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.

Atmospheric Sulfur and Nitrogen Deposition in Five Nature Reserves of Sichuan Basin to Qinghai-Tibetan Plateau Transect Region,Southwest-ern China

Enhanced sulfur and nitrogen deposition has been observed in many transect regions worldwide,from urban/agricultural areas to mountains.The Sichuan Basin(SCB),with 18 prefectural cities,is the most economically-developed region in western China,while the rural Qinghai-Tibetan Plateau(QTP)lies west of the SCB.Previous regional and national atmospheric modeling studies have sug-gested that large areas in the SCB-to-QTP transect region experience excessive deposition of sulfur and nitrogen.In this study,we ap-plied a passive monitoring method at 1l sites(one in urban Chengdu and 10 from fivenature reserves)in this transect region from September 2021 to October 2022 to confirm the high sulfur and nitrogen deposition fluxes and to understand the gaps between the mod-eling and observation results for this transect region.These observations suggest that the five reserves are under eutrophication risk,and only two reserves are partially under acidification risk.Owing to the complex topography and landscapes,both sulfur and nitrogen de-position and critical loads exhibit large spatial variations within a reserve,such as Mount Emei.Regional atmospheric modeling may not accurately capture the spatial variations in deposition fluxes within a reserve;however,it can capture general spatial patterns over the entire transect.This study demonstrates that a combination of state-of-the-art atmospheric chemical models and low-cost monitoring methods is helpful for ecological risk assessments at a regional scale.

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.

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.

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。

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%。

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.

Removal of Copper from Acid Mine Drainage (AMD) or Acid Rock Drainage (ARD)

Acid mine drainage is wastewater from a mine having a low pH and an elevated level of dissolved heavy metals. These metals are harmful to aquatic, animal and human life. This paper looks at the removal of copper from acid mine drainage using ion exchange to less than 1 mg/l. A weak acidic cation resin was used. Spectrophotometric determination of copper with sodium diethyldithiocarbamate was used to determine the copper concentrations in the treated water. Using regression analysis, the experimental results gave a correlation coefficient of 0.977 and a coefficient of determination of 99.5%. Results indicated that the higher the flows rate the shorter the period after which the copper concentration in the treated water reaches 1 mg/l. At pH 3.85 and 5.09, the resin performed better and at pH above 6.62 and between pH 3.0 and below the resin’s does not perform well. The higher the resin height the greater is the resin exchange capacity and the longer it takes for the copper concentration to reach 1 mg/l in the treated water. The higher the wastewater copper concentration the shorter the time it takes the resin to reach 1 mg/l. The results for this experiment indicated that acid mine drainage can be treated well by ion exchange resins, but it is also very important to establish suitable operating conditions.

基于载铀树脂饱和再吸附-淋洗一体化工艺的U型塔设计研究

针对部分酸法地浸铀矿工艺在浸出中后期存在的浸出液铀浓度偏低、HSO_(4)^(-)离子竞争吸附、吸附饱和树脂容量低、固定床淋洗合格液铀浓度低等问题,设计了一种离子交换设备U型塔,研究了采用饱和再吸附与淋洗一体化工艺处理载铀树脂,考察了处理后淋洗液中铀浓度的变化。结果表明:经U型塔一体化工艺处理后,淋洗合格液中铀质量浓度升至43~50 g/L;U型塔运行稳定,树脂运移顺畅,塔内铀浓度梯度分布合理。该设备适用于地浸采铀浸出液处理过程,有一定的推广应用价值。

离子交换树脂回收酸性溶液中钨的试验研究

白钨矿酸浸过程钨以钨同多酸形式产出,此分解方法为白钨矿冶炼提供了新的途径,但后续从钨同多酸浸出液中回收钨是关键。本文比较了不同阴离子交换树脂对钨同多酸溶液的吸附行为,确定大孔弱碱性阴离子交换树脂D301为最佳树脂。主要考察了D301树脂用量、溶液pH值、吸附温度、钨浓度和吸附时间对树脂吸附钨的影响。结果表明,在树脂用量为5倍理论量,溶液pH值为2~3,吸附温度为40℃,钨(WO_(3))浓度为50~100g/L,吸附时间为240min的条件下,D301树脂对钨同多酸溶液中的钨吸附率达99.4%以上。同时,研究了载钨树脂的解吸行为,结果表明,对D301载钨树脂解吸效果最好的解吸剂种类为NaOH溶液,在NaOH溶液用量20mL、浓度4mol/L以及解吸温度50℃、时间60min的条件下,钨的解吸率可达97.94%。

