Preparation and Performance of Organically Modified Montmorillonite Composite Separation Membrane

A new composite separation membrane was developed by using organically modified montmorillonite(OMMT)as an additive.The effects of OMMT on the modification and properties of PVDF composite membranes were investigated.It is found that different kinds and amounts of OMMT into the casting solution can obviously change the pure water flux,separation performance and hydrophilicity of composite membrane in varying degrees.When the TA/PDA-MMT was 0.5 wt%,the pure water flux of the membrane reached the maximum,which was 584.7 L/(m^(2)·h),about 6 times that of the original membrane.The OMMT/PVDF composite membrane had good hydrophilicity and stability in the treatment of oily wastewater.The development of novel OMMT/PVDF composite membrane will provide a new idea for solving the problem of oily wastewater treatment.

Layer-by-layer fabrication of montmorillonite coating immobilizing Cu_(2)O nanoparticles for continuously catalyzing glycerol to dihydroxyacetone

Microreactors are increasingly used for green and safe chemical processes owing to their benefits of superior mass and heat transfer,increased yield,safety,and simplicity of control.However,immobilizing catalysts in microreactors remains challenging.In this investigation,a technique for creating Cu_(2)O/montmorillonite catalyst coating,using electrostatic attraction for layer-by-layer self-assembly,was proposed.The montmorillonite film's morphology and thickness could be efficiently regulated by adjusting the degree of exfoliation and surface charge of montmorillonite,alongside layer-by-layer coating times.The Cu_(2)O nanoparticles were immobilized using the flow deposition approach.The resulting Cu_(2)O@montmorillonite-film-coated capillary microreactor successfully transformed glycerol into dihydroxyacetone.The conversion of glycerol and product selectivity could be controlled by adjusting the molar ratio of reactants,temperature,residence time,and Cu_(2)O loading.The maximum glycerol conversion observed was 47.6%,with a 27%selectivity toward dihydroxyacetone.The study presents a technique for immobilizing montmorillonite-based catalyst coatings in capillary tubing,which can serve as a foundation for the future application of microreactors in glycerol conversion.

Vertically aligned montmorillonite aerogel-encapsulated polyethylene glycol with directional heat transfer paths for efficient solar thermal energy harvesting and storage

The conversion and storage of photothermal energy using phase change materials(PCMs)represent an optimal approach for harnessing clean and sustainable solar energy.Herein,we encapsulated polyethylene glycol(PEG)in montmorillonite aerogels(3D-Mt)through vacuum impregnation to prepare 3D-Mt/PEG composite PCMs.When used as a support matrix,3D-Mt can effectively prevent PEG leakage and act as a flame-retardant barrier to reduce the flammability of PEG.Simultaneously,3D-Mt/PEG demonstrates outstanding shape retention,increased thermal energy storage density,and commendable thermal and chemical stability.The phase transition enthalpy of 3D-Mt/PEG can reach 167.53 J/g and remains stable even after 50 heating-cooling cycles.Furthermore,the vertical sheet-like structure of 3D-Mt establishes directional heat transport channels,facilitating efficient phonon transfer.This configuration results in highly anisotropic thermal conductivities that ensure swift thermal responses and efficient heat conduction.This study addresses the shortcomings of PCMs,including the issues of leakage and inadequate flame retardancy.It achieves the development and design of 3D-Mt/PEG with ultrahigh strength,superior flame retardancy,and directional heat transfer.Therefore,this work offers a design strategy for the preparation of high-performance composite PCMs.The 3D-Mt/PEG with vertically aligned and well-ordered array structure developed in this research shows great potential for thermal management and photothermal conversion applications.

