Combination of on-line preconcentration by di(2-ethylhexyl) phosphoric acid resin in the presence of complexing agent with microwave plasma-atomic emission spectrometry for the determination of rare earths

The adsorption of rare earths, lanthanum, cerium, neodymium, and yttrium by di(2-ethylhexyl) phosphoric acid (D2EHPA) resin in the presence of a complexing agent, EDTA, was investigated. Flow injection was selected as the injecting method. Various parameters, sample pH, sample loading time, sample flow rate, EDTA concentration, EDTA flow rate, eluent concentration, and eluent flow rate, were studied and optimized. Under the optimum conditions, the method allowed the determination of rare earths with detection limits of 1.09 μg/L (lanthanum), 3.31 μg/L (cerium), 2.05 μg/L (neodymium), and 1.25 μg/L (yttrium). High repeatabilities were obtained for all the four rare earths (RSD<5%). The proposed method was applied to the determination of the rare earths in water samples with a recovery range of 95.8%-103.3%.     

Synergistic extraction of rare earth by mixtures of 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester and di-（2-ethylhexyl） phosphoric acid from sulfuric acid medium

The extraction of Nd^3＋ and Sm^3＋, including the extraction and stripping capability as well as the separation effect of Nd^3＋ or Sm^3＋, from a sulfuric acid medium, by mixtures of di-（2-ethylhexyl） phosphoric acid （HDEHP, H2A2（0）） and 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester （HEH/EHP, H2L2（0）） were studied. The distribution ratios and synergistic coefficients of Nd^3＋ and Sm^3＋ in different acidities were also determined. A synergistic extractive effect was found when HDEHP and HEH/EHP were used as mixed extractants for Sm^3＋ or Nd^3＋. The chemical compositions of the extracted complex were determined as Nd.（HA2）2-HL2 and Sm.（HA2）2-HL2. The extraction equilibrium constants, enthalpy change, and entropy change of the extraction reaction were also determined.     

P204萃取铒的热力学和动力学研究

用含萃取剂P204的磺化煤油对稀土离子Er~（3+）进行萃取平衡研究,得到了萃取平衡式和平衡常数。用恒界面槽测量稀土离子的萃取速率和反萃速率,考察了Er~（3+）浓度、H~+浓度、P204液度和络合物浓度对反应速率的影响,从而得到了反应速率的表达式。提出了界面反模型,用动力学及界面张力实验进行了验证。     

A comparative investigation into floatability of bastnaesite with three di/trialkyl phosphate surfactants

Flotation separation and recovery of rare earth minerals (REM) have returned to an important position due to the growing strategy demand for rare earth elements (REE). In this paper, a comparative investigation into the floatability of bastnaesite ((Ce,La)FCO₃) was conducted by using three di/trialkyl phosphate collectors, di(2-ethylhexyl) phosphate (DEHPA), dibutyl phosphate (DBP) and tributyl phosphate (TBP). The density functional theory (DFT) computation recommends that the chemical activity of the three phosphate collectors is in order of DEHPA ≥ DBP >> TBP, and their hydrophobization as-suggested by the lgP (oil-water partition coefficient) value is in the order of DEHPA > TBP > DBP. The micro-flotation indicates that the preferable pH values for flotation of bastnaesite with the three phosphate collectors are 7.0–8.0, and DEHPA achieves much higher flotation recovery of bastnaesite, followed by DBP, and then TBP, which coincides with their reactivity and hydrophobicity, the two prerequisites for froth flotation. The contact angle, zeta potential, Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) deduce that DEHPA likely reacts with the Ce(Ⅲ) atoms of bastnaesite interface through its O atom(s) of the P(=O)–O^– group to generate the Ce–O–P bonds, and its two 2-ethylhexyl groups orient outside for attaching bubbles, resulting in flotation enrichment of bastnaesite. Furthermore, this investigation offers a novel strategy for developing collectors in selective beneficiation of REM.     

Study on a novel flat renewal supported liquid membrane with D2EHPA and hydrogen nitrate for neodymium extraction

The Nd(III) extraction in flat renewal supported liquid membrane(FRSLM),with polyvinylidene fluoride membrane and renewal solution including HNO3 solution as the stripping solution and di(2-ethylhexyl) phosphoric acid(D2EHPA) dissolved in kerosene as the membrane solution,was investigated.The effects of pH in the feed phase,volume ratio of membrane solution to stripping solution,concentra-tion of HNO3 solution and concentration of carrier in the renewal phase on extraction of Nd(III) were also studied,respectively.As a result,the optimum extraction conditions of Nd(III) were obtained when concentration of HNO3 solution was 4.00 mol/L,concentration of D2EHPA was 0.100 mol/L,and volume ratio of membrane solution to stripping solution was 1.00 in the renewal phase,and pH was 4.60 in the feed phase.When initial concentration of Nd(III) was 2.00×10-4 mol/L,the extraction percentage of Nd(III) was up to 92.9% in 75 min.     

