Spherical Resorcinol‐Formaldehyde Resin Testing for Cesium Removal from Hanford Tank Waste Simulant

Abstract

A new spherical form of resorcinol‐formaldehyde (RF) resin was tested for efficacy of cesium removal from Hanford tank waste. Two spherical RF formulations, prepared by varying curing temperature, were tested. Both resins had a tight particle size distribution and a high degree of sphericity. Small‐scale column testing (on ～20‐mL resin beds) was conducted evaluating the cesium load profile with AZ‐102 simulated tank waste and the cesium elution profile using 0.5 M HNO₃ eluant. The load and elution profiles were compared in side‐by‐side testing with ground‐gel RF resin and SuperLig® 644, the Waste Treatment Plant baseline ion exchanger. Although breakthrough capacity was not as high as the other resins tested, the spherical RF resin met plant cesium loading requirements with the AZ‐102 simulant matrix. Excellent reproducibility of cesium load and elution was demonstrated over three process cycles with no evidence of degraded performance. Residual cesium on the resin beds after elution was nearly a factor of 10 lower than that of the ground‐gel RF and SuperLig^® 644.     

Recovery of purified radiocesium from acidic solution using ammonium molybdophosphate and resorcinol formaldehyde polycondensate resin

Separation of Cs⁺ from acidic solution was investigated using ammonium molybdo- phosphate (AMP) based sorbents. Four sorbents including two AMP powders and two composites prepared by coating of AMP powder on polymethylmethacrylate (PMMA) beads were used in this study. Equilibrium sorption isotherms for Cs⁺ on AMP sorbents were determined. The effect of H⁺ concentration on Cs⁺ uptake by AMP–PMMA beads was examined. Two column runs were carried out to establish the Cs⁺ separation performance of AMP–PMMA beads from 1.0 M nitric acid having Cs⁺ concentration equivalent to 10 Ci of ¹³⁷Cs per litre. Recovery of Cs⁺ from loaded AMP–PMMA column was carried out by dissolution of AMP using NaOH solution. The feasibility of ion exchange purification of the recovered Cs⁺ solution was examined using resorcinol formaldehyde polycondensate resin (RFPR). The Cs⁺ sorption isotherm on RFPR from Cs-bearing dissolved AMP solution was determined. Purification of Cs⁺ from dissolved AMP solution was studied in two column runs using RFPR in loading-elution cycles. The results of these studies are useful in formulating a scheme for the recovery of purified ¹³⁷Cs product from high level waste for large-scale utilization as a radiation source in industrial irradiators.     

废渣中银回收的研究

采用HCI溶液处理含银废液和废渣,然后用K2CO3和KOH将沉淀进行转化,将转化的沉淀溶解于稀HNO3中,制成AgNO3溶液,并将其浓缩结晶和二次重结晶,即制得固体AgNO3,其纯度可以达到99．8％以上,杂质含量符合国家产品分析纯(A．R)标准。     

Separation and Recovery of Silver(I) Ions from Base Metal Ions by Melamine‐formaldehyde‐thiourea (MFT) Chelating Resin

Abstract

Melamine‐formaldehyde‐thiourea (MFT) chelating resin were prepared using melamine (2,4,6‐triamino‐1,3,5‐triazine), formaldehyde, and thiourea and this resin has been used for separation and recovery of silver(I) ions from copper(II) and zinc(II) base metals and calcium(II) alkaline‐earth metal in aqueous solution. The MFT chelating resin was characterized by elemental analysis and FT‐IR spectra. The effect of pH, adsorption capacity, and equilibrium time by batch method and adsorption, elution, flow rate, column capacity, and recovery by column method were studied. The maximum uptake values of MFT resin were found as 60.05 mg Ag⁺/g by batch method and 11.08 mg Ag⁺/g, 0.052 mg Zn²⁺/g, 0.083 mg Cu²⁺/g and 0.020 mg Ca²⁺/g by column method. It was seen that MFT resin showed higher uptake behavior for silver(I) ions than base and earth metals due to chelation.     

