红辉沸石对重金属铅离子的吸附性能

研究了红辉沸石对重金属铅离子的吸附性能:当pH值在4~5时,红辉沸石具有较好的吸附能力,其对铅的饱和吸附容量达0.831 mg/g.同时使用氯化钠和氯化铵对沸石进行改性,并用红外光谱法进行表征,证明处理后的红辉沸石结构上产生了明显的变化,有利于提高其吸附性能,其对铅的饱和吸附容量可达1.091 mg/g.     

Hydrothermal preparation and crystal habit of X-zeolite powder

The preparation of X-zeolite powder was investigatedin hydrothermal system, the crystal growth process of X-zeolite in hydrothermal condition was characterized by means of X-ray diffraction, scanning electron microscope and infrared ray. The results show that X-zeolite powder with uniform granularity and intact crystal shape can be obtained in hydrothermal system of acid-treated stellerite-NaOH-NaAl(OH)4-H2O; the crystallite size is in the range of 2 - 3μm. The best reaction time of hydrothermal preparation is 6 h. The formation phases of X-zeolite crystal are as follows: dissolution of feedstocks → formation of [SiO4]4- and [AlO4]5- tetrahedron, many-membered ring,β cage → formation of crystal nucleus and nano-particle → aggregation growth of nano-particle → coalescence growth of crystallite. The crystal habits of X-zeolite are intimately related with crystallization orientation ofβ cage in crystal and with its coupling stability on every crystal face family.     

红辉沸石吸附性能及其在肥料中应用

以不同粒度改型红辉沸石作为复合化肥的添加剂，探讨了其对肥料中有益组分钾元素的吸附行为。结果显示，改型红辉沸石的添加量为10％、粒度为74μm时，能较好地吸附和实现固定钾，使钾缓慢释放，延长肥料的肥效，同时肥料不结块，可提高成球率，降低成本，有利于贮藏，改善土壤环境。     

红辉沸石的耐酸性研究

红辉沸石是辉沸石族矿物中的一种，属正交晶系，化学成分主要为SiO2和Al2O3，其次为CaO。利用化学成分分析和X射线衍射分析等测试手段，深入研究了不同浓度酸处理红辉沸石的主要化学成分及晶体结构变化特征，进而揭示了红辉沸石的耐酸性。研究表明，红辉沸石的耐酸性较差，其酸稳定浓度为约5％，结构完全破坏酸浓度为15％。酸处理后可成为非晶质的高硅质矿物材料。     

Cation exchange resin-catalysed esterification of acetic acid with 2-(1-cyclohexenyl)cyclohexanone

Self-aldol condensation of cyclohexanone yields a mixture of 2-(1-cyclohexenyl)cyclohexanone (I), 2-cyclohexylidenecyclohexanone (II) and subsequent condensation products. An acid-treated clay catalyst was employed to selectively obtain the β γ-unsaturated ketone (I). (I) was separated from the reaction mixture by fractional vacuum distillation and subsequently esterified with acetic acid to synthesise the corresponding ester, 2-(2-cyclohexyl acetate)cyclohexanone, a precursor of [1,1-biphenyl]-2,2'-diol, which has applications in plasticizers, pesticides, as a diluent in epoxy resins, etc. The applicability of cation exchange resins and an acid-treated clay for the esterification of 2-(1-cyclohexenyl)cyclohexanone with acetic acid was explored. This revised version was published online in July 2006 with corrections to the Cover Date.     

酸改性膨润土负载ZnCl2催化松节油直接异构-歧化反应研究

以自制酸改性膨润土负载ZnCl2为催化剂,采用傅里叶红外光谱( FT-IR) 和气相色谱-质谱联用(GC-MS)技术对松节油直接催化异构-歧化液相反应进行研究.FT-IR 分析表明,在反应产物谱图中蒎烯吸收峰3023 cm-1、1653 cm-1和3067 cm-1消失,苯环的骨架吸收峰1645 cm-1 和1456 ...     

