Adsorption of Acid Blue 193 from aqueous solutions onto Na-bentonite and DTMA-bentonite

Dodecyltrimethylammonium bromide-modified bentonite (DTMA-bentonite) was prepared and tested as an adsorbent for an acid dye (Acid Blue 193, AB193) removal from aqueous solution in comparison with Na-bentonite. The effect of various experimental parameters was investigated using a batch adsorption technique. In this manner, the adsorption isotherms, adsorption kinetics, and temperature and pH effects upon Acid Blue 193 adsorption on Na-bentonite and DTMA-bentonite were thoroughly examined. Results show that a pH value of 1.5 is favorable for the adsorption of Acid Blue 193. The isothermal data could be well described by the Freundlich equation. The dynamical data fit well with the pseudo-second-order kinetic model. The adsorption capacity of DTMA-bentonite (740.5 mg g(-1)) was found to be around 11 times higher than that of Na-bentonite (67.1 mg g(-1)) at 20 degrees C. Thermodynamic parameters such as activation energy (E(a)) and change in the free energy (DeltaG(0)), the enthalpy (DeltaH(0)), and the entropy (DeltaS(0)) were also evaluated. The overall adsorption process was exothermic but it is only spontaneous at 20 degrees C. The results indicate that Na-bentonite and DTMA-bentonite could be employed as low-cost alternatives to activated carbon in wastewater treatment for the removal of color which comes from textile dyes.     

介孔分子筛Ti-AlKIT-1的制备、表征与催化性能

分别采用直接(ds)和后合成法(ps)合成含铝的介孔分子筛Al(ds or ps)KIT-1。 以钛酸四丁酯Ti（OEt）4为钛源,将钛嫁接在AlKIT-1表面制备出Ti-AlKIT-1样品。 用傅里叶变换红外光谱、X射线粉末衍射、固体核磁共振(MAS NMR)、固体紫外 可见漫反射光谱（DRS）、能谱(EDS)和N2吸附-脱附对样品进行了表征,并以双氧水氧化环己醇为探针考察了样品的催化活性。 实验结果表明,分子筛Ti-AlKIT-1具有规整的介孔孔道结构,钛进入介孔分子筛骨架而成为四配位的骨架钛,铝的存在形式与样品AlKIT-1的预处理有关,经铵溶液洗涤的Al(ds)KIT-1中没有非骨架铝。 Ti-AlKIT-1在催化双氧水氧化环己醇反应中铝和钛存在明显的协同作用。 样品Ti-Al(ds)KIT-1表现出更高的催化作用,这与其具有较高的比表面积、较大的孔容和较高钛铝比有关,80 ℃反应48 h,重复使用3次后,环己醇的转化率降低至51.3%,仅下降4.31%。     

静态法和X射线吸收精细结构光谱技术研究腐殖酸对Eu(III)在高庙子膨润土上的吸附影响

膨润土由于其高吸附性和低渗透性而受到广泛的研究. 在本文中, 利用XRD、FTIR和酸碱滴定对我国内蒙古高庙子膨润土进行了详细的表征和分析. 用静态法研究在温度为25± 2 ℃和0.01 mol/L NaClO4溶液中, pH值、腐殖酸、接触时间和Eu(III)初始浓度对Eu(III)在钠基膨润土上的吸附影响. 研究结果表明Eu(III)的吸附受pH值影响明显. 在低pH值条件下, 腐殖酸对Eu(III)的吸附影响微弱, 而在高pH值条件下腐殖酸降低Eu(III)的吸附. X射线吸收精细结构光谱(XAFS)技术对吸附在膨润土上的Eu(III)局域微观结构研究结果表明, 在pH为4.15条件下, Eu在膨润土上与其周围的氧原子间的距离大约为2.39 Å. 本文中的研究结果对于评估其他三价镧系和锕系元素在作为填充材料的膨润土上的吸附和迁移具有重要的意义.     

Adsorption of U(VI) onto the carboxymethylated chitosan/Na-bentonite membranes: kinetic,isothermic and thermodynamic studies

The carboxymethylated chitosan (CMC)/Na-bentonite (Na-Bt) composite membranes were prepared and throughly characterized. The Na-Bt/CMC mass ratio was optimized, and CB10 (membrane with Na-Bt/CMC mass ratio of 10%) was selected as the best membrane for U(VI) sorption. XPS analysis indicates that the main mechanism for UO₂²⁺ sorption onto CB10 is through inner-surface complexation. The sorption kinetics followed pseudo-second order model, indicating the chemisorption as the rate-controlling step. The U(VI) sorption on CB10 is endothermic and spontaneous, with the maximum mono-layer adsorption capacity of 115.6 mg/g at pH 5.0 and 298 K. Finally, the U(VI)-loaded CB10 can consecutively desorbed and reused for several cycles.     