Synthesis,Characterization, and Applications of a New Chelating Resin Containing 4-2-(Thiazolylazo) Resorcinol (TAR)

A new phenol–formaldehyde based chelating resin containing 4-(2-thiazolylazo) resorcinol (TAR) functional groups has been synthesized and characterized by Fourier transform infrared spectroscopy and elemental analysis. Its adsorption behavior for Cu(II), Pb(II), Ni(II), Co(II), Cd(II), and Mn(II) has been investigated by batch and column experiments. The chelating resin is highly selective for Cu(II) in the pH range 2 ～ 3, whereas alkali metal and alkaline earth metal ions such as Na(I), Mg(II), and Ca(II) are not adsorbed even at pH 6. Quantitative recovery of most metal ions studied in this work except Co(II) is achieved by elution with 2M HNO₃ at a flow rate of 0.2 mL min^?1. A similar trend is observed for distribution coefficient values. The quantitative separations achieved on a mini-column of chelating resin include Cd(II) – Cu(II), Mn(II) – Pb(II), Co(II) – Cu(II), Mn(II) – Ni(II), and Mn(II) – Co(II) – Cu(II). The recovery of copper(II) is quantitative (98.0–99.0%) from test solutions (10–50 mg/L) by 1 mol/L HNO₃-0.01 mol/L EDTA. The chelating resin is stable in acidic solutions below 2.5 M HNO₃ or HCl as well as in alkaline solution below pH 11. The adsorption behavior of the resin towards Cu(II) was found to follow Langmuir isotherm and second order rate.     

Investigating the Extent of Urea Formaldehyde Resin Cure in Medium Density Fiberboard: Resin Extractability and Fiber Effects

The degree of resin cure achievable in urea formaldehyde (UF) resin is known to influence the hydrolytic stability of UF resin. In the current study, a significant difference in water extractable resin components has been observed between cured pure resin and that from medium density fiberboard (MDF) panels. Results show some 50 to 70% of resin components may be removed on water extraction from resinated MDF fiber and panel samples. In contrast, cured pure UF resins have only a small fraction of resin mass extractable into water with nitrogen-containing components remaining incorporated into the cured resin. The relatively high resin mass losses from panel material together with loss of nitrogen-containing components suggest not only free urea, but urea-methylene species are labile and readily extractable into water. Wax contributes to differing panel extractability when pressed at either 100 or 160°C, whereas panel resin loading has a significant effect on extractable resin components. A lower resin loading led to relatively greater resin extractability, which was corroborated by the extractability of resin-fiber mixtures up to 50% resin content. An assessment of extracted panel residues suggests a relative decrease of urea and urea-formaldehyde condensation products after water extraction. With UF resin highly mobile on fiber during MDF manufacture, the results suggest resin components may separate, leading to their incomplete incorporation into a cured, cross-linked UF resin matrix, with an implication that resin cure on fiber may not be complete compared to that found with pure resin.     

新工艺生产高品质环氧树脂的废水污染防治

介绍了两步法高品质环氧树脂生产新工艺，针对其工艺过程以及吸收处理挥发性溶剂产生的高浓度有机废水污染防治措施进行分析和论述，并提出替代方案。     

利用地沟油和对苯二甲酸废料生产醇酸树脂的理论和实践

以地沟油和对苯二甲酸废料为原料合成醇酸树脂,通过对原料的组成及合成工艺的理论分析,确定采用碱漂法去除地沟油的杂质,采用混合酸多步法除去对苯二甲酸废料中的杂质,采用二段法合成醇酸树脂。经中试和扩大生产,合成的醇酸树脂固形物中40%来自地沟油,25%来自对苯二甲酸废料,其余为甘油和松香,与传统工艺相比,本工艺生产醇酸树脂每吨原料成本降低1 522元,是一条经济有效的资源化利用工艺路线。     

Recovery of 137Cs from Laboratory Waste using Solvent Extraction with Sodium Tetraphenylboron (TPB)

The paper describes a method for the recovery of ¹³⁷Cs from an aqueous radioactive laboratory waste solution containing ¹³⁷Cs (2 µg/mL) in the presence of high concentration of Na⁺ using solvent extraction technique. The method comprises of adjustment of pH to the acidic range (pH = 2), contacting the aqueous radioactive solution with sodium tetraphenylboron (TPB) in nitrobenzene, whereby ¹³⁷Cs binds with tetraphenylboron anions and gets separated. Results of this investigation indicate that ¹³⁷Cs could be efficiently and selectively extracted from an aqueous solution media containing high concentration of Na⁺ under mildly acidic pH into an organic phase and back extracted with small volume of 3 M HNO₃, thus enabling concentration. The proposed method was successfully applied in real samples.     

