萃取还原重量法测铂钯物料中的金

用王水分解试样 ,盐酸煮沸脱硝 ,水稀释沉淀银。在 2 - 4mol/L HCl介质中 ,用2 0 m L/g Au甲基异丁基甲酮两次萃取金 ,草酸 -氢氧化钠反萃取还原金。金泥经净化、洗涤、烘干后 ,于 80 0℃灼烧至恒重。金的回收率达 99.93%。     

用P507从硫酸体系中萃取分离镓与铁锌离子

采用P507萃取剂对硫酸体系中的Ga3+与Fe2+, Zn2+进行萃取分离,考察了料液酸度、萃取剂浓度、时间、温度对萃取的影响,绘制萃取等温线;通过比较负载有机相中3种离子用不同浓度HCl和H2SO4反萃的效果及规律,提出用HCl洗脱Fe2+和Zn2+后,再用H2SO4反萃Ga3+的分离方案,并绘制反萃等温线. 结果表明,以40%(j) P507+磺化煤油为有机相,在相比O/A=1:1、温度25℃、时间20 min条件下,经过4级逆流萃取,Ga3+萃取率可达98.48%,同时19.56%的Fe2+和38.42%的Zn2+共萃进入有机相. 负载有机相用6 mol/L HCl洗涤3次可完全洗脱Fe2+和Zn2+而不损失Ga3+,除Fe2+和Zn2+后的负载有机相用100 g/L H2SO4按O/A=4:1、25℃、10 min,经过4级逆流反萃,Ga3+反萃率达97.64%.     

粉煤灰酸浸溶液中铁铝离子的萃取分离

采用N503和TBP、正辛醇、煤油组成的复合萃取体系,对粉煤灰酸浸溶液中的铝与铁进行萃取分离,考察盐酸浓度、氯离子浓度、萃取剂比例对Fe3+萃取率的影响,以低浓度HCl溶液反萃负载铁有机相,并通过逆流实验确定最佳工艺条件. 结果表明,采用N503:TBP:正辛醇:煤油=3:1:1:5(j)的萃取体系,在初始铁浓度为0.96 mol/L、铝浓度为0.22 mol/L、萃取相比O/A=2:1条件下,经5级逆流萃取,Fe3+的萃取率大于99.8%,铝几乎没有损失. 用0.01 mol/L HCl溶液作反萃剂,反萃相比O/A=2.5:1,经6级逆流反萃,反萃液中铁浓度达1.8 mol/L. 分析了有机相负载铁前后官能团的红外光谱图.     

磷酸浸取磷矿酸解液中提取稀土的研究

对磷酸浸取含稀土磷矿得到的酸解溶液中稀土萃取回收进行研究。通过对萃取剂的选择,萃取和反萃条件的试验优化选取,从脱钙后得到的粗磷酸中利用萃取剂P204进行萃取,当相比为2∶1,P204浓度2 mol/L时,经过六级萃取后,萃取率达到97.13%。在相比O/A=1∶1,以6 mol/L HCl进行反萃时,一级反萃率可达到50%以上,采用六级可达近90%。     

N，N—二苄基甘氨酸萃取和分离金属离子的研究

本文用反相纸层析法在HCl中考察了N，N－二基甘氨酸对25种离子的萃取能力，结果表明，此萃取剂对Zr^4 ,As^5 等9种离子具有较强的萃取能力。     

t-BAMBP萃取分离高钾卤水中的铷

本研究采用以D80为稀释剂的t-BAMBP萃取体系,从高钾卤水中萃取分离铷。考察了稀释剂种类、萃取剂浓度、萃取相比、碱度、萃取时间、水洗相比、反萃剂酸度、反萃相比、反萃时间等相关因素对分离的影响。选定萃取剂浓度为0.8 mol/L t-BAMBP,碱度0.8 mol/L NaOH,萃取相比2.5/1,萃取时间1 min,水洗相比2.5/1,反萃酸度1mol/L HCl,反萃时间1 min,反萃相比5/1等条件。经两次四级萃取,一次五级水洗,两次两级反萃获得纯度达97.5%的RbCl,铷总萃取率达92.7%。     