含Co纳米介孔分子筛的制备与表征

用两步水热法合成出了含Co介孔分子筛,采用XRD,FT-IR,TPR,AFM,BET,B JH等方法对样品的物化性能进行了表征.结果表明合成出了纳米级具有介孔结构的CoMCM-41.样品在550℃焙烧可以将模板剂有效去除而不影响孔结构.所得CoMCM-41比表面积大于500 m2/g,平均孔径分布为3.57 nm,粒径分布在20~40 nm范围内.     

Sorption of Eu(III) on GMZ bentonite in the absence/presence of humic acid studied by batch and XAFS techniques

Bentonite has been extensively studied because of its strong sorption ability and low permeability. In this work, the Na-bentonite from Gaomiaozi County (China) has been characterized by XRD, FTIR and acid-base titration. The sorption of Eu(III) on Na-bentonite in the absence/presence of humic acid (HA) was studied at T = 25 ± 2 °C and in 0.01 mol/L NaClO₄ solution. The effects of pH, HA, contact time and initial Eu(III) concentrations were also investigated. The results indicate that the sorption of Eu(III) on Na-bentonite was dependent on pH values. The presence of HA had little effect on Eu(III) sorption at low pH values, but decreased Eu(III) sorption at high pH values. X-ray absorption fine structure spectroscopy (XAFS) was applied to characterize the local structural environment of the adsorbed Eu(III) on bare Na-bentonite and HA-bentonite hybrids. The results indicate that Eu(III) was bound to O atoms at a distance of about 2.39 Å at pH 4.15. The results are crucial for the evaluation of the sorption and migration of other trivalent lanthanides and actinides in bentonite as backfill materials.     

Preparation and investigation on tetradecanol and myristic acid/cellulose form-stable phase change material

In this paper, a novel form-stable phase change material (FS PCM) was prepared by incorporating the eutectic mixture of tetradecanol (TD) and myristic acid (MA) into the hydroxylpropyl methyl cellulose (HPMC). HPMC is used as support material, and the eutectic mixture is used as phase change material. The Fourier-transform infrared spectroscopy (FT-IR), X-ray diffractometer (XRD) and scanning electron microscopy (SEM) were used to study the chemical structure, crystallization behavior and morphology of the FS PCM, respectively. FT-IR, XRD and SEM showed that the TD–MA was distributed uniformly in HPMC by physical interaction. Specific surface area (BET) and pore size analysis determined the pore characteristics of the composite, and the results showed the porosity of HPMC. The thermal properties, thermal stability and thermal reliability were detected by differential scanning calorimetry (DSC), thermogravimetric analysis (TG), thermal cycling test and leakage test. The TG, DSC and leakage analysis results revealed that the absorption of eutectic mixture into HPMC is nearly 50% and without seepage from the composite. The peak temperatures of melting and solidifying were 34.61 and 31.09 °C, and latent heat was 102.11/84.58 J g^?1 by DSC. TG and cycling experiment detected that the FS PCM showed good thermal stability and reliability performance.     

块状壳聚糖多孔支架内交替浸渍沉积磷灰石层

在聚合物支架内沉积羟基磷灰石涂层有望提高支架的生物活性和骨传导性. 本研究采用交替浸渍沉积法, 以块状壳聚糖(Cs)三维多孔支架为沉积模板, 在氯化钙溶液和磷酸氢二钠溶液中交替浸渍, 沉积了羟基磷灰石(HA)涂层. 应用XRD、FT-IR、SEM、孔隙率测试、焙烧法和压缩实验对沉积前后支架的组成、形貌、孔隙率、无机物沉积量以及压缩强度进行了表征. 研究结果表明, 支架上沉积物为低结晶度的碳酸羟基磷灰石, 沿c轴择优生长, 与天然骨中磷灰石类似. 扫描电镜照片显示, 磷灰石在支架孔壁上的沉积量呈梯度分布, 外部沉积量多于内部, 靠近支架表面孔隙部分堵塞, 但内部仍保持连通的孔隙结构. 经6次交替浸渍处理的支架, 孔隙率为94.0%, 羟基磷灰石沉积量达到总质量的13.5%, 压缩强度则由0.055 MPa提高到0.109 MPa.     

One-step synthesis of manganese dioxide/polystyrene nanocomposite foams via high internal phase emulsion and study of their catalytic activity

This paper is devoted to the preparation of manganese dioxide/polystyrene nanocomposite foams via a novel and facile one-step method using high internal phase emulsion as templates. Scanning electron microscopy (SEM), Fourier transform infrared spectrometer (FT-IR), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analyses (TGA) techniques were used to characterize the resulting composites. SEM measurements revealed the porous network structure, the average pore diameters ranged from 3.8 to 30.4 μm. The presence of manganese dioxide was identified by XPS pattern, XRD, pattern and FT-IR spectra of the resulting composites. The TGA thermograms showed that the maximum content of manganese dioxide in the nanocomposite foams reached about 15.5%. The applications of the nanocomposite in the oxidative degradation of methylene blue exhibited good catalytic activity in the presence of H₂O₂ as an oxidant.     

