New crosslinked N‐vinylpyrrolidone copolymers: Synthesis and sorptive properties

The crosslinked copolymers of N‐vinylpyrrolidone with 1,4‐(N,N′‐bismaleimido)benzol and with trimethoxyvinylsilane were synthesized by free radical copolymerization. The copolymers were characterized by FTIR spectroscopy and thermal analysis. The values of specific surface area and porosity of the copolymers were determined with use of low‐temperature adsorption. Sorption capacity of the copolymers toward Re (VII), Mo (VI), and W(VI) ions was investigated and was found to depend strongly on the pH. A possibility to separate Re(VII) and Mo(VI) ions with use of the copolymers under investigation in their combined presence in neutral and alkaline media was shown. Moreover, in the conjoined presence of Mo(VI) and W(VI) ions at pH 5–14, tungsten(VI) can be separated from molybdenum(VI) with the copolymer of N‐vinylpyrrolidone with trimethoxyvinylsilane. POLYM. ENG. SCI., 56:1303–1312, 2016. © 2016 Society of Plastics Engineers     

Adsorption behavior and separation of vanadium(V), molybdenum(VI), and rhenium(VII) ions on crosslinked polymers containing acrylic acid derivative moieties

The radical polymerization of [2‐(acryloyloxy)ethyl]trimethylammonium methyl sulfate and [3‐(methacryloylamino)propyl]trimethylammonium chloride by using ammonium peroxydisulfate as initiator and N,N′‐methylene‐bis‐acrylamide as crosslinker agent at 70°C for 17 h was carried out. The crosslinker agent in the feed ranged between 2 and 6 mol %. The resins were completely insoluble in water and characterized by elemental analysis and FTIR spectroscopy. The metal ion binding capacity of these resins with V(V), Mo(VI), and Re(VII) were investigated using the batch equilibrium type. The pH, but not the crosslinking percentage in the feed, influenced the retention capacity of the resin, particularly for V(V) and Re(VII). Thus, at pH 1 only < 15% of V(V) was retained, but at pH 3 higher than 97% of V(V) was adsorbed. The resin–ion equilibrium was achieved between 15 min and 2 h depending on the resin, ion, and crosslinking degree. According to the pH, it is possible separate Re(VII) and Mo(VI) from V(V) at pH 1.0. To reuse the resins, the ions were stripped by using HCl, H₂SO₄, and Na₂CO₃ at different concentrations. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 369–376, 1999     

Selective Adsorption of Mo(VI) From Re(VII) Containing Effluent on Orange Waste Gel Modified by Ethylenediamine,Diethylamine, and Triethylamine

New adsorption gels were prepared by chemically immobilizing functional groups of ethylenediamine, diethylamine and/or triethylamine on orange waste, named OW-en, OW-DEA, and OW-TEA, respectively. By comparing with the adsorption of other coexisting metals, such as Re(VII), Pb(II), Fe(III), Zn(II), Mn(VII), Ca(II), and Cu(II), the novel gels exhibited selectivity only for Mo(VI) and the adsorption behavior obeys the Langmuir model. The maximum adsorption capacity for molybdenum was in the order, OW-en (2.17 mol/kg) > OW-TEA (1.26 mol/kg) > OW-DEA (0.88 mol/kg). A kinetic study for the adsorption of molybdenum at various temperatures confirmed that the endothermic adsorption process followed pseudo-second order kinetics. In addition, its excellent adsorption characteristics for Mo(VI) were confirmed by the adsorption and elution tests using a column packed with the OW-en gel, especially by separation of Mo(VI) from Mo-Re containing industrial effluent.     

