Pb2+ binding by polyaspartyl polymers and their application to Pb2+ removal from glycyrrhizin

Polyaspartate is an excellent Pb²⁺‐binding agent in comparison with some polyaspartamide derivatives with different side chains, in that it possesses a higher Pb²⁺ uptake and a lower Pb²⁺ equilibrium concentration. Equilibrium sorption data for Pb²⁺ on polyaspartate can be well fitted with the Freundlich and Langmuir models. Experimental results show that a crosslinked polyaspartate hydrogel is superior to poly(acrylic acid)‐based resins and polystyrene‐based chelating resins. IR spectra and X‐ray photoelectron spectra reveal that the polyaspartate hydrogel binds Pb²⁺ by both an ion‐exchange mechanism and a chelating mechanism. The polyaspartate hydrogel is also an effective agent for the removal of Pb²⁺ from glycyrrhizin. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2215–2220, 2005     

NO emission of oxygen-enriched CH4/O2/N2 premixed flames under electric field

This work investigates the electric field effect on nitrogen oxide (NO) pollutant formation and emission composition of premixed flames in order to provide better insight on the mechanism of controlling the combustion process by electro-physical means. The present study aims to investigate experimentally the effect of radial DC electric field on premixed laminar methane flame. The electric field effect on flame shape, emission composition and NO emission index of flame is investigated experimentally under the action of direct-current electric field under varying equivalence ratio and level of oxygen enrichment. The results show that ionic wind effects cause the distortion in flame shape. The ionic wind effects diminish with increasing flow rate and level of oxygen enrichment. Minimal effects on NO are measured for flames under the influence of electric field and vanished as the level of oxygen enrichment is increased. This was well supported by the temperature profile measurement in the post flame gas showing no field-induced modification also. It seemed that the action of an electric field on a flame with a geometry that remains practically undeformed produces very minimal effect on pollutant emission.     

甲醇吹除气中氢的回收方法

对目前甲醇吹除气中氢回收的两种方法进行了比较、分析。     

Advanced oxidant reactivity pertaining to granular activated carbon beds for air pollution control

The Pennsylvania State University is researching an advanced oxidation system, which includes an air-phase photolytic chamber, an air/water stripping tower, and granular activated carbon (GAC) beds, for controlling volatile organic compounds (VOCs).A laboratory-scale experimental procedure has been employed that simulated certain aspects of several full-scale installations. The apparatus has been used to characterize the loading capacity and mass transfer zone of selected VOCs on coconut shell GAC. The GAC bed has then been placed in series with an ultraviolet reactor, which generates ozone and advanced oxidants in order to regenerate the loaded GAC at intensities of advanced oxidants that were higher than full-scale installations.VOC loading tests revealed that the adsorption of methyl isobutyl ketone (MIBK) was characterized by a well-defined mass transfer zone. Upon exposure to UV/O₃, desorption and/or destruction of the MIBK and other VOCs occurred most prominently within the first inch of the GAC bed. This correlated with the penetration of advanced oxidants into the GAC bed, which also occurred most significantly in the bed's first inch. However, the amount of oxidant penetration increased with time. The removal of oxidants from air by GAC was accompanied by a decrease in mass of the GAC. The ability of oxidants to penetrate a GAC bed was altered when the bed was loaded with a VOC.     

烷烃中少量芳烃的固定床和模拟移动床吸附

在实验研究烷烃中少量芳烃的固定床吸附动态过程和模拟移动床吸附动态过程的基础上,用固定床和模拟移动床线性推动力模型进行了模拟计算,可得到如下结论:在本文的实验条件下,固定床吸附动态模型和模拟移动床吸附动态模型拟合的结果均与实验值相符;但从技术性能指标和技术经济指标两个角度都反映出对脱除烷烃中的少量芳烃的吸附分离过程,用固定床吸附过程比模拟移动床吸附过程更具有可行性。这些结果为在直链烷基苯的生产过程中,降低循环烷烃中芳构化物的含量,实现延长脱氢催化剂的寿命,提高烷基苯的产量提供了技术基础。     

