炭化叶脉网络生长MOFs材料制备透明超级电容器

可穿戴和便携式电子设备迫切需要发展透明超级电容器等电化学储能器件。炭化树叶叶脉由连续的碳纤维网络构成,具有非常好的透明性,且兼具导电性好和质量轻的优点。本文以炭化菩提树叶叶脉网络为集流体,通过溶剂热法在其上原位生长了Ni/Co混合金属-有机框架材料（Ni/Co-MOF）。炭化叶脉的连续碳纤维网络有利于电子连续传输及电解液的输运;Ni/Co-MOF中混合金属中心有利于提供更多的电化学位点存储电荷。所制备的炭化叶脉网络@Ni/Co-MOF透明电极在1mA/cm²电流密度下表现出1.15F/cm²的高面积容量,经过1000次循环后,容量保持率为105.4%,仍具有良好的循环稳定性。以炭化叶脉网络@Ni/Co-MOF和炭化叶脉网络@活性炭组装成非对称透明超级电容器,在1.6V的大电势窗口、1mA/cm²的电流密度下,得到的面积容量为0.47F/cm²、面积能量密度为0.61W·h/cm²;并具有良好的循环稳定性,在循环300圈后,容量保持率为93.6%。炭化叶脉网络@MOF材料的方法将为制备透明功能器件如传感器、光电器件、太阳电池和锂离子电池等应用提供了新途径。     

分子筛材料在VOCs吸附中的研究进展

挥发性有机化合物（VOCs）的大量排放对我国大气环境已造成严重污染。本文综述了针对工业VOCs排放浓度低、风量大、含水等特点,分子筛作为较成熟的吸附材料在VOCs吸附处理中的应用。影响分子筛吸附VOCs的因素有孔径结构、表面性质、疏水性等。研究表明,与吸附质动力学尺寸相匹配的孔径和具有多级孔的分子筛吸附性能优良,引入适宜补偿阳离子也可加强吸附。文中指出：提高硅铝比或硅烷化改性来提高分子筛疏水性以及免除模板剂使用,降低成本,减小污染成为当下发展主流;在制备方法上打破传统水热合成法,使用固相法、微波辅助、晶种导入来降低能耗,实现绿色合成已成为新兴话题;研发多功能整体式材料以及吸附法和多种方法相结合来处理VOCs已成为未来发展趋势。     

废弃蛋壳源高性能钙基吸收剂的制备及其碳捕集性能

基于食品工业废弃蛋壳,本文利用不同有机酸反应制取乙酸钙、柠檬酸钙及葡萄糖酸钙共三种蛋壳源有机钙。在高温固定床反应器及热重分析仪上研究了不同前体所制成钙基吸收剂的碳循环捕集性能及碳酸化特性。进一步通过XRD分析了不同钙基吸收剂的物相组成,通过N₂吸附仪及SEM分析了循环前后钙基吸收剂结构特性及微观形貌的变化。结果表明,在三种蛋壳源有机钙中,葡萄糖酸钙所制成的钙基吸收剂具有较高的反应活性和相对最佳的碳捕集性能,首次碳酸化转化率高达85.33%,其钙基吸收剂相比其他吸收剂晶粒更小,20~100nm孔径范围内的孔隙较为发达,具有相对较强的抗烧结能力。经过20次循环实验发现,随着循环次数的增加,几种钙基吸收剂小颗粒均团聚烧结成大颗粒,造成孔隙结构缺失,孔隙率降低,影响其后续碳捕集性能。     

自修复防腐涂层的研究现状

通过物理屏蔽作用把金属和腐蚀环境进行隔绝的有机涂层,由于其经济、有效和操作方便的特点而成为主要的防腐措施。然而,环境因素往往不可避免地导致涂层产生裂纹,并最终导致涂层失效。具有自修复能力的涂层在发生破损后,由于其能够主动的修复涂层的破损部位而得到了广泛的关注。相对于具有单一物理屏蔽性能的涂层,具有自修复性能的涂层可以降低破损涂层维修期间的人力和物力成本,在未来的发展中具有很大的潜力。本文根据自修复涂层的愈合机理及其发展历程,把自愈合涂层分为自主修复型、借助外部刺激的非自主修复型和针对特定环境能够做出有效响应的智能自修复涂层,并对其研究现状及优缺点进行阐述。     