氨基改性苯乙烯树脂的合成及其对铼的吸附

离子交换法因适于低浓度物质的分离富集而被广泛应用于湿法冶金行业,新型高效吸附材料的合成与应用成为该领域的发展趋势。针对铀矿中伴生铼这一稀缺资源需要同步回收的现状,根据新近研发的氨基改性苯乙烯阴离子交换树脂(LSC-Re),通过静态和动态吸附解吸试验,系统考察了溶液酸度、初始浓度、吸附时间、吸附温度等因素对吸附性能的影响,结果表明：在室温(25℃)下,铼溶液初始浓度为100 mg·L^-1,该树脂6 h达到吸附平衡,酸度对该树脂吸附铼的影响不大,树脂在pH=1.5时铀铼分离效果最佳,分离系数可达到41.68;树脂的饱和吸附容量达到129.3 mg·g^-1;从热力学和动力学角度分析,吸附过程符合Langmuir吸附等温模型和准二级动力学模型,且吸附是自发的吸热过程。动态吸附解吸试验中,控制溶液流速0.5 ml·min^-1,动态饱和吸附容量达到76.17 g·L^-1,饱穿比为2.35,用1 mol·L^-1 氨水进行解吸铼效果较好,8个树脂床体积可将其解吸完全,由此可见富集倍数接近70倍,具有良好的工业应用前景。     

Sorption properties of polymers based on N‐substituted maleimides

Physicochemical and functional properties of 2,2‐diallyl‐1,1,3,3‐tetraethylguanidinium chloride copolymers with N‐(n‐carboxyphenyl)maleimide, of N‐vinylpyrrolidone with N‐(n‐carboxyphenyl)maleimide, and of N‐vinylpyrrolidone with N‐phenylmaleimide have been investigated. Specific surface area and porosity of the copolymers under investigation have been determined by using the low‐temperature adsorption method. Electron microscope investigations in surfaces of the polymers have evinced that all of them have a spongy microstructure, the N‐vinylpyrrolidone copolymer with N‐(n‐carboxyphenyl)maleimide being the most homogeneous of these. Sorption capacity of the copolymers toward Re(VII) ions has been investigated. The process is described by the Langmuir isotherm. The pH is the most important parameter for sorption process of Re(VII). In the conjoint presence of Re(VII) and Mo(VI) in a solution of acid and ammoniac mediums, rhenium can be separated from molybdenum by using the sorbents under investigation at pH > 4.5 or at hydrochloric acid concentrations 0.1 mol L^?1 and more. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

离子交换法处理含Cr(Ⅵ)废水的研究

采用201×7强碱性阴离子交换树脂处理模拟含Cr(Ⅵ)废水,探讨了废水酸度、交换时间、浓度对Cr(Ⅵ)去除率的影响以及树脂再生所需的合适温度和再生剂浓度。结果表明,201×7强碱性阴离子交换树脂处理模拟含Cr(Ⅵ)废水,具有交换容量大、交换效果好、树脂再生条件较简单等优点。并对实际含铬废水进行了处理,废水中Cr(Ⅵ)的初始浓度为1 540 mg/L,处理量达52 BV(床体积)时,出水中Cr(Ⅵ)的浓度仍小于0.5 mg/L,达到国家排放标准。树脂交换容量约80 mg/g。用8%NaOH溶液,在50℃条件下进行再生效果较好,再生率大于95%,可实现树脂的重复使用。     

2,2′‐(Methylimino)bis(N,N‐dioctylacetamide) (MIDOA), A New Tridentate Extractant for Technetium(VII), Rhenium(VII), Palladium(II), and Plutonium(IV)

2,2′‐(Methylimino)bis(N,N‐dioctylacetamide) (MIDOA) was developed as a new extractant for technetium. MIDOA has a similar backbone to TODGA, N,N,N′,N′‐tetraoctyldiglycolamide, where the nitrogen atom bearing a methyl group replaces the ether oxygen in TODGA. MIDOA is highly lipophilic and ready to use in the HNO₃–n‐dodecane extraction system. The distribution ratio (D) for Tc(VII) is extremely high. In addition, Cr(VI), Re(VII), Mo(VI), W(VI), Pd(II), and Pu(IV) are well extracted by MIDOA. MIDOA has high selectivity toward certain oxometallates. The D(Tc) values decrease gradually with HNO₃, H⁺, and NO₃ ^? concentrations, and the log D vs log [MIDOA] dependence indicates the species extracted to be the 1:1 metal‐ligand complex. It is clear that MIDDA [2,2′‐(methylimino)bis(N,N‐didodecylacetamide)] and IDDA [2,2′‐(imino)bis(N,N‐didodecylacetamide)], which have structures analogous to MIDOA, have similar extraction behavior to that of MIDOA.     

