Solvent impregnated resins for the removal of low concentration phenol from water

The focus of this investigation is the development of a solvent impregnated resin for phenol removal from dilute aqueous solutions. Using a solvent impregnated resin (SIR) eliminates the problem of emulsification encountered in liquid–liquid extraction. Impregnated MPP particles and impregnated XAD16 particles are successfully used for phenol extraction. Impregnated MPP particles are preferred, as impregnated XAD16 particles show less mechanical strength and are more expensive. Impregnated MPP particles perform better compared to other synthetic adsorbents and basic ion exchangers. The maximum phenol capacity of impregnated MPP particles with 0.99 mol Cyanex 923 kg⁻¹ SIR is 4.1 mol kg⁻¹ SIR (386 mg g⁻¹ SIR) and of MPP particles containing 1.47 mol Cyanex 923 kg⁻¹ SIR it is 5.08 mol kg⁻¹ SIR (478 mg g⁻¹ SIR). The regenerability of impregnated MPP particles is easy and complete, and the particles are stable during several cycles. The equilibrium constants for the extraction of phenol are determined as K_chem = 37 L mol⁻¹ and K_phys = 18 (mol L⁻¹) (mol L⁻¹)⁻¹. With these values the SIR isotherms can be satisfactorily described.The results indicate that SIR technology is a promising alternative for the conventional phenol removal technologies at low phenol concentration levels.     

Resin screening for the removal of pyridine-derivatives from waste-water by solvent impregnated resin technology

The selective removal of pyridine derivatives by solvent impregnated resins has been studied. A solvent impregnated resin consists of a macro-porous particle that is impregnated with a solvent. This technology allows the use liquid–liquid extraction in fixed-bed operation, and prevents problems like entrainment and irreversible emulsification. 4-Cyanopyridine was chosen as model pyridine derivative, and 4-nonylphenol was used as solvent. The aim of this study was to select the most suitable resin for this application. While in the literature there are mainly two types of resins used, MPP and Amberlite XAD type, a comparative study has not yet been conducted. In this study, a series of resins were impregnated with the solvent and applied in sorption experiments to study on the effect of the resin properties on the capacity, selectivity and mass-transfer rates of the solvent impregnated resins. It was found that the capacity could be estimated accurately with the previously developed liquid–liquid extraction equilibrium model. Additionally, the selectivity was determined by the solvent properties, and hardly affected by the resin matrix. The mass-transfer rates were primarily determined the by particle diameter, whereas the effect of the porosity is small. On the basis of the results it was established that Amberlite XAD4 had the best combination of capacity, mass-transfer rate, mechanical strength, selectivity and pressure drop over a fixed-bed column and was therefore chosen for a more detailed study. The results showed that the breakthrough curve is broad due to mass-transfer limitations. The loading cycle of the column could be described with great accuracy using the mathematical model developed in this study. Regeneration of the column could be performed efficiently with a pH-swing using hydrochloric acid at a pH of 1. The fixed bed column was percolated with 7000 bed volumes of aqueous solutions varying in composition. No reduction in the capacity was observed which demonstrated that the SIR consisting of Amberlite XAD4 and 4-nonylphenol is highly stable.     

Noble metal catalysts highly-dispersed on Sm-doped ceria for the application to internal reforming solid oxide fuel cells operated at medium temperature

The synthesis of MTBE was studied in the gas phase at elevated temperatures (up to 175°C) and low pressures (150 kPa) where the MTBE formation rate is limited by thermodynamic equilibrium, using various solid acid catalysts (Amberlyst-15 resin, silica-alumina, HY and H-ZSM-5 zeolites). All the zeolites studied were found to exhibit better selectivities to MTBE than the commercially used Amberlyst-15 resin catalyst. The formation of byproducts increased with increasing temperature and appeared to have a strong enhancing effect on catalyst deactivation. H-ZSM-5 seems to be more suitable for high temperature formation of MTBE because of its excellent selectivity towards MTBE and low deactivation behavior.     

