Adsorption of Environmental Pollutants on Pillared Montmorillonite

Both inorganic and organic pillared montmorillonites were used to adsorb phenol. Batch kinetics and isotherm studies were carried out to evaluate the effect of equilibrium time and pH on adsorption of phe- nol by montmorillonites and re-adsorbing characteristics of pillared montmorillonites. The adsorption of phenol increased with increasing solution pH values. The elimination ratio of phenol from the solution by the absorption of organic modified pillared montmorillonite (OrPMt) reached equilibrium quickly after vibrating for 5 minutes. Meanwhile for organic montmorillonite (OrMt), pillared montmorillonite (PMt) and montmorillonite (Mt), the time to reach phenol-absorption equilibrium were 20, 30 and 90 minutes, respectively. The adsorbing capacity of the pillared montmorillonite modified with surfactant improved greatly. The phenol-adsorbing capacity of pillared molltmorillonites mainly depended on microporous structure and surface component of the modified clays. After calcination at 500 ℃, the pillar structure and the basal spacing (1.83 um) were still stable. So the pillared montmorillonite could be recycled, and it was a potential material for adsorbing environmental pollutants.

Preparation and Microstructure of Al-pillared Interlayered Montmorillonite

Al-pillared interlayered montmorillonite (Al-PILM) was prepared using the artificial Na-montmorillonite from the Qingfengshan bentonite mine as a starting material mixed with Al-pillaring solutions.The microstructure of the materials was studied by an X-ray powder diffractometer and a Fourier transform infrared (FTIR) spectrometer.The results indicated that the basal spacing [d(001) value] of the materials was increased significantly to 1.9194 nm relative to Na-montmorillonite (1.2182 nm).After calcined for 2 h at 300℃,the basal spacing was stabilized at 1.8394 nm and the layered structure of the materials was not destroyed.Thermal analysis was conducted by a thermal gravimetry and differential thermal analysis (TG-DTA) instrument,it showed that Al-PILM lost physically adsorbed water below 230.6℃ and water formed by dehydroxylation of the pillars at around 497.1℃, with a peak of the phase transformation at 903.0℃.

Synthesis and Characterization of Al-Cr-Pillared Montmorillonite with High Thermal Stability and Adsorption Capacity*

Al-Cr-pillared montmorillonite was synthesized by using bentonite and Al-Cr pillaring solutions as starting materials.The basal spacing and specific surface areas of the materials were significantly increased relative to those of untreated clays.When the Al/Cr molar ratio(R) was 0.10,the d(001) value and specific surface area of pillared montmorillonite were 1.9194 nm and 165.7 m2 g -1,respectively.Thermal stability of the materials was determined using calcined tests and X-ray diffraction (XRD) analysis.The materials formed at different R(0.05;0.10;0.15;0.25) exhibit a high thermal stability at 300℃,especially at initial R=0.10,the basal interlayer spacing of materials is stabilized at 1.7313 nm after calcined at 500℃ for 2 h.Adsorption behavior of the materials was studied by adsorption experiments.The results show that the Al-Cr-pillared montmorillonites exhibit much stronger adsorption capacity on Cr 6+ in aqueous solution than untreated clays do.

Effects of Layer Change and Chemical Composition on Thermal Stability and Catalytic Activity of Pillared Montmorillonite

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Preparation and Properties of Pillared Montmorillonite by Polyhydroxyl-aluminum-manganese Cations

Al-Mn-pillared montmorillonite(AMPM) was prepared by using the artificial Na-montmoril-lonite from the Qingfengshan bentonite mine as starting materials mixed with Al-Mn pillaring solutions at different Al/Mn molar ratios (R). The basal spacing and specific surface area of the materials were increased significantly compared with untreated clays. When R = 0.5, the d (001) value and specific surface area of pillared montmoril-lonite were 1.8987 ran and 146.01 m2 g-1, respectively. The thermal stability was determined using calcined tests , X-ray diffraction ( XRD ) analysis, thermal gravimetry and differential thermal analysis (TG - DTA). The materials formed at initial R = 0.5 exhibited a high stability, the basal interlayer spacing was stabilized at 1.7859 nm after calcined for 2 h at 300℃. The adsorption behavior of the materials was studied by adsorption experiments. The results show the AMPM and calcined Al-Mn-pillared montmorillonite ( CAMPM) exhibit a strong capacity of adsorbing the Zn(Ⅱ) in aqueous solution at pH 10.0.