Separation and Purification of Flavonoid from Ginkgo Extract by Polyamide Resin

An efficient separation process of flavonoid from Ginkgo extract was developed in this study. Polyamide resin offered the fine adsorption capacity, and its adsorption rate at 25°C fitted well to the Langmuir isotherm. Dynamic adsorption and desorption experiments were conducted to optimize the separation process of total flavonoids from the Ginkgo extract. After one run, the content of total flavonoids increased from 24.0% to 55.0%. The method will provide a potential approach for large-scale separation and purification of flavonoid for its wide pharmaceutical use.     

Optimization Studies for the Recovery of Thorium from Advanced Heavy Water Reactor High Level Waste (AHWR-HLW) Solutions Using Green Solvents

An Advanced Heavy Water Reactor (AHWR) has been specifically designed to exploit Th/²³³U as fuels. The reprocessing is focused mainly on the recovery of ²³³U and Pu from the spent fuels leaving bulk of Th (～100 g/L) in the High Level Waste (HLW) solutions. No systematic attempts have been made so far to identify suitable solvents for the recovery of thorium from high level waste (HLW) solutions generated after AHWR spent fuel reprocessing. Tri-n-butyl phosphate (TBP), though the work horse for nuclear fuel reprocessing as an extractant, suffers from the serious limitation of third-phase formation during the extraction of macro concentrations of thorium. Two straight chain dialkyl amides such as N,N-dihexyl octanamide (DHOA), and N,N-dihexyl decanamide (DHDA) as well as TBP were evaluated for the recovery of the thorium from AHWR-HLW solutions. Attempts were made to identify suitable solvent (extractant + diluent) system and optimize the conditions for the recovery of thorium from HLW solutions. Selectivity of the solvents was examined for thorium extraction over fission products/structural materials under AHWR raffinate solutions. Counter-current centrifugal contactor runs were also carried out on simulated waste solutions to validate the optimized conditions for the recovery of thorium from the simulated AHWR waste solutions.     

大孔吸附树脂分离纯化银杏叶总黄酮的研究

利用4种大孔吸附树脂分离纯化银杏叶总黄酮.结果表明,HPD100型大孔吸附树脂最适合分离纯化银杏叶总黄酮,该树脂的静态饱和吸附量(以干树脂计)为63.8 mg·g-1,静态洗脱率为91.2%,动态饱和吸附-洗脱量为14.0 mg·g-1,洗脱剂为70%乙醇,洗脱剂用量为4倍树脂体积,树脂可重复使用7个周期.     

Use of Calix[4]-bis-2,3-naphthocrown-6 for Separation of Cesium from Pressurized Heavy Water Reactor Simulated High Level Waste Solutions (PHWR-SHLW)

Abstract

Distribution studies on Cs(I) were carried out from pressurized heavy water reactor (PHWR) simulated high level waste (SHLW) solution using calix[4]-bis-2,3-naphtho-crown-6 as the ligand. A mixture of 1:1 nitrobenzene and toluene was evaluated as a suitable diluent. The distribution ratio of Cs(I) increased with the aqueous feed acidity upto 3 M HNO₃ and decreased thereafter due to extraction of hydronium ions. The maximum D_Cs value at ～3 M HNO₃ suggested the possible application of the system for the recovery of radio-cesium from high level waste solution. The addition of 0.4% (v/v) Alamine 336 (a tertiary amine) facilitated the quantitative stripping of Cs(I) with distilled water. Quantitative extraction of Cs(I) from SHLW containing 0.32 g/L of Cs was observed in five contacts at O/A = 1/2 with 2.5 × 10^?3 M calix[4]-bis-2,3-naphtho-crown-6. Similarly, quantitative stripping of Cs(I) from the loaded organic phase was achieved in two contacts with distilled water at a volume ratio (O/A) of 2. Selectivity studies carried out using several radiotracers such as ¹⁴³Ce, ¹⁴⁰La, ¹⁴⁰Ba, ¹³⁷Cs, ¹⁰³Ru, ⁹⁹Mo, ^99mTc, ⁹⁷Zr, ⁹¹Sr, etc. indicated excellent selectivity for Cs. The reagent exhibited excellent chemical stability up to a period of six months.     

