CaCl2/蛭石与LiCl/蛭石吸附性能研究

采用干浸渍法制备复合吸附剂CaCl2/蛭石、LiCl/蛭石.在25℃,70％的相对湿度条件下,对不同样品的孔径分布、颗粒尺寸、盐含量、循环稳定性以及吸附性能进行了研究.结果表明,复合吸附剂CaCl2/蛭石以1:1比例配制时吸附性能最佳;较小颗粒尺寸能够有效提高复合吸附剂的吸附性能,LiCl/蛭石样品、CaCl2/蛭石样...     

空气取水用蛭石/MgCl2/MgSO4复合吸附剂的研究

利用蛭石浸渍MgCl2/MgSO4二元盐溶液制备复合吸附剂.探究在开式环境下复合吸附剂对空气中水蒸气的吸附性能.对复合吸附剂在不同吸附温度、吸附湿度工况下的吸附性能进行了实验研究,探究了浸渍盐的质量浓度和二元盐的比例对复合吸附剂吸附性能的影响,并在实际工况下进行取水实验.结果表明,该复合吸附剂相比纯MgCl2/蛭石复合...     

蛭石负载壳聚糖处理金属铜离子

文章采用共混沉降法制备了蛭石-壳聚糖复合吸附剂,并用此复合吸附剂处理废水中的重金属Cu2+,考察了吸附剂投加量、吸附时间、溶液pH、Cu2+浓度对吸附的影响。实验得出在温度为25℃、吸附时间为25 min、投加量为0.25 g/L、pH为7,用壳聚糖/蛭石质量比为0.06,吸附效果较好,吸附率可达93.75%。     

蛭石吸附亚甲基蓝的性能研究

根据蛭石的国内外研究现状,采用颗粒蛭石为吸附剂,分析研究其对于亚甲基蓝的吸附性能,探索了不同时间、浓度和蛭石量对亚甲基蓝的吸附量和去除率影响规律。实验结果表明,当颗粒蛭石0.5 g和亚甲基蓝浓度为100 mg/kg时,在240 min左右达到吸附平衡;吸附液的p H值应大于7时效果最佳;蛭石与亚甲基蓝的最高比为1∶425。通过本课题蛭石对染料吸附性能的研究,将对蛭石在水处理中的应用具有一定的指导意义。     

基于活性碳纤维毡复合吸附剂的储热性能

研制了一种以活性碳纤维毡为基质、氯化锂（LiCl）为吸湿盐的复合吸附剂,并辅以硅溶胶进行固化成型。该复合吸附剂可用于以水为吸附质的热化学吸附储热系统,并对其微观结构、吸附性能和储热性能进行了表征研究。制备了不同含盐量的复合吸附剂样品,并根据样品的溶液泄漏现象,确定ACFLi30为最佳样品。通过试验测量,获得ACFLi30样品的热导率、孔比表面积、孔体积和孔径等参数。并对多种温湿度工况下的平衡和动态吸附性能进行测试,研究了不同温湿度条件下样品的吸附特性。结果表明样品的吸水量可达1.1 g/g（20℃、75% RH）。利用同步热分析仪测试了复合吸附剂的储热密度,ACFLi30的质量和体积储热密度分别达到1.08 kW·h/kg和588.2 kW·h/m³。与膨胀蛭石和活性氧化铝等基质相比,活性碳纤维毡基质在体积储热密度更具优势。     