塞曼效应石墨炉原子吸收法测定河水中微量铍

用石墨炉原子吸收法测定河水中的微量铍,具有较高的灵敏度(可达到PPb级),试样制备手续简便、快速,缺点是灰化、原子化阶段挥发损失;基体干扰严重。若采用乙酰丙酮—二甲苯萃取后再用HCl反萃取进行分析测定,则手续冗长繁杂。同时由于水中铍浓度一般是极其微量的,经过繁杂的试样处理损失也较大,这样将会引起很大的测定误差。Runnele~1等人推     

从发酵液中分离提取5-氨基乙酰丙酸盐酸盐的新工艺

5-氨基乙酰丙酸(ALA)在农业、医学等领域应用广泛,市场前景广阔。今采用膜分离、反应萃取和浓缩结晶相结合的新工艺从发酵液中提取5-氨基乙酰丙酸盐酸盐(ALA·HCl),有效提高了产品的回收率,降低了生产成本。分离过程中先对离心后的发酵液进行超滤除杂,反渗透浓缩,预处理过程ALA回收率为86.4%;然后以体积比1:1的磷酸二(2-乙基己基)酯-正己醇混合液为萃取剂,20℃下进行二级萃取。初始水相pH6.5,两次萃取有机相和水相的体积比R均为0.5;两级萃取所得的有机相混合后,再在30℃下用1mol·L-1盐酸对有机相进行反萃取,水相和有机相的体积比r为0.5。萃取过程ALA的回收率为79.8%。所得反萃水相经脱色、真空蒸发浓缩后二次冷却结晶。分离过程ALA·HCl的总收率达到55.2%,产品纯度大于99.5%。     

萃取法从油田卤水中提硼的试验研究

采用溶剂萃取法对青海柴达木盆地南翼山富钾油田卤水中的硼进行了提取试验研究。针对萃取、反萃取的条件进行了单因素实验,主要考察了萃取剂和反萃取剂的种类及体积分数、相比、时间等试验条件,确定了适合该卤水萃取提硼的工艺路线。萃取提硼的较优条件为:以异辛醇为萃取剂,磺化煤油为稀释剂,萃取剂体积分数为50%,相比O/A=1∶1,萃取时间15min;反萃取提硼的较优条件为:以0.1mol/L HCl为反萃剂,相比O/A=1∶1,反萃取时间15min。     

磷酸三丁酯/丁酸乙酯体系协同萃取提锂的研究

以磷酸三丁酯(TBP)为萃取剂、丁酸乙酯(EB)和FeCl_3为协萃剂,煤油为稀释剂,从盐湖卤水中进行了萃取提锂的实验研究。系统考察了卤水酸度、萃取剂浓度、铁锂摩尔比、相比等因素对锂萃取率的影响。体系的最佳工艺条件为:TBP、EB、煤油的体积分数分别为40%、20%和40%;卤水酸度为0.05 mol/L;Fe/Li摩尔比为1.5;相比为O/A=2/1;反萃剂为2 mol/L的HCl,反萃相比O/A=1/1。在最佳萃取条件下,锂的单级萃取率最高可达87.12%。应用稀盐酸对负载有机相进行反萃,锂的单级反萃率超过90%。本文的研究结果表明:TBP/EB/FeCl_3/煤油体系对从盐湖卤水中分离锂具有较好的应用前景。     

The oxidative dehydrogenation of methanol over a novel low‐loading Ag/SiO2–TiO2 catalyst

Catalytic oxidation of methanol to formaldehyde was carried out over Ag/TiO₂-SiO₂ catalysts prepared by chemical reduction. The catalytic activity was measured at the temperature interval 820-920 K, O₂/CH₃OH molar ratio between 0.35 and 0.50 and at the space velocity of 1.2 × 10⁵ h^-1. The optimal content of silver determined by chemical analysis was about 1.7 wt%. The yield of formaldehyde over this catalyst was ~13% higher than that of the industrial pumice-supported silver catalyst and even ~3.5% higher than that of electrolytic silver. The XRD patterns for silver particles supported on TiO₂-SiO₂ are corresponding to Ag(111), (200) and (220), respectively. SEM was used to determine its morphology and particle size. Isolated silver particles were observed on the surface of the catalyst. O₂ chemisorption by using the pulse technique was carried out to determine the free silver surface areas. The average silver particle size from the calculation of selective oxygen chemisorption was found to be in good agreement with that observed from SEM. This revised version was published online in July 2006 with corrections to the Cover Date.     

