Weak Hydrochloric Acid Research Articles

Comparison of Extraction Ability between a Mixture of Alamine 336/Aliquat 336 and D2EHPA and Ionic Liquid ALi-D2 from Weak Hydrochloric Acid Solution

The development of extraction systems to improve the extraction efficiency of metals using commercial extractants and ionic liquids is of importance. The extraction behavior of Co(II) between mixture of Alamine 336/Aliquat 336 and D2EHPA and synthesized ionic liquid ALi-D2 was compared in this work. Some factors, such as equilibrium pH, properties of the extractants, and concentration of components in the mixture had a remarkable effect on the extraction of Co(II). The interactions occurring in the mixtures as well as the change in solution pH were analyzed. Co(II) was completely extracted by ionic liquid when equilibrium pH was higher than 6.5, while it was difficult to extract Co(II) by employing the mixture of D2EHPA and Alamine 336/Aliquat 336. The formation of ionic liquid in the mixture of D2EHPA and Aliquat 336 was verified through FT-IR spectra. In addition, the competition extraction of hydrogen ion and Co(II) by ionic liquid ALi-D2 was explained. Among the three kinds of extractants, the ionic liquid showed the best extraction efficiency for Co(II) and pH control from weak acidic solutions. The present study provides valuable information on the extraction behavior of metal ion by the mixtures of commercial extractants, and thus can give some light on the development of metal extraction systems.

Solvent Extraction Separation of Co(II) and Ni(II) from Weak Hydrochloric Acid Solution with Ionic Liquids Synthesized from Organophosphorus Acids

Solvent Extraction Separation of Co(II) and Ni(II) from Weak Hydrochloric Acid Solution with Ionic Liquids Synthesized from Organophosphorus Acids

Uranium and molybdenum recovery from copper leaching solutions using ion exchange

This work shows the technical feasibility to recover uranium and molybdenum from industrial copper leaching solutions (PLS). Both were obtained as by-products from hydrometallurgical operations of the Chilean copper mining industry, using the ion exchange technique. This process recovered uranium and molybdenum, without disturbing or changing the normal operation of the overall copper production process. Uranium concentration was 17 mg/L, while molybdenum concentration was 50 mg/L. Four different anionic resins were tested, along with the influence of impurities over the breakthrough and saturation points achieved. In a first instance, two resins were chosen based on their Langmuir parameters, namely, maximum load capacity (Qmax) and separation factor (RL): L-MP62 and M43. The overall dynamic process consisted in a pre-conditioning step for the resin, using a weak hydrochloric acid solution. Next, the copper PLS solution feeds the fixed bed of the ion exchange column. Once the PLS solution saturates the anionic resin, a hydrochloric solution extracts uranium, and a sodium hydroxide solution extracts molybdenum. The final products were purified elution solutions with 500 mg/L uranium and 800 mg/L molybdenum, respectively.

Decalcified allograft in repair of lytic lesions of bone: A study to evolve bone bank in developing countries.

Background:The quest for ideal bone graft substitutes still haunts orthopedic researchers. The impetus for this search of newer bone substitutes is provided by mismatch between the demand and supply of autogenous bone grafts. Bone banking facilities such as deep frozen and freeze-dried allografts are not so widely available in most of the developing countries. To overcome the problem, we have used partially decalcified, ethanol preserved, and domestic refrigerator stored allografts which are economical and needs simple technology for procurement, preparation, and preservation. The aim of the study was to assess the radiological and functional outcome of the partially decalcified allograft (by weak hydrochloric acid) in patients of benign lytic lesions of bone. Through this study, we have also tried to evolve, establish, and disseminate the concept of the bone bank.Materials and Methods:42 cases of lytic lesions of bone who were treated by decalcified (by weak hydrochloric acid), ethanol preserved, allografts were included in this prospective study. The allograft was obtained from freshly amputated limbs or excised femoral heads during hip arthroplasties under strict aseptic conditions. The causes of lytic lesions were unicameral bone cyst (n = 3), aneurysmal bone cyst (n = 3), giant cell tumor (n = 9), fibrous dysplasia (n = 12), chondromyxoid fibroma, chondroma, nonossifying fibroma (n = 1 each), tubercular osteomyelitis (n = 7), and chronic pyogenic osteomyelitis (n = 5). The cavity of the lesion was thoroughly curetted and compactly filled with matchstick sized allografts.Results:Quantitative assessment based on the criteria of Sethi et al. (1993) was done. There was complete assimilation in 27 cases, partial healing in 12 cases, and failure in 3 cases. Functional assessment was also done according to which there were 29 excellent results, 6 good, and 7 cases of failure (infection, recurrence, and nonunion of pathological fracture). We observed that after biological incorporation, the graft participates in bone physiology and morphology. We did not observe any adverse host graft antigenic reaction.Conclusions:We conclude that decalcified allograft is suitable alloimplant for use in benign lesions of bone, is easy to prepare and store, and is thus well suited for use in developing countries.

