Trace metal contents of acidic,basic and neutral components of a cyclohexanol extract of Kosova Basin lignite

A sample of Kosova Basin lignite was extracted with cyclohexanol. The yield of extract was 19.98 wt%. The extract was fractionated into acidic, basic and neutral components and benzene- and petroleum ether-insoluble fractions. After ashing with HClO₄ and HNO₃, eleven elements (K, Ca, Mg, Fe, Pb, Zn, Cu, Mn, Cr, Cd and Ni) were analysed by atomic absorption spectroscopy and seven elements (Al, Ba, Sr, Be, B, Ga and V) by inductively coupled plasma optical emission spectroscopy. A majority of the elements (Fe, B, Al, Zn, Pb, Cu, Ca, Mg, Sr, Ga and V) were found concentrated in the acidic and phenol fractions, while K, Ni, Ga and Cu predominated in the amine fraction. The metals thus analysed were associated with heteroatoms.     

Speciation of major and selected trace elements in IGCC fly ash

The speciation of Ga, Ge, Ni, V, S and Fe in fly ash from IGCC power plant were investigated for possible further extraction process by combining conventional mineral and chemical analysis, leaching tests, wet sequential extraction, Mössbauer and XAFS spectroscopies. The results shown that Ge occurs mainly as water-soluble species, GeS and/or GeS₂ and hexagonal GeO₂. Ga is present as an oxide, Ni occurs mainly as nickeline (NiAs), with minor proportions of Ni arsenates and vanadium as V(III) with minor amounts of V(IV) in the aluminosilicate glass matrix. Pyrrhotite and wurtzite-sphalerite are sulfide species containing Fe and Zn, but an important fraction of iron is also present in the aluminosilicate glass. These clear differences between the speciation of the above elements in this material and those reported for fly ash from conventional PC combustion.     

Extraction and Separation of Germanium Using Cyanex 301/Cyanex 923. Its Recovery from Transistor Waste

Abstract

The extraction of Ge(IV) from HCl, HNO₃ and H₂SO₄ media in toluene solution of Cyanex 301 and Cyanex 923 is investigated. It is almost quantitatively extracted (～95%) in Cyanex 301 and Cyanex 923 at 8 molL^?1 HCl but the extractions from H₂SO₄ and HNO₃ are poor in the entire investigated range of acid molarity. Detailed investigations were carried out from HCl medium. Based on the slope analysis data the extracting species is identified as GeCl₄·2R (R=Cyanex 301/Cyanex 923). The extraction of Ge(IV) is higher and comparable in diluents like toluene, n‐hexane and kerosene (160–200°C) and there is no correlation between the dielectric constant and the percent extraction. The extractants are stable towards prolonged acid contact and there is negligible loss in their extraction efficiency even after recycling them for several cycles. The extraction behavior of commonly associated metal ions namely As(V)/(III), Sn(IV), Tl(III), In(III), Ga(III), Fe(III), Al(III), Hg(II), and Cu(II) has also been investigated. Based on the partition data conditions for attaining some binary and ternary separations involving Ge(IV) have been optimized. The separation data have been fused to develop a scheme for the recovery (93%) of pure germanium (～99%) from semi conductor waste.     

Chemical nature and potential mobility of phosphorus in fertilized grassland soils