心电图仪用ABS塑料纽扣上化学镀银的大批量氯化

银/氯化银(Ag/AgCl)电极有多种应用,心电图仪用一次性Ag/AgCl电极便是其中之一。在带有一个直径3mm、长5mm的柄的ABS塑料钮扣(直径10 mm)的一个面上,尝试以二价钴为还原剂,化学镀一层1～2μm的银,然后在酸化的氯化物溶液中以化学镀银表面为阳极进行氯化处理。为了获得良好的Ag/AgCl电对,只有平面部分是氯化物而并非将整个覆银表面都转化。上述柄用作金属接点依次与探针连接。由于原材料是ABS塑料,且每毫克的覆银量只有1μm左右,因此损失降到最低。     

Coating silver nanoparticles on poly(methyl methacrylate) chips and spheres via ultrasound irradiation

Ultrasound irradiation is used for anchoring silver nanoparticles with an average size of ～ 51 nm onto the surface of poly(methyl methacrylate) PMMA chips (2 mm diameter), and silver nanoparticles with an average size of ～ 20 nm onto the surface of the PMMA spheres (1–10 μm). The sonochemical reduction was carried out under argon atmosphere at room temperature. The silver nanoparticles were obtained by the irradiation of a mixture containing the PMMA, silver nitrate, ethylene glycol, ethanol, water, and 24% (wt) aqueous ammonia for 2 h, yielding a PMMA‐nanosilver composite. By controlling the atmosphere and reaction conditions, we could achieve the deposition of silver nanoparticles onto the surface of poly(methyl methacrylate). The silver‐deposited PMMA chips (loaded with 0.01–1.0 weight percent silver) were successfully homogenized in melt by extrusion and then injection molded into small, disc‐shaped samples. These samples were analyzed with respect to their directional spectral optical properties in UV, VIS, and IR spectroscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

C3H6选择性催化还原NO催化剂Ag／γ—A12O3的研究

采用低负载量的(0～3％)Ag／γ-A12O3体系作为C3H6选择性催化还原(C3H3-SCR)NO的催化剂，考察了银负载量、反应温度、空速对NO转化率的影响．同时对于原料气中氧的作用进行了研究．结果表明：银负载量为1．5％时，催化剂表现出最高的反应活性；在考察的条件范围内，原料气中含氧对NO的还原有促进作用，适宜的氧浓度为0．27％；反应温度的过高会导致还原气中C3H6大幅度转化为CO2。     

Silver electrowinning from silver(I)–calixarene complexes by two-phase electrolysis

Results are reported, providing the basis for an elegant new process for metal recovery from acidic solutions, by integrating solvent extraction (SX) and electrowinning (EW) in a single process, rather than operating them separately, as in conventional SX–EW processes. Calixarene-tetramide and its thio-analogue were used for the extraction of silver(I) ions from aqueous phases into dichloromethane, both compounds achieving extraction efficiencies >90%. The effects were determined of extractant and silver(I) concentrations, aqueous phase pH, and the presence of sodium ions, on the distribution of Ag(I) between aqueous and organic phases. Due to the impossibility of stripping the extracted metal conventionally, electro-reductive stripping of silver(I) from the loaded organic phase was carried out in the calixarene/nitric acid two-phase system. The effects were also investigated of current density or electrode potential on silver deposition current efficiencies and cell voltages. Based on experimental data, a new process for silver(I) removal from very dilute solutions was proposed that showed high percentage extractions of silver(I) from the aqueous phase, coupled to direct EW of silver from the calixarene complex in the loaded organic phase, regenerating the extractant for recycle. Current efficiencies in the range from 60% to 90% and cell voltages <3.5 V were achieved simultaneously in this process.     