石墨烯-13X/LiCl复合吸附剂开式吸附-解吸性能

利用不同质量分数的石墨烯（MLG）与13X/LiCl合成新型复合吸附剂。通过扫描电镜（SEM）和N₂吸附表征复合吸附剂的微观形貌和孔隙特性,测试了复合吸附剂开式环境下的水蒸气吸附及解吸性能,并探究复合吸附剂中石墨烯质量分数对吸附解吸性能的影响。通过80%相对湿度（RH）的高湿工况进一步筛选出盐的质量分数为18.4%的13X/LiCl为最佳盐含量的吸附剂（MZ）作为合成复合吸附剂的基质。实验结果表明：石墨烯增加了复合吸附剂的结构性参数（比表面积,孔体积及孔径）,其中比表面积由未添加石墨烯的MZ [(262±3)g/m²],最大可提升至12G-MZ [(304±4)g/m²];复合吸附剂表现出优异的水蒸气吸附性能,所有复合吸附剂的相对吸附量均高于MZ（0.554g/g）,3G-MZ吸附性能最佳,水蒸气吸附量高达0.587g/g,是13X的2.7倍;除12G-MZ外,随着吸附剂中石墨烯质量分数的增加,水蒸气解吸率随之增加,其中9G-MZ的解吸率接近90%,较MZ（81.8%）提升了9.7%。该研究可为复合吸附剂应用于吸附空气取水提供基础研究数据。     

空气取水用硅胶/MgCl2复合吸附剂吸附性能研究

通过浸渍法合成了一种硅胶/MgCl₂新型复合材料。探究了球型硅胶孔径和粒径、MgCl₂溶液浓度、吸附环境温湿度对硅胶/MgCl₂复合吸附剂吸附性能的影响。实验表明,复合吸附剂的吸附能力与硅胶孔径成正比,与硅胶粒径成反比。在25℃、50%RH下,SG-A/M20、SG-B/M20、SG-C/M20的平衡吸附量分别为0.25,0.37,0.39 g/g;在25℃、35%RH下,SG-D/M20、SG-A/M20、SG-E/M20的平衡吸附量分别为0.21,0.16,0.14 g/g。RH为35%～80%时,复合吸附剂的吸附量随RH增大而增大,温度为25～35℃时,复合吸附剂的吸附量随温度升高先增大后减小。在25℃、RH 80%下,SG-B/M20取得最大吸附量0.58 g/g。复合吸附剂在110℃下脱附90 min水蒸气脱附率>98%。SG-B/M20、SG-C/M20具有良好的循环稳定性,经8次吸附-脱附循环后吸附量减小量<0.03 g/g。硅胶/MgCl₂复合吸附剂的水蒸气吸附性能探究,...     

改性蛭石对HgCl2吸附性能研究

采用H2O2和微波联合技术对蛭石进行膨胀,并利用改性剂进行改性,以提高蛭石对HgCl2的吸附性能。分别用单因素试验和正交试验讨论了改性蛭石吸附HgCl2的最优条件,并对改性蛭石吸附HgCl2的吸附热力学进行研究。结果表明,蛭石经H2O2微波高火膨胀改性后膨胀率达46.78倍,经1.5 mol/L的Na2S进一步改性,在蛭石用量为0.2 g,溶液pH为6,吸附时间为30 min,室温条件下对HgCl2最大吸附量可达到6.31 mg/g。吸附热力学结果表明,改性蛭石吸附HgCl2的吸附等温线符合Freundlich吸附等温方程。膨胀改性蛭石是一种廉价、性能好的HgCl2吸附剂,这对环境保护技术具有重要意义,同时丰富了吸附理论。     

纳米蛭石片/聚氯乙烯复合塑料的制备及其性能

随着人们环保意识的增强，环保型聚氯乙烯(PVC)塑料添加剂正在不断推进，利用天然矿物蛭石代替非环保PVC塑料添加剂成为行业新趋势。采用液相高速剪切/分级离心法制备了纳米蛭石片悬浮液，通过溶剂置换法制备了纳米蛭石片/PVC复合塑料，研究了纳米蛭石片含量对其紫外、导热性能，阻燃性能、热稳定性和拉伸性能的影响。结果表明：纳米蛭石片尺寸在150 nm～1.1μm，保持了蛭石原有结构特征。纳米蛭石片添加量为15%(质量分数)时，纳米蛭石片/PVC复合塑料的拉伸强度提高了50.8%，极限氧指数提高了7.3%，导热系数降低了17.8%，老化热稳定时间提高了140 min，脱氢热解时间提高了24 min，具有优异的热稳定性能和抗紫外性能。在PVC制品中加入蛭石将会提高复合塑料的各项性能，对于高性能PVC制品制备具有重要的实际意义。     