This paper describes results from a study of the effects of various applications of phosphorus (P) on the amounts, forms and potential mobility of P in grassland soils (0-7.5 cm) collected from four locations in the United Kingdom (Hertfordshire, Devon) and New Zealand (Taranaki, Canterbury). A sequential extraction scheme (NH₄Cl, NH₄F, NaOH I, H₂SO₄, NaOH II, residual P) designed to isolate P associated with aluminium (Al), iron (Fe) and calcium (Ca) was used to characterise P in the grassland soils from each location which had received various quantities of mineral fertilizer, organic manure and lime. Concentrations of total P in the soils ranged from 540 to 3,994 mg P kg^-1, and sequential extraction recovered 80–94% of total soil P. Extractable forms of inorganic P and organic P accounted for 40–52% and 31–50% of total soil P respectively. Inorganic and organic P present in the NaOH I fraction (P associated with Fe, Al and organic matter) accounted for most of the P which accumulated in soil from P inputs. Distribution of accumulated soil P between the various inorganic and organic P fractions appeared to be mainly controlled by the nature and availability of sorption surfaces which act as sinks for inorganic P. Phosphate sorption index data for the various soil sets indicated that the mean value of bicarbonate extractable inorganic P (Olsen P) which represented effective P saturation ranged from 61 to 217 mg P kg^-1. Potentially mobile soil P as determined by extraction with 0.01M calcium chloride (CaCl₂) was found to be most strongly correlated to the NH₄F, NaOH I and H₂SO₄ inorganic P fractions using a Freundlich isotherm.     

正丙醇-硫氰酸铵-水体系析相萃取分离和富集锗的研究

研究了正丙醇-硫氰酸铵-水体系析相萃取分离和富集锗的行为及与一些金属离子分离的条件.结果表明,硫酸铵能使正丙醇的水溶液分成两相,在分相过程中,Ge(Ⅳ)和硫氰酸铵生成的Ge(SCN)62-与质子化正丙醇C3H7OH2+形成的缔合物[Ge(SCN)62-][C3H7OH2+]2能被正丙醇相完全萃取.当正丙醇、硫氰酸铵和硫...     

Functionalization of Fluorinated Benzenesulfonamides and Their Inhibitory Properties toward Carbonic Anhydrases

Substituted tri‐ and tetrafluorobenzenesulfonamides were designed, synthesized, and evaluated as high‐affinity and isoform‐selective carbonic anhydrase (CA) inhibitors. Their binding affinities for recombinant human CA I, II, VA, VI, VII, XII, and XIII catalytic domains were determined by fluorescent thermal shift assay, isothermal titration calorimetry, and a stopped‐flow CO₂ hydration assay. Variation of the substituents at the 2‐, 3‐, and 4‐positions yielded compounds with a broad range of binding affinities and isoform selectivities. Several 2,4‐substituted‐3,5,6‐trifluorobenzenesulfonamides were effective CA XIII inhibitors with high selectivity over off‐target CA I and CA II. 3,4‐Disubstituted‐2,5,6‐trifluorobenzenesulfonamides bound CAs with higher affinity than 2,4‐disubstituted‐3,5,6‐trifluorobenzenesulfonamides. Many such fluorinated benzenesulfonamides were found to be nanomolar inhibitors of CA II, CA VII, tumor‐associated CA IX and CA XII, and CA XIII. X‐ray crystal structures of inhibitors bound in the active sites of several CA isoforms provide structure–activity relationship information for inhibitor binding affinities and selectivity.     

Distributions of trace elements in Western Canadian coal ashes

Concentrations of 52 minor elements in coal ash were determined using spark source mass spectroscopy. Hg levels in raw coal were investigated by cold vapour atomic absorption spectrophotometry. The concentration of elements are compared to other available data and to levels in the Earth's crust. F levels in coal ash exceed 500 μ g^?1 and may be greater than 1 wt% in raw coal. Approximately half the elements (B, S, Ni, Zn, Ga, Ge, Se, Sr, Y, Mo, Sn, Sb, I, Ba, Pr, Nd, Sm, Eu, Ho, Hf, Pt, Hg, Pb, Tl, Bi, U) investigated are enriched in the coal ash with respect to the Earth's crust. The ranges in minor element concentrations in coal ash and coal from different global regions are very similar.     