Separation of butyric acid in fixed bed column with solvent impregnated resin containing ammonium ionic liquid

Batch equilibrium and fixed bed column extraction experiments for the extraction of butyric acid (BA) into solvent impregnated resin (SIR) have been done. Microporous Amberlite XAD-1180N was impregnated with an ammonium ionic liquid (IL) trialkylmethylammonium bis(2,4,4-trimethylpentyl)phosphinate. The BA extraction capacity isotherm has not a Langmuir type shape and no finite capacity was observed. The loading of the impregnated IL with the extracted BA at 37 °C is in agreement with the loading from L/L extraction equilibrium of BA at 25 °C. Capacity of freshly prepared SIR particles is superior to classical porous ion-exchangers. Both the temperature and the superficial velocity in column influence the shape of the breakthrough-curve in fixed bed extraction of BA using SIR. Sharpening of the breakthrough curve was observed with the increasing temperature and decreasing superficial velocity. Stripping with water is not efficient for the regeneration of the loaded column after extraction because of low concentration of the product acid in the obtained effluent. Higher BA concentration was achieved by stripping with 0.15 kmol m⁻³ and 0.075 kmol m⁻³ NaOH solutions. The combination of initial water stripping coupled with consecutive stripping by alkali can be beneficial for decreasing the consumption of chemicals and further processing of the product. After two extraction/stripping cycles, a stable capacity was achieved and sustained for 14 cycles, showing the possibility of long-term application of the prepared SIR in real technology.     

Cadmium(II) recovery from hydrochloric acid solutions using Amberlite XAD-7 impregnated with a tetraalkyl phosphonium ionic liquid

Cyphos® IL-101 (tetraalkyl phosphonium ionic liquid, IL) was immobilized in a synthetic resin (Amberlite XAD-7) for preparing an solvent impregnated resin (SIR). This SIR was tested for Cd(II) sorption in HCl solutions. Optimum sorption occurs for HCl concentrations close to 3–4 M through an ion exchange mechanism involving phosphonium cation and . Sorption capacity increased with IL loading, though a fraction of the IL remained inactive, being bound to the polymer support. Sorption capacity is poorly influenced by metal ions that do not form chloroanionic species. Uptake kinetics are controlled by the resistance to intraparticle diffusion. The intraparticle diffusivity coefficient increased with temperature, initial metal concentration but decreased with increasing IL loading (probably due to a decrease of the interfacial area and a slow diffusion of metal ions in the organic phase that fills the porous network). Metal desorption and resin recycling can be performed using nitric acid (0.1 M) with sorption and desorption performances maintained for at least five cycles.     

Selective Recovery of Platinum Group Metals from Spent Automobile Catalyst by Integrated Ion Exchange Methods

Selective recovery of platinum group metals (PGMs), such as Pd, Pt, and Rh, from spent automobile catalyst has been investigated by integrated ion exchange method using dihexyl sulfide (DHS) impregnated resin and commercial weak anion exchange resin (Diaion WA-21) as adsorbents. Batchwise adsorption revealed that the DHS impregnated resin possesses the selective adsorption ability for Pd and WA-21 possesses selectivity for all PGMs, especially Rh. Chromatographic separation of Pd with column packed with DHS impregnated resin can be selectively achieved. The chromatographic separation of Pd and Pt with a column packed with WA-21 is effectively progressed, while that of Rh is insufficient yield due to a slow adsorption rate. Separation of Rh from other two PGMs can therefore be achieved by switching the eluent. Both adsorbents show almost no adsorption abilities for other heavy metals containing in the spent automobile catalyst. Sequential chromatographic operation of the column packed with DHS impregnated resin followed by the column packed with WA-21 can be finally achieved to recover mutual PGM from leaching solution of spent automobile catalyst.     

APDC浸渍树脂及其在分析上的应用

用ＰＳＤ－ＣＨ２ＣＬ树脂和ＡＰＤＣ（吡咯烷二硫代甲酸铵）溶液制成一种带有ＡＰＤＣ功能基的浸渍树脂，研究了Ｍｎ，Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ离子在ＰＡＤＣ树脂柱上的吸附和解吸特征，并测定了ＰＨ，流速等预富集的最佳条件和外加离子的影响，建立了ＡＰＤＣ树脂分离，富集ＰＩＸＥ法测定天然水中Ｍｎ，Ｆｅ，Ｃｏ，Ｎｉ，Ｃｕ，Ｚｎ的一种新方法。     

KINETICS OF ZINC REMOVAL FROM COBALT ELECTROLYTES BY ION EXCHANGE

ABSTRACT

The removal of trace zinc concentrations from the INCO (Port Colborne) cobalt advance electrolyte by solvent impregnated ion exchange was studied in column and batch tests. The resins OC 1026, SIR 272 and SIR 302 were compared in terms of zinc loading and selectivity.