Studies of adsorption behavior of crosslinked chitosan for Cr(VI), Se(VI)

In this work, it was found that crosslinked chitosan (CCTS) had strong adsorption ability for some anions under certain conditions. Cr(VI) and Se(VI) existed in anion forms in aqueous solution, and their adsorption rates by CCTS were 97% for Cr(VI) at pH 3.0 and 95% for Se(VI) at pH 4.0. In addition, the adsorption balance time and isotherm of CCTS for Cr(VI) and Se (VI) were discussed and adsorption mechanism was explained. This research will be useful for designing CCTS‐based adsorption for metallic toxin removal and preconcentrating Cr(VI) and Se(VI) in their trace analysis. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3216–3219, 2000     

Preparation of cellulosic ion exchange fiber using an ionic liquid as reaction reagent and medium

A cellulosic ion exchange fiber (CIEF) was prepared by using room‐temperature ionic liquid 1‐(3‐chloro‐2‐hydroxypropyl)‐3‐methylimidazolium chloride as reaction reagent and medium. The results showed the degree of substitution of the CIEF was up to 0.78. The product was characterized by Fourier transform infrared spectrometry, thermogravimetric analysis, scanning electronic microscope. The thermal stability of the CIEF was over 200°C. The adsorption experiments of CIEF for Cr(VI) were performed. The adsorption capacity of CIEF for Cr(VI) was found to be 196.1 mg g^?1 at 30°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

从钼精矿焙烧烟尘中分离回收稀有金属铼

通过采用伯胺N_(1923)与中性膦TBP组成的协同萃取体系,分离回收钼精矿焙烧烟尘中微量铼的工艺流程,比较了此体系在不同条件下对铼（Ⅶ）、钼（Ⅵ）等离子的萃取效率和分离效果。铼在萃取过程中浓缩了20倍以上,整个回收工艺流程简单、分离效果较好。     

Fixed‐Bed Adsorption Study for Fumaric Acid Removal from Aqueous Solutions by Amberlite IRA‐400 Resin

A fixed‐bed adsorption study was carried out by using a strong base anion‐exchange resin (Amberlite IRA‐400) for the removal of fumaric acid from aqueous solutions. The breakthrough curves were obtained as a function of flow rate, temperature, feed pH, and inlet fumaric acid concentration. The total adsorption capacity and the percent fumaric acid removal of the resin were calculated. The Yoon‐Nelson model was applied to the experimental data to predict the breakthrough curves and to determine the characteristic column parameters required for process design. The breakthrough curves fit the model predictions well.     

Adsorption thermodynamics and kinetics of Cr(VI) on KIP210 resin

Series of resin selection experiments were carried out and the KIP210 strong base anion exchange resin was confirmed to have the maximum equilibrium adsorption capacity to remove Cr(VI) from wastewater. The adsorption thermodynamics and kinetics of Cr(VI) on KIP210 resin were investigated completely and systematically. The static experiments were performed to study the effects of various parameters, such as shaking speed, resin dosage and pH during the adsorption process. The results indicate that the effect of external diffusion is eliminated at 160 rpm, the best pH value is 3.0 and the removal percentage of Cr(VI) increases with the increase of the resin dosage. The adsorption of Cr(VI) on KIP210 agrees well with the Langmuir isotherm and the adsorption parameters of thermodynamics are ΔH = 26.5 kJ mol⁻¹, ΔS = 126.7 J mol⁻¹ K⁻¹ and ΔG < 0. It demonstrates that the adsorption of Cr(VI) on KIP210 is a spontaneously endothermic physisorption process. Moreover, the adsorption process can be described well by a pseudo-second-order kinetic model and the activation energy is 30.9 kJ mol⁻¹. The kinetic analysis showed that the adsorption rate is controlled by intraparticle diffusion. The resin is successfully regenerated using the NaOH solutions.     