表面功能化的介孔分子筛SBA-3的表征

采用γ-氨丙基三乙氧基硅烷（AM）,通过表面硅烷化反应,对脱模板后的纯 硅六方介孔分子筛SBA-3进行了表面功能化,并通过XRD,TEM,低温N_2吸附, FTIR和吸附染料分子的UV-vis漫反射光谱等对功能化样品的结构、孔性质和表面极 性等进行了详细表征。结果表明,功能分子锚接后,样品的六方结构基本保持。样 品的表面硅羟基由于被消耗而明显减少,导致表面极性降低。另外,由于功能分子 占据了部分孔道空间,样品的孔容、表面积和孔径下降。     

纳米Fe3O4/PVDF磁性复合膜的原位制备及表征

通过膜相渗透原位化学沉积法制备了聚合物基Fe3O4/聚偏氟乙烯（PVDF）磁性纳米复合膜，研究了复合膜制备的适宜条件，采用红外光谱（FT-IR）、差热分析（DSC）、X射线衍射、扫描电镜（SEM）等手段对复合膜的组成、结构进行了表征和分析，通过气体渗透法测定了复合膜的孔径随制备条件的变化情况. FT-IR和XRD图谱结果表明，在基膜中原位生成Fe3O4后不影响基膜PVDF的分子结构；复合膜中的Fe3O4粒子尺寸为68 nm左右，复合膜的磁化率达0.044 cm3•g－1；复合膜的磁化率、平均孔径、最大孔径及孔径分布范围随反应条件的改变而有明显变化.     

介孔二氧化钛的合成及其对甲基橙降解的光催化活性

以十六烷基三甲基溴化铵为模板剂,通过水解钛酸正丁酯合成了介孔二氧化钛分子筛,探讨了合成条件的影响。采用X射线粉末衍射(XRD)、红外光谱(FT-IR)、透射电子显微镜(TEM)和N2吸附-脱附等技术对介孔二氧化钛的晶相、结构、形貌、比表面积和孔径分布进行了表征。实验结果表明:得到的介孔二氧化钛分子筛的孔径为4-4.3nm,用抽提的方法去除模板剂得到的介孔二氧化钛的比表面积比焙烧的要高。以甲基橙为模型污染物,检验了所合成介孔二氧化钛的光催化性质。     

Ni-Fe-B/MCM-41非晶态合金的合成与表征

用化学还原沉积法制备了Ni-Fe-B／MCM-41负载型非品态合金催化材料。通过XRD,FT-IR,TPR,SEM,TG及BET研究了非晶态合金对介孔分子筛载体结构的影响及非晶态合金负载后性质和形态的变化。结果表明：非晶态合金没有破坏介孔分子筛的结构,Ni-Fe-B／MCM-41的热稳定性和氧化能力与Ni-Fe-B相比,均有一定提高。     

Characterisation of organoclays and adsorption of p-nitrophenol: environmental application

Organoclays were synthesised through ion exchange of a single surfactant for sodium ions, and characterised by a range of method including X-ray diffraction (XRD), BET, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM). The change in surface properties of montmorillonite and organoclays intercalated with the surfactant, tetradecyltrimethylammonium bromide (TDTMA) were determined using XRD through the change in basal spacing and the expansion occurred by the adsorbed p-nitrophenol. The changes of interlayer spacing were observed in TEM. In addition, the surface measurement such as specific surface area and pore volume was measured and calculated using BET method, this suggested the loaded surfactant is highly important to determine the sorption mechanism onto organoclays. The collected results of XPS provided the chemical composition of montmorillonite and organoclays, and the high-resolution XPS spectra offered the chemical states of prepared organoclays with binding energy. Using TGA and FT-IR, the confirmation of intercalated surfactant was investigated. The collected data from various techniques enable an understanding of the changes in structure and surface properties. This study is of importance to provide mechanisms for the adsorption of organic molecules, especially in contaminated environmental sites and polluted waters.     