The OC 1026 resin demonstrated superior zinc loading and selectivity characteristics, but retained significant amounts of cobalt. Cobalt loading was determined to be closely related to the electrolyte pHdrop across the column. Resin pre-treatment with the advance electrolyte at pH 3 acts to diminish the pH drop across the column, and hence reduced the cobalt retained. Results from batch tests were fitted to kinetic models to gain an insight into process mechanisms. It was found that pre-treatment enhanced the apparent diffusion coefficient inside the resin phase by nearly an order of magnitude, improved exchange kinetics by allowing a lower pH reduction during the loading process, and improved Co²⁺/Zn²⁺ exchange in a matrix of the cobalt complex. Breakthrough curve analysis was also undertaken to determine the rate determining steps in the column process.

Further work is needed in X-ray microprobe analysis of resin samples from various portions of the column after loading, to gain a better understanding of the column loading process. The use of zinc selective electrodes in batch tests could also be undertaken to obtain more accurate estimates of diffusion and mass transfer coefficients.     

Adsorption studies of Cr(III) ions from aqueous solutions by DEHPA impregnated onto Amberlite XAD7 – Factorial design analysis

The present paper investigates the adsorption of Cr(III) ions using the SIR, prepared by impregnation of Amberlite XAD7 with di-(2-ethylhexyl)-phosphoric acid (DEHPA), which has been chosen as an extractant for the purpose of this study. The Amberlite XAD7–DEHPA resin was impregnated with DEHPA and ethylic alcohol as solvent trough dynamic column impregnation method. The influence of different physicochemical parameters (pH, resin dosage, initial concentration of Cr(III) ions, contact time and temperature) upon the adsorption capacity of XAD7–DEHPA, in the Cr(III) ions removal process from aqueous solution, has been investigated. The pH for Cr(III) ions adsorption was found as 3.0 for this material. The results showed that the adsorption equilibrium was reached after 45 min. The adsorption process is best described by the pseudo-second order kinetic model. Langmuir adsorption isotherm gave a satisfactory fit of the equilibrium data. The maximum adsorption capacity is ∼3 mg Cr(III) ions/g SIR. The thermodynamic studies allowed us to determine the thermodynamic parameters ΔG°, ΔH° and ΔS°. In this paper the factorial design of experiments was used to study the performance of the adsorption process.     

Selective Recovery of Copper,Cobalt, and Nickel from Aqueous Chloride Media using Solvent Impregnated Resins

Selective recovery of copper, cobalt, and nickel from acidic chloride media was investigated with solvent impregnated resins (SIRs) containing acidic organophosphorus extractants. The adsorption of each metal with the SIR proceeds via a cation exchange mechanism. An SIR containing 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC-88A) has high selectivity for Cu²⁺, and the order of selectivity is Cu²⁺ > Co²⁺ > Ni²⁺. Effective adsorption-elution can be achieved by chromatographic operation for the selective recovery of Cu²⁺ from a ternary metal solution. High selectivity for Co²⁺ was observed using a SIR comprising bis-2,4,4-trimethylpentylphosphinic acid (Cyanex 272) and can be effectively separated from a Co and Ni binary metal solution by column adsorption. A simple and effective process flow sheet is proposed for selective recovery of Cu²⁺, Co²⁺, and Ni²⁺ from aqueous chloride media using the two SIRs.     

溶剂浸渍树脂吸着螺旋霉素的动力学模型研究

本文根据颗粒扩散控制机制,认为溶剂萃取过程和固体内表面的吸附同时发生,建立了有限浴条件下溶剂浸溃树脂吸着螺旋霉素的动力学模型.浸渍树脂静态吸附螺旋霉素的计算值与实验值接近,得到螺旋霉素在浸渍树脂内的有效扩散系数为3.7×10~(-12)～29.4×10~(-12)m~2/s.线性吸附等温线条件下的分析解与非线性条件下的数值解比较,表明线性假设能较好地反映实际过程.     