Highly efficient and reversible CO2 capture by tunable anion‐functionalized macro‐porous resins

Anion functionalized strategy has been proposed for the synthesis of macro‐porous resins [IRA‐900][An] through the neutral reaction of the basic resin [IRA‐900][OH] with the corresponding donors. Combining CO₂ adsorption results and FT‐IR, solid‐state ¹³C NMR characterization as well as quantum chemical calculations, chemical adsorption mechanism was verified and tunable capture of CO₂ was realized. Among them, the anion functionalized resin [IRA‐900][Triz] exhibits an extremely high adsorption capacity (4.02 mmol g^?1 at 25°C, 0.15 bar), outperforming many other good adsorbents. Finally, we discuss the thermostability and recycling stability of [IRA‐900][Triz], which shows a great potential in the industrial capture of CO₂. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3008–3015, 2017     

Preconcentration and Determination of Pb (II) in Aqueous Samples using Functionalized Dowex 1X8

Synthetic resin Dowex 1X8 was functionalized with α-Nitroso β-Naphthol (Dowex-αNβN) and with 8-Hydroxy Quinoline (Dowex-8HQ) to form chelating resin. The resultant chelating resins were characterized using scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The efficiency of these resins for the removal/preconcentration of Pb (II) from aqueous samples was evaluated. Optimum conditions of pH, time of equilibrium, and sample volume were investigated for maximum retention of Pb (II) from aqueous solutions. At optimum conditions, 100% adsorption was observed for the functionalized resins. Both Freundlich and Langmuir isotherms were applied to the adsorption data and it was observed that data fits well to Langmuir isotherm. Various parameters such as shaking time, type, and concentration of eluents were investigated for the recovery of Pb (II) from the chelating resins. For Dowex-αNβN and Dowex-8HQ, 100% recovery with a preconcentration factor of 100 was achieved with 0.5 and 2 M HCl, respectively. The selectivity and specificity of the functionalized resins was also evaluated by studying the effect of various foreign ions and the results have been compared with the unmodified Dowex.     

Separation of uin- and multivalent cations and selective de-ionisation by a phosphonic cation exchanger

The phosphonic cation exchanger in its free acid form is able to remove multivalent cations even from neutral and medium acidic solutions of salts of strong acids completely, and is regenerated by a stoichiometric amount of a regenerating agent. It is therefore possible to separate multivalent cations from univalent cations in a simple way by means of a phosphonic cation exchanger, followed by a weakly basic anion exchange resin. This results in a selective or partial de-ionisation of solutions with an eventual recovery of multivalent cations using an economical regeneration dosage and with a minimum of waste.     

Cr(VI)‐containing wastewater treatment by means of ion exchange on weak‐ and strong‐base anion exchangers

The aim of this research work was a thermodynamic and kinetic study of the retention of Cr(VI) ions from a K₂CrO₄ solution on macroporous weak‐ and strong‐base anion exchangers, Lewatit M 64 A and Lewatit MP 500 A, respectively. Also, the correlations among the ion‐exchange rate, the retention capacity of Cr(VI), and some process parameters were established. The parameters studied mainly were the concentration of Cr(VI) ions and the type of the counterions coupled with active groups from the anion exchangers. The results led to the conclusion that, for the Lewatit M 64 A resin, there is the following order of the Cr(VI) retention capacity: RCl > R₂SO₄ > ROH, while for the strong‐base anion exchanger, the retention capacity for the Cr(VI) ions is different: ROH > RCl > R₂SO₄. In the Cl^? form, both anion exchangers have the same retention‐capacity values. On the other side, the weak‐base anion exchanger in SO and OH^? forms presents the lowest retention‐capacity values. The process kinetics also presents some differences: for the Lewatit M 64 A resin, the ion‐exchange rate has lower values, especially in the OH^? form. This result is attributed to the increase of the OH^? ion concentration in the solution and its presence hinders the dissociation of the active groups of a weak‐base anion exchanger. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2093–2098, 2002     

