯树脂对茶多酚具有最大的吸附量,交联度为22%的大孔氨甲基聚苯乙烯树脂对茶多酚具有最大的吸附选择性.