Vapor‐Liquid Equilibrium of MTBE‐Methanol,MTBE‐Methanol‐Calcium Chloride and MTBE‐Methanol‐Lithium Chloride Mixtures

Isobaric vapor‐liquid equilibria of methyl tert‐butyl ether (MTBE)‐methanol, MTBE‐methanol‐calcium chloride, and MTBE‐methanol‐lithium chloride mixtures were measured at 93.57 kPa using a Malanowski equilibrium still which circulates both the vapor and liquid phases. The experimental results of the salt‐free system showed that MTBE‐methanol forms a minimum boiling azeotrope of 69.80 mol.‐% MTBE at 93.57 kPa and 322.67 K. The experimental results of the salt‐free system were predicted using the original UNIFAC and the UNIFAC‐Dortmund methods, where the vapor‐phase compositions were predicted with root‐mean‐square deviations (RMSD) of 0.0046 and 0.0091, respectively, and the bubble point temperatures were predicted with RMSD of 0.36 and 0.71 K, respectively. The Wilson and the nonrandom two‐liquid (NRTL) models could satisfactorily correlate the experimental data of the salt‐free mixtures with RMSD in the vapor‐phase compositions calculation of 0.0047 and 0.0059, respectively and in bubble‐point temperatures calculation of 0.20 and 0.40 K, respectively. Addition of either calcium chloride or lithium chloride to the MTBE‐methanol mixtures resulted in salting‐out the MTBE and shifting the azeotropic point to a vapor composition of 76.5 mol.‐% and 93.0 mol.‐% MTBE, respectively. Both the Tan‐Wilson and Tan‐NRTL models could satisfactorily predict the bubble‐point temperatures of the MTBE‐methanol‐calcium chloride mixtures with RMSD of 0.143 and 0.130 K, respectively, and the vapor phase compositions with RMSD of 0.0055 and 0.0041, respectively.     

利用异丁烯生产MTBE应用前景探讨(上)

介绍了美国异丁烯资源利用概况,对国内外MTBE生产近况及其前景作了叙述,并将以乙醇替代MTBE。最终提出几点国内今后NTBE装置的出路及措施的初步想法。     

水溶液中丁醇在树脂上的吸附

水溶液中丁醇在树脂上的吸附杨立荣姚善泾朱自强（浙江大学化工系，杭州３１００２７）焦朝晖（浙江临海制药厂，临海３１７０００）关键词丁醇吸附吸附热力学１前言发酵产物在发酵液中浓度一般在２０～１００（ｇ／Ｌ）之间［１］，如丙酮／丁醇发酵液中总溶剂浓度为１８...     

Adsorption of Norfloxacin from Aqueous Solution onto Modified Coal Fly Ash

Batch adsorption experiments were carried out for the removal of norfloxacin from aqueous solution using modified coal fly ash as adsorbent. The effects of various parameters such as contact time, initial solution concentration and temperature on the adsorption system were investigated. The optimum contact time was found to be 100 min. The equilibrium experimental data can be well fitted by the Freundlich model. Thermodynamic parameters such as ΔG, ΔH and ΔS were also calculated. The negative Gibbs free energy change and enthalpy change indicated the spontaneous and exothermic nature of the adsorption, and the negative entropy change indicated that the adsorption process was aided by decreased randomness.     

Adsorption Characteristics of Congo Red from Aqueous Solution onto Tea Waste

The feasibility of using tea waste (TW) as a low-cost adsorbent for the adsorption of an anionic dye (Congo red) from aqueous solution has been investigated. Adsorption in a batch process was conducted to study the effect of adsorbent dosage, initial dye concentration, contact time, pH, and temperature. The experimental data were analyzed by the Langmuir, Freundlich, and Temkin models. The adsorption system was best described by the Langmuir isotherm (R ² > 0.99). Adsorption kinetics followed a pseudo-second-order model (R ² > 0.99). The effect of mechanical treatment (vibratory mill) was also studied. The experimental results showed that using this physical treatment leads to an increase in the adsorption capacity of TW from 32.26 to 43.48 mg/g. Thermodynamic analyses revealed that the adsorption of Congo red on TW was endothermic and spontaneous in nature. The results indicated that TW can be employed as a potential low-cost adsorbent for the removal of Congo red from aqueous solution.     

