D001树脂吸附铁离子后的脱附研究

通过脱附试验,选用HCl对D001树脂进行再生,考察了脱附剂浓度、脱附时间、脱附温度对树脂脱附效果的影响;通过吸附试验,考察了D001树脂在不同HCl浓度下对铁离子的吸附.试验结果表明,25℃时,质量分数为20%的HCl在对吸附铁离子的D001树脂(吸附量为11.729mg/g)进行脱附,60min时可达到较大的脱附量...     

Desorption of cadmium from algal biosorbent

Desorption of metal-laden new biosorbent material was studied using batch and column equilibrium elution processes. Equilibrium screening tests of cadmium desorption established a solution of HC1 as the most appropriate eluant at approximately pH 1.0. The desorption of Cd by protons was indicated to be a reversible exchange with a stoichiometric coefficient of 1.24. The solid to liquid ratio (biosorbent mass to elutant volume) is described as a key parameter in determination of elution efficiency, affecting simultaneously the pH at desorption equilibrium, the concentration of cadmium released, and the concentration ratio of the overall metal recovery process. When the pH is maintained constant, the solid to liquid ratio has little influence on metal recovery but still controls the concentration ratio. Recycling a small amount of eluant through a desorption column with metal-laden biosorbent material resulted in very high solid-to-liquid ratios (up to 130 g/L) leading to high value of 70 for the metal concentration ratio of the sorption/desorption process. No loss of cadmium biosorbent properties was observed in three consecutive metal uptake/desorption cycles.     

Second Order Isothermal Desorption Kinetics

A new method is presented to analyze recombinative desorption from surfaces in an isothermal mode. The activation energy for desorption obtained this way is accurate as long as it is coverage independent. Second order recombinative desorption experiments of ¹⁵N₂ and D₂ from Ru(001) were used to demonstrate this method. The activation energies were E _a(N₂) = 48±2 kcal/mol and E _a(D₂) = 22±1 kcal/mol for coverages below 0.1 and 0.2 of saturation coverage, respectively. Studying N/Ru(001) provides evidence for bulk nitrogen atoms that slowly diffuse to the surface leading to isotope scrambling.     

Use of three types of magnetic biochar in the removal of copper(II) ions from wastewaters

Three types of magnetic biochars (MBC1, MBC2, and MBC3) were synthesized from biochar using NaBH₄ as a reducing agent of Fe(II) to Fe(0) to remove copper(II) ions from different wastewaters. Based on the research it was found that removal of copper(II) ions by MBC1 occurs with a yield of 99.8% for the concentration 50 mg/dm³ and decreases to 71.7% at 200 mg/dm³. The maximum pH sorption was found at pH 5. The highest correlation coefficient values (65.55 mg/g) were obtained for the Langmuir isotherm model. Application of 0.5 mol/dm³ HNO₃ as a desorbing agent gives the highest desorption percentage 98.92%.     

尿素解吸改造小结

介绍了该公司对解吸系统进行改造的情况,改造效果良好,既增大了解吸系统的操作弹性,降低了氨耗,又保护了环境。     

pH和有机配体对Cu-Pb复合污染土壤中Cu的解吸行为的影响

以黄棕壤为供试土壤,研究了pH对Cu-Pb复合污染土壤中Cu的解吸行为的影响。实验结果表明,无论以EDTA还是以C IT为萃取剂,pH值都会对Cu的解吸情况产生重要影响。当解吸液pH值为4.0时,Cu的解吸量最小;Cu的解吸率在各个pH下的大小顺序大致为:pH 5.6的>pH 3.0的>pH 4.0的。     

超重力对活性炭上苯酚脱附性能的影响

研究了超重力对活性炭上苯酚脱附性能的影响及脱附动力学,并与传统脱附法进行了对比.结果表明,在常温、常压、超重力因子β=55.14、液体流率为40 L/h、碱液浓度为0.5 mol/L、吸附时间为90 min的条件下,苯酚脱除率达93.01%,较相近条件下传统脱附法提高了3.88倍;采用拟二级动力学模型对实验数据进行拟合,脱附速率常数由较相近条件下传统脱附法的13.66×10-4提高到超重力条件下的29.59×10-4,表明超重力强化了液固传质,对脱附有利;两种方法中以碱液为脱附剂的脱附性能均优于蒸馏水为脱附剂.     

超声场对氢键缔合体系解吸平衡的影响研究

Effects of ultrasound on intensification of separation process were investigated through the experiment of desorption equilibrium behavior. Tri-butyl phosphate (TBP) on NKA-X resin and phenol on a solvent impregnated resin, CL-TBP resin, were used for desorption processes. The desorption rate was measured with and without ultrasound. Desorption equilibrium was studied under various ultrasonic power densities or thermal infusion. Results showed that the desorption rate with ultrasound was much higher than that with normal thermal infusion. Both ultrasound and thermal infusion broke the desorption equilibrium existed at room temperature. However, after the systems were cooled down, the amount of solute desorbed in the liquid phase in the presence of ultrasound was much higher than that at the temperature corresponding to the same ultrasound power. It is proved that the initial desorption equilibrium was broken as a result of the spot energy effect of ultrasound.     