变性淀粉取代聚乙烯醇生产Al2O3刚玉陶瓷的胶粘剂研究

论述了变性淀粉取代聚乙烯醇(PVA)生产Al2O3刚玉陶瓷的意义及聚乙烯醇结构与吸附性能的关系，并且根据胶粘机理，通过分析Al203胶粒的表面特性和变性淀粉的结构，说明了变性淀粉可以取代聚乙烯醇。     

Predicting N mineralized in a Georgia Coastal Plain field

The N mineralized from soil organic matter provides an important portion of N available for crop production. The objective of this study was to determine the amount of spatial variability in N mineralization potential in a field and to evaluate three different methods that might be used to estimate this variability. The three methods tested included predicting the N mineralized from surface soil properties as well as from a biological and a chemical procedure. Three soils varying in N mineralization potential were selected for the study from a field in the Georgia Coastal Plain. The N mineralized from these soils was determined by an N balance of unfertilized and cropped plots. The amount of N mineralized could not be reliably predicted from surface soil organic C, although surface soil clay concentration was positively correlated with the N mineralized. The N mineralized that was predicted using mineralization parameters determined by aerobic incubation, adjusted daily for soil water content and temperature, was approximately 50% of the field measurements of N mineralized. The values of NH₄-N extracted with hot 2 M KCl were related significantly to N mineralized in the field (r²= 0.60) and also to the zero order rate constant of mineralization, k₀ (r²= 0.77), determined from the N mineralized in the aerobic laboratory incubation.     

Phenol adsorption on porous and non-porous carbons

Phenol physisorption on a series of porous and non-porous amorphous carbons was studied at 298 K. Grand Canonical Monte Carlo computer simulations were performed to simulate phenol adsorption from the gas phase. Phenol is adsorbed in a solid-like state within the pores and there is no well-developed multilayer regime. The ‘t’ plot method was adapted to phenol adsorption and the results obtained are in agreement with the model solids employed. The simulated adsorption isotherms were compared with experimental results obtained for adsorption from aqueous solutions of phenol. BET surface areas were calculated. Other characteristics of the adsorption system analyzed were: adsorption energy distribution functions, density profiles, distribution of molecules according to gas-solid energy, and local isotherms.     

Micropore characterization using the Dubinin-Astakhov equation to analyze high pressure CO2 (273 K) adsorption data

The characterization of the pore structure of microporous materials is of interest because of the usefulness of these materials in many applications. Of these, the characterization of carbon adsorbents is particularly problematic because of the presence of small pores with size on the order of small molecules (micropores) along with a wide distribution of pore sizes, and their non-crystalline structure. In this paper, we present results obtained using the Dubinin-Astakhov equation to analyze data from high pressure CO₂ adsorption at 273 K to characterize two sets of microporous carbons. Our results support the conclusions of previous workers that the Dubinin-Astakhov (DA) equation is able to linearize adsorption data that gives rise to curved Dubinin-Radushkevich plots. However, when applied over different ranges of relative pressure on the adsorption isotherm, the Dubinin-Astakhov plots result in different values of micropore volume and characteristic adsorption potential. Furthermore, DA analysis of CO₂ (273 K) adsorption data over a wide range of pressures (10^–3–22000 Tort), gives results different from DA analysis of CO₂ (273 K) isotherms measured at low pressures only (10^–3–830 Tort). It would appear desirable to apply the DA equation to data that reflects the entire range of micropore filling on the adsorption isotherm, as opposed to data over a limited relative pressure range. For CO₂ adsorption at 273 K, this would necessitate adsorption studies at high pressures, to about 28 atm. Micropore volumes obtained in this manner, agreed with the total pore volumes determined by nitrogen (77 K) adsorption for all the activated carbons studied.     

聚苯胺/涤纶导电织物再掺杂及洗涤性能的研究

采用现场吸附聚合法制备了聚苯胺 /涤纶导电织物 ,采用不同种类的酸对其进行再掺杂 ,研究了酸的种类对织物导电性能的影响 ,并对导电织物进行了洗涤实验及洗涤牢度实验。结果表明 :无机酸对导电织物的掺杂效果优于大多数有机酸。导电涤纶织物的导电性能受洗涤液酸碱度的影响 ,其中碱性洗涤液使导电性能降低 2个数量级 ,酸性洗涤液使导电性能下降 1个数量级 ,而且聚苯胺在涤纶织物表面具有良好的附着性