Direct extraction of Mo(VI) from acidic leach solution of molybdenite ore by ion exchange resin:Batch and column adsorption studies

The adsorption behavior of ion exchange resin D301 in the extraction of hexavalent molybdenum from high acidic leach solution was investigated. SEM, EDS and Raman spectra analyses were applied to studying the adsorption capacity, reaction kinetics and possible adsorption mechanism in detail. Results showed that the adsorption capacity of D301 resin for molybdenum from high acidic leach solution was up to 463.63 mg/g. Results of the kinetic analysis indicated that the adsorption process was controlled by the particle diffusion with the activation energy 25.47 k J/mol（0.9-1.2 mm） and 20.38 k J/mol（0.6-0.9 mm）. Furthermore, the molybdenum loaded on the resin could be eluted by using 2 mol/L ammonia hydroxide solution. Besides, dynamic continuous column experiments verified direct extraction of molybdenum from acidic leach solutions by ion exchange resin D301 and the upstream flow improved dynamic continuous absorption.

Study on the influence of humic acid of different molecular weight on basic ion exchange resin's adsorption capacity

In this paper, humic acid （HA） was ultra-filtered into different molecular weight sections and was characterized by multielement analysis, UV254/TOC, FT-IR and three-dimensional fluorescence spectrometric. Since humic acids of different molecular weights have different hydrophilic and molecular size, the maximum adsorption capacity of basic ion exchange resins appears on the humic acid whose molecular weight ranges from 6000 to 10,000 Da.

Kinetic Study of Esterification of Lactic Acid with Isobutanol and n-Butanol Catalyzed by Ion-exchange Resins

The esterification reactions of lactic acid with isobutanol and n-butanol have been studied in the presence of acid ion-exchange resin Weblyst D009. The influences of catalyst loading, stirrer speed, catalyst particle size, initial reactant molar ratio and temperature on the reaction rate have been examined. Experimental kinetic data were correlated by using the pseudo-homogeneous, Langnluir-Hinshelwood and Eley-Rideal models. Nonideality of the liquid phase was taken into account by using activities instead of molar fractions. The activity coefficients were calculated according to the group contribution method UNIFAC. Provided that the nonideality of the liquid is taken into account, the esterification kinetics of lactic acid with isobutanol and n-butanol catalyzed by the acid ion-exchange resin can be described using all threemodels with reasonable errors.

Cleaning the Ion Exchange Resin Sorption of Uranium from Silicic Acid Solution ＂Ayanat＂

The authors discovered a new way to clean the ion exchange resin sorption of uranium from silicic acid used solution ＂Ayanat＂. The method reduces the costs of regeneration of ion exchange resin and its reuse in the sorption of uranium.

Elution Behaviour of Monocarboxylic Acids on a Cation-exchange Resin Column

The retention mechanism of monocarboxylic acids on a cation-exchange resin column was investigated. It was assumed that both Donnan membrane equilibrium and adsorption equilibrium were involved in the chromatographic process. On the basis of the proposed mechanism, an equation was derived for correlating distribution coefficient, Kd, dissociation constant, Aa, and adsorption equilibrium constant, K, of the analyzed acid. By this approach, retention data for some aliphatic acids under different operating conditions were predicted. Results are reasonably in agreement with experiment.

Removal of Co(Ⅱ) from aqueous solutions by NKC-9 strong acid resin

A strong acidic ion exchange resin(NKC-9)was used as a new adsorbent material for the removal of Co(Ⅱ)from aqueous solutions.The adsorption isotherm follows the Langmuir model.The maximum adsorption capacity of the resin for Co(Ⅱ)is evaluated to be 361.0 mg/g by the Langmuir model.It is found that 0.5 mol/L HCl solution provides effectiveness of the desorption of Co(Ⅱ)from the resin.The adsorption rate constants determined at 288,298 and 308 K are 7.12×10-5,8.51×10-5and 9.85×10-5s-1, respectively.The apparent activation energy(Ea)is 12.0 kJ/mol and the adsorption parameters of thermodynamic are-H Θ=16.1 kJ/mol,-SΘ=163.4 J/(mol·K),-G Θ 298 K=-32.6 kJ/mol,respectively.The adsorption of Co(Ⅱ)on the resin is found to be endothermic in nature.Column experiments show that it is possible to remove Co(Ⅱ)ions from aqueous medium dynamically by NKC-9 resin.

The Synthesis of Cyclic Amino Acids

Several cyclic amino acids (1-4) were synthesized from glycine. Isocyanate ester was prepared as the key intermediate and reacted with dibromoalkanes to afford the target compounds.

Treatment of drilling wastewater using a weakly basic resin

Macroporous weak basic anion exchanger （D301R） was used to remove organic substances from drilling wastewater. The effect of pH, temperature and contact time on adsorption behavior was investigated in batch experiments, which indicated that the COD （Chemical Oxygen Demand） removal ratio of drilling wastewater was approximately 90%, and the COD of treated wastewater was below 70 mg/L under appropriate operating conditions. A mixed liquor of NaOH and NaCI was selected as desorbent because of its better elution performance. The results of column dynamic adsorption and regeneration showed that the COD of wastewater could be efficiently removed by D301R resin, and the resin was easily regenerated by the selected desorbent.

