焙烧态镁铝水滑石对刚果红的脱色性能研究

采用单滴法合成了n(Mg)/n(Al)=3的镁铝水滑石Mg3Al-LDH及其焙烧态产物Mg3Al-CLDH,并对刚果红溶液进行了吸附脱色试验。XRD分析结果说明合成的Mg3Al-LDH样品具有水滑石的典型结构,Mg3Al-CLDH在吸附刚果红阴离子后重新恢复为水滑石的层状结构。相同条件下Mg3Al-CLDH对刚果红的脱色率高于Mg3Al-LDH。对质量浓度为100mg/L的刚果红溶液,当Mg3Al-CLDH投加量为0.7g/L,pH值为5～10时,室温下反应40min,脱色率可达99%以上。Mg3Al-CLDH重复再生4次循环利用,刚果红脱色率仍在90%以上。表明Mg3Al-CLDH能够有效吸附溶液中的刚果红阴离子,可用于水体中阴离子染料的脱色处理。     

对苯乙烯磺酸钠修饰水滑石／丁苯橡胶复合材料的制备与性能研究

利用共沉淀法合成了硝酸根型水滑石（NO3-HT）,将其与对苯乙烯磺酸钠（SSS）进行离子交换,制备对苯乙烯磺酸钠修饰的水滑石（SSS—HT）。用红外光谱（IR）、X-射线衍射（XRD）、热重分析（TGA）对水滑石的结构和性能进行了表征。结果表明,经对苯乙烯磺酸钠修饰后的水滑石层间距由硝酸根型水滑石的0．8nm扩大到了1．88nm．对苯乙烯磺酸钠型水滑石的热稳定性有所提高。将其与丁苯橡胶（SBR）混炼。制备水滑石／橡胶复合材料。用红外光谱、硫化仪、力学性能测试仪及热重分析对其结构与性能进行了研究。实验结果表明,随着水滑石含量的增加,SBR／水滑石复合材料的焦烧时间和正硫化时间逐渐缩短且经过有机修饰的水滑石变化幅度更大,同时水滑石的加入也提高了橡胶的热稳定性和力学性能。     

钼、钨类水滑石材料的合成、结构及催化环氧化性能

通过与大体积的有机阴离子对甲基苯磺酸根预柱撑的镁铝类水滑石(HTL)进行离子交换,制备了不同层间离子交换量(W/Al摩尔比和Mo/Al摩尔比分别为7:6,7:20,7:60)的钨、钼-类HTL催化材料,并用IR、UV-Vis、PXRD、SEM、TGA、XPS等表征结构.以H2O2为氧化剂,氯丙烯为底物,初步考察了W、Mo-HTL催化氯丙烯环氧化性能.结果表明,随着负载量的增大,有机阴离子红外吸收峰的强度随之减弱,钨、钼物种对应的红外吸收峰增强,证实层间有离子交换作用发生.钼-HTL中钼呈多种配位状态:钨-HTL中,仅当负载量比较高的时候,钨-HTL中钨呈现多种配位形态.材料系层状结构,随钨、钼量的增加,层间距有不周程度的增大.实验条件下,钨、钼-HTL对氯丙烯环氧化均有活性,钨-HTL比钼-HTL的活性高;对于W、Me-HTL,较高选择性分别为85.2%和77.3%,双氧水转化率为41.2%～94.3%.材料中多种配位形态存在,可致使H2O2有效利用率降低.     

锌锰铝复合氧化物制备及其催化性能

采用共沉淀法合成了锌锰铝类水滑石前驱体,经过焙烧处理后制备了锌锰铝复合氧化物,用于催化H2O2氧化分解亚甲基蓝,探讨了H2O2用量、亚甲基蓝初始质量浓度、催化剂用量和反应时间对降解脱色率的影响。实验表明,在H2O2质量分数为3%,亚甲基蓝初始质量浓度为25 mg/L,催化剂用量为1.0 g/L,反应时间为4 h时,亚甲基蓝平均脱色率可达到92.23%。     

马来酸酐酰化β-环糊精柱撑Zn/Al-CO_3型水滑石的制备及表征

通过酯化反应合成马来酸酐酰化β-环糊精(β-CD),采用成核/晶化隔离法制备了Zn/Al水滑石(LDHs),并以水滑石为前驱体,用返混法进行插层组装合成马来酸酐酰化β-CD柱撑Zn/Al水滑石,利用XRD、FTIR对其结构进行表征。结果表明,利用返混法进行插层组装,可以成功的将马来酸酐酰化β-CD阴离子插入Zn/Al水滑石层间,其层间距由原来的0.76 nm增大为3.43 nm。     