活性炭纤维对水溶液中醋酸丁酯的吸附性能研究

研究了以活性炭纤维为吸附剂从水溶液中吸附醋酸丁酯的吸附静力学、动力学规律及动态吸附特性。实验表明，活性炭纤维对醋酸丁酯的吸附量较大，吸附速度快，动态吸附、脱附性能好。该方法可行，具有一定的实用价值。     

铵型阳离子树脂吸附L-左卡尼汀

通过研究pH变化对L-左卡尼汀在铵型磺酸基阳离子树脂上吸附过程的影响,确定相关工艺条件和参数。     

微波辅助制备柱撑膨润土对刚果红的吸附性能

用微波辅助制备锆铝柱撑膨润土,考察其对废水中刚果红染料的吸附行为,并对吸附前后柱撑膨润土进行表征,以探索吸附机理. 结果表明,在原始溶液pH和室温条件下,初始浓度为50 mg/L的刚果红溶液,吸附剂用量为4 g/L时,吸附45 min后即能达到吸附平衡,柱撑膨润土的吸附容量为12.17 mg/g,脱色率达97.64%;其吸附过程符合准二级动力学方程,粒子扩散不是唯一的速率控制步骤;锆铝柱撑膨润土对刚果红的等温吸附符合Langmuir方程;XRD与FT-IR表征结果表明,吸附过程主要以物理吸附为主.     

饮用水源突发性柴油污染的吸附法应急处理模拟试验

通过室内模拟实验,研究了膨胀石墨对饮用水源水突发性柴油污染的应急消减性能。考察了振荡速率、水体pH、膨胀石墨投加量和水温对吸附效果的影响,测定了吸附等温线,对吸附规律进行了探讨。结果表明,膨胀石墨可快速高效地消减突发性柴油污染。在本研究条件下,振荡速率、水体pH和水温对柴油的吸附无显著性影响。当膨胀石墨投加量为5g/L时,历时5s即可将1 000 mg/L的柴油去除97%以上。等温吸附规律可用Freundlich模型较好的拟合,拟合得到的线性方程可为应急处理水源地突发柴油污染提供基础模型。     

Recovery of heavy oil from contaminated sand by using exfoliated graphite

Heavy oil was recovered from contaminated sand through capillary suction into exfoliated graphite with differentpacked densities by using model sands, alumina powders, with different particle sizes. For efficient recovery it was important to have an appropriate combination of average size of sand particles and packed density of exfoliated graphite. Pumping of heavy oil into exfoliated graphite occurs as a balance in an attracting capillary force between exfoliated graphite and sand, the former being stronger than the latter because of the hydrophobic nature of the surface of graphite.     

Effect of compatibility of cellulose acetate/poly(vinyl butyral) blends on pervaporation behavior of their membranes for methanol/methyl tert‐butyl ether mixture

Binary blends and their blend membranes of cellulose acetate (CA) and poly(vinyl butyral) (PVB) are prepared by solution blending. The compatibility of the blends is studied by viscometry and Fourier transform IR. It is found that the incompatibility of the blends is markedly manifested when the weight fraction of PVB in the CA/PVB blends (W_PVB) is located at higher regions. On the other hand, compatibility is obtained for the CA/PVB blends with lower W_PVB values, especially at about 0.2. This compatibility is believed to play a key role in the good pervaporation behavior of CA/PVB blend membranes. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2434–2439, 2002     

水溶液条件下膨润土对葡萄糖分子的吸附作用(英文)

采用X射线衍射谱和红外吸收光谱分析膨润土对于葡萄糖分子的吸附特性,研究了膨润土的吸附等温线。同时,探究了膨润土与葡萄糖溶液的接触时间及溶液的初始pH值等对于膨润土吸附作用的影响。以Freundlich模型为基础对等温线数据进行拟合和分析。结果表明:在水溶液条件下,膨润土中的主要成分为蒙脱石,在其层间能够吸附葡萄糖分子;随着初始溶液pH值的增加,膨润土对于葡萄糖分子的吸附能力逐渐增强,吸附效率逐渐提高。     

多壁碳纳米管对有机物的吸附研究

研究多壁碳纳米管(MWNTs)对水中有机物间苯二酚的吸附。分别讨论了不同的吸附参数(如温度、时间、pH)条件下,碳纳米管对间苯二酚吸附量的变化情况,并采用Langmuir和Freundlich模型对MWNTs的吸附等温线进行拟合。结果表明:MWNTs的吸附平衡时间为1h;MWNTs吸附是一个自发的放热过程,低温对其吸附有利;当溶液的pH值在4附近时,MWNTs对间苯二酚的吸附量达到最大;MWNTs对间苯二酚的吸附符合Freundlich和Langmuir等温模型。     

Adsorption of Phenol from Aqueous Solutions on Jojoba Nuts Residue

Equilibrium isotherms for the adsorption of phenol from aqueous solutions of three types of Jojoba nuts residue were determined at 30, 40 and 55 °C. Types I and II were the residue after extracting the oil by leaching or by a pressing process, respectively. The third type was obtained by thermally treating the residue remaining after pressing. The phenol concentration ranged from 0–100 ppm in the aqueous solutions. A low adsorption capacity relative to activated carbon was obtained on types I and II, while the adsorption capacity of type III was much higher than types I and II. The results show that Jojoba nuts residue show good potential for adsorption of phenolic compounds if subjected to some type of treatment (activation). As the temperature increased from 30 to 55 °C, the adsorption capacity of types I and II decreased, but the increase had a negligible effect on type III. The experimental data were fitted to the appropriate adsorption models. The models used were Langmuir, Freundlich, Koble‐Corrigan and Redlich‐Peterson.     