退役锂电池放电废水特征有机污染物解析

为研究退役锂电池盐水溶液放电产生的放电废水有机物的种类与来源,首先采用单因素优化方法对萃取剂类型、pH、萃取次数3个因素进行液-液萃取前处理优化实验,获得最佳萃取预处理条件。接着采用气相色谱与质谱联用（GC-MS）程序中分流比和升温模式对比实验,建立了放电废水有机成分定性分析方法,并对检出的有机污染物进行分类与来源判断。研究结果表明,选取乙酸乙酯为萃取剂,调节放电废水pH至9.38,以8000 r/min离心5min（4℃）,且采用间歇三次萃取时分离效果最优。对放电废水SIM定性扫描检测出10类有机污染物,其中酸酯类、酰胺类、烷烃类物质较多,且来源于反应衍生物与电解液添加剂的占比较大,分别为33.3%与20%,包括电解质增塑剂间苯二甲酸二(2-乙基己基)酯,电解液溶剂效应产物1,4-环己烷二羧酸二甲酯、磷酸 三(2-氯乙基)酯,电解液添加剂硬脂酰胺、十六碳酰胺、十四酰胺、1,4-环己烷二甲醇二乙烯醚,退役锂电池塑料外壳中抗氧剂原料3,5-二叔丁基苯酚等。这些物质对水环境均具有不同程度的毒性危害,需进一步检测各有机物浓度并揭示其迁移转化规律,建立退役锂电池放电废水重点关注有机污染物清单。     

蛭石层状膜的制备及有机溶剂纳滤性能

受全球能源形势与环境问题影响,新型膜分离技术尤其是二维层状膜在分离领域展现出广阔的应用前景。然而,目前使用的二维纳米材料化学环境相对复杂,且膜制备成本高昂,限制了其工业化推广。天然蛭石廉价易得,剥离简单,表面只含有硅羟基且其含量易于调控,可精确调控所制备层状膜层间亲疏水性,实现有机溶剂的高效渗透和极性与非极性溶剂的高效分离。研究发现：蛭石层状膜展现出优异的极性溶剂分子传递能力,而非极性溶剂则相对较低,其中乙腈分子渗透性高达1650L/（m²·h·bar)（1bar=0.1MPa）,甲苯分子渗透性仅为37.8L/（m²·h·bar),乙腈与甲苯的分离因子高达43.6,展现出优异的分子分离性能。本文所制备蛭石层状膜具有1.36nm的规则平直层间传递通道,对分子动力学直径大于层间距的结晶紫（1.5nm）、亮蓝（1.6nm）、酸性黄14（1.9nm）等染料分子的截留率均大于90%,截留性能优良。同时,蛭石层状膜具有良好的压力循环稳定性及抗污染能力, 展现出巨大的分离应用潜力。     

Simultaneous oxidation of aromatic compounds using Sr-doped lanthanum manganites as catalysts

Strontium-doped lanthanum manganites, La_1-xSr_xMnO₃ (LSMO), are promising and affordable catalysts for oxidative degradation of volatile organic compounds. LSMO catalysts (x = 0, .1, .2, and .3) were prepared by the citrate-nitrate autocombustion (CNA) and coprecipitation synthesis. The phase composition was confirmed by X-ray diffraction and Rietveld refinement analysis, while the oxygen content was determined by Mohr's salt permanganate titration. Morphology and porosity of prepared catalysts was correlated to catalytic oxidation of benzene, toluene, ethylbenzene and o-xylene. It was observed that both synthesis methods yielded catalysts of similar average pore size diameter and specific surface area, but the pore size distribution differed: CNA-prepared catalysts had a multimodal pore size distribution, while the coprecipitated ones had a single maximum at 4 nm. Catalysts prepared by the CNA method have shown a higher catalytic activity in the temperature range 373–723 K, as the presence of Mn³⁺/Mn⁴⁺ mixed valences increased their reducibility.     