TiO_(2)/MMT复合材料降解盐酸四环素的研究

为解决抗生素废水排放带来的环境污染问题,以蒙脱土(MMT)为原料,采用水解法制备TiO_(2)/MMT复合材料,利用扫描电镜(SEM)、X射线衍射(XRD)、傅里叶红外光谱(FT-IR)和X射线光电子能谱(XPS)对TiO_(2)/MMT进行物相表征。以盐酸四环素(TC)为目标降解分子,考察了所制备的复合材料对TC的降解性能,并采用紫外-可见分光光谱(UV-vis)跟踪检测TC降解过程。物相表征表明,TiO_(2)均匀分散在MMT的表面;TiO_(2)/MMT中TiO_(2)为锐钛矿相。TiO_(2)/MMT回收样检测到N元素存在。活性数据表明,30%TiO_(2)/MMT(400℃,2 h)复合材料具有最优光催化降解TC性能,在紫外光下对100 mg/L TC的降解率达87.64%,优于纯TiO_(2)(68.74%)和纯MMT(72.22%)。循环试验6次后,催化剂对TC降解率仍达到75%,表明TiO_(2)/MMT对TC具有较高的降解活性和化学稳定性。·O_(2)^(-)和h^(+)是TiO_(2)/MMT光催化降解盐酸四环素的主要活性物质。

Design of Wood/Montmorillonite (MMT) Intercalation Nanocomposite

Studying new wood composites through nano science and technology (NSC) will develop new compounding theory of wood, and accelerate the combination of new technology, wood science, material science and other disciplines. The compounding of wood and inorganic MMT on nanoscale molecular level has high potential to greatly improve the mechanical properties, fire retardance, abrasion resistance, decay resistance, dimensional stability and other properties of wood. Based on the great achievements of polymer/montmorillonite (MMT) nanocomposites, this paper reviewed nano intercalation compounding methods (i.e. in-situ intercalative polymerization and direct polymer intercalation), and discussed the structure, properties and modification of montmorillonite (MMT). According to the main chemical components and particular structure of wood, the authors discussed the liquefaction and plasticization of wood, compared the dissolvability and meltability between wood and polymer, and then systematically put forward the basic idea, technological processes and schematic diagram to prepare wood/MMT nanocomposites (WMNC). The key technology to prepare WMNC is either to introduce delaminated MMT nanolayers into wood with the help of some intermediate polymers, or to obtain liquefied wood or plasticized wood from the complicated natural composite. It is applicable and effective to realize wood/MMT nanoscale compounding with the help of proper intercalation agent and medium polymer through the proposed 搊ne-step?or 搕wo-step?impregnating processes.

Hydration Characteristics and Mechanical Properties of Cement-Based Materials Modified by Calcined Zeolite and Montmorillonite

Montmorillonite and clinoptilolite zeolite were used as representative materials to prepare calcined clay-cement binary cementitious materials in order to study the effect of calcination treatment on the activation of clay minerals and the activity difference between layered and framed clays in this research.The influence of different calcined clay content(2%,4%,6%,8%,10%)on the fluidity,compressive strength,microstructure,phase change,and hydration heat of cement-based materials were analyzed.The calcined clay improves the fluidity of cement-based materials as compared with the uncalcined group.The addition of calcined montmorillonite(CMT)improves the development of mechanical strength,and the optimal compressive strength reaches 85 MPa at 28 days with 8%CMT.However,the activity of calcined clinoptilolite zeolite(CZL)is weak with few reaction sites,which slightly reduced the mechanical strength as compared to the blank sample.The addition of CMT changes the microscopic morphology of hydration products such as C-S-H and C-A-H,leading to the formation and transformation of ettringite in the early stage.It promotes the gradual polymerization of Si-O bonds into Si-O-Si bonds simultaneously,which accelerates the early hydration process.However,CZL acts mainly as a filling function in the cementitious system.In brief,CMT as an admixture can improve the mechanical properties of cement,but CZL has little effect.This work provides a guideline for the applications of calcined clay in cement,considering the influence of clay type on workability and mechanical strength.

