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991.
建立了抑制电导检测离子色谱法同时测定甲基亚磺酸钠中氯离子和硫酸根离子的方法.Cl-和SO42-分别在0.2~25 mg/L(r=0.9999)和0.1~10 mg/L(r=0.999 6)浓度范围内线性关系良好,甲基亚磺酸钠中Cl-和SO42-的方法平均回收率分别为102%(RSD为0.36%)和101%(RSD为0.61%),检出限分别为0.011和0.014 mg/L.该方法具有线性范围良好、检出限低、操作简便、可靠等优点,可作为甲基亚磺酸钠中的Cl-和SO42-质量控制方法. 相似文献
992.
993.
994.
高负硬度矿井水脱碱处理工艺研究 总被引:1,自引:0,他引:1
针对河南某矿井水处理站供水碱度过高,导致碱度严重超过回用水水质指标,采用药剂法和离子交换法去除碱度。试验结果表明:Ca(OH)_2-CaCl_2脱碱法中Ca(OH)2最佳投加量为350 mg/L,CaCl_2最佳投加量为400mg/L,去除率达86.1%,药剂成本为0.549元/m~3;NaOH-CaCl_2脱碱法中NaOH最佳投加量为350 mg/L,CaCl_2最佳投加量为850 mg/L,去除率达87.9%,药剂成本为1.555元/m3;氯型树脂脱碱法的出水脱碱率可达到99.9%,药剂成本为0.423元/m3。综合考虑出水水质和药剂成本等因素,可选用氯型树脂脱碱工艺处理矿井水。 相似文献
995.
针对废弃混凝土中的再生骨料表面附着大量残留的水泥浆,以及新老砂浆之间缝隙过大,进而导致再生混凝土的耐久性能出现问题,结合粉煤灰的特点,提出对再生骨料进行改性处理,在混凝土中掺入一定量的粉煤灰,从而填充再生骨料存在的缝隙过大的问题。最后,利用电通等试验方法对改性混凝土试件的抗氯离子渗透性能进行测试,并通过实验结果表明粉煤灰可改善再生混凝土结果,提高抗渗透性能,并当掺量在28%时,抗氯离子渗透性能最佳。 相似文献
996.
Reactivity of Hydroxamate Ions in Cationic Vesicular Media for the Cleavage of Carboxylate Esters 下载免费PDF全文
Neha Kandpal Hitesh K. Dewangan Rekha Nagwanshi Sandeep K. Vaishanav Kallol K. Ghosh Manmohan L. Satnami 《Journal of surfactants and detergents》2017,20(2):331-340
The hydrolysis of carboxylate esters viz. p‐nitrophenyl acetate (PNPA), p‐nitrophenyl butyrate (PNPB) and p‐nitrophenyl octanoate (PNPO) in the presence of cationic vesicles of the surfactant dioctadecyldimethylammonium bromide (DODAC) by different hydroxamate ions i.e. acetohydroxamate (AHA?), benzohydroxamate (BHA?) and salicylhydroxamate (SHA?) were studied. The kinetic data was supported by spectrophotometric measurements. The effects of vesicular size on the reaction have been discussed. The differential reactivity under endo‐ and exovesicular conditions has also been evaluated. Critical vesicle concentrations (CVC) of cationic vesicular surfactants were determined from conductometric and fluorimetric measurements at 300 K. Fluorescence probe pyrene and pyrene‐1‐carboxaldehyde have been used for determination of CVC. Further, thermodynamic parameters viz. Standard Gibb's energy (?G°), enthalpy (?H°), and entropy (?S°) of vesicles has also been evaluated within a temperature range of 303.15–328.15 K. 相似文献
997.