A型沸石抗菌剂的体外抑菌性能

以广西天然红辉沸石为原料制备了A型沸石分子筛,采用离子交换法制备二甲酸钾沸石抗菌剂。用X射线衍射、红外光谱对其进行表征分析,证明A型沸石分子筛成功接枝吸附了二甲酸钾。采用试样压片法对A型沸石抗菌剂的抑菌性能进行检测,结果表明：A型沸石抗菌剂对5种菌株均有一定的抑菌效果,其中对大肠杆菌的抑菌作用最强;浓度为0.2～0.3 mol·L^-1的盐酸可有效提高A型沸石抗菌剂的抑菌性能,抑菌圈直径达12.43 mm。     

Acid-treated bentonite-supported Ni catalysts via rapid microwave-assisted drying for nitrobenzene hydrogenation

Acid-treated bentonite-supported Ni catalysts were prepared using a microwave-assisted drying process, characterized and used for the hydrogenation of nitrobenzene to aniline. Microwave-assisted drying of the catalyst reduced the drying time from 3?h with a traditional heating method to 10?min; after drying by microwave irradiation, the acid-treated bentonite-supported Ni catalysts were more stable due to a smaller crystallite size, a higher dispersion of metallic Ni and stronger interactions between Ni and the acid-treated bentonite support than the traditional drying method. Catalytic studies conducted at 300°C with a nitrobenzene liquid hourly space velocity of 3.6?mL?g^?1?h^?1 and a H₂ gas hourly space velocity of 4,800?mL?g^?1?h^?1 indicated that the catalyst prepared using the microwave heating method maintained a nitrobenzene conversion of >99.9% with an aniline selectivity >93% during a 60-h reaction. In addition, the catalyst dried using a traditional method only functioned for 16?h.     

Acid- and base-treated Fe3+-TiO2-pillared clays for selective catalytic reduction of NO by NH3

Fe³⁺-ion-exchanged delaminated pillared clays (PILCs) have been found previously to be more active than the vanadia-based catalysts for selective catalytic reduction (SCR) of NO by NH₃. The effects of acid treatment of the clay (before pillaring) and base treatments of the TiO₂-PILC (before ion exchange) on the activities of the Fe–TiO₂-PILC catalysts were studied. It was found that the acid treatment increased the activity (by 33%), but the base treatments decreased the activity (although they increased the cation exchange capacity of the pillared clay and, hence, the Fe content). The activities of the catalysts were directly related to their surface Brønsted acidities as identified by FT-IR of chemisorbed NH₃.     

Lewis and Brønsted acid catalysis with AlMCM-41 and AlMMS: dependence on exchange cation

Mesoporous solid acid catalysts based on AlMCM-41 and AlMMS have been prepared. The two catalysts exhibit similar unidimensional pore structures with hexagonal symmetries. AlMMS shows less long-range order than AlMCM-41 but is considerably easier to synthesise. The catalytic activities have been measured and compared in the Lewis-acid-catalysed alkylation of toluene with benzyl chloride, and the Brønsted-acid-catalysed alkylation of toluene with benzyl alcohol. Activities have been measured for catalysts ion-exchanged with H⁺, Fe³⁺, Al³⁺ and Na⁺, and following thermal activation at temperatures of 150–350°C. They have also been compared with K10, a mesoporous acid-treated clay catalyst. Results show that the acid-treated clay is the most active of the three catalysts in both reactions. For all catalysts, the Fe³⁺ forms exhibit the highest Lewis acid catalytic activities, and the Al³⁺ and H⁺ forms show higher Brønsted acid activities. Infrared spectra of adsorbed pyridine show relative concentrations of Lewis and Brønsted acid sites consistent with this. Differences in the dependence of catalytic activities on thermal activation temperature are interpreted in terms of the hydration properties of the catalysts.