Adsorption Equilibrium Parameters of Trace Impurities

Abstract

Atmospheric air contains various trace impurities which include oxides of nitrogen, carbon, sulphur, and light hydrocarbons. Prior to cryogenic distillation of air to produce oxygen, nitrogen, and argon, these trace impurities have to be removed since many of these compounds constitute a safety hazard in the plant. In this study, adsorption has been considered for their removal and adsorption behavior of ethylene, acetylene, nitrous oxide, acetonitrile, methyl tert-butyl ether, methyl sulfoxide, dimethyl sulfoxide, and methanol have been studied in the Henry's Law low concentration region with several different adsorbents. Adsorption equilibrium parameters have been determined with samples of Alcan pure alumina, Alcan alumina/13X composites Actiguard 600/650PC, CABSORB Chabazite, Ceca13X, and Clinoptilolite by using the concentration pulse chromatographic technique. Heat of adsorption values and van't Hoff plots have been presented.     

两种海水脱硫催化剂性能的研究

在海水脱硫恢复系统中,为了提高海水脱硫催化剂的脱硫效果,降低吸收塔出口海水中S(IV)浓度,对聚丙烯腈碳纤维和天然斜发沸石两种催化剂进行了改性、表征。并在不同的p H值条件下对同一催化剂,以及在同一p H值条件下对不同的催化剂的催化效果进行了研究。结果表明,改性后的聚丙烯腈碳纤维和天然斜发沸石结构没有发生变化,催化效果却大大提高;在p H值为6时,两者的催化效果均最佳;同时,改性斜发沸石(400-Fe-Clin)的催化效率高于改性聚丙烯腈(PAN1)基碳纤维。     

焦化废水用改性斜发沸石吸附水中氨氮的研究

研究了焦化废水用改性斜发沸石对水中氨氮的吸附行为,考察了pH值、氨氮初始浓度以及竞争阳离子等对钠型沸石吸附氨氮的影响,同时进行了钠型沸石的吸附动力学研究.     

斜发沸石对氨氮废水吸附性能的实验研究

用江苏丹徒天然斜发沸石进行模拟氨氮废水的脱氮实验研究.结果表明,在氨氮溶液初始浓度为300mg/L、pH值为2.5～8.5时,天然斜发沸石对氨氮的吸附量较高,吸附等温线符合Freundlich方程,相关系数都在0.99以上,吸附动力学符合准二级吸附动力学模型,并以化学吸附为主;应用于畜禽废水处理中,氨氮去除率达85.6%.     

Linear hexane isomerization over the natural zeolite based catalysts depending on the zeolite phase composition

A range of Pd-containing catalysts on the basis of mordenite–clinoptilolite rocks of different starting phase compositions is synthesized. Final phase composition and acidity of rocks change as the conditions of their dealumination are changed. The efficiency of catalysts synthesized is weakly influenced by change of mordenite component contents within 50–80%, and it is not inferior to the efficiency of the catalysts on the synthetic mordenite basis. The nature of active sites as trifunction ones and isomerization mechanism are proposed.     

Adsorption of nitrogen and carbon monoxide on clinoptilolite: Determination and prediction of pure and binary isotherms

Adsorption of N₂ and CO has been studied on a natural Turkish clinoptilolite at near ambient conditions. Pure isotherms up to 101.3 kPa pressure, and binary isotherms at 101.3 kPa total pressure were determined chromatog-raphically at 303 K. Pure isotherms were modelled using the Langmuir model and the Wilson and Flory - Huggins forms of the Vacancy Solution Theory. Binary isotherms were predicted using both forms of the Vacancy Solution Theory, the Extended Langmuir model, and the Ideal Adsorbed Solution Theory. These predictions were compared to experimentally determined binary isotherms. Clinoptilolite is shown to be a particulahly promising sorbent for the separation of CO and N₂. The Wilson form of the Vacancy Solution Theory was the only model flexible enough to provide a reasonable prediction of the binary isotherms.     

改性斜发沸石处理电镀废水中的重金属离子

沸石是一族含水铝硅酸盐矿物,具有特殊的晶体化学结构,拥有离子交换、高效选择性吸附、催化、耐酸、耐辐射等优异的性能和环境属性.天然斜发沸石经改性可增强吸附性能.在静态条件和动态条件下,研究了改性斜发沸石对电镀废水中重金属离子Cu2 ,Cr6 ,Zn2 ,Cd2 ,Pb2 的吸附性.结果表明,改性斜发沸石对重金属离子有较好的吸附性,pH值是影响吸附的主要因素.本技术用于电镀废水处理,可成功地使废水中重金属离子的含量降低到国家规定的排放标准以下,处理后的废水经解吸再生后可重复使用.     

负载型TiO2光催化剂对几种有机物的降解实验研究

以斜发沸石作为载体,用溶胶-凝胶法制备了TiO2/沸石光催化剂.利用IR、XRD 等手段对其进行了表征.以太阳光为光源,光解率为评价指标,对几种不同结构有机物的降解实验表明,TiO2/沸石光催化剂对有机物的降解有明显的选择性.光催化效果在反应初期主要依靠沸石的吸附作用,最终的光解率由有机物的分子量及所带电荷决定,有机物的浓度越大,光解率越低.