Synergistic extraction of cerium from sulfuric acid medium using mixture of 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester and Di-（2-ethyl hexyl） phosphoric acid as extractant

Synergistic extraction of cerium(IV) from sulfuric acid medium using mixture of 2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester(HEH/EHP, HL) and Di-(2-ethyl hexyl) phosphoric acid (HDEHP, HA) as extractant was investigated. The results indicated that the maximum synergistic enhancement coefficients were obtained at the mole fraction of HEH/EHP=0.6, and cerium(IV) was extracted into organic phase in the form of Ce(SO4)0.5HL2A2. A cation exchange mechanism was proposed for the synergistic extraction of Ce(IV). The equilibrium constants and thermodynamic functions such as △G, △H, and △S were determined in the extraction of Ce(IV) from sulfuric medium using mixture of HEH/EHP and HDEHP.     

以柠檬酸和过氧化氢为络合剂电感耦合等离子体原子发射光谱法测定选矿样品中钨和钼

以盐酸、硝酸、氢氟酸、硫酸、柠檬酸和过氧化氢溶解样品,选择W239.709 nm和Mo 284.823 nm的谱线分别作为钨和钼的分析线,用ICP-AES光谱法测定了样品中钨和钼含量。利用柠檬酸和过氧化氢与钨酸、钼酸络合作用,抑制钨酸和钼酸的析出,促使样品的快速溶解,确保了钨、钼测定结果的准确性。钨和钼的检出限分别为0.015 μg/mL 和0.003 μg/mL,测定下限分别为0.075 μg/mL和 0.015 μg/mL。当钨、钼含量分别在0.1~100 μg/mL范围内,其校准曲线均呈线性关系,且线性相关系数都在0.999 5以上。采用本方法测定钼矿石标准样品和选矿流程样品中钨、钼时,测定值与认定值或硫氰酸盐光度法或重量法的测定值相符。用钨矿石标准样品和选矿流程样品进行加标回收试验,测得钨的加标回收率在96%～105%之间,钼的加标回收率在94%～102%之间。     

Adsorption of Ce(IV) in nitric acid medium by imidazolium anion exchange resin

N-methylimidazolium functionalized anion exchange resin in NO3-form(RNO3) was prepared and used for adsorption of Ce(IV)in nitric acid medium.The adsorption amount increased with shaking time increasing and the adsorption equilibrium was obtained within 180min.Ce(IV) was partially reduced to Ce(III) and the reduction percent of Ce(IV) increased with shaking time increasing.But RNO3 was morestable than other resins due to the high resistance to oxidation.A little increase of adsorption amount was found with ...     

Separation of Tb~(3 ) , Dy~(3 ) , Ho~(3 ) , Er~( 3 ) with Solvent Impregnated Resins Containing Di-(2,4,4-trimethylpentyl) Phosphinic Acid

Separation of Tb~(3 ) , Dy~(3 ) , Ho~(3 ) , Er~( 3 ) with Solvent Impregnated Resins Containing Di-(2,4,4-trimethylpentyl) Phosphinic Acid     

金属离子和正辛醇对二(2-乙基己基)磷酸钠微乳体系相行为的影响

对于由二(2-乙基己基)磷酸钠(NaDEHP)、正辛烷、水、金属盐和正辛醇组成的微乳体系，研究了金属离子(Na^ ，Ca^2 ，Mn^2 ，Fe^3 ，Co^2 ，Ni^2 ，Cu^2 ，Zn^2 ，Al^3 )和正辛醇对相行为的影响。当金属盐或正辛醇含量增加时，体系发生WinsorⅠ→Ⅲ→Ⅱ型转变。在影响微乳体系相行为中起主要作用的是金属-HDEHP配合物的亲油性。     

Study on the Separation of Rare Earths with the Method of H(DEHP)-Extraction Chromatography

Separation of rare earths was investigated by extraction chromatography where H(DEHP)wasused as a stationary phase,while HCl and H_2SO_4 solutions as a mobile phase.The average separation fac-tors of rare earths,β_(HCl) and β_(H_2SO_4),are 3.79 and 4.57.respectively.The β_(La)~(Ce) in HCl and H_2SO_4 systems areas high as 28.5 and 26.3,respectively.The elution acidity in the study can be down to one tenth and one four-teenth of that in HEH(EHP)system.     