Ultralow voltage imprinting in GeS2–Ga2S3–AgI glasses for visible to middle-infrared diffraction gratings

A diffractive optical element (DOE) covering visible to middle-infrared regions is imprinted in chalcohalide glass by microthermal poling under ultralow voltages (~125 V). The effect of the poling voltage on the surface profiling, optical diffraction, optical transmittance, and anode-side structural rearrangement is investigated. Deformation of the surface profiling and diffraction order increase with increasing poling voltage, showing a saturation voltage of 125 V and a decrease in the transmittance within 10%. In addition to the normal vertical migration of silver ions, an obvious and unexpected transverse migration of silver ions and mutual structural transformation occur between homopolar bonds Ge–Ge (Ga–Ga) and S–S and the heteropolar bond Ge–S (Ga–S), which are key to forming the surface profiling and subsurface structures. Formation of the DOE mainly depends on the periodic subsurface microstructure rather than surface profiling. Thus, simple and inexpensive processes can fabricate broadband wavelength-based DOEs for military, medical and biological applications.     

Water based fractionation of particles

A feed of particles covering a wide range of particle sizes and densities was placed into a novel separator, referred to as the Reflux Classifier, and fractionated at a series of fluidization velocities. Double fractionation was then achieved when each product was sieved into narrow size fractions. For the coal particles used in this study, the ash % was determined for each of the samples. The ash % correlated strongly with particle density, and hence was a useful proxy for the particle density. A new Fractionation Algorithm was developed, which provided a method for estimating the feed size and density distribution from the Double Fractionation data. The cumulative yield % versus the cumulative ash % curves for each size fraction, and for the overall feed were then determined. The findings from the study were validated against accurate results obtained using the sink-float method. Excellent agreement with the curves obtained using the sink-float method was obtained. The sink-float method requires the use of heavy liquids; these are invariably toxic and expensive, hence a viable alternative is needed. The water based fractionation method, in conjunction with the Fractionation Algorithm, may prove to be a suitable substitute for the sink-float method. Precise details of the method and algorithm are therefore provided in order to permit the adoption of this new approach by other laboratories.     

Ge extraction from gasification fly ash

Water-soluble germanium species (GeS₂, GeS and hexagonal-GeO₂) are generated during coal gasification and retained in fly ash. This fact together with the high market value of this element and the relatively high contents in the fly ashes of the Puertollano Integrated Gasification in Combined Cycle (IGCC) plant directed our research towards the development of an extraction process for this element. Major objectives of this research was to find a low cost and environmentally suitable process. Several water based extraction tests were carried out using different Puertollano IGCC fly ash samples, under different temperatures, water/fly ash ratios, and extraction times. High Ge extraction yields (up to 84%) were obtained at room temperature (25 °C) but also high proportions of other trace elements (impurities) were simultaneously extracted. Increasing the extraction temperature to 50, 90 and 150 °C, Ge extraction yields were kept at similar levels, while reducing the content of impurities, the water/fly ash ratio and extraction time. The experimental data point out the influence of chloride, calcium and sulphide dissolutions on the Ge extraction.     

Volatile trace element behaviour in the Sasol fixed-bed dry-bottom (FBDB)™ gasifier treating coals of different rank

Trace element simulation and validation of model predictions for the elements Hg, As, Se, Cd and Pb have recently been undertaken for the Sasol^® FBDB™ gasification process operating on lump coal. The validation was conducted by interpolating the residual trace elements content remaining behind in the solid coal/char/ash fractions after sequential mining of a quenched commercial-scale gasifier operating on low rank grade C bituminous Highveld coal used for gasification in South Africa. This paper extends the research understanding by comparing the volatile trace element behaviour of these same elements, using the same gasification technology, but operating on North Dakota lignite. The focus will be on the behaviour of the volatile Class III trace elements: Hg, As, Se, Cd and Pb within the Sasol^® FBDB™ gasifier as function of coal rank. This study excludes the downstream gas cleaning partitioning and speciation behaviour of these elements.Findings indicate that although the feed concentration and mode of occurrence of these elements differ quite substantially between the two coal types studied, that the volatilization profiles of the elements are indeed quite similar; being within 0.1%-15% lower in the case of the lignite when compared to the bituminous coal. In both cases, Hg was found to be the most volatile and As the least; with the volatility order varying slightly for the metals Se, Cd and Pb for the two coal types. The differences observed in the trace element volatilization rate are supported by the temperature profile which was inferred from the reflectance of vitrinite (RoV) measurements of the dissected fuel bed material. The highly reactive lignite, is successfully gasified at a lower temperature than is the case for bituminous coal using the Sasol^® FBDB™ gasification process. Speciation predictions have earlier shown that: H₂ Se, CdS, PbS/Pb/PbCl, and AsH₃ species possibly exist in the gas phase. In reality, organically-associated trace elements will also be volatilized into the gas phase, but due to a lack of thermodynamic data for the lignite organo-metallic species at this stage only inorganic associations could be modelled.     