CaCl_2改性蛭石对Pb~(2+)的吸附性能研究

针对重金属污染严重威胁人类健康这一问题,文章使用改性蛭石研究了其对Pb~(2+)的吸附性能。将天然蛭石加入到一定浓度的CaCl_2溶液中,得到CaCl_2改性蛭石,从理论上阐述了改性方法的机理,提出最佳改性方案,并通过SEM表征其形貌特征。从蛭石用量、反应时间、溶液浓度、pH值等方面探讨了CaCl_2改性蛭石对Pb~(2+)的吸附效果。实验表明CaCl_2改性蛭石可以很好的用于Pb~(2+)的吸附处理。     

Effect of doubly organo-modified vermiculite on the properties of vermiculite/polystyrene nanocomposites

Vermiculite (Verm)/polystyrene (PS) nanocomposites were prepared by dispersing a doubly organo-modified Verm (DOVerm) in PS via in situ polymerization (DOVerm/PS 1/99, 3/97, 5/95, and 7/93 mass/mass ratios). The morphology of Verm/PS nanocomposites evolved three stages as the content of DOVerm decreased in the nanocomposites: intercalation at high filler content, intermediate state of intercalation to exfoliation, and exfoliation of Verm in PS matrix with a low filler content. The morphological changes of Verm/PS nanocomposites were confirmed by the X-ray diffraction (XRD) patterns and the transmission electron microscopy (TEM) images. Compared with the pure PS, the nanocomposites filled with Verm showed significant enhancements on thermal stability and dynamic mechanical properties. Interestingly, the nanocomposites filled with 1 and 7 mass% of DOVerm exhibited more pronounced effects of Verm on the properties. It was proved that the double organo-modification clearly enhanced the ultimate properties of the Verm/PS nanocomposites.     

蛭石/PBAT复合薄膜的制备与性能

使用蛭石（VMT）作为填料,以可生物降解的聚对苯二甲酸-己二酸丁二醇酯（PBAT）作为基体,采用熔融-吹塑法制备出蛭石/聚对苯二甲酸-己二酸丁二醇酯（VMT/PBAT）复合薄膜,并通过添加聚苯乙烯马来酸酐共聚物（SMA）作为相容剂制备了VMT/PBAT/SMA复合薄膜。对纯PBAT薄膜、VMT/PBAT和VMT/PBAT/SMA复合薄膜的热性能、流变性能、水蒸汽阻隔性能、断面微观结构和力学性能进行了测试。结果表明,相比纯PBAT薄膜,蛭石的填充使VMT/PBAT复合薄膜的热稳定性降低,相容剂SMA的添加增强了VMT/PBAT/SMA复合薄膜的热稳定性;蛭石的添加使复合薄膜的结晶度降低了约2%。水蒸汽透过量测试表明,两种复合薄膜水蒸汽阻隔性能符合国家标准;VMT的添加使VMT/PBAT复合薄膜的拉伸强度和断裂伸长率降低,而添加相容剂SMA使VMT/PBAT/SMA复合薄膜的拉伸强度和断裂伸长率相比VMT/PBAT复合薄膜提高约10 %。     