Modification of regenerated cellulose membrane by impregnation of silver nanocrystal clusters

Regenerated cellulose forms a very important class of basic material with diverse applications because of its hydrophilicity and insolubility in water. Thus, one of the applications of regenerated cellulose is used to fabricate membranes. However, short operational lifetime is one of the disadvantages of the regenerated cellulose. In this research, surface modification of the cellophane membrane was carried out by silver nanoclusters. Silver colloids were formed in situ by chemical and photochemical reduction, and then, silver particles were deposited uniformly onto the surface of the cellophane membrane. The maximum amount of silver deposition was found to be 2.55% by weight in this modification. The modified and unmodified membranes were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray analysis to indicate silver nanocrystalline cluster particles on the modified membrane. SEM images indicate well-dispersed silver particles with an average size of 0.65 μm on the membrane. XRD patterns showed that the size of the silver crystals was 3.9 nm. The surface properties of modified and unmodified membranes were studied by the contact angle. Water absorption, oxidative resistance, salt permeability, and thermal stability were investigated. This study revealed that the modified membrane is more resistant against the oxidative cleavage than the unmodified one moreover, the salt permeability increased after the treatment. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48292.     

载银二氧化钛光催化杀菌性能的研究

以偏钛酸为前驱体,浸渍一定浓度的硝酸银溶液,用热沉积法制备出载银二氧化钛。用XRD测定载银二氧化钛的结构,扫描电镜观测形貌,研究了载银量、光强、二氧化钛浓度、细菌浓度对光催化杀菌的影响。结果表明:制备的粉体为超细锐钛矿型二氧化钛,颗粒为均匀的类球形,粒度约为100～200nm。在二氧化钛颗粒上负载约1.6%的银可以扩展光源利用范围至可见光,光催化作用与银协同杀菌;但银量过高,则主要体现银的杀菌效果。光强增加,杀菌效果提高;二氧化钛的浓度为1.5g/L时杀菌效果最好;细菌浓度低于106细胞/mL时,载银二氧化钛杀菌率可以达到90%以上。     

Sorption of gold and silver on carbon adsorbents from thiocyanate solutions

Sorption recovery of thiocyanate gold and silver complexes on different carbon adsorbents has been studied using model solutions with concentrations 0.08-0.82 mmol/l and 0.16-1.06 mmol/l for gold and silver, respectively. The potassium thiocyanate concentration in these solutions was 0.25 mol/l and the pH of the contacting solution was ∼2. The degree of recovery exceeded 90% for gold and 80% for silver. The separate step-by-step desorption of thiocyanate gold and silver complexes was carried out by varying the initial concentration of thiocarbamide (desorption agent). The degree of recovery of noble metals can be increased up to 95% using basic thiocarbamide solutions (in 0.1-0.2 M NaOH) at the higher temperature of the process (up to 150 °C).     

国内外银镜还原剂对比试验

在各项工艺参数基本相同的情况下,将国内外银镜还原剂在自动化镀银生产线上进行了银转化率对比试验,用滴定法测定镜子单位面积银的含量,分析了还原剂对硝酸银的转化率,结果表明,德国还原剂对银的转换效率为813％,英国还原剂对银的转换效率为70．8％。     

Fabrication of silver nanoparticles dispersed in palm oil using laser ablation

In this study we used a laser ablation technique for preparation of silver nanoparticles. The fabrication process was carried out by ablation of a silver plate immersed in palm oil. A pulsed Nd:YAG laser at a wavelength of 1064 nm was used for ablation of the plate at different times. The palm coconut oil allowed formation of nanoparticles with very small and uniform particle size, which are dispersed very homogeneously within the solution. The obtained particle sizes for 15 and 30 minute ablation times were 2.5 and 2 nm, respectively. Stability study shows that all of the samples remained stable for a reasonable period of time.