Improving physical properties of poly(vinyl alcohol)/montmorillonite nanocomposite hydrogels via the Hofmeister effect

Hydrogel is a kind of three-dimensional crosslinked polymer material with high moisture content.However,due to the network defects of polymer gels,traditional hydrogels are usually brittle and fragile,which limits their practical applications.Herein,we present a Hofmeister effect-aided facile strategy to prepare high-performance poly(vinyl alcohol)/montmorillonite nanocomposite hydrogels.Layered montmorillonite nanosheets can not only serve as crosslinking agents to enhance the mechanical properties of the hydrogel but also promote the ion conduction.More importantly,based on the Hofmeister effect,the presence of(NH_(4))_(2)SO_(4)can endow nanocomposite hydrogels with excellent mechanical properties by affecting PVA chains'aggregation state and crystallinity.As a result,the as-prepared nanocomposite hydrogels possess unique physical properties,including robust mechanical and electrical properties.The as-prepared hydrogels can be further assembled into a high-performance flexible sensor,which can sensitively detect large-scale and small-scale human activities.The simple design concept of this work is believed to provide a new prospect for developing robust nanocomposite hydrogels and flexible devices in the future.

Optimum preparation technology for Chinese fir wood/Ca-montmorillonite (Ca-MMT) composite board

For this study, an intercalation compounding method was used to prepare Chinese fir wood/Ca-montmorillonite （Ca-MMT） composite board to improve its properties such as surface mechanical properties, flame retardance and dimensional stability. By virtue of water-soluble phenolic resin （PF）, Chinese fir wood and Ca-MMT were mixed by pressure and vacuum impregnation. The optimum impregnation technology of Chinese fir wood/Ca-MMT composite board was obtained by using an orthogonal design and a single factor design of pressure and vacuum impregnation, using weight percent gain （WPG） as the basic index. The results are as follows： 1） On the basis of the orthogonal design and an actual experiment, the optimum preparation technology of Chinese fir wood/Ca-MMT composite board is 20% PF resin dispersion concentration （wt%）, 1.0 CEC amount of organic intercalation agent, 0.098 MPa vacuum degree, 5% concentration of Ca-MMT and 1.0 MPa pressure. 2） The WPG of the composite board samples of 450 mm length was much larger than that of the samples of 600, 750 and 900 mm length. Warm water extraction contributed little to WPG

CeO_(2)/MMT纳米复合材料的制备及其可见光催化氧化性能研究

采用沉淀法和水热法合成CeO_(2)/MMT纳米复合材料,利用XRD、SEM、BET和UV-Vis DRS等方法对材料的结构、形貌、织构特性和光吸收性能进行分析。在长弧氙灯照射下,模拟太阳可见光降解四环素,研究降解液pH、CeO_(2)与MMT的质量比、催化剂用量及抗生素初始浓度等参数对CeO_(2)/MMT光催化的降解性能的影响。结果发现,CeO_(2)/MMT光催化氧化性能较CeO_(2)的要好,且催化氧化反应宜在酸性溶液中进行,当CeO_(2)与MMT的质量比为2时,取得良好的催化降解效果;随着催化剂用量的增大,催化降解率增大,最佳催化剂用量宜为2.5 g/L;四环素初始质量浓度在0.02 g/L以下,降解效果较好;在最佳工艺条件下,CeO_(2)/MMT对四环素的降解率达95%左右。自由基捕获实验发现,CeO_(2)/MMT可见光催化氧化降解过程中•O_(2)^(-)和h^(+)两个活性基团起主要作用,其催化性能稳定,重复使用效果较好。

