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。     

Rapid separation of thorium-234 from uranyl nitrate hexahydrate by adsorption on filter paper from ether solution

A simple method has been developed for the rapid separation of²³⁴Th /UX1/ from uranyl nitrate hexahydrate. The method is based on selective dissolution of uranyl nitrate by diethyl ether on a filter paper. It is shown that almost all UX1 is adsorbed by the filter paper which can be desorbed and brought into solution by 5N HCl or HNO₃. The effect of different parameters on the separation have also been investigated.     

A simple and low-energy strategy for the separation of water and acetonitrile

As acetonitrile is a widely used solvent for the chemical industry, the recovery of acetonitrile from acetonitrile wastewater is significant for both industrial cost reduction and environmental protection. In this article, a simple, low-energy, and low-cost strategy is proposed for the effective separation of acetonitrile from high-concentration acetonitrile wastewater. The approach is based on a sequential combination of two steps: salt-induced phase separation and hydrophobic filtration. The acetonitrile wastewater was first induced to split into two phases by salt, that is, the acetonitrile-rich phase and the water-rich phase, then the above two phases were poured into the hydrophobic filter paper funnel for the separation. It was shown that NaCl is a suitable salting-out reagent, and that hydrophobic filter papers—obtained from modification by butyltrichlorosilane and octyltrichlorosilane were the optimal choice for hydrophobic filtration. The salt-induced phase separation process is able to increase the volume fraction of acetonitrile in the acetonitrile-rich phase up to 92%. The acetonitrile-rich phase can pass through the hydrophobic filter paper, whereas the water-rich phase was intercepted. The hydrophobic filter paper retained strong hydrophobicity and high acetonitrile-separating capacity after 3 months storage, or upon immersion in acetonitrile-water mixtures for 12 h, or applied for 25 consecutive separations.     

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.     

Quantitative inorganic paper chromatography direct determination of nickel in microgram quantities

A method has been developed for the direct determination on filter paper of nickel, after Chromatographic separation of interfering elements. The sample is dissolved in ₃N hydrochloric acid and the solution is spotted on filter paper, together with standard solutions of nickel. After chromatographic development with a mixture of acetone, hydrochloric acid and acetylacetone, the nickel spot, which has scarcely moved, is made visible by spraying with a solution of rubeanic acid, and its reflectance is measured with a Beckman DU Spectrophotometer at 625 mμ. Most interfering elements have moved away because of their high R_F values. In the presence of large amounts of aluminiun, chromium, titanium or vanadium, a preliminary extraction of the nickel is necessary. Several technical alloys have been analyzed successfully by this method, for which only 0.045 ml of solution, containing 0.45–9 μg of nickel, are needed, although its precision is equal to that of the best colorimetric methods.     

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.     

Preconcentration of trace elements from pure manganese and manganese compounds with activated carbon as collector

A method is described for separation of traces of Bi, Cd, Co, Cu, Fe, In, Ni. Pb, Tl, and Zn from pure manganese and manganese compounds and their determination by flame a.a.s. After the metal or manganese dioxide samples have been dissolved in acid (and manganese salts in water) the trace elements are compleed with potassium xanthogenate. The solution is then filtered through a small filter paper covered with activated carbon, whereby complex compounds are separated from the matrix. When the charcoal is treated with acid, a trace concentrate is obtained which is nearly free of manganese. The detection limits for the analysis of 10-g samples of manganese metal are <0.5 p.p.m., and for 30-g samples of MnCl₂-4H₂O are ? 0.1 p.p.m. The relative standard deviation, in general,is lower than 5%.     

The determination of cadmium,copper, iron,lead and zinc in aerosols by atomic-absorption spectrometry

The determination of five elements in filter papers loaded with air particulate matter has been investigated. After a wet destruction of about 10 cm² of filter material by a standard procedure, analysis was carried out with a flame atomic absorption method for zinc and a flameless procedure for Cd, Cu, Fe and Pb. Furnace program parameters for each of the elements in different acid solutions are reported. The interferences of some common anions and the most abundant cations in aerosol material are described. For some urban and industrial samples, the results are compared with those obtained by energy-dispersive x-ray fluorescence. Accuracy was checked against standard samples.     

Radiochemical neutron activation analysis for determination of Au,Ag, Pt and Pd in geological samples

A procedure for separation of Au, Ag, Pt, and Pd in geological samples has been developed. After irradiation, samples were fused with Na₂O₂ and silver was separated by filtering through a PbCl₂ filter in 4M nitric acid solution. Au, Pt and Pd were concentrated with rhodium and thiourea as rhodium sulfide and the separation process of these elements was carried out by a chromatographic method. Au, Pt and Pd were retained on a Dowex-1×8 anion column in 1M HCl. Pd was eluted from the column by using a mixture of 75% HCl acid-25% acetone. Au was eluted by using a mixture of 10% HCl-90% acetone. In the gold fraction, Pt was also determined through the photopeak of¹⁹⁹Au radionuclide (158 keV). The method was simple and rapid.     

Paper Chromatographic Separations of Metal Ions on Collidinium Tungstoarsenate Papers

Abstract

A systematic study of the chromatography of metal ions on collidinium tungstoarsenate papers has been performed using seven different mixed solvent systems. R_f values of 30 metal ions have been determined by ascending technique and are discussed. The study demonstrates that specific extraction of both Sn(ii) and Sn(iv) is possible in 0.1 mol dm^?3 HNO₃ in 80% (v/v) 1-propanol and their mutual separation can be carried out in solvent system 1 mol dm^?3 HCl in 33% (v/v) 1-propanol. In addition some binary and ternary separation of metal ions have also been achieved on these papers. For a comparison R_f values on plain papers have also been determined in all the solvent systems.     