甲基磺酸亚铈催化合成柠檬酸三(2-乙基)己酯的研究

合成了甲基磺酸亚铈,研究了以甲基磺酸亚铈催化柠檬酸和2-乙基己醇的酯化反应,考察了反应温度、催化剂用量、醇酸摩尔比等因素对反应结果的影响,对合成的产品进行了红外光谱分析.实验结果表明,甲基磺酸亚铈催化合成柠檬酸三(2-乙基) 己酯的最佳反应条件为:n (2-乙基己醇):n(柠檬酸)＝3.60:1,催化剂用量0.25% (以酸的物质的量计),反应温度120℃～130℃,负压操作.在最佳反应条件下,柠檬酸三(2-乙基)己酯收率在98.0%以上.反应结束后,催化剂通过简单的相分离即可重复使用.甲基磺酸亚铈重复使用5 次后,其催化活性无明显下降,产品收率仍可达到90%以上.     

Structure Reactivity Studies on the Extraction of Rare Earths by Di(2-ethylhexyl)chloroalkyl Phosphonates

The extractive separation properties and the extractive regularity of the lanthanide elements by fivedi(2-ethylhexyl)alkyl phosphonates with various alkyl structure:di(2-ethylhexyl)chloromethyl phosphonateCH_2ClP(O) (OC_8H_(17)-i)_2(1),di(2-ethylhexyl)β-chloroethyl phosphonate ClCH_2CH_2P(O) (OC_8H_(17)-i)_2(2),di(2-ethylhexyl)α-chloroethyl phosphonate CH_3CHClP(O)(OC_8H_(17)-i)_2 (3),and correspondingdi(2-ethylhexyl)methyl phosphonate CH_3P(O)(OC_8H_(17)-i)_2 (4),di(2-ethylhexyl)ethyl phosphonateC_2H_5P(O) (OC_8H_(17)-i)_2 (5),in nitrate system have been studied.The coordination compounds were prepared.The structure of these extractants and their coordination compounds were further explored by IR and ~(31)P NMRspectra.     

Synthesis,crystal structure,and fluorescence of two dimeric europium（Ⅲ） complexes with 2-（trifluoromethyl）benzoate

Two complexes [Eu2（2-TFMBA）6（2,2′-bipy）2]·2H2O （1） and Eu2（2-TFMBA）6（1,10-phen）2 （2） （2-TFMBA=2-（Trifluoromethyl） benzoate; 2,2′-bipy=2,2′-bipyridine; 1,10-phen= 1,10-phenanthroline） were synthesized by solvent method and determined by X-ray diffraction analysis. Complex 1 crystallizes in monoclinic system with space group P21/c, whereas complex 2 crystallizes in triclinic system with space group Pi. Both are binuclear molecules with an inversion center. In complex 1, two center Eu^3＋ ions are linked together by four 2-TFMBA ligands in bidentate-bridging mode. Each Eu^3＋ ion is eight-coordinated with six O atoms from five 2-TFMBA ligands and two N atoms from one 2,2′-bipy molecule. In complex 2, two center Eu^3＋ ions are linked together by four 2-TFMBA ligands in two modes, namely, bidentate-bridging and tridentate-bridging. Each Eu^3＋ ion is nine-coordinated with seven O atoms from five 2-TFMBA ligands and two N atoms from one 1,10-phen molecule. The two complexes both exhibited strong red fluorescence under ultraviolet light, and the ^5D0→^7Fj （j=0-4） transition emissions of Eu^3＋ ion were observed in their emission spectra.     

2-(2,4-咪唑偶氮)-5-二甲氨基苯甲酸分光光度法测定钴

研究了新显色剂2-(2,4-咪唑偶氮)-5-二甲氨基苯甲酸(IZDBA)的合成及与钴的显色反应条件。2-氨基咪唑硫酸盐采用亚硝酸盐重氮化后,与间-二甲氨基苯甲酸偶联形成IZD- BA。在pH 8.0的NH_3.H_2O—NH_4Cl缓冲溶液中,IZDBA与Co~(2 )形成组成比为2:1的稳定紫色络合物,其最大吸收波长为610 nm,表观摩尔吸光系数为4.15×10~4L·mol~(-1)·cm~(-1),Co~(2 )质量浓度在0～0.8 mg/L范围内遵守比尔定律。方法具有较好的选择性和灵敏度,可以不经分离直接测定合成工业废水中微量钴,RSD(n=6)为2.2%,加标平均回收率为104.5%。     

Synthesis and Structural Determination of Eight Coordinate NH_4[Yb(Ⅲ)(Cydta)(H_2O)_2]·5H_2O