Specific Ion Effects of Salt Solutions on Colloidal Properties of Octadecylamine Hydrochloride 下载免费PDF全文
Flotation continues to be a major technique for the production of potash from low grade, complex systems containing a variety of ores and ions. The specific ion effects on the behavior of the flotation collector in the KCl flotation system becomes important to the interpretation of the flotation mechanism. In this work, specific ion effects on the turbidity, surface tension and aggregation behavior of the common collector in KCl flotation, octadecylamine hydrochloride (ODA), have been investigated. The results from turbidity and surface tension studies of ODA solutions show that both cations and anions can affect the colloidal properties of ODA. Molecular dynamics simulations show that the binding that energy barrier between ODA headgroups and anions is principally responsible for the specific anion effect of γ CAC of ODA solutions. In addition, the ion effect on the ODA aggregation particle size was also studied by using transmission electron micrographs (TEM) and dynamic light scattering. The data reveal that the presence of salt ions can induce the formation of larger ODA colloidal particles, on which the cation effect is more significant. This work provides detailed information of specific ion effect on colloidal properties of ODA, which may promote a further understanding of the flotation mechanism and help to improve the flotation of KCl from brine sources. 相似文献
998.
Adsorption fixed bed models are of paramount importance in chemical and environmental engineering research. Although the related literature is rich, the vast majority of models employed are either phenomenological, based on chemical reaction kinetics, or limited to systems that obey simple equilibrium isotherms (favorable, unfavorable, linear, and rectangular) combined to linear driving force (LDF) for the solid-phase mass transfer kinetics and ideal plug flow. This paper complements the existing studies by presenting and analyzing a versatile nondimensional fixed bed model equipped with diffusion-based mass transfer kinetics and nonideal flow terms and adapted to deal with S-shaped (sigmoidal) isotherms. A discussion is conducted on the rather unusual fixed bed dynamics produced by systems that follow S-shaped isotherms, a subject which has been rarely and nonsystematically discussed in the related literature. Thus, this study aims at providing better understanding of the interactions of S-shaped isotherms, mass transfer, and axial dispersion on the shape of adsorption fixed bed breakthrough curves and comes to clarify and complement previously published results, especially on the unexplored effects of the isotherms’ inflection point on the breakthrough curves. 相似文献
999.
建立了离子色谱-柱后衍生测定灭多威中痕量盐酸羟胺的新方法。样品经净化后,采用Ion Pac CS16离子交换色谱柱、安培检测器检测,外标法定量。结果表明:盐酸羟胺在0.02~1.0 mg/L质量浓度范围内,线性关系良好,线性相关系数为0.999 8。方法回收率为95.3%~98.1%,相对标准偏差均小于3%。检出限(信噪比3)为2.5μg/L。该方法简便,灵敏度高,无杂质干扰,前处理简便,可用于灭多威中痕量盐酸羟胺的测定。 相似文献
1000.
Efficient dual‐mode up‐conversion and down‐shifting emission in β‐NaYF4:Yb3+,Er3+ microcrystals via ion exchange 下载免费PDF全文
Shaohua Fan Shikai Wang Hongtao Sun Shiyu Sun Guojun Gao Lili Hu 《Journal of the American Ceramic Society》2017,100(7):3061-3069
We report efficient dual‐mode up‐conversion (UC) and down‐shifting (DS) emission in a single Yb3+/Er3+‐co‐doped β‐NaYF4 microcrystals with controlled morphology and size via a simple Na+ ion‐exchange modification (IEM) method. IEM well preserves the crystal structure and monodispersed morphology of hydrothermal‐synthesized β‐NaYF4. Meanwhile, IEM gives rise to the significant enhancement of UC emission intensity up to 3800 times and strongly enhanced DS emission intensity of Er3+ and Yb3+ by several times in β‐NaYF4:Yb3+,Er3+ microcrystals. IEM also strongly prolongs the DS emission lifetimes of Er3+ and Yb3+ in visible and near‐infrared region. The enhanced UC and DS emission intensities and prolonged lifetimes in β‐NaYF4:Yb3+,Er3+ are mainly ascribed to the dispersing of localized Yb3+ and Er3+ clusters during IEM. 相似文献