高效锂离子筛吸附剂MnO2·0.5H2O的软化学合成及吸附性能研究

以MnCl2·4H2O,LiOH·H2O等试剂为初始原料,采用溶胶-凝胶、水热处理、固化等软化学合成步骤制备了锂离子筛前驱体Li1.6Mn1.6O4,并经稀盐酸抽锂后得到了高选择性锂离子筛吸附剂MnO2·0.5H2O.着重对合成过程中锂锰比,氧化剂用量等因素影响进行了探讨,并对所制备吸附剂的吸附性能进行了研究.结果表明,经软化学合成步骤制备的锂离子筛对Li 有良好的吸附量和选择性,在未来从海水、卤水等液态锂资源富集或提取锂的应用中具有很大的潜力.     

Separation of digitalis cardenolides by HPLC

The separation of Digitalis cardenolides has been carried out by HPLC on an adsorbent column. By choice of suitable mobile phase, isocratic elution permitted resolution of mixtures of (a) aglycones, (b) secondary glycosides, and (c) primary glycosides, while gradient elution provided a means of resolving more complex mixtures of these cardiac steroids. HPLC could therefore be used in the quality control of cardiotonic drugs replacing the TLC tests for related compounds currently used, and by suitable calibration could replace the colorimetric assay procedure normally used for such drugs.     

Design of two-dimensional photonic crystal biosensor using DNA detection

Abstract

In this paper, the photonic crystal biosensor is investigated theoretically with, concomitantly, high quality factor, transmission and sensitivity. This biosensor is made out of two waveguide couplers and one L2 resonant cavity formed by removing two air holes. For biosensor analysis, the 2D finite difference time domain (FDTD) method and the plane-wave expansion (PWE) approach are applied. Four slots placed into the cavity and the three rows of functionalized holes nearby the resonant cavities are filled with DNA. For the optimized structure, the biosensor quality factor is found to be over 3.7468?×?10⁶ and the sensitivity is of order 460?nm/RIU. The designed structure has high sensitivity, which is an important parameter in biosensing applications.     

排水监测质量保证体系的建立

依据ISO9000质量管理标准和ISO／IEC17025标准，从排水监测管理的目标、技术要求及完善与提高三个方面论述了建立排水监测质量体系的方法和措施，以确保排水监测的各项质量活动能够科学、公正、适时、有效地开展，并对排水监测体系中各要素制定管理方法及控制措施，以不断完善排水监测的管理，提高排水监测质量水平。     

Photolysis of poly(o-acetylstyrene) in solution

Dilute solutions of poly(o-acetylstyrene) (POAS) were exposed to long-wave (λ ≥ 300 nm) UV radiation under high vacuum at 25 ± 1°C. Methane and much smaller amounts of ethane were formed, indicating α-cleavage (Norrish Type I). The quantum yield for CH₄ formation (5 × 10^?5 mol einstein^?1) was an order of magnitude lower than that observed for similar studies of POAS films. Molecular weight ( M _n) measurements indicate that chain scission occurs, and this is attributed to β-scission of the macroradicals formed by H-abstraction at the α-C atoms by the carbonyl triplet, and to a lesser extent, by the CH₃ radicals. Quenching by both naphthalene and cyclooctadiene conformed to Stern–Volmer kinetics. The effects on chain scission of a number of additives with varying transfer activities were found to be complex and unexpected. Rates of scission not only increased, even when substances with high transfer activity (e.g., cumene) were present, but also varied with the concentration of additive, being higher at lower additive concentrations. It would appear that solvent quality has a dominant influence (these additives are poor solvents). Tighter coiling of the polymer in the solutions containing poorer solvents results in more segment-segment contacts and with them more photoreduction and chain scission. However, at higher nonsolvent concentrations, diffusive separation of the fragments (and chain scission) becomes more difficult, and the balance is shifted in favor of cyclization (and perhaps also intermolecular crosslinking). The relative high photostability of POAS in solution (cf. thin film) has been interpreted in terms of increased competition from photoisomerization. © 1992 John Wiley & Sons, Inc.     

SOLVENT QUALITY AND SOLUTION BEHAVIOR OF NYLON 12

The refractive index increment,dynamic and static laser light scattering,intrinsic viscosity[η]and Huggins constant(K_H)of nylon 12 have been measured in m-cresol and sulphuric acid/water system at 10-60℃.The intrinsic viscosity,R_H,R_g,A_2,and(~2)~(1/2)(calculated from viscosity data)and"a"values of nylon 12 are found to be higher in m-cresol than in sulphuric acid.All these parameters decrease with the increase in water contents in sulphuric acid.The refractive index increment,K_H and activation energy show an opposite trend to that of[η].The intrinsic viscosity,R_H,R_g,A_2, and(~2)~(1/2) have maximum values around 30-40℃in sulphuric acid/water system,whereas in m-cresol they fall at about 20℃.It has been concluded that the variation in size,interaction parameter(second virial coefficient),[η]and K_H of the polymer solutions with the alteration in solvent composition and temperature are the out come of change in thermodynamic quality of solvents,selective adsorption,hydrogen bonding and conformational transitions.It has also been concluded that the increase in temperature first enhances the quality of the solvent,encourages hydrogen bonding and specific adsorption, and then deteriorates,bringing conformational transitions in the polymer molecules.However,the addition of water to sulphuric acid continuously deteriorates the solvent quality.This characteristic of the solvent system brings conformational changes in the polymer especially at low temperatures.     

