液-液萃取气相色谱法测定四氯化钛水解体系中痕量四氯化碳的不同萃取剂萃取能力对比

比较了液-液萃取气相色谱测定精四氯化钛水解样品中四氯化碳方法中使用的庚烷、正己烷、正辛烷、异辛烷4种萃取剂对痕量四氯化碳的萃取效果。结果表明:4种萃取剂对四氯化碳都有较好的响应, 色谱图上的峰位和峰形都较好, 而且四氯化钛中三氯甲烷、一氯乙酰氯、三氯乙酰氯共存杂质对四氯化碳的测定没有干扰。对于庚烷、正己烷、正辛烷、异辛烷, 校准曲线的线性相关系数分别为0.990 8、0.997 2、0.998 7、0.999 5, 检出限分别为0.003 2、0.001 5、0.004 4、0.001 1, 样品加标平均回收率分别为95.4%、98.8%、96.4%、99.6%, 相对标准偏差分别为2.6%、4.0%、4.6%、1.6%。因此, 4种萃取剂对四氯化碳都有较好的萃取能力, 但异辛烷的萃取能力最强, 稳定性也较好。     

银氧化锡合金废料电解综合回收工艺研究

采用直流电解法和化学法回收银氧化锡(AgSnO2)合金废料中的银和锡。优化得到的电解银工艺参数为:槽电压1.5~3.0 V,电解周期为24 h,电解液中Ag⁺浓度为150~260 g/L,HNO3浓度为15~20 g/L,同极距120~140 mm,极板排布为六阴极五阳极间隔交替排列。一个周期银氧化锡废料电解银直收率接近95%,主体纯银粉在阴极析出。富含氧化锡的阳极泥和残极用硝酸浸出少量残余银,不溶渣还原熔炼回收锡,硝酸浸出的含银溶液中加入氢氧化钠调节pH值到10,沉淀得氧化银,500℃焙烧得到单质银。废料中的银和锡均得到有效回收。全流程银的回收率不低于99%。     

活性碳纤维负载钴酞菁对取代酚的催化氧化

为去除难降解的酚类物质,以活性碳纤维负载钴酞菁(CoPc-ACF)为催化剂、以H2O2为氧化剂组成新型催化氧化体系(CoPc-ACF/H2O2).该体系能充分发挥CoPc-ACF中活性碳纤维的吸附特性和钴酞菁的催化性能.以对硝基苯酚、对甲氧基苯酚和取代氯酚为对象,研究该体系对其的吸附催化氧化性能.采用UPLC检测酚类物...     

超细活性氧化锌在轿车子午线轮胎胎面胶中的应用

对超细活性氧化锌在轿车子一轮胎胎面胶中的活尼效果分两组配方做了实验。结果表明,超细活性氧化锌由于活性高、等效用量小,与普通氧化锌相比有加快硫化速度的效果,并能改善胶料的加工性能,提高硫化胶的扯断永久变形、耐老化性和耐疲劳性能;超细活性氧化锌胶料加入活性碳酸钙后,能胶料生产成本,提高经济效益。     

Oxidative dimerisation of methane on a supported Pd-Ag catalyst using a diffusion controlled ceramic wall reactor

Supported palladium-silver oxides were used as catalysts for the partial oxidation of methane by molecular oxygen in a tubular reactor with ceramic wall separation. The ceramic wall controls the O₂ supply in the catalyst bed. The results indicate that the reactor configuration can play an important role in methane oxidation. C₂H₆, C₂H₄, CO₂ and H₂O were obtained at temperatures less than 300 °C. At this temperature any contribution from homogeneous gas phase reaction can be ruled out.     