Polyurethane/organic vermiculite composites with enhanced mechanical properties

In this article, a series of polyurethane (PU)/organic vermiculite (OVMT) composites are prepared by intercalating polymerization. 1,4‐cyclohexane diisocyanate (CHDI) as hard segment of PU is designed to improve the decomposition temperature of composites. Vermiculite (VMT) is modified by method of cation exchange with octadecyl trimethyl ammonium bromide (OTAB); the resulting product OVMT with the function of physical cross‐linking disperses well in soft segment of PU polycarbonate polyol (PCDL), which improves the mechanical properties of composites obviously. This modification further enlarged the interlayer of OVMT and improved the properties of composites. The structure and properties of OVMT and PU/OVMT composites are characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, thermogravimetric analysis, scanning electron microscope, and tensile strength test. The results showed that the layer spacing of OVMT increased 1.41 nm compared with that of VMT (the value of layer spacing of VMT is 0.96 nm) and further enlarged to 2.92 nm by the loading of PCDL. The tensile strength and the strain at break of PUCPB/OVMT (3.0%) composites reached 26.8 MPa and 443%, respectively. The temperature resistance of PUCPB/OVMT (3.0%) composites is above 300°C, which is more suitable for the steam channeling plugging of heavy oil. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43219.     

Preparation and properties of new EPDM/vermiculite nanocomposites

Novel nanocomposites based on ethylene‐propylene‐diene rubber (EPDM) and maleic anhydride‐modified vermiculite (VMT) were prepared. Maleic anhydride (MA) acts both as the intercalation agent for VMT and as a vulcanizing agent for EPDM matrix. It also acts as a compatibilizer for EPDM and VMT phases. From analysis by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), the silicate layers of the VMT were exfoliated and dispersed uniformly in the EPDM matrix as monolayers. The thermal properties of the nanocomposites were investigated by dynamic mechanical thermal analysis and thermogravimetric analysis; a strong rubber‐filler interaction in the nanocomposites was manifested in the measured temperature range by the result of storage modulus. At the same time, there was some enhancement in degradation behavior between the nanocomposites and EPDM matrix. The nanocomposites exhibited a great improvement in tensile strength and modulus, as well as elongation at break. Finally, the effects of MA addition on the formation of nanometric reinforcement and on the mechanical properties of nanocomposites are discussed. POLYM. COMPOS., 26:706–712, 2005. © 2005 Society of Plastics Engineers     

Gas barrier properties of butyl rubber/vermiculite nanocomposite coatings

Gas barrier properties of butyl rubber/vermiculite nanocomposites coatings are described here. The coating formulations consisting of a butyl rubber latex (the rubber particles are about 1 μm in diameter) to which exfoliated vermiculite was added were applied to a poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) coated Anapore ceramic disc; composites containing 0, 20 and 30 wt% of vermiculite were evaluated. The permeability of the nanocomposite coatings to various gases was measured and compared to permeation models for composites with flake-like fillers proposed by Cussler, Nielsen, Fredrickson and Bicerano, and Gusev and Lusti. The gas permeability of the nanocomposite materials was decreased remarkably by the presence of the high loadings of vermiculite. Diffusion coefficients computed from time lag data also decreased remarkably with the vermiculite content. TEM and SEM were used to observe the internal structure of the nanocomposite membranes in an effort to gain further understanding of the permeability properties. Aspect ratios ranging from 100 to 480 were predicted from the gas permeation results and the above models. TEM experiments could not provide a precise estimate of the aspect ratio but the range predicted from the models are of this order. Apparent solubility coefficients, computed by dividing the experimental permeability by the diffusivity obtained from the time lag observation, increased significantly with vermiculite content in contradiction to the theoretical prediction. Independent gas sorption isotherm experiments for CO₂ were measured and found to be larger than that in butyl rubber possibly due to adsorption on the vermiculite. While this turned out to be a very complicated system, it seems clear from these results that the transient tortuosity factor defined by the time lag is significantly larger than the steady-state tortuosity factor defined by permeability.     

