广西某铝母液中镓钒铝的偕胺肟螯合树脂吸附与解吸试验

广西某铝土矿浸出循环母液中富含镓、钒,为给镓的分离、回收工艺研究提供依据,研究了偕胺肟螯合树脂吸附镓、钒、铝的规律和盐酸解吸的规律。结果表明:①偕胺肟螯合树脂对镓具有较高选择性,对铝的吸附率非常低;吸附温度对树脂吸附镓、铝的影响较小,对吸附钒影响较大,钒吸附率随温度升高而增大;树脂对镓的吸附速率比钒快很多;该吸附过程符合准二级动力学模型和颗粒扩散模型;镓的最优吸附条件为吸附温度25℃,吸附时间60 min。②在25℃情况下较低浓度的盐酸就能高效、快速解吸偕胺肟螯合树脂吸附的镓、铝,且受解吸温度的影响较小,钒难以解吸;提高盐酸浓度和解吸温度,盐酸对钒的解吸率明显上升;镓的最优解吸条件为盐酸浓度1.0 mol/L,解吸温度25℃,解吸时间5 min。③由于偕胺肟螯合树脂对铝土矿浸出循环母液中镓和钒的吸附率较高,且钒解吸困难,影响树脂的再生和循环利用。为了高效、低成本分离、回收镓,需在树脂吸附镓之前先采用氢氧化钠沉淀并回收原液中的钒,以尽量降低溶液的钒含量。     

Improving the functional properties of soy glycinin by enzymatic treatment. Adsorption and foaming characteristics

In this contribution we have determined the effect of limited enzymatic hydrolysis on the interfacial (dynamics of adsorption and surface dilatational properties) and foaming (foam formation and stabilization) characteristics of a soy globulin (glycinin, fraction 11S). The degree of hydrolysis (DH=0%, 2%, and 6%), the pH of the aqueous solution (pH=5 and 7), and the protein concentration in solution (at 0.1, 0.5 and 1 wt%) were the variables studied. The temperature and the ionic strength were maintained constant at 20 °C and 0.05 M, respectively. The rate of adsorption and surface dilatational properties (surface dilatational modulus, E, and loss angle) of glycinin at the air–water interface depend on the pH and DH. The adsorption decreased drastically at pH 5.0, close to the isoelectric point of glycinin, because of the existence of a lag period and a low rate of diffusion. The interfacial characteristics of glycinin are much improved by enzymatic treatment, especially in the case of acidic aqueous solutions. Hydrolysates with a low DH have improved functional properties (mainly foaming capacity and foam stability), especially at pH close to the isoelectric point (pI), because the native protein is more difficult to convert into a film at fluid interfaces at pH≈pI. The foam capacity depends on the rate of diffusion of protein to the interface and is much improved by the enzymatic treatment. Foam stability correlates with surface pressure and, to a minor extent, with surface dilatational modulus at long-term adsorption with few exceptions.     

Hydroxypropylmethylcellulose surface activity at equilibrium and adsorption dynamics at the air–water and oil–water interfaces

The surface behaviour of hydroxypropylmethylcelluloses (HPMC) was studied at the air–water (A/W) and oil–water (O/W) interfaces. At the A/W interface, the π-C isotherms were sigmoidal and presented inflexions as the HPMC bulk concentration increases, related with different structural patterns adopted by the biopolymer segments. The behaviour of these biopolymers at the O/W interface resulted different. No inflections in the adsorption isotherm were observed, denoting the absence of any change in the structure of the adsorbed monolayer. The order in the interfacial activity was different at the two interfaces.The dynamics of adsorption showed that the surface pressure (π) values and the rate of adsorption/penetration were lower at the O/W interface.Analogously to π values, the surface dilatational modulus was smallest at the O/W interface, however at long-term adsorption strong viscoelastic films are formed at the O/W interface.     

聚氯乙烯多乙烯多胺树脂吸附造纸废水中金属离子的热力学行为研究

通过改变吸附的温度,测得不同离子的吸附量,根据分配系数D与温度T的关系式lgD=-△H0/RT C 作图,由其斜率求得反应的焓变,从而从理论上说明温度对吸附的影响,同时通过改变金属离子的浓度,根据Freundlich 吸附等温式作出其吸附等温线,并求出有关常数,从而从理论上说明吸附反应进行的难易程度及树脂对金属离子吸附能力的大小.     

First-Principle Investigation of O2 Adsorption on the NiTi Alloy (110) Surface

The discrete-variational method within the framework of density functional theory was used to investigate the process of O2 adsorption occurring on the surface of NiTi alloy. The calculated results showed that O2 exhibits the adsorption state of O2δ-(0.36<δ <0.70). O2 only interact with one nearest surface Ti atom, and the Ti atom only adsorbs one oxygen atom of the O2 molecule.Other cluster atoms would not be influenced in the adsorption process. The density of state analysis showed that the interaction between Ti and O atom is mainly contributed to 2p (O) and 4s (Ti) orbitals.     