Gallery-templated Synthesis of Titanium/Silicon-containing Mesoporous Montmorillonite-based Catalytic Materials

A mesoporous titanium/silicon -containing montmorillonite-based catalytic materials has been synthesized by novel gallery-templated techniques. XRD, SEM, framework IR, and N2 adsorptiondesorption isotherms provided evidence of the formation of Si/Ti pillars. The synthetic materials show potential catalytic application for hydroxylation of phenol with peroxide.

Dehalogenation of Aryl Halides Catalyzed by Montmorillonite Immobilized Bimetal Catalyst in Aqueous System

A novel bisupported bimetal catalyst PVP-PdCl2-FeSO4/Al-Mont-PEG600 was prepared by immobilization of PVP （poly （N-vinyl-2-pyrrolidone）） supported bimetallic catalyst using alumina pillared inartificial montmorillonite as the carrier. This catalyst has good dehalogenation activity and selectivity to aryl halides o-chlorotoluene in aqueous system in the presence of phase transfer catalyst （PEG） and sodium formate as hydrogen source. The catalyst also shows good reusability.

Structure and Catalytic Activity of Nickel-substituted Mica- montmorillonite Clay Crosslinked with NH2(C3H3)Si(OC2H5)2

Nickel-substituted mica-montmorillonite clays(Ni-SMM) were synthesized, the pillared clays, Si-Ni-SMM, were prepared from the Ni-SMM intercalated with NH2(C3H5)Si(OC2H5)3.The pillar perhaps consists of tripolymer of silica according to the judgement from the pillar height (8. 5A ) data. The results of IR, ESR and XRD indicate that the hydroxy group in the octahedral layer is attacked by crosslinking agent. Thus the silicon oxide pillars become directly linked via oxygen to the nickel atoms in the octahedral layer. The change of the ratio of Lewis to Bronsted acidity on Si-Ni-SMM reduced at 400℃ by H2 shows that the hydrogenating component such as Ni in the framework of SMM plays an important role in catalyst deactivation in H, atmosphere. This kind of action may be due to spilled- over hydrogen.

Cr-Al、Fe-Al、La-Al柱撑蒙脱石的制备及其吸附特性

以天然钠基蒙脱石为原料,按n(总金属阳离子)/m(蒙脱石)=10 mmol/g的比例制备出Fe-Al、Cr-Al和La-Al柱撑蒙脱石;采用化学元素分析、X射线衍射分析、红外光谱分析等手段对柱撑蒙脱石进行表征;并研究3种柱撑蒙脱石对水中Cu2+离子的吸附性能及其影响因素。结果表明:Cr-Al柱撑蒙脱石层间距d(001)由原矿的12.406 1 nm增大到19.764 9 nm,柱撑效果优于Fe-Al和La-Al柱撑蒙脱石,Cr-Al柱撑蒙脱石在60℃、pH值为6、时间为12 h的条件下,使用12.0 g/L的添加量吸附Cu2+离子,去除率最高,吸附效果优于Fe-Al和La-Al柱撑蒙脱石。

微波辅助Cr-Al柱撑蒙脱土催化降解亚甲基蓝

采用区别于传统水浴加热法的微波辅助加热法合成聚合羟基阳离子,在微波的条件下把Cr(3+)和Al(3+)缓慢加入到Na_2CO_3溶液中制备出Cr-OH、Al-OH、Cr-Al-OH聚合羟基阳离子,并制备出不同Cr(3+)/(Cr(3+)+Al(3+))比值的柱撑蒙脱土。借助X射线粉末衍射(XRD)、傅立叶红外光谱(FTIR)等手段对结构改变进行表征。在微波辅助条件下通过改变柱撑蒙脱土用量、染料初始质量浓度、振荡时间来探究铬铝柱撑蒙脱土对亚甲基蓝印染污水的最佳吸附性条件。结果表明:铬铝聚合羟基阳离子柱撑蒙脱土的层间距增大,同时表面增加了大量活性-OH基团,使蒙脱土对亚甲基蓝去除率高达97.74%。

Arrangement models of alkylammonium cations in the interlayer of HDTMA^+pillared montmorillonites