Desorption mass spectrometry of olestra

Field desorption (FD), fast atom bombardment (FAB) and plasma desorption (PD) mass spectrometry have been used for the characterization of olestra, a mixture of octa-, hepta- and hexaesters of sucrose formed by reaction of sucrose with long-chain fatty acids (C₁₂–C₁₈). Most previous applications of desorption ionization mass spectrometry have involved polar compounds; however, the relatively low-polarity olestra is also amenable to these techniques with proper sample preparation. Field desorption provides molecular weight information, but the transience of the signals limits the usefulness for observing fragmentation and measuring ester distributions. In addition, FD may not be sensitive enough to allow characterization of fractions isolated from analytical high-performance liquid chromatography (HPLC) columns. Fast atom bombardment produces longer-lasting signals, which permit characterization of components over a wide mass range. However, signal-to-noise fluctuates substantially, depending on analyte solubility in the matrix, making the characterization of partial esters collected from HPLC uncertain and difficult. Plasma desorption mass spectrometry is the easiest and most sensitive technique for olestra characterization but provides the lowest mass resolution. Because it requires no more than a few μg of material, it is effective for the characterization of HPLC fractions. Furthermore, it is the only method, of the three investigated, that allows detection of intact dimeric species having molecular masses in the 3,000 to 5,000 dalton range.     

有机胺溶液解吸CO_2的研究进展

随着温室效应的日益严重,人们对CO2的处理吸收给予了越来越多的关注。CO2既是一种污染物,也是一种工业资源,除了可以用其生产尿素、纯碱等化工产品外,还可将其用于石油开采以提高石油采收率。工业上CO2的分离提纯方法很多,其中以有机胺水溶液为吸收剂的CO2吸收法广泛应用于天然气、炼厂气、合成气及烟道气等各种气体净化工艺中。本文综述了国内外有机胺溶液解吸CO2的研究进展,指出了各种方法的优缺点,以便更好的回收和利用CO2。     

Factors Affecting on the Sorption/Desorption of Eu (III) using Activated Carbon

Abstract

The sorption and desorption of Eu (III) on H‐APC activated carbon using a batch technique has been studied as a function of carbon type, shaking time, initial pH solution, temperature, particle size of carbon, and concentration of the adsorbent and the adsorbate. The influence of different anions and cations on adsorption has been examined. The experimental data have been analyzed by Langmuir, Freundlich, and Temkin sorption isotherm models and the adsorption data for Eu (III) onto activated carbon were better correlated to the Temkin isotherm and the maximum absorption capacities obtained was 46.5 mg g^?1. Anions of phosphate, carbonate, oxalate, and acetate were found to increase the adsorption of Eu (III), whereas nitrate, chloride and all studied cations, potassium, sodium, calcium, magnesium, and aluminum have a negative effect on the adsorption capacity. More than 99% europium adsorbed on H‐APC eluted with 0.5 M HCl solution. The activated carbon prepared from apricot stone using 70% H₃PO₄ could be considered as an adsorbent that has a commercial potential for Eu (III) treatment.     

用铜精矿生产硫酸铜的新工艺

介绍了一种用铜精矿粉制备硫酸铜的新方法，该方法使用一种廉价的复配添加剂，使铜精矿中的铁在焙烧过程中形成难溶于稀硫酸的碱式硫酸铁复盐。浸取滤液不需除铁，直接降温结晶便可生产出达标的硫酸铜产品。其优化工艺条件为：添加剂加量为铜精矿粉的4％-6％（质量分数），焙烧时问为3h，浸取时间为2．5—3h，浸取液硫酸加量控制在55～60g／L。采用此新工艺，硫酸铜收率可达95％以上。具有流程短、投资少、操作简单、铜利用率高、易工业化实施等特点。     

仿生防污涂料的发展概况

介绍了无污染新型海洋防污涂料———仿生防污涂料;概述了它两方面技术的发展情况:①采用新型高分子材料,赋予涂层特殊的表面结构和特性。②提取天然物质作为防污剂。展望了这类涂料的应用前景。     

Desorption of the surfactant from the particle surface during latex film formation