Synergistic Solvent Extraction of Lanthanides(III) with Mixtures of 4-benzoyl-3-methyl-1-phenylpyrazol-5-one and Some Novel Carbamoyl- and Phosphorylmethoxymethylphosphine Oxides

The solvent extraction of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y from weak acidic hydrochloric acid solutions into an organic phase containing 4-benzoyl-3-methyl-1-phenylpyrazol-5-one (HP) and neutral tridentate organophosphorus ligands R2P(O)CH2OCH2C(O)NBu2 R = Bu (I), R = Ph (II) and R2P(O)CH2OCH2P(O)R12 R = R1 = Bu (III); R = Bu, R1 = Ph (IV); R = R1 = Ph(V) has been studied. A considerable synergistic effect was observed in the presence of HP in the organic phase containing tetraoctyldiglycolamide (TODGA) and neutral organophosphorus ligands I - V. A successive replacement of C(O)NAlk2 groups in the diglycolamide extractant molecule by P(O)Ph2 groups leads to an increase in the extraction efficiency of Ln(III) ions when toluene was used as diluent. Phosphoryl-containing podand I possess a higher extraction efficiency towards Ln(III) ions than TODGA. The extraction equilibrium was investigated and the equilibrium constants were calculated. It was found that the lanthanide(III) ions are extracted as LnLP3 and LnL2P3 complexes with mixtures of HP and I in toluene from weak acidic solutions.

AMS 14C age of the Upper Palaeolithic skeletons from Sungir site, Central Russian Plain

Bones of three human individuals, found at the Upper Palaeolithic site of Sungir (central European Russia) in graves with unique adornments and other rich burial goods, have recently been 14C-dated at the NSF-Arizona AMS Facility. Collagen for dating was extracted using slow demineralization of whole bone fragments in weak hydrochloric acid. For the Sungir 1 burial, a 14C value of ≈19200 BP was obtained; for the double burial Sungir 2 and 3, 14C values of ≈26200–27200 BP (average ≈26400 BP) were obtained. This contradicts earlier 14C dates made at the Oxford AMS Lab, with collagen extracted following Longin's technique: ≈22900 BP for Sungir 1; and ≈23800–24100 BP (average ≈23900 BP) for Sungir 2 and 3. The use of two different techniques of collagen extraction for the Tucson and Oxford dates might be the cause of the age differences. Additional studies need to be conducted to resolve these 14C age differences.

AMS 14C age of the Upper Palaeolithic skeletons from Sungir site, Central Russian Plain

Bones of three human individuals, found at the Upper Palaeolithic site of Sungir (central European Russia) in graves with unique adornments and other rich burial goods, have recently been 14C-dated at the NSF-Arizona AMS Facility. Collagen for dating was extracted using slow demineralization of whole bone fragments in weak hydrochloric acid. For the Sungir 1 burial, a 14C value of ≈19 200 BP was obtained; for the double burial Sungir 2 and 3, 14C values of ≈26 200–27 200 BP (average ≈26 400 BP) were obtained. This contradicts earlier 14C dates made at the Oxford AMS Lab, with collagen extracted following Longin's technique: ≈22 900 BP for Sungir 1; and ≈23 800–24 100 BP (average ≈23 900 BP) for Sungir 2 and 3. The use of two different techniques of collagen extraction for the Tucson and Oxford dates might be the cause of the age differences. Additional studies need to be conducted to resolve these 14C age differences.