Selective extraction of In(III), Ga(III) and Zn(II) using a novel extractant with phenylphosphinic acid

A new extractant, [N,N-di(2-ethylhexyl)amino]methylphenylphosphinic acid (DEAPP), was synthesized to de-velop the mutual separation techniques of In(III), Ga(III) and Zn(II). The extraction selectivity for In(III), Ga(I I) and Zn(II) with DEAPP was higher than that of the commercial phosphorus acid extractants such as D2EHPA and PC-88A. The extraction selectivity for metal ions in 1 mol·L?1 aqueous ammonium nitrate solution with DEAPP was in the following order:In(III) N Ga(III) N Zn(II). These selective extraction behaviors indicate that the amino moiety of DEAPP plays an important role in the mutual separation of In(III), Ga(III) and Zn(II). The extraction equilibria of In(I I), Ga(II ) and Zn(II) with DEAPP (=HR) were expressed by the following reactions:In3++2eHRT2?InR3eHRT+3H+, Ga3++1.5eHRT2+NO3??GaR2eHRTeNO3T+2H+, and Zn2++2eHRT2?ZnR2eHRT 2 + 2H+. The extraction equilibrium constants of In(III), Ga(III) and Zn(II) with DEAPP were determined to be Kex,M=1.7 × 104 [dm3·mol?1], 4.17 [(dm3·mol?1)0.5], and 1.55 x 10?2 [–], respectively.     

Solvent fractionation of petroleum pitch for mesophase formation

Petroleum pitch (Ashland A240) has been subjected to thermal treatment and solvent fractionation to produce refined pitches to be evaluated as impregnants for C-C composites. The solvent fractions were obtained by sequential Soxhlet extraction with solvents such as hexane, benzene, and pyridine. Thermal treatment to 408 °C produced a mesophase pitch (≈50% mesophase); an appreciable portion of the mesophase was soluble in strong solvents. There were substantial differences in chemical composition and in pyrolysis behaviour of the fractions. As the depth of fraction increased, the pyrolysis yield and bloating increased, and the microstructure of the coke became finer until glassy microconstituents were formed in the deepest fractions.     

