Masahiko Murakami

Comparative study of IBMK and DIBK as extraction solvents in strongly acidic media: extraction behaviour and kinetic stability of Cu(PCD)(2) in these solvents.

The use of di-isobutyl ketone (DIBK) and isobutyl methyl ketone (IBMK) as the solvent for extraction of copper(II) from strongly acidic media (0.01-8M hydrochloric acid) with ammonium l-pyrrolidinecarbodithioate has been studied. In contrast to IBMK, the volume of the DIBK extract remains the same, irrespective of the acidity of the aqueous phase. A certain amount of free acid is transferred into both solvents, and affects the kinetic stability of the chelate extracted; the free acid can be completely removed by washing the extract with water, and partly by filtering it through a dry filter paper. However, the chelate extracted into DIBK exhibits excellent stability without such treatment, since the amount of free acid in DIBK is much smaller than that in IBMK. When DIBK is used, the copper chelate can be quantitatively extracted as long as the extraction is done from acidic media.

Effect of acidity on the extraction and kinetic stability of the copper(II)/APCD/IBMK system in strongly acidic media

The extraction of copper(II) from strongly acidic solution (0.01-8M hydrochloric acid) with ammonium 1-pyrrolidinecarbodithioate in isobutyl methyl ketone has been investigated. The shaking time needed for quantitative extraction decreases as the acidity is increased. The effect of the mutual solubility of the organic solvent and the aqueous phase is significant when the acidity of the aqueous phase is increased. The acidity of the aqueous phase mainly affects the kinetic stability of the chelate during the shaking period, rather than the decomposition of the chelating agent. The kinetic stability of the chelate apparently depends on the mole ratio of reagent to copper, the half-lives for the chelate extracted from 4M hydrochloric acid being 29.0, 40.0 and 85.0 min for reagent: metal mole ratios of 10, 100 and 1000, respectively.

Novel sorbent extraction technique using a chelating agent impregnated porous PTFE filter tube : Preconcentration of rare earth elements (REEs) with bis(2-ethyl-hexyl)hydrogen phosphate (HDEHP) loaded porous ptfe filter tube prior to determination by ICP-MS

Abstract Sorbent extraction and elution of rare earth elements (REEs) by using bis(2‐ethyl‐hexyl)hydrogen phosphate (HDEHP) impregnated porous PTFE filter tube were studied. A 100 ng amount of each REEs was quantitatively extracted by filtering 1000 mL of matrix‐free solution under pH 2.0–3.2. For a synthetic seawater sample, extractability of lighter REEs (La–Sm) was lowered; optimum pH range to simultaneously extract all REEs was shifted to 2.9–3.2, and limit of sample volume for quantitative extraction was decreased to 100 mL for La–Sm [although heavier REEs (Eu–Lu) were quantitatively extracted from 1000 mL]. Extracted REEs were quantitatively eluted by filtering through 5 mL of 10 mol/L−1 hydrochloric acid to the tube. Hence, maximum preconcentration factors were of 200‐ and 20‐fold for Nd–Lu and La–Sm, respectively. Total recovery of 0.5–10 ng of REEs spiked to 300 mL of natural sea salt solution was tested; quantitative recovery (95.9% for Gd–102% for Eu) were obtained for all REEs except La (54.9%). The REEs in the natural sea salt solution were also determined by ICP‐MS after preconcentration with the present method [RSD=16% (La)–1.1% (Yb), n=3].

Application of APCD/DIBK extraction system in strongly acidic media: Determination of traces of copper and nickel in titanium metals by extraction-flame atomic-absorption spectrometry.

Extraction of nickel in strongly acidic solution (0.01 approximately 8M hydrochloric acid) with ammonium 1-pyrrolidinecarbodithioate (APCD) into di-isobutyl ketone (DIBK) has been studied, and the APCD/DIBK system has been applied to simultaneous extraction and flame atomic-absorption spectrometric determination of trace amounts of copper and nickel in titanium metal. Nickel could be extracted with copper from strongly acidic solution such as up to 5M hydrochloric acid with APCD/DIBK system. The extraction from such a strongly acidic media made it possible to extract nickel with copper, since it did not require the addition of a large amount of the masking agent which prevents the hydrolysis of the matrix titanium and also prevents the extraction of nickel. Thus, they could be extracted directly from the titanium metal sample digested by concentrated hydrochloric acid with a small amount of tetrafluorohydroboric acid. Effect of coexistence of a large amount (at least 0.2 g) of iron on the extraction of both elements could be prevented by keeping most of the matrix titanium as Ti(III). With the method described here, mug/g levels of copper and nickel in titanium metal could be rapidly determined with good precision and accuracy.

Fast algorithms for computing Jones polynomials of certain links

We give a fast algorithm for computing Jones polynomials of 2-bridge links. Given the Tait graph with n edges of a 2-bridge diagram, this algorithm runs with O(n) additions and multiplications in polynomials of degree O(n), namely in O(n^2logn) time. We also propose an algorithm that, given the Tait graph with n edges of a closed 3-braid diagram, computes the Jones polynomial of the closed 3-braid link in O(n^2logn) time.