Hierarchical porous metal-organic frameworks/polymer microparticles for enhanced catalytic degradation of organic contaminants

This work reports on a simple microfluidic strategy to controllably fabricate uniform polymeric microparticles containing hierarchical porous structures integrated with highly accessible catalytic metal organic frameworks for efficient degradation of organic contaminants. Monodisperse (W1/O)/W2 emulsion droplets generated from microfluidics are used as templates for the microparticle synthesis. The emulsion droplets contain tiny water microdroplets from homogenization and water nanodroplets from diffusion-induced swollen micelles as the dual pore-forming templates, and Fe-based metal-organic framework nanorods as the nanocatalysts. The obtained microparticles possess interconnected hierarchical porous structures decorated with highly accessible Fe-based metal-organic framework nanorods for enhanced degradation of organic contaminants via a heterogeneous Fenton-like reaction. Such a degradation performance is highlighted by using these microparticles for efficient degradation of rhodamine B in hydrogen peroxide solution. This work provides a simple and general strategy to flexibly combine hierarchical porous structures and catalytic metal-organic frameworks to engineer advanced microparticles for water decontamination.     

Nickel-based metal−organic framework-derived whisker-shaped nickel phyllosilicate toward efficiently enhanced mechanical,flammable and tribological properties of epoxy nanocomposites

Metal−organic framework-derived materials have attracted significant attention in the applications of functional materials. In this work, the rod-like nickel-based metal−organic frameworks were first synthesized and subsequently employed as the hard templates and nickel sources to prepare the whisker-shaped nickel phyllosilicate using a facile hydrothermal technology. Then, the nickel phyllosilicate whiskers were evaluated to enhance the mechanical, thermal, flammable, and tribological properties of epoxy resin. The results show that adequate nickel phyllosilicate whiskers can disperse well in the matrix, improving the tensile strength and elastic modulus by 13.6% and 56.4%, respectively. Although the addition of nickel phyllosilicate whiskers could not obtain any UL-94 ratings, it enhanced the difficulty in burning the resulted epoxy resin nanocomposites and considerably enhanced thermal stabilities. Additionally, it was demonstrated that such nickel phyllosilicate whiskers preferred to improve the wear resistance instead of the antifriction feature. Moreover, the wear rate of epoxy resin nanocomposites was reduced significantly by 80% for pure epoxy resin by adding 1 phr whiskers. The as-prepared nickel phyllosilicate whiskers proved to be promising reinforcements in preparing of high-performance epoxy resin nanocomposites.     

A ternary mechanism for the facilitated transfer of metal ions onto metal–organic frameworks: implications for the ‘‘versatility’’ of these materials as solid sorbents

Although metal–organic frameworks offer a new platform for developing versatile sorption materials, yet coordinating the functionality, structure and component of these materials remains a great challenge. It depends on a comprehensive knowledge of a “real sorption mechanism”. Herein, a ternary mechanism for U(VI) uptake in metal–organic frameworks was reported. Analogous MIL-100s (Al, Fe, Cr) were prepared and studied for their ability to sequestrate U(VI) from aqueous solutions. As a result, MIL-100(Al) performed the best among the tested materials, and MIL-100(Cr) performed the worst. The nuclear magnetic resonance technique combined with energy-dispersive X-ray spectroscopy and zeta potential measurement reveal that U(VI) uptake in the three metal–organic frameworks involves different mechanisms. Specifically, hydrated uranyl ions form outer-sphere complexes in the surface of MIL-100s (Al, Fe) by exchanging with hydrogen ions of terminal hydroxyl groups (Al-OH₂, Fe-OH₂), and/or, hydrated uranyl ions are bound directly to Al(III) center in MIL-100(Al) through a strong inner-sphere coordination. For MIL-100(Cr), however, the U(VI) uptake is attributed to electrostatic attraction. Besides, the sorption mechanism is also pH and ionic strength dependent. The present study suggests that changing metal center of metal–organic frameworks and sorption conditions alters sorption mechanism, which helps to construct effective metal–organic frameworks-based sorbents for water purification.