Multi-element removal from road-deposited sediments using weak hydrochloric acid

Dilute HCl is a widely applied partial digestion procedure in geo-environmental investigations. Concentrations of HCl from 0.07 to 12 M have been applied to digest solid media, either shaken at room temperature ("cold") or heated to temperatures of 80–95 °C ("hot"). From an exhaustive literature survey, 0.5 M HCl was selected as the most appropriate single leach partial digestion procedure for examining potentially contaminated road-deposited sediments (RDSs). Both cold and hot HCl treatments were examined using objective criteria to identify the leach that produced the most environmentally meaningful data. The treatments were judged according to minimal breakdown of the aluminosilicate lattice and/or liberation of refractory-associated fractions of Al, Cr, and Fe; high recoveries for suspected contaminants (Cu, Pb, and Zn); and contaminant concentrations independent of clay content, organic C content, carbonate content, and cation exchange capacity. Based on all criteria, the cold 0.5 M HCl procedure was identified as superior to the hot HCl treatment. The cold treatment showed limited removal of Al, Cr, and Fe from the residual fraction, with the hot treatment having three- to sevenfold greater removal efficiencies. This suggests significant breakdown of structural lattice and liberation of elements from fractions not generally considered environmentally important. Hot HCl removed quantitative amounts of Cu and Zn from the road sediments, indicating structural release. The greater structural breakdown associated with hot HCl is a major disadvantage for studies examining bioavailability. All data point to the superiority of a cold HCl leach for geo-environmental contaminant studies. Electronic supplementary material to this paper can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00254-002-0598-8

Radionuclides from Chernobyl hot particles in the environment of North-Eastern Poland - A leaching experiment

The north-eastern Poland is the area where fallout of Chernobyl fuel-like hot-particles occurred. Experiment on the leaching out of radionuclides from forest litter was performed. Five samples were subsequently leached out by : a weak hydrochloric acid (fulvic acid fraction), ammonia water (humic acid fraction) and 2 M HCl (soluble fraction). Residue was analysed as well, after full mineralisation. Results on total activities and its distribution between fractions obtained for : 137 Cs, 90 Sr, 239+240 Pu, 238 Pu and 241 Am are presented. Relatively high activities of plutonium were observed in humic acid fractions. This founding support suggestions by other authors on possible complexing of Pu by humic acid.

Calcium Oxalate Crystals in the Green AlgaSpirogyra hatillensis(Zygnematales, Chlorophyta)

Vegetative cells of the freshwater green alga Spirogyra hatillensis Transeau contain numerous cruciate inclusions that are up to 34 μm long. A crystalline nature was shown by birefringence in polarized light. Rather than occurring free in the large central vacuole, these inclusions were associated with cytoplasmic strands that suspended the nucleus in a cytoplasmic embayment of the central vacuole and with the parietal cytoplasm, which contains the spiral chloroplasts. Some crystals moved directionally along the cytoplasmic strands, and their movement was arrested by cytochalasin B, indicating that actin microfilaments had a role in crystal movement. Solubility tests showed that the inclusions were composed of calcium oxalate; they were not soluble in concentrated acetic acid or sodium hypochlorite, but they dissolved rapidly without effervescence in weak hydrochloric acid. The Yasue cytochemical test for calcium oxalate stained the crystals intensely. The crystals were associated with a water‐soluble organic matrix that retained the shape of the crystal after demineralization. Scanning electron microscopy showed crystals to have arms with tapered tips and rhombohedral cross sections or with truncated ends and rectangular sections. Crystal growth in the Z‐axis occurred at the intersection of the axes as well as at other sites along the arms. Transmission electron microscopy showed the presence of bounding membranes around the mineral inclusions. A colorimetric enzymatic test for oxalate was used to quantify this compound in S. hatillensis, and it was also used in conjunction with microscopic examination. Neutral red was found to accumulate in numerous small vacuoles, up to 2 μm in diameter, that were present in the parietal cytoplasm and in the cytoplasmic strands supporting the nucleus. In filaments undergoing conjugation as part of sexual reproduction, unfused cells contained crystals, but zygotes did not.

CALCIUM OXALATE CRYSTALS IN THE GREEN ALGA SPIROGYRA SP. (ZYGNEMATALES, CHLOROPHYTA)

Specimens of an unidentified species of the freshwater green alga Spirogyra were found to have abundant cruciate cellular inclusions up to 34 micrometers long. A crystalline nature was shown by birefringence in polarized light. Despite their large size and complex shape, these inclusions did not occur free in the large central vacuole. Instead, they were associated with cytoplasmic strands that spanned the space between gyres of the parietal spiral chloroplasts and with strands that suspended the nucleus in a cytoplasmic embayment of the central vacuole. Some crystals moved directionally along the cytoplasmic strands, and their movement was arrested by cytochalasin B, suggesting that actin microfilaments had a role in crystal movement. Solubility tests showed that the inclusions were composed of calcium oxalate; they dissolved rapidly in weak hydrochloric acid without effervescence, but they were not soluble in concentrated acetic acid or sodium hypochlorite. A colorimetric enzymatic test for oxalate was used to demonstrate microscopically the presence of oxalate and to quantify the amounts. The calcium oxalate crystals were surrounded by a water‐soluble organic matrix that retained the shape of the crystal even after demineralization. Scanning electron microscopy was used to examine the morphology of isolated crystals.