从脱硫脱氰废液中回收硫氰酸铵

本研究提出一项新的工艺技术，它是以ＮＨ＿４ＣＮＳ－（ＮＨ＿４）＿２Ｓ＿２Ｏ＿３－Ｈ＿２Ｏ三元水盐系相图为理论基础，采用结晶法从Ｆ．Ｒ．脱硫脱氰废液中回收硫氰酸铵。本文介绍了其工艺流程和工艺参数，硫氰酸铵产品的纯度可达９５．０％～９９．５％。其总收率达６０％以上。     

焦化企业废气废水回收利用浅析

近年来随着工业污染带来全球环境问题,各个地方也不断将高消耗、高浪费企业向集约化企业的转型提上重要的高度。然而在大多数企业转型的时候,基础性企业仍就是不可替代的,焦化企业主要是将煤炭生产成焦炭,其生产成品在其他工业生产中是必不可少的原料之一,焦化企业在生产过程中,无法避免的会产生掺杂CO_2、SO_2等有害物质的废气,及含有硫、碳等元素的废水,对环境污染十分严重。在对焦化企业废气、废水回收利用现状以及对策进行了浅析。     

大孔吸附树脂提取分离牛膝总甾酮

对大孔吸附树脂提取分离牛膝总甾酮的吸附和洗脱性能进行了研究。结果表明,D型大孔吸附树脂对牛膝总甾酮的吸附量为28 9mg/g;在pH=2～10,吸附流速<1 2BV(BV:树脂柱床体积)/min,用φ(C2H5OH)=85%的乙醇2BV,牛膝总甾酮就可以被完全洗脱;经D型大孔吸附树脂提取分离后,提取物中总甾酮质量分数可达到60%,蜕皮甾酮质量分数可达到10%以上,说明大孔吸附树脂提取分离牛膝总甾酮的方法可行。     

Separation and Recovery of Silver(I) Ions from Base Metal Ions by Thiourea- or Urea-Formaldehyde Chelating Resin

Abstract

In the present work, thiourea-formaldehyde (TF) and urea-formaldehyde (UF) chelating resins have been synthesized and they have been used in the adsorptions of Ag(I), Cu(II), and Zn(II) metal ions by batch and column methods. The effect of initial acidity of Ag(I) solution and the adsorption capacities of TF and UF resins by batch method and the separation of Ag(I) ions from Cu(II) and Zn(II) base metal ions by the column method were examined experimentally. The adsorption capacities of TF and UF resins were found as 58.14 and 47.39 mg Ag(I)/g by batch method and 30.7 and 4.66 mg Ag(I)/g, 0.80 and 0.121 mg Cu(II)/g, and under 0.002 mg Zn(II)/g by the column method, respectively. It was found that Ag(I) ions showed higher affinity towards TF resin than UF resin, compared with Cu(II) or Zn(II) ions, and Ag(I) could be separated more effectively by TF resin from Cu(II)and Zn(II) ions.     

CODcr测定废液中银的回收与利用

对重铬酸钾法测定CODCr的废液组成进行了估算,提出了以氯化银沉淀形式收集CODCr废液中的银离子,用Zn-H2SO4体系还原氯化银沉淀的方法,采用该方法可得到纯度为99.6%的金属银粉,回收率为94.8%,回收的银粉可用于CODCr的分析。回收银后的废液在碱性条件下加过量硫化钠生成硫化铬、硫化亚汞和硫化亚铁共沉淀,达到去除Cr3+,Hg2+和Fe3+的目的,清液可排放。     

大孔树脂对小叶榕叶的总黄酮吸附分离特性

以大孔吸附树脂为吸附剂,研究了其对小叶榕黄酮(FFLF)的吸附分离特性,选择10种大孔吸附树脂,比较了其对FFLF的吸附率和解吸率,筛选出最佳树脂种类,并对其动力学曲线和动态吸附性能进行了考察。结果表明,D101树脂对FFLF有较好的吸附和解吸效果,适合于FFLF的分离纯化。当上样液质量浓度为25 g/L,pH=4,上样液流速为2.5 mL/min时,D101树脂对FFLF吸附量大;以w(EtOH)=50%为洗脱剂,洗脱液流速为3mL/min时,对FFLF解吸率达92%。