The orientation of HDTMA+ in the interlayer of organic pillared montmorillonites prepared at different concentrations of HDTMA+ have been studied using X-ray powder diffraction (XRD) and theoretical calculation. A series of arrangement models of HDTMA+ in the interlayer of montmorillonite have been proposed as lateral-monolayer (LM), lateral-bilayer (LB), pseudotrilayer (PT), paraf-fin-type-monolayer (PM), paraffin-type-bilayer (PB). With the increase of the concentration of HDTMA+, the arrange-ment model of HDTMA+ in the interlayer of montmorillo-nites changes as lateral-monolayer→lateral-bilayer→para- ffin-type monolayer→pseudotrilayer→paraffin-type-bilayer and the packing density of HDTMA+ in the interlayer in-creases gradually. In the intermediate stages, different mod-els may coexist.

Influence of Drying and Calcination on Remaining Amount and Immobile Character of Titanium on Titanium-pillared Montmorillonite

Remove of titanium （Ti） from titanium-pillared montmorillont （TIPM） is not expected during its application as adsorbent and photocatalyst, etc. But studies on immobilization of Ti on TIPM are seldom reported. In this work, TIPM was synthesized from TIC14 and Na＋-montmorillont （Na＋-MMT）. Then the prepared TIPM was heated at different temperatures （100, 240 and 450 ~C） to yield three TIPM samples （TIPM1, TIPM2, and TIPM3）. Inductively coupled plasma optical emission spectrometer （ICP-OES） was used to determine the effect of heating temperature on the remaining amount of Ti on TIPMs. A two-step treatment method which is often used in the pretreatment and application of TIPM was developed to investigate the immobile character of Ti on TIPMs. X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FT-IR）, N2 adsorption/desorption isotherm, thermogra- vimetric analysis and differential scanning calorimetry （TG-DSC） were also used to characterize TIPMs before and after the treatment. The results show that with an increase in heating temperature, the amount of Ti species re- mained on T1PM decreases gradually and Ti immobilization is strengthened on TIPM. For TIPM3, less than 2% Ti is removed from TIPM3 after the treatment required to simulate the practical conditions of TIPM in its application, while those of TIPM1 and TIPM2 are 6.6% and 8.4%, respectively. The reason may be that when TIPM is heated, Ti species intercalated into MMT become chemically bonded with the framework of MMT and partially migrate into the layer structure, which make Ti immobile on TIPM firmly during the treatment process.

Cr-Al柱撑蒙脱石对矿坑水中重金属离子的吸附试验研究

针对某露天矿矿坑水中重金属离子含量较高的特点,采用天然钠基膨润土制备Cr-Al多金属复合柱撑蒙脱石,并开展了对矿坑水中重金属离子的吸附试验研究,探讨吸附时间、Cr-Al柱撑蒙脱石添加量、溶液pH值等3种因素对重金属离子去除率的影响,确定了Cr-Al柱撑蒙脱石对矿坑水中重金属离子吸附处理的最佳反应条件及去除率。研究表明:Cr-Al柱撑蒙脱石能够与矿井水中重金属离子Zn^2+、Cu^2+、Pb^2+发生离子交换反应,当设置反应时间为10h、溶液pH值为6、采用80~100目Cr-Al柱撑蒙脱石添加量为10.0g/L时,重金属离子Zn^2+、Cu^2+、Pb^2+的去除率分别达到83.9%、84.2%、84.4%,去除率最大,吸附效果最佳,为该露天矿矿坑水处理和再利用提供参考。

Facile Synthesis of Al-pillared Mesoporous Montmorillonite Assisted with Concentrated Al13 Solution

Al-pillared mesoporous montmorillonite was facilely synthesized from concentrated Al13 solution obtained by vacuum concentrating-ultrasonic pillaring strategy.Concentrated Al13 solution could reduce the process of pillare and increase pillaring efficiency.The absolute value of layer distance could be increased by 0.96 nm via concentrated Al13 solution pillare.27Al NMR indicates that Al Keggin ions of concentrated Al13 are arranged in a more regular way by vacuum concentrating method.The Al-pillared mesoporous montmorillonite from concentrated Al13 solution has bigger specific surface area and even pore size distribution which were characterized by X-ray diffraction（XRD） and nitrogen adsorption measurement.Furthermore the catalytic activity of Ai-pillared montmorillonite loaded Ni and Mo catalysts was tested by the hydrodesulfurization of thiophene.The thiophene conversion reached 77.5％,which was higher than the corresponding value reported in the literature.