阴离子交换树脂对茶氨酸的吸附动力学和热力学

以酶法制备茶氨酸,研究了碱性条件下阴离子交换树脂对茶氨酸的吸附与分离. 结果表明,强碱性树脂对茶氨酸的吸附性能优于弱碱性树脂,且其吸附容量受pH值的影响较小,pH=9.0时凝胶型强碱性树脂HZ202对茶氨酸的平衡吸附量可达96.3 mg/g. 对HZ202吸附茶氨酸的吸附等温模型及动力学、热力学参数进行了分析,结果表明,茶氨酸在HZ202树脂表面为非均一分布,Spis模型可较好模拟其吸附等温线数据;热力学参数计算结果显示,不同温度下吸附过程的吉布斯自由能变DG均为负值,表明吸附为自发的放热过程;吸附过程的焓变DH=20.9~418.4 kJ/mol,可判断其为化学吸附. 茶氨酸吸附过程符合准二级动力学方程,吸附过程受化学反应控制,提高茶氨酸初始浓度可提高吸附速率.     

阴离子交换树脂对磺基水杨酸的吸附解吸性能

用阴离子交换树脂(D201)吸附的方法研究了磺基水杨酸的富集及回收。测定了溶液的pH值、温度、吸附时间等因素对吸附的影响,探讨了吸附的热力学和动力学特性。结果表明:D201树脂在pH=2—11时,吸附能力最好,等温吸附服从Freundlich经验式,吸附动力学符合Lagergren一级速率方程,颗粒内扩散是速率控制步骤之一,膜扩散也共同影响着吸附过程。在295—313 K条件下,磺基水杨酸吸附质量分数为380—420 mg/g的吸附焓变为-13.73—-8.422 kJ/mol,自由能变为-19.89—-21.45 kJ/mol,吸附熵变为20.88—41.62 J/(K.mol),吸附速率常数为0.025 3—0.056 5 min-1,吸附活化能为34.04 kJ/mol。315 K下用质量分数10%NaCl+2%NaOH溶液可定量洗脱,洗脱率达99%。     

Experimental review of microwave-assisted methods for synthesis of functional resins for sorption of rhenium(VII)

The microwave-assisted syntheses of anion exchange resins were carried out in the presence of selected organic solvents and amines, applying variable radiation density. The polymers were used for sorption of ReO₄^–, after which, the collected results were set together with the applied synthesis parameters. The greatest Re(VII) sorption capacity of 470 mg Re g^?1 was revealed by a resin obtained within 10 min in the presence of N,N-dimethylformamide and 2-methylimidazole at power of 160 W. The outcome of the present research constitutes a set of guides allowing to enhance the resource-efficiency of the process.     

Removal of As(V) and Cr(VI) Ions from Aqueous Solution using a Continuous,Hybrid Field‐Gradient Magnetic Separation Device

Abstract

A continuous flow colloidal affinity magnetic separation device is used for the removal of As(V) and Cr(VI) from aqueous solutions. Langmuir isotherms fit the adsorption behavior of the individual ions on Orica MIEX^® ion exchange particles. In a mixture of equal weight percent As(V) and Cr(VI), the adsorption of As(V) begins only above a critical cut‐off concentration, implying preferential adsorption of the higher valence ion at the available sites. Cr(VI) is removed selectively from the mixture in the continuous flow device, consistent with the presence of a higher concentration of the higher valence ion in the proximity of a charged (anion‐exchange) surface.