Aging of Iron (Hydr)oxides by Heat Treatment and Effects on Heavy Metal Binding

Amorphous iron (hydr)oxides are used to remove heavy metals from wastewater and in the treatment of air pollution control residues generated in waste incineration. In this study, iron oxides containing heavy metals (e.g., Pb, Hg, Cr, and Cd) were treated at 50, 600, and 900 °C to simulate their transformations caused by heat treatment prior to disposal or aging at a proper disposal site. The transformations were investigated by XRD, SEM, XANES, EXAFS, surface area measurements, pH static leaching tests, and extractions with oxalate and weak hydrochloric acid. It was found that at 600 and 900 °C the iron oxides were transformed to hematite, which had a greater thermodynamic stability but less surface area than the initial products. Heat treatment also caused some volatilization of heavy metals (most notably, Hg). Leaching with water at pH 9 (L/S 10, 24 h) and weak acid extraction showed that heat treatment caused a part of the metals bound in the oxides to be released, thus increasing metals leachability by 1−2 orders of magnitude depending on the metal. Pb and Cd were released in particularly significant concentrations, suggesting less incorporation into the iron oxides after heat-induced transformation. For Pb, this transformation of the chemical state of the bound metal was clearly supported by the X-ray absorption fine structure (XAFS) studies. A fraction of the bound Cr remained stable even after treatment at the highest temperature used in the study. It was concluded that the heat treatment of iron oxides may be advantageous to improve the thermodynamic stability of the product but that thermal treatment at both 600 and 900 °C significantly reduced the binding capacity for heavy metals.

Prediction of stress-rupture life of glass/epoxy laminates

This paper reports an effort to predict the life of quasi-isotropic E-glass/epoxy composite laminates under constant load and in an acid environment. An experimental program involving stress-rupture tests of unidirectional coupons immersed in a weak hydrochloric acid solution was conducted to determine their stress-life response. Creep tests were conducted on unidirectional coupons parallel and transverse to the fibers, and on ±45° lay-ups to characterize the lamina stress- and time-dependent compliances. Lamina data were used in a composite stress-rupture life model, based on the critical element modeling approach, to predict the life of quasi-isotropic laminates. Predictions compare favorably with experimental data. Discrepancies underscore the need for detailed materials characterization in the actual service environment.

Fine Structure and Evolutionary Significance of Sagittocysts of Convolutriloba longifissura (Acoela, Platyhelminthes)

Sagittocysts are extrusomes found only in acoel turbellarians. They are needlelike secretory products, on the order of 18-50 pxm long and 1-5 pxm wide, and consist of a fibrous cortex, a central filament, and an intermediate lucent layer. We discovered sagittocysts in Convolutriloba longifissura, for which they had not been known before, by using confocal microscopy and a phalloidin-conjugated fluorescent stain that strongly labeled a mantle of muscle around the distal neck of the sagittocyst-secreting cell, the sagittocyte. The muscle mantle apparently plays a role in ejecting the sagittocyst. Positions of the sagittocysts revealed by confocal microscopy suggests their role in defense as well as in prey capture. By electron microscopy, the differentiation of sagittocysts was evident in the proximal part of the sagittocyte. The muscle mantle on the neck of the sagittocyte is conical in shape; its ribbon-like myocyte enwraps the neck in a tight spiral. Extrusion of sagittocysts could be induced by stimulation with electrical pulses, light pulses, or weak hydrochloric acid; only the whole sagittocyst was ejected, not its central filament. The presence of sagittocysts in species of Convolutriloba is sufficient to reassign the genus to the family Sagittiferidae. We establish the new subfamily Convolutrilobinae, with 3 species in the genus Convolutriloba, and new subfamilies for the remaining sagittiferids as well. As extrusomes, sagittocysts are comparable to nematocysts, colloblasts, rhabdites, and other extrusomes common especially to lower eumetazoans, and the origin of all such extrusomes may correlate with the origin of the eumetazoan

Transport of cadmium and zinc to rocky reef communities in feces of the blacksmith ( Chromis punctipinnis), a planktivorous fish