Ammoxidation of toluene over Y-Ba-Cu-Co-O perovskites

Ammoxidation of toluene over the perovskites YBa₂Cu₃O_6.1, YBa₂Cu₂CoO_6.7 and YBaCuCoO_4.9 was investigated at 400 °C. At low partial pressures of O₂ benzonitrile was selectively formed, while CO₂ was the main product at high pressures of O₂. Systematic differences in activity were observed for the three phases and are related to the crystal contents of Cu and Co. At low O₂ pressures, Cu-sites are active for nitrile formation, while Co-sites give CO₂. At high O₂ pressures, the activity for CO₂ of Cu-sites increases more than that of Co-sites due to filling of near-surface oxygen vacancies.     

Fe~(2+)注人Al_2O_3陶瓷及其退火改善材料表面电学性能的研究

对透明Al_2O_3陶瓷进行了Fe元素的离子注入。用“Van der Pauw”方法测定注入层的电阻率,并结合Hall效应测量,确定样品载流子浓度和迁移率。 本文主要阐述未经退火和退火的Fe~(2+)注入Al_2O_3陶瓷表面电性能,并应用Rutherford背散射技术等方法进行分析比较,试图得到有关晶格损伤及恢复、注入离子的纵向浓度分布,缺陷等信息。最后,简要地叙述了注入层的导电机制。     

用新型碳分子筛分析永久气体

本文介绍一种新型气相色谱固定相——碳分子筛(KMS),其最大的优点是在常温下,单柱即可同时分离分析H_2、O_2、N_2、CO、CH_4、CO_2六种混合气体,柱子的保留值重现性好,峰形对称,柱效高。本文求得了在H_2和Ar作载气时KMS对上述六种气体的定性定量特性,配气的定量结果总的平均相对误差为3.67％。同时这种碳分子筛原料易得,制作简单,成本便宜。     

Swelling behaviour of rubber vulcanizates: 2. Effects of tensile strain on swelling

The effects of tensile strain on the swelling behaviour of acrylonitrile-butadiene copolymer rubber vulcanizates were studied by real-time pulsed nuclear magnetic resonance (n.m.r.) measurements and volume swelling measurements at equilibrium. It was shown that tensile strain causes an increase of the initial swelling rate evaluated by n.m.r. measurements and of the swelling ratio of the rubber matrix at equilibrium. This behaviour was discussed qualitatively in terms of the molecular mobility of the network chains on the basis of Treloar's theory for swelling under deformation. It was suggested that the presence of reinforcing fillers in the rubber matrix exerts two noticeable effects on swelling under deformation: (1) a transient effect through some oriented structure induced by stretching, which restricts the increase of the swelling rate; (2) a strain amplification effect, which causes the increase of the average local strain in the rubber matrix and enhances the swelling ratio more remarkably proportional to the filler concentration as compared with that of the unfilled system.     

Supercritical fluid extraction of fungal oil using CO2, N2O,CHF3 and SF6

The extraction of oil from fungi (Mortierella ramanniana var.angulispora) was studied using carbon dioxide (CO₂), nitrous oxide (N₂O), trifluoromethane (CHF₃) and sulfur hexafluoride (SF₆) under supercritical conditions. The oil solubility was highest in SC-N₂O followed by SC-CO₂, while both SC-CHF₃ and SC-SF₆ showed poorer solvent power. The recorded oil solubilities at 333 K and 24.5 MPa were 2.3 wt% in N₂O, 0.48 wt% in CO₂, 0.0099 wt% in CHF₃ and 0.0012 wt% in SF₆. The oil solubilities in SC-N₂O and SC-CO₂ were measured over the pressure range 15.7–29.4 MPa and at temperatures ranging from 313–353 K. N₂O always showed greater solvent power than did CO₂ at the same temperature and pressure. The solvent power of a supercritical fluid increases with density at a given temperature, and increases with temperature at constant density. The change in neutral lipid composition of the extracted oil with the extraction ratio was measured. Free fatty acids or diglycerides were extracted more easily than triglycerides or sterol esters. The change in fatty acid composition was also measured. The proportion of γ-linolenic acid in the extract remained constant throughout the extraction.