微波富集-铋膜电极微分电位溶出法快速测定水中痕量铅

研究了镀铋膜电极微分电位溶出分析法测定水中铅的方法,考察了该法测定铅的条件.结果表明,在HAc-NaAc介质中铅可在镀铋膜电极上得到灵敏的微分电位溶出峰,结合微波富集方法,检出限达0.003 mg/L,利用标准加入法对水样中痕量铅进行测定,避免了镀汞膜电极带来的健康与环境危害,结果较满意.     

多壁碳纳米管-铋膜电极微分电位溶出法测定涂料中的铅

制备了嵌入式多壁碳纳米管膜玻璃碳电极,研究了铅在电极上的电位溶出行为,建立了嵌入式碳纳米管-铋复合膜电极测定铅的微分电位溶出分析法。结果表明:富集电位为-1.1 V,HAc-NaAc(pH=4.60)缓冲溶液中,峰高与铅浓度在0.1～20.0μg/L范围呈线性,检出限为0.5μg/L,对实际样品进行测定,相对标准偏差(RSD)值在3.8%～7.1%之间,回收率在95.2%～98.7%之间。     

阳极溶出伏安法测定纯锌、铝中的铜、铅、镉

<正> 测定锌、铝中痕量杂质是鉴定纯度的基础工作。玻璃碳汞膜电极微分脉冲阳极溶出伏安法(DPASV法)已被用于测定水中铜、铅、镉。但是,纯锌、铝中砷、锑、铋、锡等对测定痕量的铜、铅、镉有干扰。利用巯基棉在0.1M盐酸介质中,能定量吸附     

微分脉冲极谱阳极溶出伏安法测定纯银中痕量的铜、铅、镉

银中杂质含量的测定是鉴定纯度的基础工作。玻璃碳汞膜电极微分脉冲极谱阳极溶出伏安法(DPASV法)已用于水中铜、铅、镉的测定,但纯银中痕量铜、铅、镉的测定方法未见报道。以DPASV法测定银中铜、铅、镉时,银产生严重干扰。现用0.1M硝酸的银样消解液,使之在通过巯基棉时银被吸附,铜、铅、镉不被吸附而加以分离,然后再测定铜、铅、镉等。本方法采用0.02M的乙酸钠-硝酸-6×10~(-5)MHg~(2 )底液,同位镀汞,玻璃碳汞膜电极DPASV法检出下限,铜2ppm、铅5ppm、镉2ppm。对纯度为     

用阳极溶出伏安法同时测定微量铅和锡

阳极溶出伏安法可分别测定铅和锡,但同时测定较为困难,这是由于锡易于水解和在介质中形成聚合物;在大多数支持电解质中(如在酸性介质中),铅和锡的溶出电位相近,使两峰重叠。为了同时测定铅和锡,我们参考了Glodowski等的方法,采用国产883型笔录式极谱仪,配用玻碳旋转电极同位镀汞。通过试验,选用适合铅和锡共存下同时测定的底液0.1M草酸-0.1M连苯三酚-5×10~(-5)M汞(Ⅱ)。在此基础上,     

汞膜电极阳极溶出伏安法测定水样中镉的研究

研究了镀汞的玻碳电极使用查分脉冲阳极溶出法测定水中的重金属元素镉,并对实验条件进行了优化。结果表明,在优化实验条件下,使用汞膜电极可以获得较好的重复性和直线性,测定实际水样可得到很好的加标回收率。镀汞玻碳电极可用于重金属元素镉的实时在线监测。     

同位镀汞电化学溶出多次半微分电分析法的研究(摘要)

本文提出同位镀汞薄膜电极阳极溶出过程中电流的1.5次和2.5次微分对电极电位曲线的理论,推导出其相应的理论曲线和有关方程,研究了有关特性,并用实验加以验     

银的电位溶出分析

电位溶出法用于分析可溶于汞的金属时,与阳极溶出伏安法有相近的灵敏度,仪器较简单。当用玻碳汞膜电极时,常以二价汞离子或溶液中溶解的氧为氧化剂。D.Jagner在玻碳电极上以高锰酸钾为氧化剂进行了汞的电位溶出分析。本文研究以高锰酸钾为氧化剂电位溶出分析银,并应用于电影洗印废水中银的分析,得到了满意的结果。     