Synthesis, characterization and catalytic behavior of functionalized mesoporous SBA-15 with various organo-silanes

Mesoporous silica SBA-15 has been synthesized and functionalized by one-step synthesis method to widen their various application possibilities. In this study, phenyltrimethoxysilane (PTMS), 3-mercaptopropyltrimethoxysilane (MPTMS) and trimethoxypropylsilane (TMPS) were used as silane precursors for the functionalization, and after treated with HCl solution, their catalytic activities were evaluated in the lactic acid-methanol esterification. The presence of anchoring of functional groups on SBA-15 was proved by XRD, FT-IR, BET surface area and pore size distributions. Good catalytic activity was observed especially for SBA-15-SO(3)H-MPTMS, and the catalytic activity order was determined as follows: SBA-15-SO(3)H-MPTMS>SBA-15-TMPS>SBA-15-PTMS, which is directly associated with the surface area, pore size and pore volume. As compared with homogeneous catalyst, SBA-15-SO(3)H-MPTMS heterogeneous catalyst shows remarkable performance, such as separation, recovery and reusability.     

Incorporation of heteropoly acid,tungstophosphoric acid within MCM-41 via impregnation and direct synthesis methods for the fabrication of composite membrane of DMFC

A heteropoly acid, tungstophosphoric acid (here-in-after TPA) with super acid strength was successfully encaged by two different methods, impregnation and direct synthesis. XRD and FT-IR analyses indicate that significant amount of TPA encaged by impregnation method should have been washed out upon washing treatment for TPA-MCM-41 powder. Due to significant loss of TPA upon washing, TPA was directly synthesized within MCM-41 pore channels using sodium tungstate dehydrate, disodium hydrogenphosphate dodecahydrate and hydrochloric acid. Compared to impregnation method, TPA was more effectively encaged and XRD analyses clearly show that reasonable amount of TPA in TPA-MCM-41 remains even after washing. A uniform distribution of directly synthesized TPA within MCM-41 pore channel was also confirmed by TEM images. In second part of this study, various TPA-encaged MCM-41 powders were used to fabricate composite membranes. For comparison, composite membranes fabricated with calcined MCM-41 and raw TPA, Nafion^® 115 and casting Nafion^® membrane were also prepared.     

苯官能化MCM-41的合成、表征、磺酰化及与二胺的反应

以三乙氧基硅基苯((C₂H₅O)₃Si-Ph，（(triethoxysilyl)benzene，TESB)以及正硅酸乙酯（TEOS）的混合液为硅源，以溴代十六烷基吡啶(CPBr)为模板剂，在HCl介质中合成了苯官能化的有机-无机杂化介孔分子筛MCM-41。对合成的分子筛用FT-IR、PXRD、TEM、N₂吸附-脱附等手段进行了表征。结果表明，合成的苯官能化的有机-无机杂化介孔分子筛具有良好的介孔孔道结构。用三甲基氯硅烷对分子筛表面的Si-OH进行了封端处理，用氯磺酸对合成的苯官能化的有机-无机杂化介孔分子筛进行了磺酰化，并与各种二胺进行了反应。     

YOx -MCM-41介孔分子筛的合成与表征

以十六烷基三甲基溴化铵为模板剂,偏硅酸钠为硅源,硝酸钇为钇源,用水热法合成了YOx-MCM-41介孔分子筛,经X射线粉末衍射法,FT-IR,热重分析,紫外漫反射法及N2吸附-脱附法表征。结果表明,该分子筛具有热稳定性好、比表面积大、孔道均一等典型的MCM-41介孔分子筛的特征。     

乙烯基官能化MSU-X的合成

分别在非离子表面活性剂（AEO9或Tx-15）的存在下,采用共水解缩聚一步合成了乙烯基官能化MSU-X型中孔分子筛（V-MSU-1, V-MSU-2）,并对其合成过程,材料的结构和表面性质进行了比较研究. 乙烯基官能化后, 乙烯基团以共价键的方式与SiO2骨架相连并均匀分布于孔道表面, 改善了分子筛孔道的疏水性能.不同的模板剂及前驱体中有机官能基的含量对V-MSU-X孔道特征、表面和织构性能有一定的影响.     

AlOOH在一氧化碳加氢反应中结构与性能的研究

采用沉淀水热法,通过调变水热过程中水与凝胶的质量比制备了不同的AlOOH,将其与工业甲醇催化剂C302混合形成复合催化剂,考察复合催化剂对一氧化碳加氢的影响,同时运用XRD、FT-IR、BET、NH_3-TPD-M S、TG-DTG和H_2-TPR等技术对不同AlOOH进行了表征。结果表明,水热过程中水与凝胶的质量比对AlOOH择优取向晶面、孔结构、表面酸强度等存在明显影响,进而导致复合催化剂产物中出现分布不同的低碳醇或二甲醚。其中,当水和凝胶的质量比为2∶1时,AlOOH的(020)和(120)晶面择优取向,孔容增大,且其表面具有适宜的强弱酸比例中心,复合催化剂呈现出较高的低碳醇选择性,表明AlOOH具有碳链增长的作用,这为合成气制取低碳醇催化剂提供了新的思路。