热活化温度对坡缕石结构及饱和离子交换吸附量的影响

采用X射线衍射(XRD)、Fourier红外吸收光谱(FT-IR)、扫描电子显微镜(SEM)分析了热活化坡缕石晶体结构及显微形貌,并采用zeta(ζ)电位分析仪、比表面积分析仪及原子吸收光谱仪(AAS)测定了热活化坡缕石的zeta电位、比表面积及饱和Cu2+交换吸附量。结果表明热活化温度对坡缕石zeta电位无显著影响。当热活化温度低于250℃时,坡缕石脱出吸附水及部分配位水,比表面积显著增大,但晶体结构无明显变化;热活化温度为350～650℃时,坡缕石将脱出配位水和结构水,并发生"折叠作用",使得坡缕石表面活性中心增加,至750℃时晶体结构完全破坏,而比表面积则随热活化温度的升高依次降低。坡缕石饱和Cu2+交换吸附量仅与热活化温度密切相关,当热活化温度为450℃时,坡缕石饱和Cu2+交换吸附量最大。     

以坡缕石为原料制备方沸石

以江苏盱眙坡缕石为原料,经提纯后分别采用直接碱溶法、模板剂法、溶胶-水热法制备方沸石晶体。采用XRD、SEM对产物进行表征,结果表明:三种方法都可以制备出方沸石晶体,其中溶胶-水热法制备的方沸石纯度高,结晶度好,颗粒大小均匀,粒径分布在3.5~5μm之间。模板剂的加入可以提高方沸石晶体的结晶度,但碱溶法和模板剂法得到的产物中仍含有石英和坡缕石杂质。     

吸水材料的水势及非金属矿物／高分子吸水保水复合材料的水势研穷

非金属矿物，高分子吸水保水复合材料（MPSAC）近年来由于其优异的吸水保水性能在节水农业，生态环境建设等领域得到了广泛应用。以植物细胞吸水机理和吸水材料吸水机理对比为基础，以MPSAC中坡缕石粘土，聚丙烯酸（钠）吸水保水复合材料为研究对象，借用植物生理学中水势的概念，采用水凝胶液体交换法测定吸水材料．MPSAC制备条件中不同中和度对水势变化趋势的影响，并且比较了矿物含量为10％（质量分数）时吸水材料水势与空白样吸水树脂水势的差异。通过实验可知：采用水凝胶液体交换法测量吸水材料的水势是科学的、可行的。并且用水势表征吸水材料的吸水能力比用吸水倍率更科学、更客观。此项研究对于研究由土壤-吸水材料-植物根系构成的连续的体系中水分的流动状态，揭示体系水分流动的更深层次的动力具有重要意义。通过空白样与加入10％（质量分数）坡缕石的复合样品水势的对比得知，加入适量坡缕石对于吸水材料的水势具有明显的影响。坡缕石加入后，可以使复合吸水材料的水势值增高．这样更利于水分向土壤中的释放，它所吸收的水分也更容易被植物所吸收利用。     

机械活化对钾长石颗粒表面特征的影响

采用机械活化并添加碱性助剂的方法，将钾长石进行粉碎加工，综合研究钾长石粒度分布、比表面积、表面粗糙度、颗粒形貌及相互关系；分别以激光粒度分析仪、比表面积仪测定颗粒大小、表面积，计算表面粗糙度，定量化表征颗粒特性变化；分析机械活化过程中表面积与粒度关系，以及不同碱性助剂对钾长石粉体特性的影响；研究提升钾长石颗粒活性的工艺方法、控制因素及影响机理。结果表明：无论是干法还是湿法研磨加工均能提高钾长石的比表面积和粗糙度，但湿法加工对提高比表面积和粗糙度效率更高，加入碱性添加剂及其盐类则降低比表面积与粗糙度。     