成型方式对XLPE/OMMT纳米复合材料介电性能的影响

为了研究压制成型法和挤出成型法对纳米复合材料介电性能的影响,分别采用两种成型方式制备了交联聚乙烯/有机化蒙脱土(XLPE/OMMT)纳米复合材料。探讨了不同复合材料中有机化蒙脱土的层间距变化对复合材料电阻-温度特性、介电常数和介质损耗以及电气强度的影响。结果表明:成型加工过程中的力场作用会影响OMMT的插层分散效果;挤出成型过程中的拉伸应力使试样中OMMT片层沿拉伸方向进行取向,形成了规整排列单元,载流子的迁移运动受到阻碍,从而改善了试样的电阻-温度特性;聚合物分子链段的运动受限于取向的片层间,使试样中偶极子的极化率降低,使得介电常数和介质损耗因数减小;同时,OMMT的有效插层与聚合物形成的杂化结构使电子产生漫反射现象,延长了电子运动路径,提高了挤出成型试样的电气强度。

有机化蒙脱土对XLPE/OMMT纳米复合电介质微观形态及水树枝老化特性的影响

文中采用熔融共混法分别制备了交联聚乙烯/有机化蒙脱土(XLPE/OMMT)纳米复合电介质,研究有机化蒙脱土种类对纳米复合电介质微观形态和水树枝老化特性的影响。对试样进行力学性能测试发现,OMMT质量分数为0.5%时,综合力学性能达到最佳;利用差示扫描量热法和扫描电子显微镜研究了试样的微观形态,经双十八烷基苄基季铵盐有机化改性并细化的有机化蒙脱土(OMMT3)起到明显的异相成核作用,使晶体更加完善,结晶度高达25.3%,晶体平均尺寸仅为16.67μm;采用水针电极法对各试样进行加速水树枝老化试验,剥离分散的OMMT3片层形成了更加曲折的迷宫路径,其对水分子的阻隔效应与XLPE交联网状结构对分子链运动束缚的共同作用,有效抑制了XLPE/OMMT3试样中水树枝的生长,引发概率下降至23.4%;傅里叶变换红外光谱对水树枝老化前后的化学结构进行了表征,纳米复合电介质水树区的羰基指数增加、羟基振动峰增强,表明水树枝老化是电化学降解的作用;在水树枝生长过程中,XLPE/OMMT3试样老化断链较少,表现出较优的耐热氧老化性能。

H-MMT对低物质的量比脲醛树脂胶粘剂性能的影响

将蒙脱土进行酸化处理,制备酸化蒙脱土(H-MMT)。随后在低物质的量比脲醛树脂合成体系中,加入制得的H-MMT,得到经H-MMT改性的脲醛树脂胶粘剂。通过控制加入H-MMT的投料比以及投放时间,探究其对脲醛树脂胶粘剂的黏度、固含率、游离甲醛含量以及胶接性能的影响。同时,对比分析了未改性脲醛树脂胶粘剂和H-MMT改性脲醛树脂胶粘剂的差异。研究结果表明:在脲醛树脂合成体系反应的第二阶段加入3%的H-MMT,改性脲醛树脂胶粘剂的性能最好,测得胶粘剂的游离甲醛含量为0.17%,固化时间为57.5 s,胶接强度为1.1 MPa;加入H-MMT的改性脲醛树脂胶粘剂中含有大量的醚键和羟甲基基团,可以提高胶粘剂的胶接性能;H-MMT改性的脲醛树脂胶粘剂中存在着未反应的残留尿素,进一步降低了体系的游离甲醛含量。

The Thermal and Mechanical Properties of Ultra-High Molecular Weight Polyethylene/Montmorillonite (UHMWPE/MMT) Nanocomposites Hybrid Gel Using Pressure-Induced Flow (PIF) Processing

Hybrid organic-inorganic polymer nanocomposites incorporating organically modified montmorillonite (MMT) and ultra-high molecular weight polyethylene (UHMWPE) were examined. UHMWPE/MMT hybrid nanocomposites were prepared using gel and pressure-induced flow(PIF) processing methods at a gel weight concentration of 8% UHMWPE with various organoclay contents (0, 0.4, 0.8, 1.2, and 1.6 parts per hundred parts). The interlayer properties of the nanocomposites were studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The thermal and mechanical interfacial properties of the nanocomposites were investigated through thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and the use of a universal test machine (UTM). TEM indicates that the nanocomposites are formed upon dispersion of MMT in the polymer matrix. From the DSC, TGA, and DMA results, we find that the thermal stability of the UHMWPE nanocomposites increases as the MMT content increases. The nanocomposites show higher tensile strengths than pure UHMWPE gel sheet. These findings indicate that the interfacial and mechanical properties are improved by the addition of MMT and PIF processing.