机械力化学制备锡酸锌及其在PVC中的阻燃应用

以二氧化锡（SnO₂）和氧化锌（ZnO）为原料,通过机械力化学湿法球磨,制备了锡酸锌（ZS）,再与水滑石按一定比例研磨得到锡酸锌改性的水滑石（ZS/HT）。通过扫描电子显微镜、X射线衍射、透射电子显微镜对合成的ZS与ZS/HT做了表征。将制得的ZS/HT应用于PVC制得阻燃PVC样品,当加入10%（ZS与水滑石的质量比）ZS/HT时材料的极限氧指数比纯PVC样品高3.5%,同时材料的力学性能有所增加。热重分析结果表明,ZS/HT的加入促使PVC提前分解成炭,有效提高PVC材料的残炭量。     

乙二胺双马来酰胺酸根合镧(Ⅲ)-层状矿物复合热稳定剂对聚氯乙烯的热稳定作用

利用稀土配合物具有较强协同作用的优点,将自身对聚氯乙烯(PVC)具有一定热稳定作用的乙二胺双马来酰胺酸根合镧(Ⅲ)配合物(LaL)与层状矿物,如高岭土、蒙脱土、水滑石和水镁石进行复配,通过热重分析、刚果红试验和静态烘箱老化法研究了乙二胺双马来酰胺酸根合镧(Ⅲ)与高岭土、蒙脱土、水滑石和水镁石复合物对PVC热稳定性的影响。结果表明,乙二胺双马来酰胺酸根合镧(Ⅲ)与层状矿物具有良好的协同效应,且与水镁石效果最为显著,当二者质量比为1∶1时,PVC热稳定时间由2 min提升至70 min,且能有效地抑制单一稀土热稳定剂使用时的初期着色能力。复合热稳定剂的添加大幅度提高了PVC热降解的活化能,尤其是LaL-水镁石复合物(LaL-Brucite)的添加,N_2气氛下的活化能相对于纯PVC样品,由123.5 kJ/mol提升至234.7 kJ/mol,提高了111.2 kJ/mol;空气气氛下的活化能相对于纯PVC样品,由115.9 kJ/mol提升至133.0 kJ/mol,提高了17.1 kJ/mol;有效地提高了PVC的热稳定性。     

N-十四烷基甘氨酸柱撑水滑石的制备、表征及在环氧胶粘剂中的应用

采用共沉淀法成功制备了N 十四烷基甘氨酸柱撑水滑石(简称N LDH)Mg4Al2(OH)12[C14H29NHCH2COO],并用XRD、FTIR对样品进行表征。结果表明,C14H29NHCH2COO-可进入水滑石层间,N LDH具有良好的层状结构,其层间距由0 759nm增加到2 418nm;实验结果表明,在E44/T31环氧胶粘剂体系中加入N LDH可有效改善其力学性质,当w(N LDH)=5%时,拉伸剪切强度提高了53 7%。     

Phenoxymethylpenicillin–intercalated hydrotalcite as a bacteria inhibitor

Phenoxymethylpenicillin (PMP) has been reversibly intercalated into a layered double hydroxide, and the resulting composite exhibits effective anti‐bacterial activity. Powder X‐ray diffraction studies indicate that the PMP molecules are interdigitated between the inorganic layers, and under mild acidic media, the molecules are released gradually. Therefore a sustained‐release anti‐bacterial medication is envisioned on the basis of this inorganic–drug composite. Copyright © 2005 Society of Chemical Industry     

Methanol Decomposition to Synthesis Gas Over Supported Pd Catalysts Prepared from Hydrotalcite Precursors

Supported Pd catalysts were prepared by solid-phase crystallization (spc) starting from MgAl hydrotalcite anionic clay minerals as the precursors, and were tested for the methanol decomposition to synthesis gas. The precursors based on [Mg₆Al₂(OH)₁₆CO₃ ^2-] · 4H₂O were prepared by coprecipitation from raw materials containing Pd²⁺, Mg²⁺ and Al³⁺ ions as the components of hydrotalcite. The precursors were thermally decomposed and reduced to afford supported Pd catalysts on MgAl mixed oxide. Pd-supported catalysts as a reference were also prepared by the impregnation (imp) method. The spc-Pd catalysts thus prepared afforded highly dispersed Pd metal particles and showed higher activity as well as lower activation energy than the imp-Pd catalysts. When the precursor was prepared under mild conditions, finer particles of Pd metal were formed over the catalyst, resulting in a high activity. In the case of spc-Pd catalysts, carbon monoxide adsorbed on Pd easily desorbed, compared with imp-Pd catalysts. It is likely that the high activity is due to the highly dispersed and stable Pd metal particles and the easy desorption of carbon monoxide.