坡缕石/铜复合纳米粉体对HT200摩擦副的摩擦学性能

用共混法制备1∶1的坡缕石/铜复合纳米粉体,经表面修饰后按质量比2%添加到150N基础油中,制备出含复合纳米材料添加剂的润滑油体系。用MMU-10G摩擦磨损试验机测试该润滑油添加剂对HT200对磨试样的摩擦学性能,并用高精度电子天平测定试件的失重量以评定其耐磨性能。用扫描电镜SEM、EDX等分析了摩擦磨损试验后表面成分与形貌的变化,并分析了摩擦学性能变化的机理。结果表明:制备的坡缕石/铜复合纳米粉体在基础油中分散性良好,颗粒大小不超过200nm,能明显提高摩擦副的减摩抗磨性能,平均摩擦因数下降19.1%,总磨损量下降44%,试件表面生成了含坡缕石特征元素和铜元素的自修复膜层,这是纳米坡缕石和纳米铜粒子共同作用的结果。     

热处理对坡缕石纳米材料制备及表面改性的影响

为使坡缕石矿零维纳米化和表面改性取得理想的效果,对坡缕石粒子进行热处理后在QM-4H球磨机上使用干-湿法制备出零维纳米坡缕石,并用硅烷偶联剂进行表面改性,用TEM对坡缕石纳米粒子尺寸及改性效果进行表征,考察不同温度的热处理对含矿物水较多的坡缕石矿纳米化和表面改性的影响规律,研究表明,热处理后的坡缕石使用干-湿式球磨法制备可以获得较高的纳米化程度,经表面改性后具有较好的分散效果。     

乳剂制备工艺技术动向

综述了８０年代以来国外乳剂制备工艺技术动向，介绍了内循环双注的线性化控制和计算机化；晶种引导三注技术；反应器、调变锅和成熟锅分立的双注调变技术等，以及扩散和表面活化控制成熟机理的研究。     

羟基磷灰石在生物活性物质分离与提纯领域中应用的研究进展

羟基磷灰石特殊的化学组成和晶体结构,使其具有独特的性质,如选择吸附性、化学稳定性和热稳定性等,因此它在生物活性物质的分离与提纯领域中有广泛的应用.简要综述了羟基磷灰石的基本性质和制备方法以及在分离与提纯领域中经常用到的基质材料及其相应的性质,重点介绍了羟基磷灰石的吸附机理及其在分离与提纯领域中的基本应用.     

坡缕石/聚丙烯酸(钠)高吸水复合材料的溶胀行为

以水溶液聚合法制备了坡缕石/聚丙烯酸(钠) (PAANa)高吸水复合材料,对复合材料的吸水溶胀性能进行了研究,并采用FTIR对复合材料进行表征。结果表明：10 %坡缕石/PAANa复合材料吸蒸馏水和0.9 wt%盐水倍率分别达1666g/g、115g/g,较纯PAANa的724g/g、58g/g明显提高;坡缕石/PAANa复合材料具有优异的保水及反复吸水性能;坡缕石/PAANa的吸液倍率随电解质溶液离子强度的升高而降低,降低程度顺序为 Al3+>Ca2+>Na+;坡缕石/PAANa复合材料与其他6种矿物/PAANa复合材料相比,吸液性能特别是吸蒸馏水及0. 9 wt%盐水性能大幅提高。     

中孔活性炭材料的研究进展

综述了国内外在中孔活性炭材料开发方面的研究进展。着重介绍了催化活化、界面活化、混合聚合物炭化、有机凝胶炭化、铸型炭化等孔径调控方法及其中孔形成机理。为控制活性炭材料孔径大小和分布，提高其中孔容积和吸附性能提供了参考。     

凹凸棒石/油菜秸秆木质陶瓷的制备及性能

为了资源化利用油菜秸秆等废弃物, 以油菜秸秆和凹凸棒石为原料, 以酚醛树脂为黏结剂, 通过复合、 热压、 烧结等工艺过程制备了凹凸棒石/油菜秸秆木质陶瓷。对不同原料质量配比和烧结温度下制备的复合材料进行性能测试。结果表明, 采用该工艺制备凹凸棒石/油菜秸秆木质陶瓷是可行的, 原料的选择、 质量配比、 烧结温度等参数对材料制备过程及性能均有较大的影响。油菜秸秆与凹凸棒石质量配比为1∶2时复合材料的力学性能较好, 烧结温度在600~700 ℃时, 残炭率最高; 在600~800 ℃范围内, 抗弯强度的提高达到最佳; 在800 ℃时, 导电性能得到改善。     