Trace element affinities in two high-Ge coals from China

The Lincang (Yunnan Province, Southwest China) and Wulantuga (Inner Mongolia, Northeast China) coal deposits are known because of the high-Ge content. These coals have also a high concentration of a number of other elements. To determine the mode of occurrence of the enriched elements in both coals, six density fractions from <1.43 to >2.8 g/cm³ were obtained from two representative samples using heavy-liquids. A number of peculiar geochemical patterns characterize these high-Ge coals. Thus, the results of the chemical analysis of these density fractions showed that both coals (very distant and of a different geological age) are highly enriched (compared with the usual worldwide coal concentration ranges) in Ge, As, Sb, W, Be, and Tl. This may be due to similar geochemistry of hydrothermal fluids influencing the Earth Crust in these regions of China. Moreover, Wulantuga coal (Early Cretaceous subbituminous coal) is also enriched in Ca, Mg, and Na, and Lincang coal (Neogene subbituminous coal) in K, Rb, Nb, Mo, Sn, Cs, and U. A group of elements consisting of Ge, W, B, Nb, and Sb mostly occur with an organic affinity in both coals. Additionally, Be, U, and Mo (and partially Mn and Zn) in Lincang, and Na and Mg in Wulantuga occur also with a major organic affinity. Both coals have sulfide-arsenide mineral assemblages (Fe, S, As, Sn, and Pb, and in addition to Tl, Ta, and Cs in the Lincang coal). The occurrence of Al, P, Li, Sc, Ti, V, Cr, and Zr in both coals, and Ba in Lincang, are associated with the mineral assemblage of silico-aluminates and minor heavy minerals. Furthermore, P, Na, Li, Sc, Ti, Ga, Rb, Zr, Cr, Ba, Th, and LREE (La, Ce, Pr, Nd, and Gd) in Lincang are associated with mineral assemblages of phosphates and minor heavy minerals. The two later mineral assemblages are derived from the occurrence of detrital minerals. Finally, the two coal samples have also the sulfate mineral assemblage (Ca and Sr) that probably occur as a consequence of a diagenetic oxidation and alteration of the coal seams. The enrichment of Ge in coal occurred when the organic matter was still reactive to trap Ge, but several features indicate that the enrichment was diagenetic.     

Geochemical aspects of Amynteon lignites, Northern Greece

Several lignite samples were collected from Amynteon lignite mine, Northern Greece. Chemical analysis for major and trace elements was conducted with the help of X-ray fluorescence and inductively coupled plasma-atomic emission spectroscopy methods. Trace element concentrations of Amynteon lignites have equal or slightly higher values when compared to other worldwide coals. Boron content implies that the lowest lignite beds raised in a middle brackish environment, while the upper lignite beds had a fresh water environment of deposition. Correlation and cluster analysis revealed an inorganic affinity for the elements Al, Si, Ti, Fe, Mg, K, Na, Ni, Cu, Ba, Mo and Sr, while Ca, Cr, Mn, Zn, P, Cd, Sb, Pb, S, B, Co and W, and only F showed an organic affinity. The calculated slagging and fouling indices indicate medium to high slagging and high to severe fouling propensity.     

Rationale of lead immobilization by ball milling in synthetic soils and remediation of heavy metals contaminated tailings

In this work, the use of mechanical milling for the remediation of heavy metals in synthetic soils and tailings sampled from the mining area of “Barraxiutta”, SW of Sardinia, Italy is investigated. Specifically, Pb(II) contaminated synthetic soils of sandy, bentonitic and kaolinitic type are taken into account following the results obtained in previous works. Suitable sequential extraction procedures have been performed on both untreated and treated synthetic soils. It is found that mechanical loads which occur during collisions among milling media and soils are able to modify the distribution of Pb(II) onto the different solid fractions of contaminated synthetic soils. Specifically, for sandy soils the milling treatment induces a significant increase in Pb(II) content in the Fe–Mn oxides fraction. On the other hand, for bentonitic and kaolinitic soils, Pb(II) content in both carbonate and Fe–Mn oxide fractions is augmented after treatment. Such phenomena may contribute to Pb(II) immobilization efficiency since the heavy metal trans-speciation occurs in favor of fractions characterized by stronger bonds and lower solubility.As for the heavy metals contaminated tailings, their immobilization is obtained using both ball and attrition milling devices under specific ball to powder ratio values. The degree of metals immobilization is evaluated by analyzing the corresponding leachable fraction obtained through the Synthetic Precipitation Leaching Procedure (SPLP) proposed by EPA. X-ray diffraction and granulometric analyses revealed no significant alterations of the intrinsic character of the tailings after milling except for a relatively small increase in particles size.The increase in immobilization efficiency when tailings are mechanically treated may be due to specific phenomena induced during milling such as entrapment of heavy metals into aggregates, solid diffusion of metals into the crystalline reticulum of soil particles, the formation of new fresh surfaces onto which heavy metals may be irreversibly adsorbed as well as metal trans-speciation onto tailings fractions characterized by stronger bonds and lower solubility.     