Novel sorbent extraction technique using a chelating agent impregnated porous PTFE filter tube: preconcentration of In(III) with a bis(2-ethylhexyl) hydrogen phosphate (HDEHP) loaded porous PTFE filter tube

The sorption and elution of In(III) on a porous PTFE filter tube impregnated with bis(2-ethylhexyl) hydrogen phosphate (HDEHP) was studied. A 1 µg portion of In(III) in 1000 ml of sample solution was quantitatively complexed with HDEHP adsorbed onto a porous PTFE filter tube by passing the solution through the micropores of the filter tube. Preconcentrated In(III) was then quantitatively recovered provided that the elution, which consisted of cyclical filtering of 0.1 ml of 4 mol l–1 hydrochloric acid through the filter tube for 1 min, was repeated 3 times. The total volume of the eluent was only 0.3 ml in this case; therefore, over 3300-fold of enrichment was attained within 90 min of total preconcentration time. This method was applicable to the preconcentration of In(III) in highly saline samples. A 2.5 µg portion of In(III) could be quantitatively extracted from 500 ml of synthetic seawater and be recovered into 0.5 ml of 4 mol l–1 hydrochloric acid, with subsequent determination by flame AAS. The average recovery and the RSD of the results were 100% and of 1.4%, respectively (n = 5).

Speciation of Inorganic Arsenic in Groundwater as Molybdoarsenate by On-Site Solid-Phase Extraction and Graphite Furnace Atomic Absorption Spectrometry

ABSTRACT Solid-phase extraction was used for on-site speciation and preconcentration of inorganic arsenic in groundwater involving the retention of molybdoarsenate on activated carbon. A total of 0.25 µg of As(V) in 50–500 mL of sample was selectively retained on 100 mg of activated carbon in a mini-column as molybdoarsenate at pH 2. A total of 0.1 mL of 0.26 mol/L ammonium molybdate was introduced for every 50 mL of the sample. As(III) was quantitatively retained with As(V) by adding 0.01 mL of 0.02 mol/L KMnO4 solution for every 50 mL of the sample prior to the addition of ammonium molybdate. The retained As(V) was quantitatively eluted by circularly passing 3 mL of 1 mol/L NH4OH through the column for at least 5 min with determination by graphite furnace atomic absorption spectrometry. A palladium chemical modifier was used to provide a detection limit and blank equivalent concentration of 0.047 and 0.19 µg/L, respectively (n = 6, sample volume of 50 mL). Concomitant ions in seawater or river water did not cause interferences. The method was used for the preconcentration of arsenic in groundwater from Chiba, Japan. The recoveries of fortified As(V) (2 µg/L) were from 89 to 98%. Concentrations of 0.35–1.6 µg/L of As(V) were determined with a relative standard deviation less than 3.7% for five replicates. The recoveries of 2 µg/L fortified As(III) were from 92 to 103%.

Decomposition of Cu(PCD)2 extracted into IBMK and DIBK phases from hydrochloric acid media

The decomposition of the bis(1-pyrrolidinedithiocarbamato) copper(II) complex [Cu(PCD)(2)] extracted into isobutyl methyl ketone (IBMK) and di-isobutyl ketone (DIBK) from hydrochloric acid solution (0.01-8M) has been studied with UV-visible and ESR spectrometry. The mixed-ligand complex CuCl(PCD) is formed as an intermediate and CuCl(2) or CuCl3(-)(3), are formed as final products, in the decomposition of Cu(PCD)(2). The concentration of free hydrochloric acid dissolved in the extract has also been determined, and the effect of the free acid on the decomposition has been studied. The decomposition reaction of Cu(PCD)(2) extracted from hydrochloric acid solution can be thought of as a ligand substitution by Cl(-), and occurs with both IBMK and DIBK extraction.

Extraction of copper(II) with the APCD/DIBK system from concentrated hydrochloric and nitric acid media: estimation of true limit of acidity for the extraction

The extraction of copper(II) from strongly acidic solution (0.01-8M hydrochloric and 0.01-5M nitric acid) with ammonium 1-pyrrolidinecarbodithioate in di-isobutyl ketone has been studied. Compared with the hydrochloric acid system, a considerably larger amount of the reagent is needed for complete extraction of copper chelate from nitric acid solution as the extract is more unstable in the nitric acid system. The decomposition of copper chelates extracted from nitric acid is based on the oxidation of the reagent and the chelate; the spectral change of the extract from nitric acid suggests that the copper(II) chelate is initially oxidized to copper(II) and then decomposes. The upper limit of the acidity of both acids from which the copper chelate can be quantitatively extracted strongly depends on the reagent concentration; the limit with 8 x 10(-2)M APCD (500-fold reagent: metal molar ratio) was taken as 8 and 4M for hydrochloric and nitric acid, respectively.

The Teaching Materials of the LCD Device Manufacture to Conflict with Device of the Advanced Technology

109 1.はじめに 産業界からの後押しもあり、文部科学省は教育現場に おけるICT教育を強力に推進している。そのマンマシン インターフェイスをつかさどるディスプレイは無くては ならない機器である.今の学生・生徒にはIT機器はあっ て当たり前の道具であるが,その構造や原理については ブラックボックスである.道具を使いこなせることは必 要であるが,新技術を生み出す技術者にとって仕組みに ついて理解することも重要である.学生たちに科学技術 に関心を持たせるために身近なインターフェイスである 液晶ディスプレイを例にし,各部材を身の回りにある材 料を使い自分の手で作り上げ仕組みを知り,そして製品 であるディスプレイを組み立てさせて科学技術への興味 を抱かせることができないかを考えた. 筆者らはTwisted Nematic(TN)液晶の重要なパーツ の一つである偏光膜を市販ビニロンフィルムとルゴール 溶液から簡単に,かつ短時間で作成できることを報告し た.そこでこの偏光膜を用いた授業展開を検討し,高等 学校指導要領に記載されている「原子」の単元で「電 子や光が粒子性と波動性の両方の性質を兼ね備えている ことを理解させる」ことを実感させる教材としてTN液 晶デバイスの作製実験を試みた. TN液晶デバイスの構造は大きく分けて3部分からな る.1つめは光の方向を揃える偏光膜で,2つめは液 晶の向きを揃え,電場を与える透明導電性基板(ITOガ