羟基Fe-Al、Cr-Al柱撑蒙脱石的制备及热稳定性研究

本研究采用钙基蒙脱石成功地制备了羟基Fe-Al,羟基Cr-Al柱撑蒙脱石。柱撑蒙脱石的层间距达到19 ,比表面积310m2/g ;层间域空间热稳定性可达700℃。文中对柱撑蒙脱石的制备条件、酸性的起因 。

无机-有机柱撑蒙脱石对苯酚的吸附

分别用无机有机改性柱撑蒙脱石对苯酚进行吸附试验，研究它们吸附苯酚的适宜条件及吸附等温线（２５℃）。结果表明，用表面活性剂改性的柱撑蒙脱石，能大幅度提高对苯酚的吸附能力。柱撑蒙脱石对苯酚的吸附能力主要取决于改性粘土吸附剂的微孔结构和表面组分，而不仅仅依赖于表面积。经５００℃高温灼烧后柱撑蒙脱石柱结构及层间距（１．８３ｎｍ）稳定，因而柱撑蒙脱石可再生循环使用。

不同链长烷基季铵离子在蒙脱石层间域内排列方式的对比

选用含不同烷基长链的三种季铵盐——十二烷基三甲基溴化铵(DDTMAB)、十四烷基三甲基溴化铵(TDTMAB)、十六烷基三甲基溴化铵(HUTMAB),对河北钠交换蒙脱石进行了有机柱撑实验,以X射线衍射分析方法对实验产物进行了对比研究。结果表明,由于烷基链中所含的碳原子数目不同,三种长链季铵离子对蒙脱石的柱撑效果不同,DUTMA^+在蒙脱石层间域内可形成平卧单层、平卧双层和假三层三种不同排列方式;TDTMA^+与DDTMA^+在低浓度条件下形成的前两种排列方式相同,而第三种则不同,为倾斜单层排列;HUTMA^+有机柱撑产物中除了具有前两者的排列方式外,还具有倾斜双层排列方式。不同排列方式的复合产物可以多相共存。此外,随着柱撑剂浓度的增加,三种长链烷基季铵离子在蒙脱石层间域内的排列方式及其演化是不同的。

介孔硅层柱蒙脱石材料合成的新方法与表征

利用十六烷基三甲基溴化铵 (CTAB)将天然钠基蒙脱石改性成有机蒙脱石 ,以十二烷胺为模板剂 ,正硅酸乙酯为层柱前驱体 ,在室温下合成了新型介孔硅层柱蒙脱石材料 .用 XRD,TG,FTIR以及 N2 等温吸附 -脱附等技术对产物进行了表征 .结果表明 ,合成材料具有大通道 (净层间距为 2 .75 nm)、介孔孔径且孔分布窄 (平均孔径为 2 .1 7nm)、比表面积高 (SBET=82 1 .6 m2 /g)、热稳定性高 (大于 80 0℃ )等特征 .同时 ,通过改变中性胺的链长 ,研究了孔结构的调变规律 ,分析了材料的成孔机理和热稳定性提高的原因 .

柱撑蒙脱石的微结构变化研究

制备了柱撑蒙脱石，并运用^(27)Al核磁共振谱等技术对柱化溶液中的Al的状态进行了研究，运用X射线定向衍射技术、红外光谱、差热、热重分析及原子力显微镜等技术对往化粘土中Keggi结构的作用及热稳定性进行了研究.结果表明，AlCl3溶液在［OH－］／［Al^(3+)］＝2．4时水解生成的Kegin离子最多.柱撑蒙脱石层间距在自然状态下为2．53um，300℃灼烧后层间距稳定在1．83um，具有较好的热稳定性．

柱撑蒙脱石制备与表征

本文采用多种方法制备keggin离子，并探索出制备稳定keggin离子的适宜酸碱度，用此柱化剂制备出层间距为2．4～2．5nm的柱撑蒙脱石。应用X射线走向衍射技术、红外光谱、差热分析对往撑蒙脱石进行表征，用BET、吡啶吸附考察了其表面物理化学性质。结果表明，用Keggin离子制备出的柱撑蒙脱石其层间距在自然状态下为2．4～2．5nm，350C灼烧，层间距稳℃定在1．8nm，且具有耐热性能好、较大的比表面积和较强的Lewis酸位中心等特点．