Engineered humanized diabodies for microPET imaging of prostate stem cell antigen-expressing tumors

We have previously demonstrated preclinical in vivo targeting of prostate stem cell antigen (PSCA) using a humanized anti-PSCA 2B3 monoclonal antibody (mAb). However, humanization resulted in 5-fold loss of apparent affinity relative to the parental mAb (1 nM). In this study, diabodies (scFv dimers of 55 kDa) were generated from 2B3 including variants with different linker lengths as well as back-mutations to original murine residues to improve affinity. Parental 2B3 (p2B3) and back-mutated 2B3 (bm2B3) diabodies (Dbs) with five- or eight-amino acid linkers (p2B3-Db5, p2B3-Db8, bm2B3-Db5 and bm2B3-Db8) were evaluated for binding to PSCA by flow cytometry and affinities were determined by surface plasmon resonance. Back-mutation restored the affinity from 5.4 to 1.9 nM. Stability, evaluated by size exclusion, revealed that diabodies with eight-residue linkers existed as a mixture of dimeric and monomeric species at low concentrations (相似文献   

煤中锗的资源分布及煤伴锗提取工艺的研究进展

介绍了煤中锗资源的分布规律及我国的锗煤富集区分布情况。阐述了水冶法、火冶法、微生物浸出法和干馏法处理含锗烟尘的研究进展,并进行了不同工艺的对比。在火冶法中,着重介绍了燃烧富集、二次富集处理含锗褐煤及采用氯化蒸馏法处理含锗烟尘的工艺,并以含锗褐煤为例,对热电联产富集锗、氯化蒸馏提锗的处理过程进行了物料平衡分析。简要分析了煤伴锗提取工艺中存在的问题,并指出提锗工艺的改进方向和建议。     

Globotriose-functionalized gold nanoparticles as multivalent probes for Shiga-like toxin

Compared to monovalent carbohydrates, multivalent carbohydrate ligands exhibit significantly enhanced binding affinities to their interacting proteins. Here, we report globotriose (P(k) ligand)-functionalized gold nanoparticle (AuNP) probes for the investigation of multivalent interactions with the B(5) subunit of Shiga-like toxin I (B-Slt). Six P(k)-ligand-encapsulated AuNPs (P(k)-AuNPs) of varying particle size and linker length were synthesized and evaluated for their potential as multivalent affinity probes by using a surface plasmon resonance competition assay. The affinity of these probes for the interacting proteins was greatly affected by nanoparticle size, linker length, and ligand density on nanoparticle surface. For example, the 20-nm 20-P(k)-l-AuNP, which had a relatively long linker showed a >10(8)-fold increase in affinity compared with the mono P(k) ligand. This intrinsic high-affinity AuNP probe specifically captured the recombinant B-Slt from Escherichia coli lysate, and the resulting purity of the B-Slt was >95 %. We also developed a robust P(k)-AuNP-based detection method for Slt-I by combining the technique with silver enhancement.     

Geochemical distribution of trace elements in coal: modelling and environmental aspects

The present work consists of verifying a theoretical model based on mass distribution of trace elements in coal. Many versions of the model were tested using 42 elements in 8 different coals (5 American, 2 Brazilian and 1 Spanish). The calculated partial concentrations of elements in organic and inorganic (sulfide, carbonate and sulfate) fractions were obtained. These results could be summarised as following: B, Be, Br, Ge and V are associated to organic coal fraction while As, Cd, Co, Cu, Dy, Hg, Lu, Mo, Ni, Pb, Se, W and Zn occur mainly in sulfide minerals and Ba, Cr, Cs, Ga, Mn, Rb, Sb, Sn, Sr, Ta, U and Zr are distributed in the non-sulfide fraction. Finally, the volatility of trace elements was estimated using the calculated partial concentrations in organic and sulfide fractions. The applicability of this parameter in related environmental problems was discussed, comparing model results with experimental and theoretical literature data of the mobilisation of these species into atmosphere.