Recycling of used engine oil by different solvent

The refining of lubricating oils from waste lubricating oil was examined utilizing a novel blend of solvent extraction and activated alumina adsorbent. The activity of these solvent extraction blends {toluene, butanol and methanol (A)}, {toluene, butanol and ethanol (B)} and {toluene, butanol and isopropanol (C)} was evaluated experimentally, oil to solvent proportions from 1:1 to 1:3 were analyzed for mixture blend (C). The results confirm solvent mixture (A) gave good efficiency with the highest percent sludge removal. The maximum percent of sludge removal improves with the increase of solvent to oil ratios. The physical properties of the recycle oil were measured. The results show the change in the properties of recycling oil and have good efficiency.     

Regeneration of AgXO@SBA-15 for reactive adsorptive desulfurization of fuel

Adsorbent regeneration is critical for a continuous adsorption–regeneration process and often underestimated. In this work,the regeneration of bifunctional AgXO@SBA-15 for [O]-induced reactive adsorptive desulfurization of liquid fuel is reported and further investigated. The spent AgXO@SBA-15 was regenerated in various types of solvents followed by calcination and tested in multiple desulfurization–regeneration cycles. The effects of regenerate solvents were also compared systematically. The original and regenerated AgXO@SBA-15 was characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, N_2 adsorption, X-ray photoelectron spectroscopy and atomic absorption spectrometry. The recovery of desulfurization capacity using various solvents follows the order of acetonitrile [ acetone [ ethanol [ methanol [ water. Owing to the complete reduction of silver species to Ag~0 and severe agglomeration of Ag~0, the bifunctional AgXO@SBA-15 demonstrating [ 85%(2.60 mg-S/g) of sulfur removal dramatically reduced to \ 46%(1.56 mg-S/g) after only 1 st-cycle regeneration. It is suggested that polar organic species strongly adsorbed(or residual) on the spent AgXO@SBA-15, in that case, after solvent wash may contribute to the accelerated decomposition of Ag~+ to Ag~0 in the following calcination step. The desulfurization capacity decreased rather mildly in the later regeneration runs. Cautious choice of regeneration conditions and strategies to rational design stabilized adsorbents is required to avert the adsorbent deactivation.     

Study on adsorption refrigeration cycle utilizing activated carbon fibers. Part 1. Adsorption characteristics

Thermal heat driven adsorption systems using natural refrigerants have been focused on the recent energy utilization trend. However, the drawbacks of these adsorption systems are their poor performance in terms of system cooling capacity and coefficient of performance (COP). The objective of this paper is to improve the performance of thermally powered adsorption cooling system by selecting new adsorbent–refrigerant pair. Adsorption capacity of adsorbent–refrigerant pair depends on the thermophysical properties (pore size, pore volume and pore diameter) of adsorbent and isothermal characteristics of the pair. In this paper, the thermophysical properties of two PAN types of activated carbon fibers (FX-400 and KF-1000) are determined from the nitrogen adsorption isotherms. The standard nitrogen gas adsorption/desorption measurements on various adsorbents at liquid nitrogen of temperature 77.3 K were performed. Surface area of each adsorbent was determined by the Brunauer, Emmett and Teller (BET) plot of nitrogen adsorption data. Pore size distribution was measured by the Horvath and Kawazoe (HK) method. As of the adsorption/desorption isotherms, FX-400 shows very small hysteresis when the value of P/P_o exceeds 0.4, while KF-1000 has no hysteresis in the whole range of P/P_o. The adsorption capacity of FX-400 is about 30% higher than that of KF-1000. The adsorption equilibrium data of activated carbon fiber (ACF)-methanol are presented and correlated with simple equations. The adsorption equilibrium data of ACF (KF-1000)-water also presented in order to facilitate comparison with those of ACFs-methanol pair. The results will contribute significantly in designing the adsorber/desorber heat exchanger for thermally driven adsorption cooling system.     

Study on adsorption refrigeration cycle utilizing activated carbon fibers. Part 2. Cycle performance evaluation

Thermal heat driven adsorption systems have been gained considerable attention on the recent energy utilization trend. However, the drawbacks of these adsorption systems are their poor performance. It is urgently necessary to improve the system performance of the adsorption cycles. There are two major ways for the system performance improvement. One is to develop new adsorbent material well suited to low temperature heat regeneration. The other is to enhance heat and mass transfer in the adsorber/desorber heat exchanger. The objective of the paper is to investigate the system performance of an adsorption cycle. The cycle utilizes activated carbon fiber (ACF)/methanol as adsorbent/refrigerant pair. In this paper, specific cooling effect SCE and COP of the system are numerically evaluated from the adsorption equilibrium theory with different hot, cooling and chilled fluid inlet temperatures. It is confirmed that the influences of hot, cooling and chilled fluid inlet temperatures on the system performance are qualitatively similar to those of silica gel/water pair. Even though, the driving temperature levels of ACF/methanol and silica gel/water are different. There is an optimum condition for COP to reach at maximum for ACF/methanol pair. Particularly, the ACF/methanol system shows better performance with lower chilled fluid inlet temperature between −20 and 20 °C.     

盐酸溶液中六次甲基四胺对黄铜的缓蚀作用及吸附热力学研究

采用失重法研究了不同温度下不同浓度的六次甲基四胺在10%盐酸介质中对黄铜的缓蚀作用.结果表明,六次甲基四胺在10%盐酸介质中对黄铜的腐蚀有良好的抑制作用,六次甲基四胺吸附于黄铜表面,其吸附规律服从Langmuir等温式,由此获得了相关热力学参数.