The blacksmith ( Chromis punctipinnis), an abundant planktivorous reef fish off southern California, releases fecal material as it forages in the water column during the day and shelters in reefs at night. This behavior results in direct transportation of cadmium and zinc to reef communities. Cadmium and zinc concentrations, measured in fish feces after digestion in weak hydrochloric acid to better assess metal levels potentially available to detritivores, averaged 24·2 μg cadmium and 368 μg zinc g −1 dry weight of feces. Concentrations of both metals varied significantly among the five sampling dates. Fresh feces spiked with 109Cd and 65Zn adsorbed additional metals for 9 and 6 h, respectively, but the increase was negligible (<0·1%). The total amount of weak-acid-leachable cadmium and zinc egested by sheltering blacksmiths is approximately 4·4 μg and 66·8 μg m −2 night −1, respectively, and may represent more cadmium and almost as much zinc as is transported by the passive settlement of particulate material from the water column. This transport mechanism between planktonic and benthic communities via feces of reef fishes is probably widespread in temperate and tropical seas.

An improved method for the hydrolysis and MBTH analysis of dissolved and particulate carbohydrates in seawater

An improved method for the bulk characterization of particulate and dissolved combined carbohydrates in seawater is presented. Seawater samples are dried under vacuum and the residue is hydrolyzed with 12 M H 2SO 4. Carbohydrates in the hydrolysate are subsequently quantified spectrophotometrically by MBTH (3-methyl-2-benzothiazolinone hydrazone hydrochloride) analysis. Sulfuric acid was more effective in hydrolyzing high-molecular-weight structural carbohydrates (cellulose, chitin, and alginic acid) than weak (0.09 N) hydrochloric acid. Sulfuric acid hydrolysis of dissolved and particulate samples yielded estimates of carbohydrates equal to or greater (two- to four-fold) than those resulting from dilute (0.09 N) HCl hydrolysis. In samples from the Gulf of Mexico, total dissolved carbohydrates determined after sulfuric acid hydrolysis varied from 20 to 56 μM C and from 10 to 28% of the dissolved organic carbon determined by high-temperature catalytic oxidation.

Dissolution of aluminosilicates in hydrochloric acid solutions. I. Dissolution rates of cations and change in specific surface area of the residues

Dissolution of aluminosilicates in weak hydrochloric acid solution was studied. In general, sodium ions were at first dissolved into the solution, and then aluminum ions began to dissolve after the dissolution of sodium ions was almost completed. The amount of sodium and aluminum ions dissolved was just equivalent to the amount of acid consumed. In the course of dissolution of both ions, dissolution of silicon was also observed. From these facts, it was suggested that silicon atoms were dissolved as the result of breaking of aluminosilicate structure, in contrast with the case of sodium and aluminum ions. Therefore, the dissolution of silicon atoms was due to a secondary effect. One silicon atom dissolved when 1.3 aluminum atoms dissolved in the case of sodium aluminosilicates No.1-6, which were synthesized in alkaline medium, while one silicon atom dissolved when 2.7 aluminum atoms dissolved in the case of No.7 and 8, which were synthesized in acid medium. It was therefore concluded that the samples synthesized in acid medium were neither sodium aluminosilicates nor sodium aluminum silicates but sodium aluminum aluminosilicates. It was also found that the degree of crystallization and adsorption volume of N2 gas on crystalline aluminosilicates decreased when these crystals were washed with acid solution.

Rapid preparation of carrier free I-131 from neutron-irradiated telluric acid

Carrierfree I-131 is prepared from neutron-irradiated telluric acid by dissolving the latter in weak hydrochloric acid and precipitating it with ethanol. The I-131 containing filtrate is made absolutely tellurium-free by passing it over a column of chromatographic grade alumina: yields of 60–65 per cent are obtained. Another 20 per cent can be eluted also carrierfree from the column by 0·01 N to 0·1 N ammonia, giving an overall yield of 80–85 per cent.

Zur kinetik der elektrochemischen abscheidung radioaktiver ionenarten auf metalloberflächen

The Nernst-Brunner equation has been applied to the electrochemical deposition of carrier-free radioactive ions on metal foils in a modified form to include decay and growth. The modified equation was shown to hold for the deposition of 212Bi(ThC) and 210Bi(RaE) on nickel foils from weak hydrochloric acid solutions under the following conditions: pure 212Bi, 212Bi in equilibrium with 212Pb(ThB), 212Bi in equilibrium with 228Th(RdTh), and 210Bi in equilibrium with 210Pb(RaD). Some indications of the purity of the deposited radio-bismuth are given.

Adrenocorticotrophic hormone; stability studies.

Summary1. ACTH activity disappears rapidly from neutral aqueous, 0.9% sodium chloride, or basic extracts of pituitary. Activity is stable in weak hydrochloric acid extracts of the gland. ACTH prepa...