Preparation and decoloration property of polystyrene-grafted palygorskite nanoparticles

The polymerization of styrene on inorganic palygorskite nanorods was carried out by reverse atom transfer radical polymerization (RATRP) in a completely controlled manner to form structurally well-defined PS-grafted hybrid nanocomposite. Well-defined PS chains were grown from the nanoparticle surfaces to yield individual particles composed of a palygorskite core and a well-defined outer PS layer. It has been found that the dispersibility of palygorskite particles in organic solvents is significantly improved by grafting polymers onto the surface of palygorskite particles. So the holding time of PS-palygorskite is prolonged in organic solvents. Active point of adsorption in palygorskite surface is adequately utilized. The polymer-grafted palygorskite nanoparticles possess excellent decoloration capacity in organic solvents.     

纳米坡缕石润滑油添加剂对灰铸铁HT200摩擦磨损性能的影响

制备坡缕石纳米粒子添加到150N基础油的润滑油体系,在MMU-10G摩擦磨损试验机上分别对该纳米粒子润滑油体系和纯150N基础油,在混合润滑条件下的铸铁HT200试样对摩时的摩擦磨损性能进行研究,并用SEM和金相显微镜对磨损表面进行观察和分析,借助EDX测定试样表面成分的变化,探讨摩擦磨损性能变化的机理。结果表明:自制备的用KH550硅烷偶联剂球磨修饰的坡缕石纳米粒子在基础油中分散性良好,在该润滑剂润滑条件下对摩的试样表面生成了自修复膜层,其磨损量明显减小,失重量下降约25.2%,平均摩擦系数下降约32.3%。     

凹凸棒／烷基糖苷悬浮液流变行为研究

以烷基糖苷（APG）为分散剂,系统研究分散剂的用量对凹凸棒悬浮液流变性的影响,运用等温吸附和Zeta电位测定技术对流变作用机制进行分析,并用六种流变模式对悬浮液的流变曲线进行了拟合,结果表明,随烷基糖苷浓度的增大,悬浮液的塑性粘度出现减小、增加再减小的趋势,其中,烷基糖苷浓度为200mg／L时凹凸棒悬浮液塑性粘度最大,该浓度也是悬浮液由“剪切变稀”向“剪切变稠”的转变点。凹凸棒／烷基糖苷悬浮液的流变曲线符合Herschel Buikley流变模型。     

Removal of Cu(II) from aqueous solution by adsorption onto acid-activated palygorskite

A series of activated palygorskite clay by HCl with different concentrations was prepared and applied as adsorbents for removal of Cu(II) from aqueous solutions. The effects of contact time, adsorbent dosages and pHs of suspension on the adsorption capacities for Cu(II) were investigated. The results showed that adsorption capacity of activated palygorskites increased with increasing the HCl concentration and the maximum adsorption capacity with 32.24 mg/g for Cu(II) is obtained at 12 mol/L of HCl concentration. The variations in IR spectra and pH of solution after adsorption Cu(II) confirmed that the numerous amount of silanol groups (Si-OH) originated by acid treatment were mainly responsible for Cu(II) adsorption onto acid-activated palygorskite. Kinetic studies indicated that the adsorption mechanisms in the Cu(II)/acid-activated palygorskite system followed the pseudo-second-order kinetic model with a relatively small contribution of film diffusion. Equilibrium data fitted well with Freundlich isotherm model compared to Langmuir isotherm model, indicating that adsorption takes place on heterogeneous surfaces of the acid-activated palygorskite. Adsorption-desorption studies presented that activated palygorskite has lower adsorption and desorption efficiencies using Cu(CH3COO)2 than that of other inorganic copper salts, such as CuSO4, Cu(NO3)2, and CuCl2.     