Adsorption behavior of benzenesulfonic acid by novel weakly basic anion exchange resins

Two novel weakly basic anion exchange resins（SZ-1 and SZ-2） were prepared via the reaction of macroporous chloromethylated polystyrene-divinylbenzene（Cl-PS-DVB） beads with dicyclohexylamine and piperidine, respectively. The physicochemical structures of the resulting resins were characterized using Fourier Transform Infrared Spectroscopy and pore size distribution analysis. The adsorption behavior of SZ-1 and SZ-2 for benzenesulfonic acid（BA） was evaluated, and the common commercial weakly basic anion exchanger D301 was also employed for comparison purpose. Adsorption isotherms and influence of solution p H, temperature and coexisting competitive inorganic salts（Na2SO4and Na Cl） on adsorption behavior were investigated and the optimum desorption agent was obtained.Adsorption isotherms of BA were found to be well represented by the Langmuir model.Thermodynamic parameters involving ΔH, ΔG and ΔS were also calculated and the results indicate that adsorption is an exothermic and spontaneous process. Enhanced selectivity of BA sorption over sulfate on the two novel resins was observed by comparison with the commercial anion exchanger D301. The fact that the tested resins loaded with BA can be efficiently regenerated by Na Cl solution indicates the reversible sorption process. From a mechanistic viewpoint, this observation clearly suggests that electrostatic interaction is the predominant adsorption mechanism. Furthermore, results of column tests show that SZ-1possesses a better adsorption property than D301, which reinforces the feasibility of SZ-1for potential industrial application.

Improved Performance of W/HZSM-5 Catalysts for Dehydroaromatization of Methane

The dehydroaramatization of methane over W-supported ZSM-5 with varying degrees of Li+ ion-exchanged catalysts was studied with and without oxygen at 1073 K and atmospheric pressure. Catalyst activity and stability were found to be influenced by the catalyst acidity related to Bronsted acid sites and by the presence of oxygen in the feed. The NH3-TPD and FTIR-pyridine results demonstrated that partially exchanged of H+ ions by Li+ into the W/HZSM-5 catalysts could be used to control the amount of strong acid sites on the catalyst surface. Without oxygen, the 3WHLi-Z (5:1) catalyst that has strong acid sites equal to nearly 74% of the original strong acid sites in the parent HZSM-5 exhibited the highest methane conversion and selectivity towards aromatics. However, the catalyst deactivated in a five hour period. In the presence of oxygen, the catalyst activity and stability could be improved further. The results of this study revealed that a suitable amount of strong Bronsted acid sites as well as oxygen addition in the feed increased the catalyst activity and stability. The 3WHLi-Z(5:1) catalyst exhibited improved performance in the dehydroaromatization of methane.

交换性离子和pH值对酸性土壤腐蚀的影响

研究了交换性酸度总量、交换性H+ 、交换性铝对A3钢在酸性土壤中的腐蚀影响 .结果表明 :深圳土作为酸性土 ,它的缓冲性能很强 ,加不同 pH的硝酸 ,对其 pH值影响不大 ;随硝酸的pH的增加 ,交换性铝、交换性酸度总量、交换性H+ 有相对减小的趋势 ,腐蚀速率增大 .当土壤pH约为 4时 ,阴极过程发生变化 ,由氧放电转为氢放电 .

通过Michael反应制备脂肪磺酸基强酸型阳离子交换树脂

A novel aliphatic sulfonie acid ion exchange resin was prepared from ethylenediamined polystyrene(PS-acyl-EDA),2-acrylamido-2-methylproanesulfonic acid(AMPS)by Michael reaction.This kind of resin has a longer chain than conventional sulphonic polystyrene resin,that is,the former is easier to react with other compound.The effect of the reaction time,reaction temperature,catalyst amount,reagent amount and the charge ration on reaction result were discussed.Under the optimum condition,the maximum loading of the sulfonie acid ion exchange resin could be up to 1.15 mmol·g-1 resin.The product was characterized with FT-IR.The filling material of chromatographic column could be prepared by this method.

双极膜电渗析清洁制备NaOH和H_2SO_4的试验研究

采用双极膜、阴离子交换膜和阳离子交换膜交替排列构成的五隔室双极膜电渗析(BMED)构型,以Na2SO4为原料制备NaOH和H2SO4。研究了电流密度和原料液浓度对膜堆操作性能的影响,并对2种不同的均相阳膜进行了对比考察。结果表明,在电流密度50 mA/cm2,Na2SO4原料液浓度10%的条件下,试验范围内NaOH的收率可达79.63%,其收率和能耗随电流密度的增大而增加;电流密度恒定时,较高的原料液浓度利于保持更小的膜堆电阻,过程能耗相应降低。将BMED制得的稀NaOH和H2SO4溶液直接用于饱和阴、阳离子交换树脂的再生处理,并将其与经常规酸碱试剂化学再生的树脂均用于反渗透产水的深度除盐制备纯水,结果前者所获水质纯度显著优于后者,表明BMED所制备的酸碱纯度更高,树脂再生更为彻底。