超声引导MMT微创旋切术治疗对女性良性乳腺肿块围术期指标术后疼痛瘢痕及并发症的影响

目的:探究超声引导MMT微创旋切术治疗对女性良性乳腺肿块围术期指标、术后疼痛、瘢痕及并发症的影响。方法:回顾分析126例于2019年1月至2022年1月期间在我院接受治疗的良性乳腺肿块患者的临床资料,根据其手术方式不同分为MMT组和常规组,MMT组采用超声引导MMT微创旋切术,共71例,常规组采用传统开放手术,共55例。对比两组围术期指标(手术时间、术中出血量、切口长度、切口愈合时间)、术后疼痛[术后2h、8h、24h视觉模拟量表(VAS)得分]程度差异,术后随访3个月,对比两组患者的瘢痕情况[瘢痕长度、温哥华瘢痕量表(VSS)]差异,比较两组并发症发生差异。结果:MMT组相较于常规组,手术时间、术中出血量、切口长度、切口愈合时间、术后各时间段VAS得分、瘢痕情况各指标、并发症总发生率均更低,差异有统计学意义(P<0.05)。结论:女性良性乳腺肿块患者应用超声引导MMT微创旋切术与传统手术组相比可提高手术效率、减少手术创伤、缩短患者术后恢复进程,还可改善患者术后疼痛情况,减少瘢痕形成及并发症发生风险。

Study on the Mechanism of Innovative Montmorillonite for Diarrhea Treatment

[Objective] This study aimed to investigate the mechanism of innovative montmorillonite for diarrhea treatment. [Method] Thirty healthy weanling piglets （Duroc x Landrace x Yorkshire） were randomly divided into five groups and fed with basal diet, basal diet ＋ 1 g/kg innovative montmorillonite, basal diet ＋ 3 g/kg innovative montmorillonite, basal diet ＋ 5 g/kg innovative montmorillonite and basal diet ＋ 3 g/kg Bacillus subtilis microecologic agent, respectively. After four weeks, blood samples were collected via precaval vein, to detect the content of TFF3, NO and SOD in serum by ELISA kits. [Result] Compared with blank control group, the content of TFF3, NO and SOD in high-dose innovative montmorillonite group was extremely significantly increased, extremely significantly reduced and significantly in- creased, respectively; the content of TFF3 and NO in middle-dose innovative mont- morillonite group was significantly increased and significantly reduced, respectively. [Conclusion] Innovative montmorillonite may exert beneficial therapeutic actions on diarrhea by increasing TFF3 and SOD levels and decreasing NO level.

P(AA-AM)/CS/MMT复合水凝胶的吸液与吸附性能

通过水溶液聚合法制备了聚(丙烯酸-丙烯酰胺)/预处理玉米秸秆(PCS)/有机蒙脱土(OMMT)复合水凝胶。采用FT-IR、XRD和SEM表征了水凝胶的微观结构和形貌,并测试了其吸液与吸附性能。结果表明,双单体接枝到纤维素骨架上,聚合物链插入了黏土片层,水凝胶的表面布满褶皱和孔隙。水凝胶的吸水率为150.2g·g^(-1),表现出良好的离子强度敏感性,对亚甲基蓝、结晶紫和孔雀石绿的吸附率分别为98.4%、97.2%和92.4%。

