天然沸石基微介孔复合催化剂的制备及其油砂沥青减黏改质性能

利用水热稳定性高的天然斜发沸石为铝源,水玻璃为硅源,Na OH为碱源,十六烷基三甲基溴化铵为模板剂,稀硫酸调节p H,再经过老化、晶化、烘干和焙烧等制备具有微介孔复合结构、良好水热稳定性和高比表面积的clin/MCM-41催化剂。将p H=10和硅铝物质的量比100条件下制得的催化剂应用于蒸汽辅助重力泄油技术开采的加拿大油砂沥青改质反应。在剂油质量比1∶10和310℃反应30 min条件下,减黏率超过90%,同时大量胶质和沥青质非烃被催化裂化为轻质油,表明clin/MCM-41催化剂是优异的油砂沥青中低温减黏催化剂。     

斜发沸石水热固化机理的探讨

采用水热法对斜发沸石进行固化,研究了水热固化时间及加水量等因素对沸石性能的影响。利用X射线衍射分析和傅里叶变换红外分析手段,探讨了斜发沸石的水热固化机理。结果表明成型压强30 MPa、钙硅比为0.8、加水量为10%、200 ℃水热固化12 h时,斜发沸石抗折强度达到最大,机理分析表明斜发沸石水热固化强度的增大是源于托勃莫来石晶相的逐渐结晶长大。     

斜发沸石的水热合成和离子交换性能及其在CH4/N2分离中的应用

以氢氧化铝为铝源,硅溶胶为硅源,通过水热法合成斜发沸石,采用XRD、TEM、BET、FT IR、TG、29Si NMR 等手段考察了OH-/Si的摩尔比、晶化时间和晶化温度等合成参数对其结构和CH4/N2分离性能的影响。基于晶化动力学曲线,由阿伦尼乌斯方程导出诱导期和生长阶段的表观活化能值,分别为915和72 kJ/mol。通过水溶液离子交换工艺分别获得Ca型或K型斜发沸石,并初步探讨了离子交换前后斜发沸石对CH4/N2的分离性能。结果表明,斜发沸石对CH4/N2的平衡选择性依赖于交换阳离子电荷类型,数量及其在骨架中的分布,其中K型斜发沸石分离效果较好,有望用于煤层气回收。     

斜发沸石中Ag+-Na+离子交换实验研究

本研究以河南信阳斜发沸石为原料,首先对河南斜发沸石进行了Na化改型,通过液相离子交换法,探讨斜发沸石中Ag -Na 离子交换特征。讨论在不同反应温度、时间、溶液浓度、pH值、静止与震荡等条件对沸石载银量的影响。实验结果表明,制备载银斜发沸石的最佳实验条件为,AgNO3的初始浓度为0.1mol/L、反应液的pH值为6.0～8.0、反应温度为60℃、在震荡的条件下反应4h时,斜发沸石具有最大的银离子交换量。     

沸石离子交换的研究现状及发展趋势

本文在分析沸石结构的基础上，讨论了国内外沸石离子交换的研究现状，探讨了沸石离子交换的几种方法及影响离子交换的各种因素，并对沸石离子交换的应用研究方向进行了展望。     

沸石法苦卤提钾工艺研究

以改性斜发沸石为离子交换剂,采用离子交换技术,做了以氯化钠溶液为洗脱剂的苦卤提钾工艺研究。单柱实验表明,洗脱温度越高、洗脱剂浓度越大以及适当流速时有利于钾富集。吸附采用模拟移动床流程,进料顺序为“低段溶液-苦卤”,钾平均吸附率可达95%以上;洗脱采用固定床流程,进料顺序为“高段溶液-中段溶液-低段吸后溶液-25%（质量分数）NaCl溶液”,得到氯化钾平均质量浓度为35.39 g/L的富钾卤水,较苦卤钾浓度提高2.7倍。在钾富集同时,苦卤中的镁、硫酸根等杂质离子亦得到了有效去除,为实现苦卤高效节能提钾奠定了基础。     