酸盐分离技术在镍电积阳极液中的应用

目前酸盐分离技术主要有树脂吸附法、离子交换法和膜分离技术三大类,但将其应用于镍湿法冶炼中镍电积阳极液的报道较少。总结了三大类酸盐分离技术的原理和应用,并分别采用树脂吸附法、扩散渗析法、特种纳滤膜和电渗析结合的方法对镍电积阳极液进行酸盐分离试验。结果表明,三种方法对镍电积阳极液均有一定的分离效果,其中树脂吸附法易饱和,需反洗再生,造成体积膨胀;扩散渗析法对硫酸的回收率在80%以上,镍的截留率在90%以上,但回收的硫酸浓度较低,同样存在体积膨胀问题;特种纳滤膜和电渗析结合法对镍离子的截留率可达90%以上,氢离子去除率可达70%以上,同时浓缩后的氢离子浓度可提高400%以上,镍离子浓度可提高500%以上,淡化液中各种离子浓度小于50 mg/L,可用作纯水,并且该方法不会造成系统体积膨胀,具有工业化应用价值。

利用D309树脂从含砷钨杂多酸溶液中回收钨的研究

采用D309大孔弱碱性阴离子交换树脂从含砷钨杂多酸的白钨矿盐酸浸出液中回收钨并将其转型为钨酸铵溶液,研究了D309树脂对[AsW_(12)O_(40)]^(3-)的吸附等温线、吸附动力学、吸附和解吸的工艺条件。结果表明:D309树脂对[AsW_(12)O_(40)]^(3-)的吸附过程遵循Langmuir等温方程,为单分子层吸附;吸附过程的控制步骤为颗粒扩散;在温度55℃、反应时间1 h、液固比2.5∶1的最佳条件下,钨的吸附率可达99.90%;在温度55℃、反应时间3 h、氨水浓度210 g/L、液固比1.25∶1的最佳条件下,钨的解吸率为91.78%。

可见光-过一硫酸盐-磁性离子交换树脂协同工艺去除水中腐植酸的效能与机理

文中研究了可见光(VI)-过一硫酸盐(PMS)-磁性离子交换(MIEX)树脂体系协同处理水中腐植酸(HA)的效能、活性氧化物质(ROS)种类及活化机理、HA的去除机理以及影响HA去除的因素。结果表明,该体系对水中HA有较好的去除效果,反应90 min后,HA的去除率达到52.9%,显示了三者的协同促进作用。树脂母体中的铁氧化物协同VI,可有效活化PMS,产生硫酸根自由基和羟基自由基等活性物质。HA的去除主要是ROS氧化HA强化MIEX树脂的吸附作用,而非自由基的矿化降解。MIEX树脂投加量以及PMS浓度的增加可促进HA的去除,而温度在298 K以上时,影响不明显。该体系在有效去除水中HA的同时,可有效去除反应过程中的副产物SO_(4)^(2-),显示了良好的应用前景。

用低交换容量聚苯乙烯型强酸性阳离子交换树脂柱色谱分离中性氨基酸

通过磺化苯乙烯 -二乙烯苯共聚物或商品化的聚苯乙烯型强酸性阳离子交换树脂 ( 0 0 1× 7)的逆磺化反应 ,得到一系列不同交换容量的聚苯乙烯型强酸性阳离子交换树脂 .研究了丙氨酸和缬氨酸及缬氨酸和亮氨酸在这些树脂柱上的色谱分离 .结果表明 ,用两种方法得到的树脂对丙氨酸和缬氨酸的色谱分离性能基本相同 ;同时中性氨基酸与聚苯乙烯型强酸性阳离子交换树脂之间的作用包括离子作用和疏水作用 ,且二者之间存在协同作用 .

酸性离子交换树脂催化酯化改质生物油的研究

以磺酸型离子交换树脂为催化剂,在模型反应的基础上,探讨了该催化剂在稻壳裂解油及其轻质馏分的催化酯化改质过程中的活性和效果,并通过气-质联用仪对酯化前后的生物油进行了成分分析.结果表明,酯化过程中采用的催化剂可以方便地分离和循环使用;生物油中的有机酸顺利地转化为相应的酯类(主要为乙酸乙酯).通过催化酯化改质后,两种生物油的理化特性均得到了有效改善,热值分别由16.80和12.76MJ/kg提高到20.08和18.33MJ/kg,相应提高了19.5%和43.6%;黏度分别由11.83和1.42mm2/s,下降到3.77和1.12mm2/s;水分分别为23.7%和28.4%,流动性明显增强,理化特性得到了明显提高.为生物油的精制加工提供了一种有效方法.

离子交换纤维对阿魏酸的吸附和解吸研究

目的 测定自制的强碱性离子交换纤维对阿魏酸的吸附和解吸的性能。方法 采用测定静态吸附速率曲线及测定30. 8K的吸附等温线的方法 ,并对不同入口浓度和不同流速下 ,阿魏酸在固定床吸附柱上的动态吸附过程进行了研究。结果 离子交换纤维对阿魏酸的静态饱和吸附量为 180 . 4mg·g-1(干纤维 ) ,用少量甲醇和稀盐酸即可将吸附在纤维上的阿魏酸完全解吸。结论 离子交换纤维对阿魏酸的吸附速率远大于D2. 96离子交换树脂对阿魏酸的吸附速率 ,是提纯和分离阿魏酸的一种新型离子交换剂。