Micro–nano structural engineering of filter paper surface for high selective oil–water separation

Cellulose-based lotus-leaf-like filter paper for selective separation of oil/water was prepared. Experimentally, cellulose nanofibril aerogel microspheres prepared by ultrasonic atomization method were coated on commercial filter papers to form unique “micro–nano” structured surface. By controlling both the morphology and chemistry of the surface, the papers could be either under-water superoleophobic or under-oil superhydrophobic. It was found that the filter papers could be engineered to effectively filter only oil or only water from their mixtures.     

pitfalls in Using Filter Paper Disks as Standard Supports In X-Ray Fluorescence Spectrometry

Abstract

Standard solutions of dimethylarsinic acid in water and methanol are deposited on Whatman No. 1 and No. 114 filter papers. The arsenic content is measured by X-ray fluorescence spectrometry. The observed specific count depends on the nature of solvents, the volume of spotting solutions, the method of spotting and the type of filter papers.     

Evaluation of filter papers as substrates for solid-surface room-temperature fluorimetry and photochemical fluorimetry

Filter papers (Whatman Nos. 1 and 41, S & S 904) and anion-exchange filter paper (Whatman DE-81) have been evaluated for their use as substrates in solid-surface room-temperature fluorescence (RTF) and photochemical fluorescence (RTPF). Several chemical treatments of filter papers are found not to reduce significantly their background fluorescence signal. Analyte fluorescence signals are 2-4 times higher on filter papers than on silica-gel TLC plates. Absolute limits of detection range between 0.6 and 40 ng on the Whatman filter papers, depending on the test compound. Filter papers are proposed as convenient, inexpensive, and easy-to-handle substrates for RTF and RTPF measurements.     

Polyimidazolyl acetate ionic liquid grafted on cellulose filter paper as thin-film extraction phase for extraction of non-steroidal anti-inflammatory drugs from water

Recently, pharmaceuticals and personal care products in the water environment exhibited potential risks to both human and aquatic organisms. In order to improve the sensitivity and accuracy of pharmaceutical detection, the polyimidazolyl acetate ionic liquid was synthesized by Radziszewski reaction and coated on cellulose filter papers as a thin-film extraction phase for extraction of non-steroidal anti-inflammatory drugs from water. The attenuated total reflection-infrared spectrometry, thermogravimetric analysis, and scanning electron microscope analyses demonstrated that the polyimidazolyl acetate ionic liquid was successfully prepared and attached to the surface of the cellulose filter paper through chemical bonding. The adsorption capacity of the homemade thin-film extraction material for the four non-steroidal anti-inflammatory drugs was greater than 8898 ng/cm² under the optimum conditions, and the desorption rate was over 90%. Then, a paper-based thin-film extraction phase-high-performance liquid chromatography-tandem mass spectrometry method was established for the extraction of non-steroidal anti-inflammatory drugs in water. This method provided limits of detection and limits of quantification were in the range of 0.02–0.15 and 0.17–0.50 μg/L, respectively. Hence, the obtained thin-film extraction phase showed excellent recovery and reproducibility for the target non-steroidal anti-inflammatory drugs with carboxyl groups from water.     

超疏水滤纸的制备与应用

对SiO2纳米粒子进行硅烷化改性,再将其修饰到滤纸上,制备出静态水接触角＞150°的超疏水滤纸,对制备条件进行了优化。 用热重分析及扫描电子显微镜对超疏水滤纸表征后发现,二氧化硅纳米粒子在滤纸纤维表面形成一层包裹层,即纳米级粗糙结构,这种结构对滤纸的疏水性具有关键作用。 对滤纸的油水分离性能进行了研究,发现其对非均相体系和高粘度油水混合物具有很好的分离效果。     

Combined furnace—flame non-dispersive atomic fluorescence spectrometry for direct simultaneous multi-element analysis of air filters

Furnace volatilization followed by atomization in the flame of a non-dispersive atomic fluorescence spectrometer is used for the direct, simultaneous, multi-element determination of Zn, Cd, Pb and Fe on air filter papers. Standardization is done by using blank filter papers impregnated with standard metal solutions. The results agree well with those obtained by a standard atomic absorption procedure.     

Halbquantitative analyse durch messung der entfärbungs-zeit von tüpfelflecken

A rapid semiquantitative method is described based on measurement of the time required for decolorization of spotreactions on filter paper strips by suitable reagents, This very simple method yields results which are accurate to ± 10%. The method has been verified for several ions (Ag⁺, Pb²⁺, JO₃^-,Cu²⁺, CrO₄^2-). The utility of this method for the characterization and differentiation of filter papers is indicated.     

The retention of iodine fission products on iodide precipitates

A fast and selective method has been developed for the separation of the iodine fission products in the primary cooling water of nuclear reactors. The parameters of the selective retention were studied on silver, thallium(I) and mercury(II) iodide. Retention experiments were performed on adequately thick layers of “free” precipitates and on precipitates fixed in filter paper. The latter method substantially increases the retention capacity. The papers with fixed precipitate are easy to handle. The filter paper with silver iodide precipitate was found to be the most satisfactory for the selective retention of fission iodine from reactor water.     

两种固定化金属螯合复合亲和膜色谱介质制备

以纤维素滤纸为基质,通过碱处理、环氧活化、偶联亚氨基二乙酸二钠、固定化Ｃｕ＾２＋后制得了大孔纤维素亲和膜。另外,在活化后的膜上通过共价交联覆盖上琼脂糖,制得了具有类似“三明治”结构且性能优于的复合亲和膜,装柱后分别制得固定化金属螯合亲和膜色谱柱。对两种亲和膜进行牛血清白蛋白等温吸附测定显示,两者的最大吸附量分别为１．１７ｍｇ／ｃｍ＾２和１．３０ｍｇ／ｃｍ＾２,与传统的琼脂糖凝胶类介质吸附量相当,表     

Chemical reactive filter paper prepared by radiation-induced graft polymerization—I

Chelating filter papers with chemically bonded amidoxime groups were synthesized by radiation-induced grafting of acrylonitrile onto filter paper (W3) followed by chemical treatment with hydroxylamine. The effect of grafting conditions such as absorbed dose, dose rate, monomer concentration and filter paper thickness on the grafting yield was studied. It was found that the degree of grafting increases with increasing absorbed dose and dose rate, and then tends to level off at high doses. The order of the dependence of the initial grafting rate on the dose is found to be of 0.33. An increasing monomer concentration was accompanied by a significant increase in grafting. At high monomer concentration the initial rate of grafting is fast followed by a slow rate. The rate of grafting is controlled by the filter paper thickness and the diffusion of monomer into the interior of the filter paper. Mechanical properties of the prepared filter paper were improved over the ungrafted paper. The amidoxime filter papers were examined for adsorption of uranium concentration ranging between 10–100 ppm.