流动注射-水杨酸法测定氨氮的余氯干扰及脱氯方法试验

流动注射-水杨酸钠法测定氨氮的含量时,次氯酸钠会对检测过程产生干扰,导致检测结果在谱图中显示为负峰。笔者试验了在含氯水样中滴加硫代硫酸钠、抗坏血酸、亚硝酸钠、亚硫酸氢钠这几种不同还原剂及不同用量对峰形的影响程度,结果表明,抗坏血酸脱氯效果及精确度更好。用抗坏血酸对氨氮0.50 mg/L(以N计)、100 mg/L次氯酸钠(以有效氯计)的标准溶液进行脱氯后进行测定,其相对标准偏差为0.227%,加标回收率P为112%,数据准确度高,重现性好,回收率符合定量检测要求。     

芒硝石灰法试制硫代硫酸钠

<正> 1 前言硫代硫酸钠俗称大苏打、海波。有着广泛的用途,如用作照像的显影剂,电镀、净化软水和皮革鞣剂,化工行业的还原剂,棉织品漂白后的脱氯剂,染毛织物的硫染剂,靛兰染料的防白剂,纸浆脱氯剂,医药工业中用作洗涤剂、消毒剂,以及退色剂等。     

JX-5F脱氯剂在200万t/a连续重整装置上的应用

随着重整生成油中氯含量的升高以及重整装置负荷的提高,原使用的活性炭类液相脱氯剂出现脱氯效果差、使用周期短、换剂频繁的问题。针对存在的问题,采用国内研发的JX-5F液相脱氯剂,用于200万t/a连续重整装置重整生成油的脱氯。介绍了JX-5F液相脱氯剂的主要性能指标和工艺运行参数,对工业应用效果进行了分析讨论。工业应用结果表明:在8.0~10.0 h-1的高体积空速条件下,JX-5F脱氯剂用于重整生成油脱氯,稳定运行4个月,脱后总氯(w)小于0.5×10-6,脱戊烷塔顶未检测到氯化氢。JX-5F脱氯剂的脱氯效果及运行周期优于原液相脱氯剂,且稳定性好,能满足工业生产要求,达到了国内先进水平。     

催化重整过程中的脱氯工艺技术研究

由于固体脱氯剂及其脱氯工艺有着简便的流程、简捷的操作以及检测精确度高等优势特征，现已在催化重整过程中得到了广泛的应用。本文首先概述了催化重整过程中氯的来源及存在的危害，其次，对催化重整过程中的脱氯工艺技术进行了分析研究。     

常温脱氯剂在重整产液化气脱氯中的应用

介绍了常温脱氯剂的研制及其在重整装首液化气脱氯过程中的应用情况,结果表明采用常温脱氯剂脱除液化气中的氯化氢效果很好,消除了碱液处理;带来的不良后果,满足了生产的需要。     

城市生活垃圾热处理中氯元素转化的热力学平衡分析

利用FactSage软件,采用热力学平衡分析法,研究了燃烧气氛、反应温度及脱氯剂对城市生活垃圾热处理过程中氯元素转化的影响。结果表明,MSW在空气或富氧气氛下焚烧,低温时氯元素的主要产物为Cl_2和HCl,超过一定温度后,全部转化成HCl,这一温度节点会随着垃圾的具体组分不同而变化;富氧下,O_2含量越高,Cl_2越多,而HCl越少;而在全实验温度范围内热解,氯元素几乎全部转化为HCl。超过一定温度(不同工况下400～800℃)时,脱氯剂丧失脱氯效果。脱氯剂的效果:CaO>CaCO_3,添加比例15%>10%>5%,热解>空气>富氧气氛(富氧时CO_2与脱氯剂生成CaCO_3,O_2含量越少脱氯效果越好)。脱氯效果与垃圾组分有关,因MSW样本2中含大量硫元素,硫元素氧化生成CaSO_4,抑制脱氯效果,故MSW样本1脱氯效果优于MSW样本2,适宜脱氯温度范围较广。     

T406型脱氯剂的研制与工业应用

报导了型脱氯剂的研制、性能试验和工厂运行结果。与国内外常见同类脱氯剂的对比试验及工业应用表明, 由化工部西北化工研究院开发研制的这一新型脱氯剂具有抗压碎强度高, 净化度高, 氯容量高的特点, 可以在常温下用于气相和液相原料中氯化物的脱除。即使在低温（4℃）下, 净化后原料中氯降至左右的情况下抓容量仍高达18％以上。该脱氯剂还能同时脱除原料中的硫。T406型脱氯剂已工业应用于混合二甲苯和氢原料的脱氯, 使用效果良好。     