A New Approach to Efficiently Disperse Aggregated Palygorskite Into Single Crystals via Adding Freeze Process Into Traditional Extrusion Treatment

This paper reports a processing technology of natural nanorod materials. Palygorskite is a type of natural nanorod hydrous clay mineral, and its basic unit is about 20–40 nm in diameter and 1–5 μm in length. Low-cost single crystals of palygorskite can be produced in mass by simply adding freeze process into traditional extrusion treatment. The dispersion state of palygorskite was investigated by X-ray diffraction (XRD), particle size distribution, SEM, transmission electron microscopy (TEM), and viscosity techniques. The effects of the freeze process and treatment time on the dispersive quality of palygorskite were also studied. The results indicated that the new approach was efficient to disperse palygorskite ore into nanometer-scale particles and the crystal bundles of palygorskite into single crystals. Moreover, the new approach had much lower breakage of the long fine fiber of palygorskite compared with the dry process. The freeze process had remarkable influence on the improvement of the dispersion of palygorskite ore. The viscosity of the sample treated with the freeze process was enhanced twice from 472 to 3894 mpa·s, which was about 2.6 times that of the sample treated without the freeze process. The treated samples showed very uniform fibers about 20–40 nm in width and 1–5 μm in length, as observed from TEM, which is in good agreement with the perfect rod-shaped crystals of palygorskite. In addition, the treated samples showed XRD patterns similar to that of the untreated palygorskite ore, which suggests that the treated samples retained their original structure.      

Experimental and theoretical studies of palygorskite clays

We have studied the structure and properties of palygorskite clays. A structure analysis was performed using two different models to reproduce the monoclinic and orthorhombic lattices, using the atomic positions and cell parameters of palygorskite structure suggested by several authors, we simulated structures using Molecular Dynamics and Quantum Mechanics. Modifications on the structure and elemental atom changes were made to obtain more stable configurations. X-ray diffraction patterns and high resolution electron microscopy images from simulated structures were compared with experimental results. It could be observed that orthorhombic model shows a better fitting than monoclinic models. These results might help to understand many of the properties of archaeological pigments, such as, Maya Blue, in which palygorskite clay was the main component.     

A combined synchrotron powder diffraction and vibrational study of the thermal treatment of palygorskite–indigo to produce Maya blue

The heating process (30–200 °C) of a palygorskite-indigo mixture has been monitored in situ and simultaneously by synchrotron powder diffraction and Raman spectroscopy. During this process, the dye and the clay interact to form Maya blue (MB), a pigment highly resistant to degradation. It is shown that the formation of a very stable pigment occurs in the 70–130 °C interval; i.e., when palygorskite starts to loose zeolitic water, and is accompanied by a reduction of the crystallographic a parameter, as well as by alterations in the C=C and C=O bonds of indigo. Mid- and near-infrared spectroscopic work and microporosity measurements, employed to study the rehydration process after the complex formation, provide evidence for the inhibition of the rehydration of MB as compared with palygorskite. These results are consistent with the blocking of the palygorskite tunnel entrance by indigo molecules with a possible partial penetration inside the tunnels. The surface silanols of palygorskite are not perturbed by indigo, suggesting that MB is not a surface complex.     

Surface characteristics and photoactivity of silver-modified palygorskite clays coated with nanosized titanium dioxide particles

This paper presents the results of a study in which nanosized titanium dioxide (TiO₂) crystal particles were coated onto the surface of palygorskite fibrous clay which had been modified by silver ions using titanium tetrachloride as a precursor. Coated TiO₂ particles with the anatase structure were formed after calcining at 400 °C for 2 h in air. Various analytical techniques were used to characterize the surface properties of titanium dioxide particles on the palygorskite. Transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses showed that TiO₂ particles were supported on the surface of the palygorskite clays and their size was in the range of 3–6 nm. The titanium oxide coatings were found to be very active for the photocatalytic decomposition of methylene blue.     

凹凸棒石基多孔陶粒的制备及性能

考察了物料配比和煅烧工艺对以凹凸棒石黏土、 锯末(造孔剂)和水玻璃(粘结剂)为原料制备的凹凸棒石基多孔陶粒(PC)性能的影响。利用所制备多孔陶粒的抗压强度作为衡量陶粒质量的指标, 通过单因素、 正交实验来优化陶粒的物料配比和煅烧工艺, 并通过XRD、 SEM表征多孔陶粒特性。结果表明: 物料的最佳质量比为凹凸棒石黏土:锯末:水玻璃=10:2:1; 在最佳煅烧条件下(700℃, 煅烧3 h)可以制备出满足国家标准的水处理用陶粒; 所制备陶粒内部存在大量分布均匀、 三维连通的气孔, 适合微生物的附着。