天然斜发沸石的改性及其对海水中K~+吸附交换容量的研究

为提高天然斜发沸石对海水中K+的吸附交换容量,对天然沸石进行了电炉、微波和超声波加热物理改性以及微波化学改性研究。重点考察了不同微波功率和处理时间时盐改性以及不同微波化学改性条件下所得沸石对海水中K+的吸附交换容量,同时对不同改性沸石的晶体结构进行了XRD表征。结果表明,天然斜发沸石经微波盐改性后对海水中K+的吸附交换容量有所提高,并随微波处理功率的增加和时间的延长而增大;经微波化学改性后吸附交换容量显著提高,可达0.71mmol/g;各种改性方式未对沸石的结构构成破坏,所得改性沸石的晶体结构基本相似。     

MnOx改性的斜发沸石及其在油墨废水净化中的应用

目的 研究一种具备吸附和降解作用的催化剂,进而更高效地净化处理油墨废水。方法 通过氧化还原沉淀法对天然斜发沸石进行MnOx改性,并研究天然斜发沸石和MnOx改性的斜发沸石对油墨废水进行净化处理。考察MnOx改性斜发沸石的晶型、孔结构和形貌,系统地研究处理时间和处理温度对油墨废水COD和色度去除率的影响规律。结果 MnOx改性的斜发沸石保持了斜发沸石的晶型结构和形貌,具有更高的比表面积、孔容量,以及更宽的孔径分布。结论 在最佳的处理条件下,与天然斜发沸石相比,MnOx改性斜发沸石具有更高的去除性能,在20 ℃下对油墨废水处理15 min,其COD和色度去除率分别可以达到98%和99%以上。     

Ammonia Removal from Aqueous Solutions by Iranian Natural Zeolite

Abstract

The capability of Iranian natural clinoptilolite for ammonia removal from aqueous solutions has been thoroughly studied. Both batch and continuous (column) experiments were carried out. The viability of this natural zeolite in reducing the leakage of ammonia to the environment through waste water streams was a main focus of this research. Through the batch experiments, the effect of process variables such as the size of zeolite particles, pH, and ammonia concentration of the feed solution on the kinetics of ammonia uptake were investigated. Ammonia removal occurred rapidly and within the first 15 minutes of contact time, a major part of ammonia was removed from the solution. An adsorption capacity about 17.8 mg NH₄ ⁺/g zeolite at feed ammonia concentration of 50 mg/L was obtained and the optimum range for pH was achieved about 5.5–7.6. The adsorption capacity of clinoptilolite in the continuous mode was about 15.16 and 15.36 mg NH₄ ⁺/g zeolite for the original and regenerated types of clinoptilolite, respectively, where feed ammonium concentration was 50 mg/L. Increasing the feed ammonium concentration to 100 mg/L did not reduce the capability of the column for its ammonium removal and up to a bed volume (BV) of 85, there was only less than 1 mg/L ammonium in the column outlet. Presence of cations such as Ca²⁺, Mg²⁺ and Na⁺ in the feed solution reduced the clinoptilolite adsorption capacity to about 11.68 mg NH₄ ⁺/g zeolite. Regeneration experiments were carried out using concentrated sodium chloride solutions, as well as tap water. Where tap water was used as the regenerant, gradual release of ammonium from exhausted clinoptilolite was observed.     

Biosorptive Behavior of Aerobic Biomass Biofilm Supported on Clinoptilolite Zeolite for the Removal of Copper

The aim of this study was to determine the behavior of aerobic biomass biofilm supported on untreated clinoptilolite zeolite in the biosorption process to reduce the concentration of copper from synthetic solutions. A systematic study in batch and continuous systems was carried out. In addition, biomass and zeolite were characterized before and after biosorption treatment by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). According to results, zeolite only acts as a support for biomass and the study of SEM and EDS indicated that copper was absorbed by bacteria that are present on the surface of the zeolite. This study showed that untreated zeolite clinoptilolite acts as a support material for biomass during copper removal, and it may be an alternative of great interest for the immobilization of biomass in the restoration process of sites contaminated with heavy metals.