饮用水中卤代苯醌类消毒副产物样品保存方法

为了解水样中卤代苯醌的最佳保存条件，提高检测结果的准确性，文中以12种卤代苯醌类消毒副产物为研究对象，针对通用保存温度(常温、4℃)、常见采样容器材质(棕色玻璃容器、棕色聚丙烯容器)和常用保存剂(抗坏血酸溶液、甲酸溶液、硫代硫酸钠溶液)对水样中卤代苯醌类物质的影响进行考察。应用超高效液相色谱-串联质谱法进行检测发现，使用棕色玻璃容器采集并向水样中添加甲酸、冷藏运输能明显提高水样中卤代苯醌的稳定性。结果显示，在检测实际样品中卤代苯醌的浓度水平时，使用棕色玻璃容器采集，采集后立即加入甲酸以降低pH、进行脱氯处理，并在低温冷藏条件下运输，5 d内检测，可以提高试验结果的准确性。     

稀土氧化物对高炉炉顶煤气中HCl脱除过程的影响

在脱氯剂制备过程中分别添加CeO_2、La_2O_3制得含稀土氧化物的高炉炉顶煤气脱氯剂,借助于固定床高炉炉顶煤气脱除HCl气体试验发现:CeO_2和La_2O_3可以改善脱氯剂的孔隙结构,细化晶粒,增加比表面积和活性度;增加活性组分在黏结剂中的分散度,提高各元素的结合能,从而同时改善脱氯剂的化学性能和机械强度。考虑到高炉炉顶煤气脱氯剂制备的生产成本,高炉炉顶煤气脱氯剂中CeO_2、La_2O_3的质量分数应该控制在6%左右。     

浅谈原油含氯特性与脱氯实验室研究

原油中的氯化物危害性极大,特别是对于石油炼制装置,不仅可以造成设备腐蚀与堵塞,而且还会造成二次加工装置催化剂中毒失活.本文首先对原油中氯化物的危害和目前有效的控制措施进行了阐述,然后列举了一种原油脱氯剂评价方法,并结合实验室原油脱氯剂评价数据,总结原油脱氯剂评价效果和影响脱氯剂效果评价的几个因素.     

Catalytic hydrodechlorination of 2,4,4′-trichloro-2′-hydroxydiphenylether under mild conditions

More than 99% of 2,4,4′-trichloro-2′-hydroxydiphenylether (TCPE) by the catalytic hydrogenation over palladium/carbon was firstly dechlorinated under mild conditions. Used molecular hydrogen as the reducing agent, TCPE was completely hydrodechorinated to 2-hydroxydiphenylether (PE) at 50 °C and under normal pressure. The solvents affected not only the rate of the dechlorination, but also the selectivity of the hydrogenation. In general, the rate of the dechlorination decreased in the order of alcohols>alkanes>arenes>heterocycles. Addition of the bases (such as sodium hydroxide, sodium carbonate, sodium bicarbonate, triethylamine and pyridine, etc.) to the reaction systems also changed the rate of the reaction and the selectivity of the dechlorination. Except for pyridine, the other bases obviously accelerated the rate of the dechlorination. When the mixture of ethanol–water was used as the reaction solvent instead of ethanol, the rate of the dechlorination was remarkably improved. When a stoichiometric amount of sodium hydroxide was utilized as the proton acceptor in ethanol–water solvent, the catalytic life and the stability of the palladium/carbon were dramatically enhanced and promoted. The dechlorination process worked well in either organic solvents or aqueous solution and thus had potential application in the remediation of contaminated industrial waste water as well.     

镍电解阳极液中镍钴的同时测定

以EDTA为滴定剂,紫脲酸铵为指示剂,NH4F、酒石酸钾钠、Na2S2O3为掩蔽剂,在氨性介质中测定镍的浓度;在pH值为8.0的氨-氯化铵缓冲液中,采用滴定比色法测得钴的浓度。测得的数据与AAS法和模拟试样进行比较,结果理想。     

Fouling of RO membranes in wastewater applications

Organic and inorganic fouling problems associated with reverse osmosis treatment of municipal wastewater were studied at the Advanced Wastewater Treatment facilities at Hoover Dam. This study indicated that the severity of organic fouling can be reduced by improving the quality of the RO feedwater; namely, by removal of food sources for bacterial growth including BOD, TOC, and ammonia. This, besides the normal secondary treatment, required lime softening and filtration. Lime softening and filtration alone, without secondary treatment, were not found to be effective. Chlorination is necessary to discourage bacterial and fungal growth. Where dechlorination is required to protect the membrane, in the case of polyamide membranes for example, sodium bisulfite was found to be superior to sodium thiosulfate. Use of ultraviolet radiation showed promise as an alternate to chlorination for RO feedwater disinfection. Inorganic fouling can be controlled by pretreatment processes including softening and removal of iron and manganese, and by reducing water recovery.     