ｅｃａｕｓｅｓｏｍｅｒａｒｅｅａｒｔｈｍｅｔａｌｃｏｍｐｏｕｎｄｓｈａｖｅｔｈｅｐｒｏｍｏｔｉｖｅａｃｔｉｏｎｔｏｔｈｅｇｒｏｗｔｈｏｆａｎｉ ｍａｌｓａｎｄｐｌａｎｔｓ[1 ] ,ａｎｄｔｈｅｆｕｎｃｔｉｏｎｏｆａｎｔｉｉｎ ｆｌａｍｍａｔｉｏｎ ,ａｎｔｉｂａｃｔｅｒｉｕｍ ,ａｎｔｉｃｏａｇｕｌａｎｔｉｏｎａｎｄａｎｔｉｃａｎｅｒ[2 ] ,ｔｈｅｉｎｖｅｓｔｉｇａｔｉｏｎｏｎｔｈｅｓｙｎ ｔｈｅｓｅｓａｎｄｓｔｒｕｃｔｕｒｅｓｏｆｔｈｅｅｖｅｒｙｋｉｎｄｓｏｆｒａｒｅｅａｒｔｈｍｅｔａｌｃｏｍｐｏｕｎｄｓ…     

2-(1,3,4-三氮唑偶氮)-5-二乙氨基苯甲酸光度法测定钴

研究了新显色剂 2 (1,3 ,4 三氮唑偶氮 ) 5 二乙氨基苯甲酸 (简称TZDBA)与钴的显色反应 ,试剂与钴在 pH5 0的HAc -NaAc缓冲溶液中形成稳定的紫红色络合物 ,其组成比为Co2 + ∶TZDBA =1∶3 ,λmax=5 69nm ;试剂的λmax为 492nm ,对比度Δλ为 77nm ,络合物表观摩尔吸光系数ε =5 82× 10 4 。Co2 + 浓度在 0～ 0 5mg/L范围内符合比尔定律。络合物形成后在强酸溶液中能稳定存在 ,可消除大量金属离子的干扰 ,有良好的选择性。方法可以不经分离直接测定维生素B1 2 和工业废水中的微量钴 ,结果令人满意     

1-(2-吡啶偶氮)-2-萘酚分光光度法测定硫酸阳极氧化液中铜

研究了铜与1-(2-吡啶偶氮)-2-萘酚(PAN)的显色反应,建立了测定硫酸阳极氧化液中铜的新方法。以TritonX-100为增溶增敏剂,明胶作稳定保护剂,在酸性条件下Cu-PAN络合物稳定保持在水相中,直接进行光度分析。该络合物在558nm处有最大吸收峰,其表观摩尔吸光系数ε=2.25×104L.mol-1.cm-1。方法检出限为0.028μg/mL,线性范围为0～3.2μg/mL,用于测定硫酸阳极氧化液中的铜,加标回收率为98.2%～105.6%,相对标准偏差≤0.34%。     

Enhancing the performance of photovoltaic cells by using down-converting KCaGd（PO_4）_2：Eu~（3＋） phosphors

The goal of this work is aimed to improve the power conversion efficiency of single crystalline silicon-based photovoltaic (PV) cells by using the solar spectral conversion principle, which employed a down-converting phosphor to convert a high-energy ultraviolet photon to the less energetic red-emitting photons to improve the spectral response of Si solar cells. In this study, the surface of silicon solar cells was coated with a red-emitting KCaGd(PO4)2:Eu3+ phosphor by using the screen-printing technique. In addition to the investigation on the microstructure using scanning electron microscopy (SEM), we measured the short circuit current (Isc), open circuit voltage (Voc), and power conversion efficiency (η) of spectral-conversion cells and compared with those of bare solar cells as a reference. Preliminary experimental results revealed that in an optimized PV cell, an enhancement of (0.64+0.01)% (from 16.03% to 16.67%) in Δη of a Si-based PV cell was achieved.     

2—（5—硝基—2—吡啶偶氮）—H酸光度法同时测定铜和镍

报道了新显色剂2-(5-硝基-2-吡啶偶氮)-H酸(简称5-NO2-PAH)同时测定铜、镍的显色体系,系统的研究了该试剂与铜、镍显色的适宜条件及共存离子的影响.结果表明在pH8.5～10.0范围内,铜、镍与试剂形成稳定的络合物,表观摩尔吸光系数分别为εCu＝4.68×104,εNi＝1.07×105,铜的浓度在0～12μg/10mL、镍的浓度在0～5μg/10mL范围内遵守比尔定律.方法用于样品测定,结果满意.