Paper chromatography in the separation of ions : Separation of silver,copper and arsenic group elements

A paper Chromatographic study ot the separability of ions of elements of the silver, copper and arsenic groups, using different solvents and a number of complexing agents, reveals that the solvents consisting of (1) acetone, hydrochloric or acetic acid (with or without ammonium iodide) and (2) tert. -butyl alcohol, hydrochloric or acetic acid, promote the complete separation of at ; least five elements present in microgram amounts in a mixture. Other complexing agents, such as thiourea, bismuthiol I, bismuthiol II and 2-mercaptobenzothiazole are not very useful in the separation of the ions. The R_I., R_T values and the sequences of separation are tabulated to show their behaviour.     

Determination of gunshot residues by neutron activation analysis

Systematic investigations of gunshot residues, deposited around the bullet hole, have been carried out. The traces were produced by firing on filter papers from distances of 5 to 200 cm using one rifle and three pistols as arms. Antimony, lead and barium were quantitatively determined after irradiating the samples in the nuclear reactor TRIGA Mainz by measurement of gamma-lines of^122mSb,¹²²Sb,^207mPo and¹³⁹Ba. The determinations were made purely instrumentally and-where the half lives were long enough-also after chemical separation of the nuclides. The amount of the elements were determined in dependence of the firing distance and of the area around the bullet hole.     

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.     

X-ray fluorescence analysis of airborn particulates in an industrial Greek city

Photon induced X-ray fluorescence is used at a medium sized Greek industrial city, to detect trace elements with 20≤Z≤40 in airborn particulates collected on filter papers.     

Cellulose Filter Paper with Antibacterial Activity from Surface-Initiated ATRP

Poly(tert-butyl acrylate) (PtBA) bruhes were successfully grafted on the cellulose filter papers via surface-initiated atom transfer radical polymerization (ATRP). Then the grafting PtBA brushes were transferred into poly(acrylic acid) (PAA) in the presence of trifluoroactic acid (TFA), which can form chelate complexes with Ag⁺. The Ag⁺ was reduced in situ to obtain the silver nanoparticles decorated cellulose filter papers. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were used to characterize the chemical structure of the resulting product. The morphologies of the filter paper at different stages of surface modification were investigated by field emission scanning electron microscopy (FESEM). The silver nanoparticles decorated filter paper performed good antibacterial ability against E. coli as compared with the original filter paper and PAA modified filter paper.     

Reversed phase chromatographic separation of zirconium,niobium and hafnium tracers with HDEHP

Effective separation of the congeneric pair of elements, zirconium and hafnium and also niobium which was in admixtures with zirconium as daughter in its isotopic form were achieved through reversed phase column and paper extraction chromatographic procedures using di-(2-ethylhexyl)phosphoric acid (HDEHP) as the liquid exchanger. In reversed phase column chromatographic separation, the tracers,⁹⁵Zr,⁹⁵Nb and^175,181Hf, were extracted by HDEHP impregnated on kieselguhr and were sequentially eluted with 6N H₂SO₄+xN oxalic acid+H₂O₂(where x=0.1, 0.5 and 2). Similarly, in reversed phase paper chromatographic study in which a coating of HDEHP on Whatman No. 1 chromatographic paper was used as stationary phase, the mobile phase, 18N H₂SO₄+0.1N oxalic acid + H₂O₂, helped in separating the elements with favorable separation factors. Under the optimal conditions, the separation and decontamination of the elements in both methods were found to be quantitative, as verified by -spectrometric studies.     

Influence of aluminum on the uptake of various cations from a solution into carrots

The influence of Al on the absorption of various elements by a carrot (U.S. harumakigosun) was investigated using a multitracer technique. An uptake experiment was conducted within the range of 0.0–2.0 ppm AlCl₃ in culture solution. By the addition of AlCl₃, uptake of elements such as Be, V, Zn and rare earth elements (REE) into roots was increased. For Be and V an approximately three-fold increase was observed. The degree of uptake enhancement of nonessential elements by AlCl₃ was generally very high, whereas some of the essential or beneficial elements exhibited a decrease in uptake with the increase of AlCl₃ concentration. This suggests that the uptake of nonessential elements might be increased through transporters with decreased selectivity due to Al. From the viewpoint of the acid rain problem, it is suggested that one of the detrimental effects of Al on plants is the imbalanced elemental absorption.     

Study of ph and substrate effects on room-temperature phosphorimetry of some indolecarboxylic acids

Room-temperature phosphorescence (RTP) of eight indolecarboxylic acids has been investigated under different pH conditions, and on several ion-exchange filter papers. RTP excitation and emission wavelengths do not change significantly with pH. The largest RTP signals are obtained from neutral solutions adsorbed on DE-81 anion-exchange filter paper, while alkaline (pH approximately 13) solutions on S & S 903 filter paper treated with DTPA (diethylenetriaminepenta-acetic acid) give stronger signals than neutral or acidic (pH approximately 1.6) solutions on the same substrate. The existence of several hydrogen-bonding interactions between the various ionic indolecarboxylic acid species and the substrates is discussed. Heavy-atom enhancement factors ranging between 4 and 550, according to the compound, are obtained with iodide. Absolute limits of detection between 100 and 500 pg demonstrate the usefulness of RTP for determination of indolecarboxylic acids at the trace level.     

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.