NiSO_(4)/OMMT复配体系协同膨胀阻燃环氧树脂的阻燃和抑烟性能

为降低环氧树脂的火灾危险性,以NiSO_(4)和有机蒙脱土(OMMT)复配体系作为协效剂用于增强膨胀阻燃环氧树脂的火安全性,通过氧指数测试仪、垂直燃烧测试仪、烟密度仪和锥形量热仪系统分析膨胀阻燃环氧树脂的阻燃和生烟性能。研究结果表明:单独添加NiSO_(4)或OMMT均能提高膨胀阻燃环氧树脂的阻燃、抑烟、热稳定性和成炭性能,将二者复配使用则表现出更优异的协效作用;当NiSO_(4)和OMMT以1∶1的质量比复配使用时,膨胀阻燃环氧树脂的极限氧指数(LOI)达到31.1%并通过UL94 V-0级测试,800℃时的残余质量达到22.6%,总释放热和总生烟量相比于纯环氧树脂分别降低56.0%,65.8%;炭层分析表明,NiSO_(4)和OMMT复配体系能提高试样燃烧后炭层的交联密度,增强炭层的致密性和隔热性,达到协效阻燃和抑烟的效果。研究结果可为提高环氧树脂基产品的阻燃和抑烟性能提供参考与借鉴。

Co_(3)O_(4)-MMT催化剂的制备及其N_(2)O催化分解性能

以MMT为载体,采用原位聚合-配位沉积法制备3种不同Co负载量的Co_(3)O_(4)-MMT催化剂。采用N 2物理吸附、XRD和TEM对载体和催化剂进行表征,并在连续流动微反装置上考察其N_(2)O催化分解性能。结果表明,与Co_(3)O_(4)催化剂相比,Co_(3)O_(4)-MMT催化剂的比表面积显著增大,且活性组分Co_(3)O_(4)具有较高的分散状态。Co_(3)O_(4)-MMT催化剂的催化活性随着Co含量的增加先升后降,其中0.015Co-MMT表现出最佳的催化活性,其活性远高于Co_(3)O_(4)催化剂,同时,该催化剂还表现出良好的催化稳定性和较好的杂质气体耐受性。

Preparation and characterization of wood/montmorillonite nanocomposites

With montmorillonite （MMT） organically modified as organophilic MMT （OMMT） and water-soluble phenol formaldehyde resin （PF） as intermediate, Chinese fir （Cunningharnia lanceolata） wood/MMT nanocomposites （WMNC） were prepared via nano intercalation compounding and characterized by XRD, SEM and FTIR. Results show that： 1） the preparation of OMMT is very successful; 2） the self-made PF can effectively intercalate into MMT to increase markably its gallery distance and even exfoliate its nano silicate laminae; 3） the XRD analysis indicates that some exfoliated MMT enters the non-crystallized region of microfibrils in wood cell walls and the crystallinity degree of wood in WMNC decreases; 4） the SEM graphs show that multiform MMT exists in WMNC. Some grains block in wood cell lumen, some layers adhere to the wood surface of the inner cell wall and some exfoliated nanolaminae even insert into wood cell walls; and 5） the FTIR analysis suggests that MMT and wood in WMNC perhaps interact via certain chemical bonding.

Cadmium adsorption in montmorillonite as affected by glyphosate

Behaviors of soil heavy metals are often affected by coexisting herbicides due to their physical and chemical interaction. Effect of glyphosate, an herbicide containing -PO 2- 3 and -COOH groups, on cadmium adsorption in montmorillonite was studied in detail. The results showed that the cadmium adsorption quantity in montmorillonite increased with increasing soil solution pH and cadmium concentration as usual, but decreased with glyphosate, which is due to the formation of a low affinity complex of Cd and glyphosate and decreasing solution pH induced by glyphosate addition. When the equilibrium solution pH was below 6.7, glyphosate has little effect on cadmium adsorption, but when the equilibrium solution pH was above 6.7, glyphosate significantly decreased cadmium adsorption quantity in montmorillonite. In addition, the adding order of Cd and glyphosate also influenced Cd adsorption quantity in montmorillonite.