同位镀铋丝网印刷电极快速检测水中铅、镉离子

针对水体中生物毒性显著的重金属离子,本文采用丝网印刷电极三电极系统,通过同位镀铋膜阳极溶出伏安法,对水体中铅、镉两种重金属离子实现快速准确定量。结果表明:铅、镉离子在铋膜电极上可以得到灵敏的溶出峰,且铅离子与镉离子的溶出峰面积在0.1 mg/L～0.7 mg/L的浓度范围内呈现良好的线性关系,线性相关系数分别为0.9932、0.9917,检出限分别达0.034 mg/L、0.028 mg/L,样品加标回收率分别为102.51%与91.07%。基于共存离子的干扰特性,重点筛选典型干扰离子,分别研究了氧化性离子与共镀"合金"离子对铅、镉两种金属离子检测稳定性的影响。本方法简单、快速、准确,为突发重金属环境污染事件现场,提供一种可靠的分析方法。     

用FDSV—1型溶出伏安仪测定铅、铜的含量

介绍使用 ＦＤＳＶ—１型溶出伏安仪测定化学试剂中铅、铜等金属离子时,用符合ＧＢ３９１４—８３规定的银基汞膜电极替代原仪器配置的玻碳电极作为工作电极,银－氯化银电极作为参比电极测定铅、铜含量的测定方法。     

How to Efficiently Remove tert-butylhydroquinone from Commercial Soybean Oils to Obtain Stripped Oils: Eliminating tert-butylhydroquinone's Influence on Oxidative Stabilities of Model Oil-in-Water Emulsions

The present study proposes an efficient method to effectively strip tert-butylhydroquinone (TBHQ) from commercial soybean oils. Ethanol, a typically common and relatively safe organic solvent, can successfully strip TBHQ by employing a liquid-liquid extraction strategy. The results show that the volume ratio of ethanol to oil is a key factor for stripping efficiency (SE), and 4:1 (v/v) is considered the optimal parameter. When compared with traditional stripping methods via adsorbing materials (such as activated charcoal or alumina powder), the proposed ethanol extraction method can more effectively strip TBHQ from commercial oils with lower adsorption loss and higher SE. Moreover, the model O/W emulsion systems prepared using ethanol stripped oils showed the highest degree of lipid oxidation. The method can completely strip TBHQ from commercial soybean oils, thereby eliminating its influence on oxidative stabilities of model oil-in-water emulsions. Practical Applications : The ethanol stripping method can be applied as a pretreatment method to completely strip TBHQ from commercial soybean oils, and subsequently eliminate the influence of TBHQ on lipid oxidation in model O/W emulsion systems during storage.     

汽提法在甲醇残液回收利用中的应用

对采用三塔精馏工艺生产甲醇过程中产生的甲醇残液组分进行了分析,并对常见甲醇残液处理方法进行了对比,详细介绍了汽提法处理甲醇残液的工业应用实例。采用汽提法回收甲醇残液,既可以回收部分甲醇,提高经济效益,又可实现环保价值。     

炼油减压精馏塔汽提工艺传质过程模拟与分析

为了揭示减压塔汽提工艺的传质过程特性,进而改进汽提操作,采用改进的减压精馏过程模拟方法和传质计算方法,分析了炼油常减压装置的汽提工艺的传质特点。在深化对于汽提工艺的理解基础上论证了采用填料汽提塔(段)的必要性以及设计、分析的基本方法。计算分析结果表明侧线汽提塔内填料分离性能保持恒定,汽提塔的分离效率与减压塔对应分离段接近,所以在设计和操作中应给予汽提塔(段)充分重视。减压塔底汽提段的工艺和水力学特点与侧线汽提塔相同。塔底汽提蒸汽质量流率应小于减压塔进料质量流率1%,否则将导致减压塔整体分离效率降低。     

Synergistic effect of various neutral donors in D2EHPA for selective neodymium separation from lanthanide series via HFSLM

The separation of Nd(III) from lanthanide series via hollow fiber supported liquid membrane (HFSLM) using synergistic extractant was investigated. Optimum extraction and stripping obtained were 94.5% and 85.1% using D2EHPA and TOPO mixtures (0.5:0.5 M/M) as the synergistic extractant. Reaction order for both extraction and stripping were first-order with rate constants of 1.444 and 1.338 min⁻¹, respectively. The experimental results were used to correlate with the models. Results showed that the concentration of Nd(III) from the experiment fitted in well with the model results. The average deviation was 1.95% and 2.18% for predictions in both feed and stripping sides, respectively.     