Extractant screening and selection for methyl tert-butyl ether removal from aqueous streams

Recovery of low concentration methyl tert-butyl ether (MTBE) from aqueous solutions is difficult. Activated carbon adsorption or air stripping suffer from low capacity and high energy input. Liquid-liquid extraction is suggested as an alternative separation technique, but requires a suitable extractant. Based on molecular considerations, an extractant screening with COSMO-RS gives a good qualitative trend. Halogenated phenols provide the highest MTBE capacity. This is confirmed by liquid-liquid equilibrium experiments. 3-Iodophenol is selected as the MTBE extractant, because it combines comparatively low toxicity and high distribution coefficient K_D. Propylbenzene is selected as the diluent. The K_D of MTBE extraction with 3-iodophenol/propylbenzene is 270 at high extractant concentrations and low MTBE concentrations. Water solubility of 3-iodophenol can possibly be minimized by additional branched alkyl chains, preferably in para position at the aromatic ring to avoid steric hindrance during hydrogen bonding. In this study, reactive extraction of MTBE is successfully performed for the first time.     

Separation of Indium from Acid Sulfate-Containing Solutions by Ion Exchange with Impregnated Resins

Indium separation using ion exchange resins from acidic polymetallic and very diluted solutions are investigated. Since the selectivity of commercial ion exchange resins have proven to be too low for an effective separation from solutions with high content of other metals, Lewatit® TP 208 was impregnated with common extractants to enhance its properties. By resin impregnation with D2EHPA and Cyanex 272, not only the selective indium recovery was reached but also the resin capacity was increased approx. two times. The best loading and elution performance were shown by Cyanex 272-impregnated Lewatit® TP 208, increasing the indium purity in the eluate from 0.75 % to 85 %.     

Recovery and enrichment of heavy metals using new hybrid Donnan dialysis systems combining cation exchange textile and solvent impregnated resin

The purpose of this work is to apply Donnan dialysis coupled with the cation exchange membrane (CMX), the cation exchange grafted textile (CET) and the solvent impregnated resin (SIR) for recovery and enrichment of heavy metal ions from dilute solutions. The influence of some analytical parameters was investigated. The transport results show that the three barriers enhance the diffusion of silver, lead and copper, but the osmosis phenomenon is limited when the transport is carried out through CET and the SIR. The results of enrichments indicate that SIR and CET increase the enrichment factor of less hydrated ions. For instance, and for a volume ratio equal to 10, the values of silver enrichment factor obtained for (CMX/CMX/CMX), (CMX/CET/CMX) and (CMX/SIR/CMX) are equal to 2.5, 8.92 and 4.98, respectively. In addition, the use of SIR improves the enrichment of lead, whereas the CET improves the silver’s one.     

Etherification on Zeolites: MTBE synthesis

Although the use of methyl-tert butyl ether (MTBE) in reformulated gasoline has raised concerns due to its detection in ground water and has led to its gradual phase out in parts of the United States, the use of heavier ethers in gasoline in the future is possible. The synthesis of MTBE provides us with an insight into etherification reactions in general. This article reviews the extensive findings over the past 15 years on the application of acidic zeolites as alternative catalysts for etherification reactions and, in particular, MTBE synthesis, and compares the results with those of the commercially used ion-exchange resins. Although the resin catalysts are very active, they have some significant drawbacks (i.e., thermal fragility, sensitivity to methanol/isobutene ratios, and corrosive/disposal problems). Zeolites have been considered to be potential alternative catalysts for MTBE synthesis due to their excellent properties such as high thermal stability and modifiable acidity. The impact of various zeolite parameters, such as Si/Al ratio, type of zeolite, and the presence of extra-lattice Al, on activity is explored. Although the specific activities of most zeolites have been found to be too low to compete at low temperatures required to avoid thermodynamic limitations, H-beta zeolite has been found to be as active as the current commercial resin catalysts being used for MTBE synthesis. In addition, all zeolites studied have been found to have high selectivities to MTBE and low sensitivities to methanol/isobutene molar ratio, permitting the use of the stoichiometric reactant ratio. Application of zeolites for the synthesis of higher ethers is suggested.     