pH和温度对亚微米强酸树脂吸附L-赖氨酸的影响

研究了溶液ｐＨ和温度对亚微米强酸树脂离子交换赖氨酸（＞３０ｇ／Ｌ）的影响，与７３２强酸树脂进行了对比，并对所得吸附等温线进行了关联，研讨其吸附模型。结果表明：ｐＨ对亚微米强酸树脂交换有明显影响，其吸附量远大于７３２树脂；温度对其影响不大，但引起了交换量极值点向ｐＨ值小的方向移动。氢型亚微米强酸树脂的吸附等温线呈现出超当量吸附和多分子层吸附两个特征，并符合ｄｅＢｏｅｒ－Ｚｗｉｋｋｅｒ公式，属极性吸附模型。

pH值对碱性离子交换树脂吸附富马酸的影响

[目的]研究pH值对碱性树脂吸附富马酸的影响。[方法]以4 mg/ml富马酸标准溶液和4款碱性树脂(D2017、17、D301、D318)为材料,考察不同pH值(2.2、2.7、3.2、3.7、4.2、4.75、.2、5.7)条件下,碱性树脂对富马酸的吸附量及溶液pH值(CpH)的变化。[结果]弱碱性离子交换树脂对富马酸的吸附量和CpH均呈S形曲线变化;强碱性离子交换树脂的CpH在2.2≤pH值≤3.7之间呈线性变化,对富马酸的吸附量呈先上升后降低趋势,pH值为3.7左右时对富马酸的吸附量最大,随后逐渐下降。[结论]溶液pH值的变化影响富马酸的离子化程度,进而影响碱性树脂对富马酸的吸附量。

强酸性离子交换树脂催化合成5-乙氧羰基-4-苯基-6-甲基-3,4-二氢嘧啶-2(H)-酮

在732型强酸性离子交换树脂催化下,以苯甲醛、乙酰乙酸乙酯与尿素为原料,一步合成了5-乙氧羰基-4-苯基-6-甲基-3,4-二氢嘧啶-2(H)-酮。优化的反应条件如下:苯甲醛、乙酰乙酸乙酯与尿素的摩尔比为1:3:2,732树脂用量为0.6g,乙醇为溶剂,反应温度为80～84℃,反应时间为2h。此时目标产物的收率为97.96%。

酸性矿山废水中多种有价金属的高效分离

酸性矿山废水(AMD)中多种有价金属的高效分离回收,是重金属减排和资源化利用的关键。文章通过中和沉淀实验和静态吸附实验探究回收有价金属的最佳沉淀和吸附pH,成功开发了中和沉淀—离子交换—中和沉淀组合工艺,并应用于大宝山AMD的处理。结果表明,AMD在pH为3.00和9.80中和沉淀时,分别沉获64%的Fe_(2)O_(3)富铁渣和51%的Mn O富锰渣。采用离子交换树脂分别在pH 3.95和6.10条件下对AMD中的Cu和Zn进行吸附,得到质量浓度为Cu^(2+)11~26 g/L,Zn^(2+)10~20 g/L的两种解吸液。通过该组合工艺,AMD中的各金属Fe、Cu、Zn和Mn的回收率分别为:96%、81%、70%和60%,实现了有价金属的高效分离回收。若采用此工艺回收大宝山2000 m^(3)/d的AMD中的铜、锌、锰硫酸盐,每年的利润为119万元,经济效益非常显著。此处理工艺为酸性矿山废水的高效资源化利用提供了新路径。

弱酸H-Na离子交换系统在蒸汽锅炉水处理中的应用

根据弱酸H型及Na型离子交换树脂的交换特性 ,结合水源水质的特点 ,选用弱酸H -Na离子交换系统处理蒸汽锅炉用水 ,具有较好的软化、降碱和部分除盐效果。通过实例说明该系统处理高硬度、高碱度的水 ,能保证低压锅炉用水水质 。

酸性离子交换树脂催化4-芳基-1H-1,2,3-三唑的合成

以酸性离子交换树脂Amberlite IR-120为催化剂,硝基烯烃和叠氮化钠为原料合成了一系列4-芳基-1 H-1,2,3-三唑衍生物。与常规方法相比,该法高效、反应条件温和且底物兼容性好。另外,催化剂通过过滤即可实现回收,重复使用6次后活性略有降低。

增强型离子交换树脂催化醚化汽油TAME的合成

在高压釜式反应器中,以甲醇和异戊烯为原料,增强型离子交换树脂Amberlyst为催化剂,制备了高辛烷值醚化汽油组分TAME。改变反应温度、催化剂用量等单一实验变量,探索得到了最佳工艺条件:反应温度70℃,催化剂用量为20%,醇/烯比为2。在最优条件下,该催化反应只需进行4.5h,TAME的摩尔产率就达到70%。