一种化学退镍剂的研制

以防染盐(间硝基苯磺酸钠)为氧化剂,研制了一种新型的化学退镍剂。通过正交实验获得了退镍剂的最佳配方为:80 g/L的防染盐,37.5 g/L的单乙醇胺,30 g/L的甘氨酸,4.5 g/L的硫代硫酸钠和0.03 g/L的十二烷基硫酸钠。讨论了退镍剂中各组分的作用。研究了温度对化学镀镍层和电镀镍层的退镍速度的影响,并通过XRD图解释了两者退镍速度的差异。     

Q235钢上中温化学镀镍磷合金工艺

采用正交试验考察了镀液中配位剂柠檬酸钠和乳酸钠含量及pH对Q235碳钢上中温化学镀层沉积速率的影响,研究了稳定剂苯并三氮唑、硫代硫酸钠及其复配对镀液稳定性和沉积速率的影响.得到较理想的工艺配方及操作条件为:NiS046H2O30 g/L,NaH2PO2·H2O 30 g/L,乳酸50 g/L,柠檬酸钠2 g/L,CH3...     

小麦秸秆接枝丙烯酸制备高吸水性树脂

以N,N'-亚甲基双丙烯酰胺为交联剂,过硫酸钾一硫代硫酸钠为引发剂,采用水溶液聚合法合成了小麦秸秆接枝丙烯酸系列高吸水树脂。研究了单体配比、丙烯酸中和度、引发剂及交联剂用量对吸去离子水的影响。结果表明,该树脂具有良好的吸水性能,吸收去离子水达617 g/g。     

Graft copolymerization to cellulose. Effect of sodium thiosulfate on hydrogen peroxide initiator system

The effect of sodium thiosulfate on the graft copolymerization of methyl methacrylate to cellulose in the hydrogen peroxide initiator system was investigated. The addition of sodium thiosulfate in general was effective for decreasing the per cent grafting and the average molecular weight of grafts and increasing the formation of homopolymer, and the effects became pronounced with increasing hydrogen peroxide concentration. Moreover, the addition of sodium thiosulfate slightly suppressed the formation of grafts at a hydrogen peroxide concentration of 3 mmole/l., but greatly promoted it at 20 mmole/l. Traces of metallic ions present in cellulose could not be eliminated sufficiently by treatment with 3N hydrochloric acid. Such ions were found to interact with hydrogen peroxide and thus participate directly in the initiation and termination of the polymerization reaction. EDTA, the chelating agent, was highly effective for suppressing such participation of metallic ions. In the hydrogen peroxide initiator system applied to the EDTA-treated samples, sodium thiosulfate caused an effective initiation of graft formation.     

高效分散剂聚丙烯酸钠的合成及应用

研究了低相对分子质量的聚丙烯酸钠合成及其作为分散剂在矾土基低水泥浇注料上的应用。该合成的特点是采用了过硫酸盐与还原剂硫代硫酸钠组成的复合引发剂体系,并且使用次磷酸钠作为新型链转移剂,代替了传统的异丙醇,最终得到所需分子量的产品。同时研究了其产品作为高效分散剂在矾土基低水泥浇注料的耐火材料上的应用,结果表明,合成的产品具有良好的分散效果。     

萃取法测定氯丙烯氧化液油相中双氧水含量

建立了氯丙烯氧化液油相中双氧水含量的测定方法。考察了硫酸溶液的用量、碘化钾溶液的用量及萃取后静置时间等条件对双氧水含量分析的影响。结果表明,最佳分析条件为样品用水萃取后,依次加入硫酸溶液、碘化钾溶液、4滴钼酸铵溶液,用硫代硫酸钠标准溶液滴至近终点。该方法准确、快速、灵敏,测定的相对标准偏差为0.69%~1.58%,回收率为91.7%~102%。