Papers by Keyword: Elution

Abstract: Objectives: The aim of the study was to evaluate monomer elution from three commercial orthodontic adhesive pastes. Methods: Three monomers BPA, Bis-GMA, and TEGDMA were observed from Green Glue (Hangzhou Westlake Biomaterials Co., Zhejiang, China), GrenGloo (Ormco Co., Glendora, CA, USA), and Transbond XT (3M Unitek, St. Paul, MN, USA). The adhesive was light-cured in a cylindrical mold with 6 mm in diameter and 2 mm thick, before immediately immerse into 10 ml extraction media of 75%ethanol in a tightly sealed container at 37°C. The solution was refreshed at four intervals of time 1, 3, 5, and 7 d. The immersion medium was determined using High-performance liquid chromatography (HPLC). Results and Conclusions: BPA were found from three adhesives. Bis-GMA was found only from Transbond XT. TEGDMA were found from both Green Glue and Grengloo. Green Glue had 10-30 times higher TEGDMA elution than Grengloo. Major elution was found from all orthodontic adhesive paste within 1 d, and decrease with time to 7 d.

Abstract: Layered double hydroxide (LDH) is a compound and has exchangeable anion intercalated in its interlayer. LDH has been investigated to apply its interlayer anion as a useful material. We have been focused on interlayer phosphate. Phosphorus is an essential element for crop plants and an exhaustive resource. In this study, we investigated the phosphate elution from Mg/Fe LDHs and controlled its amount from two points of view. Firstly, we synthesized precursor of Cl^– intercalated Mg/Fe LDH by coprecipitation using NaOH solution. Next, the yielded precipitate was aged by two methods: reflux and hydrothermal treatments. Finally, HPO₄^2– adsorbed Mg/Fe LDH was synthesized by means of anion exchange of Cl^– with HPO₄^2– in Mg/Fe LDH. In XRD and EXAFS measurements, α-Fe₂O₃ was detected in the hydrothermal samples. The elution of phosphate was observed in Na₂CO₃ aqueous solution. After 24 hours, the eluted ratio of phosphate was 67% for the reflux sample and 23% for the hydrothermal sample. The decomposition was suppressed in the latter.

Abstract: The effect of cooling condition on the chromium elution from stainless steel slags was investigated. The experiments were carried out in a muffle furnace and an induction furnace, and the leaching test was according to the standard procedure, prEN12457-2. The results show that the oxidation atmosphere enhances the elution of chromium, and the dissolving amount of chromium increases with the increase of temperature. The reducing atmosphere could restrain the elution of chromium. Therefore, it is better to take advantage of the neutral or reductive atmosphere for slag cooling in order to reduce the elution of chromium from stainless steel slag.

Abstract: Simulated soil samples, quartz sands contaminated with 2,4-D, MCPA and dicamba, are separated using the method of ethanol elusion. The experimental results show that the elution temperature, the elution method and the purity of the eluting agent have obvious influence on separation efficiency. In addition, the elution velocity and the pollutant loading of soil have less effect. The impacts of these factors on the separation efficiency of 2,4-D is higher than that of MCPA and dicamba. With the increment of temperature, the separation efficiencies of three herbicides increase rapidly when the elution temperature is below 293 K, while the separation efficiencies increase slowly when the elution temperature is above 293 K. With the reduction of purity of elution agent, the downtrend of separation efficiency in the range of 95~90% or 90~85% is steeper than that of 100~95%. Compared with oft-repeated stationary method, continuous flowing method shows the advantages for three pollutants.

Abstract: This paper chose LiMn2O4 as ion-sieve. In the ion-sieve precursor pickling experiment, the elution effects of hydrochloride, nitric acid and sulfate were compared and hydrochloride was proved the suitable eluent. By changing the acidity of pickling time, the lithium evacuation rate and the manganese solution loss rate basically achieved balance after pickling for 5 h. The static adsorption experiment suggested that when the pH was 12.5 and adsorption time was 30 h, the equilibrium adsorption capacity was 19.71 mg/g.

Abstract: Carlin Trend gold ores are often refractory by conventional cyanid, for a number reasons:1) the gold is locked up within host sulfide minerals such as pyrite or arsenopyrite; 2) the ore contains carbonaceous compounds which are preg-robbing; 3) the gold is locked up in silicate minerals. An alternative technique called diagnostic leaching, originally developed by the Anglo American Research Laboratories in South Africa, has been used successfully to distinguish between a wide variety of different gold associations, including the proportion of preg-robbing gold in carbonaceous gold ores.

Abstract: Removal of copper-cyanide complexes from electroplating industry effluent were studied by using an ion-exchange process. A kind of polypropylene strong alkaline anion exchange fiber was used to perform packed beds continuous experiments. The conditions of adsorption were wastewater pH value 9.0 and flow rate 90-120 BV•h-1 at room temperature. The packed beds were exhausted at 1300 bed volumes for copper-cyanide complexes The elution of copper-cyanide complexes from ion-exchange fiber was studied. The results showed that copper-cyanide complexes were easily eluted from ion exchange fiber using either 2.0 mol•L-1 NaNO3 or NaCl. With 1.0 mol•L-1 NaNO3 solution at 30 BV•h-1, the regenerating rate of copper-cyanide complexes was more than 95%.

Abstract: The purpose of this study is to propose and apply a MEMS-based gas chromatography (GC) device comprising a miniature serpentine column. A 2 m long, 200 μm wide and 250 μm deep column was fabricated using a wet etching process and bonded to a Pyrex cover plate. After the GC column was coated with Carbowax 20M as the stationary phase, the concentrations of benzene, toluene, Ethylbenzene and m-Xylene were successfully detected in the mixed sample. The leakage test and mixed gas separation test achieved a useful separation result for Ethylbenzene-Xylene and Benzene-Toluen mixture at a 17.1 cm/s linear flow rate in a GC chip column.

Abstract: Wear behavior of titanium materials such as C.P.Ti, Ti-6Al-4V and Ti-6Al-7Nb, was studied in simulated body fluids by means of the pin-on-disk type wear testing. The mass loss in wear testing increased with increasing the sliding distance. The a+b type titanium alloys, Ti-6Al-4V and Ti-6Al-7Nb, exhibited higher wear resistance than the C.P.Ti. Average size of the wear debris was 4.5 µm and 3.7 µm for C.P.Ti and the a+b type titanium alloys, respectively. The elution of metallic constituents into 1 mass% lactic acid solution was detected after the wear test.