Etherification on Zeolites: MTBE synthesis

Although the use of methyl-tert butyl ether (MTBE) in reformulated gasoline has raised concerns due to its detection in ground water and has led to its gradual phase out in parts of the United States, the use of heavier ethers in gasoline in the future is possible. The synthesis of MTBE provides us with an insight into etherification reactions in general. This article reviews the extensive findings over the past 15 years on the application of acidic zeolites as alternative catalysts for etherification reactions and, in particular, MTBE synthesis, and compares the results with those of the commercially used ion-exchange resins. Although the resin catalysts are very active, they have some significant drawbacks (i.e., thermal fragility, sensitivity to methanol/isobutene ratios, and corrosive/disposal problems). Zeolites have been considered to be potential alternative catalysts for MTBE synthesis due to their excellent properties such as high thermal stability and modifiable acidity. The impact of various zeolite parameters, such as Si/Al ratio, type of zeolite, and the presence of extra-lattice Al, on activity is explored. Although the specific activities of most zeolites have been found to be too low to compete at low temperatures required to avoid thermodynamic limitations, H-beta zeolite has been found to be as active as the current commercial resin catalysts being used for MTBE synthesis. In addition, all zeolites studied have been found to have high selectivities to MTBE and low sensitivities to methanol/isobutene molar ratio, permitting the use of the stoichiometric reactant ratio. Application of zeolites for the synthesis of higher ethers is suggested.     

甲基叔丁基醚与苯酚在改性HY分子筛催化剂上合成2,4-二叔丁基苯酚的研究

对改性HY分子筛催化剂研究表明,每种改性物均存在一个最佳含量．P2O5改性后HY催化剂的性能最优越。苯酚的转化率达99.60％,2,4-二叔丁基苯酚(2,4-DTBP)选择性达63.90％：这一结果是目前分子筛作催化剂合成(2,4-IDTBP)的最好结果,具有潜在的应用前景,采用常压连续流动固定床反应器,克服了釜式反应操作麻烦的缺点：使用HY分子筛催化剂,无污染、无腐蚀,为工业生产提供了艮好的环境、以MTBE做为烷基化试剂,使工业生产叔丁基苯酚可以因地制宜地扩大原料来源：MTBE价格低廉易得,运输方便,进而可以降低产品成本     

Influence of Polar Components in the Dimerization of Isobutene

Isooctane is seen as a potential replacement for methyl tert-butyl ether (MTBE) in gasoline. Isooctane can be produced via the indirect alkylation route in two steps. Isobutene is first dimerized to isooctenes, which are then further hydrogenated to isooctane. In the dimerization a polar component is used to enhance the selectivity for diisobutenes. In this study the effects of tert-butyl alcohol (TBA), methanol and MTBE in the dimerization reaction were compared on the basis of experimental results. All the oxygenates studied induced similar effects: higher selectivity for diisobutenes and lower isobutene conversion as the oxygenate content increased and temperature decreased. The different polarity of the components causes the need for more methanol or MTBE than TBA to get the same conversion and selectivity.     

改性HY分子筛催化剂催化甲基叔丁基醚与苯酚合成叔丁基苯酚的研究

甲基叔丁基醚(MTBE)作为烷基化剂,以改性HY分子筛为催化剂,在常压连续流动固定床反应器上,对苯酚烷基化合成对叔丁基和2,4 二叔丁基苯酚(2,4 DTBP)的反应规律进行了较为系统的研究。以不同改性物及其含量改性HY分子筛,可调节其表面酸量、酸分布及孔道尺寸,从而改变催化剂的反应活性及产物选择性。苯酚与MTBE烷基化反应主要在中等强度和弱的B酸中心上进行。催化剂表面的酸量和酸分布不但影响活性,同时影响2,4 DTBP的选择性。对单组分氧化物改性的HY分子筛催化剂研究表明,每种改性物均存在一个最佳含量,P2O5改性后HY催化剂的性能最优越。苯酚的转化率达99.60%,2,4 DTBP选择性达63.90%。这一结果是目前分子筛作催化剂合成2,4 DTBP的最好结果,具有潜在的应用前景。