秸秆纤维素/改性蛭石环保吸水材料的研究

以玉米秸秆纤维素及改性蛭石为原料,柠檬酸为交联剂,制备环保复合吸水材料,研究改性蛭石含量、柠檬酸/柠檬酸三钠浓度、交联温度及交联时间对材料吸水率的影响,并采用扫描电镜表征其结构。结果表明,最佳制备工艺条件为:柠檬酸/柠檬酸三钠浓度8%,交联温度70℃,改性蛭石含量2 g,交联时间1 h,在此条件下,吸水材料的吸水倍率可达到19.17;扫描电镜分析表明,秸秆纤维素与改性蛭石形成了表面粗糙、疏松多孔、比表面积较大的复合材料;吸水材料具有较好的重复利用性;当吸水时间为4 min时,吸水速率最大,可达到5.982 g/min;吸水材料的保水率随着温度升高和时间延长呈下降趋势,在20℃时保水率较好;吸水材料具有良好的耐盐能力。     

Role of vermiculite and zirconium–vermiculite on the formation of zircon–cordierite nanocomposites

The Zr^4 +–vermiculites were studied in their new role of the zircon precursor in the clay minerals mixtures which were prepared for firing of the zircon–cordierite nanocomposites. Currently there is a lack of data available about the structure of Zr^4 +–vermiculites, on which this study was performed. The modeling of the arrangement of interlayer material in the Zr^4 +–vermiculite led to new findings that water molecules are attracted more strongly by Mg^2 + cations than by Zr-tetrameric cations, and that both the tetrameric cations [Zr₄(OH)₁₄(H₂O)₁₀]^2 + and [Zr₄(OH)₈(H₂O)₁₆]^8 + may be present in the interlayer space of the Zr^4 +–vermiculites. Vermiculites from two different localities Czech Republic (Verm1) and from Brazil (Verm2) were intercalated using the zirconyl chloride (ZrOCl₂–30% solution in HCl) and the prepared Zr^4 +–vermiculites were designated as Zr^4 +–Verm1 and Zr^4 +–Verm2, respectively. Influence of the Zr^4 +–Verm1 and Zr^4 +–Verm2 in the mixtures of clay minerals on the properties of zircon–cordierite nanocomposites were investigated by their comparison with the properties of the zircon–cordierite nanocomposites, which were prepared using saturation of the clay minerals mixtures containing Verm1 and Verm2 with the zirconyl chloride (ZrOCl₂–30% solution in HCl). The zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Zr^4 +–Verm1 and Zr^4 +–Verm2 showed a maximum porosity of P = 58 and 60%, skeletal density SD = 3.2 and 3.6, and the smallest pores with a median pores diameter MDP = 18 and 15 μm, respectively, in comparison with the zircon–cordierite nanocomposites fired from the clay mineral mixtures containing Verm1 and Verm2 and saturated with zirconyl chloride solution. The type of vermiculite Verm1 or Verm2 in the clay mineral mixtures did not affect the contents of the crystalline mineral phases in cordierite and zircon–cordierite nanocomposites.     

蛭石电加热膨胀试验研究

利用自己研制的多温区电加热膨胀炉,对蛭石电加热膨胀进行了试验研究,并对影响试验结果的因素进行了分析讨论。     

A degradation study of polyamide 11/vermiculite nanocomposites under accelerated UV test

Accelerated photooxidation under ultraviolet (UV) test of polyamide 11 (PA11) films filled with unmodified vermiculite clay at 5 wt% was investigated up to 600 h. Film samples of ~60‐μm thick were prepared by melt compounding using a cast extruder and exposed to UV light irradiation at λ > 295 nm. Fourier transform infrared (FTIR) spectra indicated similar structural changes occurring in both PA11 and PA11/unmodified vermiculite nanoclay (UVMC) nanocomposite along the photooxidation process, resulting in imides and carboxylic acids as the main carbonyl products. It was however observed that the formation rate of carbonyls in the PA11/UVMC nanocomposite was slower than neat PA11. This behavior is consistent with the yellowing index evolution determined by ultraviolet–visible (UV–vis) spectroscopy. Further, the photooxidation stability of the samples was also evaluated by the onset oxidation temperature determined by differential scanning calorimetry. The results indicated a better stability of the nanocomposite film than neat PA11, corroborating well the data obtained by FTIR and UV–vis techniques. POLYM. ENG. SCI., 59:2449–2457, 2019. © 2019 Society of Plastics Engineers