Environmentally Friendly Recovery and Characterization of Oil from Used Engine Lubricants

The present paper demonstrates the review of some acid processes as well as development of some new solvent processes for reclamation of used lubricating oils. The conventional processes are found to be of low yield (? 50%), laborious, time consuming and environmentally hazardous, because of residual acidic sludge. Based on the findings, a new modified Aluminium sulphate‐sodium silicate‐acid‐base method employing a small quantity of acid and giving a high yield (? 60%) is proposed. Further, to avoid use of acid, new regeneration processes based on solvent extraction were investigated. They are termed CCl₄‐alcohol method, Dodecane‐alcohol method and Toluene‐alcohol method. These processes are not only cost effective in terms of complete solvent recovery, but are rapid, less time consuming, more environmentally friendly and gave a high yield (70–75%). The virgin lubricants (Castrol GTX and Rimula‐C) as well as oils recovered by different methods were also characterized physicochemically to determine kinematic viscosity, density, refractive index, carbon distribution, wear scar diameter, % Conradson carbon residue, % ash, % chloride, pour point, etc. Results obtained show that many of the physico‐chemical properties of the recovered oils are in good agreement with those of virgin oils. The n.d.M analysis was also performed which shows that virgin oils have 73 ± 3% paraffinic carbon, 26 ± 3% naphthenic carbon and about 1% aromatic carbon. The recovered oils also showed nearly the same chemical composition. The UV‐Visible spectra of the recovered oils are all similar to those of virgin lubricants. The results suggest that the oils recovered by solvent treatments, particularly Dodecan‐alcohol and Toluene‐alcohol methods, may serve for lubrication purposes and can be rendered as excellent as virgin lubricants with the addition of certain additives. The proposed methods may be considered as alternative cost effective green techniques for acid reclamation processes and being the motivation of the present investigation.     

Determination of free iodide in human serum: Separation from other I-species and quantification in serum pools and individual samples

A method for the determination of free iodide in human serum was developed. For this purpose iodide from pooled serum samples was separated from the organic manner by SEC. The iodide fraction subsequently was freezedried and analyzed by ion chromatography for quantification. Investigations for recovery and precision were carried out and were found to show sufficient results. For quality assurance ICP-MS was taken additionally as an total I-detector [1], using native and iodide-spiked serum samples. The iodide results of ICP-MS as well as those of IC were well corresponding. Iodine containing SEC-fractions from iodide-spiked samples showed no increased I-values except that in the iodide fractions, proving that there was no iodide conversion into other I-species (and vice versa) during the whole procedure.Free iodide from two serum pools of different healthy persons was determined as 2.25 and 2.43 g I^–/L, respectively. The values are related to total iodine levels determined by ICP-MS. For comparative reasons a table of individual iodine and iodide values is presented.Abbreviations IC ion chromatography - ICP-MS inductively coupled plasma mass spectrometry - LPLC low pressure liquid chromatography - PED pulsed electrochemical detector - SEC size exclusion chromatography - RT retention time     

Development of continuous surfactin production from potato process effluent by Bacillus subtilis in an airlift reactor

The biosurfactant surfactin has the potential to aid in the recovery of subsurface organic contaminants (environmental remediation) or crude oils (oil recovery). However, high medium and purification costs limit its use in these high-volume applications. In previous work, we showed that surfactin can be produced from an inexpensive low-solids (LS) potato process effluent with minimal amendments or pretreatments. Previous research has also shown that 95% or more of the surfactin in Bacillus subtilis cultures can be recovered by foam fractionation. In this work, we present the results of research to integrate surfactin production with foam fractionation. Experiments were performed in an airlift reactor, with continuous collection of the foam through a tube at the top of the column. Preliminary results using both purified potato starch and unamended low-solids potato process effluent as substrates for surfactin production indicate that the process is oxygen limited and that recalcitrant indigenous bacteria in the potato process effluent may hamper continuous surfactin production.     

Speciation analysis of arsenic in groundwater from Inner Mongolia with an emphasis on acid-leachable particulate arsenic

Arsenic in drinking water affects millions of people around the world. While soluble arsenic is commonly measured, the amount of particulate arsenic in drinking water has often been overlooked. We report here determination of the acid-leachable particulate arsenic and soluble arsenicals in well water from an arsenic-poisoning endemic area in Inner Mongolia, China. Water samples (583) were collected from 120 wells in Ba Men, Inner Mongolia, where well water was the primary drinking water source. Two methods were demonstrated for the determination of soluble arsenic species (primarily inorganic arsenate and arsenite) and total particulate arsenic. The first method used solid phase extraction cartridges and membrane filters to separate arsenic species on-site, followed by analysis of the individual arsenic species eluted from the cartridges and filters. The other method uses liquid chromatography separation with hydride generation atomic fluorescence detection to determine soluble arsenic species. Analysis of acidified water samples using inductively coupled plasma mass spectrometry provided the total arsenic concentration. Arsenic concentrations in water samples from the 120 wells ranged from <1 to ∼1000 μg L⁻¹. On average, particulate arsenic accounted for 39 ± 38% (median 36%) of the total arsenic. In some wells, particulate arsenic was six times higher than the soluble arsenic concentration. Particulate arsenic can be effectively removed using membrane filtration. The information on particulate and soluble arsenic in water is useful for optimizing treatment options and for understanding the geochemical behavior of arsenic in groundwater.