Experimental study of CO2 absorption/stripping via PVDF hollow fiber membrane contactor

Gas–liquid hollow fiber membrane contactor can be a promising alternative for the CO₂ absorption/stripping due to the advantages over traditional contacting devices. In this study, the structurally developed hydrophobic polyvinylidene fluoride (PVDF) hollow fiber membranes were prepared via a wet spinning method. The membranes were characterized in terms of morphology, permeability, wetting resistance, overall porosity and mass transfer resistance. From the morphology analysis, the membranes demonstrated a thin outer finger-like layer with ultra thin skin and a thick inner sponge-like layer without skin. The characterization results indicated that the membranes possess a mean pore size of 9.6 nm with high permeability and wetting resistance and low mass transfer resistance (1.2 × 10⁴ s/m). Physical CO₂ absorption/stripping were conducted through the fabricated gas–liquid membrane contactor modules, where distilled water was used as the liquid absorbent. The liquid phase resistance was dominant due to significant change in the absorption/stripping flux with the liquid velocity. The CO₂ absorption flux was approximately 10 times higher than the CO₂ stripping flux at the same operating condition due to high solubility of CO₂ in water as confirmed with the effect of liquid phase pressure and temperature on the absorption/stripping flux.     

Inline Concentration Monitoring of Binary Liquid Mixtures in the Presence of a Dispersed Gas Phase with a Modified Speed of Sound Immersion Probe

A commercial speed of sound (SOS) immersion probe has been modified in order to permit concentration measurements of liquid mixtures in the presence of dispersed gas phases. Experiments were performed in which water was removed from a polymer/water mixture via evaporation and stripping in mixed vessels of different flow patterns. The original and modified SOS immersion probe was used to monitor the water concentration. In the stripping stage, where a persistent gas phase of high volume fraction is generated, the original SOS immersion probe fails to measure the water concentration. This drawback has been successfully eliminated by means of a special SOS probe housing. The modified SOS immersion probe showed reliable inline water concentration monitoring for directed (draft tube reactor) and undirected flow pattern (ordinary stirred reactor) under boiling and stripping conditions.     

二氧化碳汽提法工艺与氨汽提法工艺的比较

从工艺设计、工艺操作、工艺安全、设备防腐、能耗以及项目投资等方面对比分析了二氧化碳汽提法尿素生产工艺与氨汽提法尿素生产工艺的特点。结果表明,2000＋TM CO2汽提法工艺优于氨汽提法工艺和改良二氧化碳汽提法工艺。     

CO_2汽提法与氨汽提法尿素工艺设备布置及配管方案探讨

根据CO2汽提法和氨汽提法尿素生产工艺技术的不同特点,以2套80万t/a尿素装置为例,分别采用不同的汽提方法进行工程项目设计,从工艺流程、设备布置、管道配置和材料选用等方面对CO2汽提法与氨汽提法尿素生产工艺进行了比较和探讨。     

Application of Ozone in Stripping of Cotton Fabric Dyed with Reactive Dyes

ABSTRACT

This paper discusses the color stripping of cotton fabric dyed with four reactive dyes using ozone. An ozone color stripping process has been optimized in terms of pH, ozone dose, treatment time and dye concentration. Color stripping efficiency of the process is evaluated in light of the color properties including Lightness (L*), Lightness Difference (?L*), and Color Difference (?E*) in addition to strength properties, i.e., copper number and degree of polymerization as well as compared with a control method (conventional reductive color stripping method). The results demonstrate maximum color stripping at an ozone dose of 10 g/h, exposure time of 45 min, and pH maintained at 5. The Stripping Efficiency, however, decreases with increasing dye concentration from 0.5% to 4%, which implies that decolorization of dyed fabric with higher initial dye concentration requires higher ozone dose and/or longer exposure time. The strength of the ozone-stripped fabric sample is almost similar to that of control. The chemical oxygen demand of effluent generated by ozone stripping process is 97% lower than the effluent produced by the conventional stripping method. The Ozone Stripping Process hence proves to be environment-friendly as it consumes less water, energy, and chemicals.