Properties of latex films are very dependent on the distribution of the surfactants in the film. It has been recognized that distribution itself depends on the desorption characteristics of the surfactant from the particle-water interface during film formation. This article deals with this problem of surfactant desorption in the particular situation of latex film formation. First, FTIR spectroscopic evidence is presented for desorption of hexadecyl pyridinium chloride (HPCI) in poly(2-ethyl hexyl methacrylate) (P2EHMA) latex films. Some consequences of desorption or non-desorption of various surfactants on the structure and properties of P2EHMA latex films are then presented. This concerns the crystallization of cationic surfactants, HPCI and hexadecyl trimethylammonium bromide (HTAB), in the films and the mechanical properties of films containing ethoxylated nonyl phenol with 10 ethoxy segments (NP10) or sodium dodecyl sulphate (SDS). In the last part, the determination of the fraction of SDS desorbing from the particle–water interface in a model poly(styrene–butyl acrylate–methacrylic acid) latex coalescing in water is described. Other methods for studying desorption are proposed.     

Desorption of water vapor in hydrogen-bonded polymer blends

Successive desorption experiments of water vapor in poly(methyl methacrylate) (PMMA) were performed at temperatures from 31.0 to 45.0°C. The solubility of water in PMMA was found to be independent of temperature in agreement with literature findings. But the results for diffusion showed stronger dependence on water concentration than those in literature. The diffusion coefficients of water in PMMA became almost independent of temperature at high water concentrations. However, at lower water concentrations, the temperature effect on diffusion was more pronounced. The observed weak temperature dependence of diffusivity at high concentrations is likely due to a high degree of clustering of water molecules found in the PMMA we prepared. Two modified polystyrenes containing 5 and 15 mol %, respectively, 4-hydroxystyrene as comonomer units were blended with PMMA to form hydrogen-bonded polymer blends. Successive desorption experiments of water vapor in the hydrogen-bonded polymer blends were carried out at 31.0°C. The solubility of water in both blends was found to increase with increasing composition of PMMA. The diffusion coefficients for PMMA and its blends increased with increasing concentration of water first, reached a maximum, then decreased with water concentration. When the desorption results were plotted with the previous study of absorption, hysteresis phenomenon of sorption existed in all blend compositions for our experimental time span. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 39–45, 1998     

尿素解吸系统改造新工艺

采用碳铵液解吸新工艺和特殊塔内件结构设计,保证塔釜尿素解吸废液中氨含量达到环保要求,同时增产尿素、节省蒸汽。     

The detailed kinetics of the desorption of hydrogen from polycrystalline copper catalysts

The kinetics of desorption of hydrogen from the copper component of an alumina-supported polycrystalline copper catalyst has been studied in detail by temperature-programmed desorption (TPD). Line-shape analysis of the hydrogen TPD spectra shows: (i) that the desorption is second order, (ii) that the desorption activation energy is in the range 64–68 kJ mol^–1 in the coverage range 7–44% of a monolayer, and (iii) that the desorption pre-exponential term has a value 10^–5 cm² s^–1 atom^–1 consistent with the desorption being second order, involving mobile adsorbates and a mobile desorption transition state.     

绿色木霉木聚糖酶在燕麦木聚糖上的亲和吸附和解析

研究了液相环境对绿色木霉木聚糖酶在水不溶性燕麦木聚糖上的亲和吸附及木聚糖酶―木聚糖复合体的解吸的影响。结果表明,燕麦木聚糖对木聚糖酶的亲和吸附作用主要依赖于它们之间的静电作用和氢键作用,疏水作用对吸附没有贡献。以pH3.0的柠檬酸―柠檬酸钠缓冲溶液为吸附体系的液相时,每克燕麦木聚糖的最大吸附容量为77IU的木聚糖酶。用含0.025mol/LNaCl、pH为7.0的柠檬酸―磷酸氢二钠缓冲溶液作为洗脱液,能将96%的被吸附的木聚糖酶洗脱下来,此时木聚糖酶活回收率为74.3%。     

An Investigation into Silane Evolution from Porous Silicon by Temperature Programmed Desorption Method

The gaseous species desorbed from porous silicon (PS) were investigated using the method of temperature programmed desorption (TPD) and fourier transform infrared spectroscopy (FTIR). Silicon wafers (25–50 cm, p^–, FZ) were anodised in 40% HF and HF/C₂H₅OH electrolytes. The PS samples were linearly heated at 1.5 K s^–1 using a custom built heating unit in a oil-free pump backed vacuum chamber at a base pressure of <10^–8 torr. A quadrupole mass spectrometer, which was used as the detector, was fitted in line of sight of the sample at a distance of about 6 mm. It was observed that silane was liberated during the heating of porous silicon samples produced from both electrolytes. The peak temperature at which this occurred was at 570 ± 10 K. This temperature coincides with the temperature of silicon-silicon bond breakage in Si–SiH₃ groups on the pore walls, as shown by the FTIR results. It is proposed that silane formation involves the reaction of the Si-silyl group with moisture: Si–SiH₃ + H₂O Si–OH + SiH₄.