Removal of Fluoride from Aqueous Solution by CaO Nanoparticles

Abstract

Colloidal particles of CaO were synthesized by the sol-gel method. The particle morphology was characterized by FT-IR, TGA, DTA, and TEM analysis. The ability of the CaO nanoparticles for removal of fluoride from aqueous solution through adsorption has been investigated. All the experiments were carried out by batch mode. The effect of various parameters viz. contact time, pH effect (pH 2–10), adsorbent dose (0.01–0.1 g/100 ml), initial fluoride concentration (10–100 mg/l) and competitive ions has been investigated to determine the adsorption capacity of CaO nanoparticles. Almost complete removal (98%) of fluoride was obtained within 30 minutes at an optimum adsorbent dose of 0.6 g/L for initial fluoride concentration of 100 mg/L. The adsorption isotherm was also studied to find the nature of adsorbate-adsorbent interaction.     

Adsorption of Zn on Synthetic Hydroxyapatite from Aqueous Solution

The aim of this paper was to discuss the changes in the double electrical layer at the hydroxyapatite /electrolyte solution interface during zinc ions adsorption. The second aim was establishing the relations between time and adsorption on this material. Hydroxyapatite of a determined specific surface area was prepared by the wet method, characterized by XRD methods, scanning and atomic microscopes. Moreover, the specific surface area was characterized and the grain sizes were determined. Studies of adsorption were carried out using ⁶⁵Zn isotopes and ionic solutions containing this ion depending on concentration and pH of the solution. Zn adsorption isotherms on hydroxyapatite were determined. The effect of the presence of zinc ions on grain sizes surface charge density and zeta potential was discussed.     

合成碳羟基磷灰石对水中苯酚的吸附

利用废弃蛋壳为原料、尿素为添加剂,合成了碳羟基磷灰石(CHAP),用于吸附水中苯酚. 利用红外光谱、扫描电镜、X射线能谱测试技术对CHAP样品表面化学进行了表征,同时考察了环境pH值、吸附时间、苯酚初始浓度及温度对苯酚吸附的影响. 结果表明,在酸性(pH=3~5)和碱性(pH=9~10)条件下,CHAP对苯酚的吸附效果较好,吸附过程符合Langmuir和Freundlich等温式,同时也符合准二级动力学模型.     

Removal of Fluoride from Aqueous Solution Using Aluminum-Impregnated Chitosan Biopolymer

Abstract

Aluminum impregnated chitosan (AIC) was prepared and applied as an adsorbent for the removal of fluoride from aqueous solutions. The process involved two stages: (i) isolation of chitosan from chitin, (ii) impregnation of aluminum in isolated chitosan at fixed pH. SEM and EDS techniques were used to characterize the composition of adsorbent AIC. Dynamic adsorption experiments on AIC were carried out at various pH, contact times, adsorption dosages, and initial fluoride concentration to determine optimum adsorption properties. The experimental data were analyzed using two adsorption models, Langmuir and Freundlich, with the later system providing the best fit. Thermodynamic parameters showed the adsorption process as spontaneous and endothermic. The adsorption process follows first-order kinetics for which a mechanism has been proposed. Reusability of the AIC was tested up to four consecutive cycles. The desorption experiment showed 92% elution of adsorbed fluoride at a pH of 12. Finally, the performance of the adsorbent material was studied on field water samples collected from a fluorosis endemic-region.     

Efficient Removal of Anionic Organic Dyes from Aqueous Solution with Cu‐Organic Frameworks

Cu‐metal‐organic frameworks (Cu‐MOFs) were synthesized in one step using copper acetate, glutamic acid, and small‐molecular organic amines at room temperature. Organic amines served as modulators to modify the structure of Cu‐MOFs. Characterization results proved that the addition of modulators changes the surface morphology. Batch adsorption data indicated high adsorption capacities for anionic organic dyes with glutamic‐Cu‐triethylamine (Glu‐Cu‐TA), higher than that of most MOFs reported. An acid pH was the optimum adsorption parameter. The easy regeneration of recycled Cu‐MOFs suggested there were weak intermolecular interactions between Cu‐MOFs and dyes. The main adsorption forces included electrostatic interaction, ion exchange, π‐π complexation, and hydrogen bonds.