Amine-functionalized metal organic framework@graphene oxide as filler in PAEK-containing carboxyl group membrane for ultrafiltration with ultra-high permeability and strong fouling resistance

Achieving high fouling resistance and permeability using membrane separation technology in water treatment processes remains a challenge.In this work,a novel mixed-matrix membrane(MMM)(poly(arylene ether ketone)[PAEK]-containing carboxyl groups[PAEK-COOH]/UiO-66-NH_(2)@graphene oxide[GO])with superb fouling resistance and high permeability was prepared by the nonsolvent-induced phase separation method,by in-situ growth of UiO-66-NH_(2) on the GO layer,and by preparing hydrophilic PAEK-COOH.On the basis of the structure and performance analysis of the MMM,the maximum water flux reached 591.25 L·m^(-2)·h^(-1) for PAEK-COOH/UiO-66-NH_(2)@GO,whereas the retention rate for bovine serum albumin increased from 85.40%to 94.87%.As the loading gradually increased,the hydrophilicity of the MMMs increased,significantly enhancing their fouling resistance.The strongest anti-fouling ability observed was 94.74%,which was 2.02 times greater than that of the pure membrane.At the same time,the MMMs contained internal amide and hydrogen bonds during the preparation process,forming a cross-linked structure,which further enhanced the mechanical strength and chemical stability.In summary,the MMMs with high retention rate,strong permeability,and anti-fouling ability were successfully prepared.

Ultra-microporous Metal-organic Framework with High Concentration of Free Carboxyl Groups and Lewis Basic Sites for CO_2 Capture at Ambient Conditions

How to rationally design effective and practical CO_2 adsorbent is a great challenge. Herein, an ultra-microporous metal-organic framework(FJI-H19) with high concentration of free carboxyl groups and uncoordinated Lewis basic sites has been synthesized from a multi-dental ligand with a high proportion of polar CO_2-philic atoms. FJI-H19 displays a relatively high CO_2 volumetric uptake(120 cm^3?cm^(–3)) with high selectivity under practical atmosphere(298 K and 1 bar). Further researches demonstrate that such high adsorption results from an unusual synergistic effect from free carboxyl group and uncoordinated N atoms. This result will provide a potential strategy for developing more effective and pratical CO_2 adsorbent based on MOFs.

Preparation of large colored microspheres with carboxyl groups for cell surface labelling

The purpose of this experiment is to prepare a kind of large colored microspheres which can be observed under optical microscope and used for cell labelling. In the presence of organic solvent, electrolyte and dye, microspheres [styrene/acrylamide/dye (St AAm-Dye ) copolymerJ were synthesized from styrene and acrylamide by means of emulsifier-free emulsion polymerization. The carboxyl groups on the surface were derived from acrylarnide by hydrazinolysis and carboxylate reaction. The diameters of microspheres and the content of carboxyl groups on the surface were measured. The effect of the polymerization condition on microsphere size was discussed. The diam6ter of the colored microsphere was 3±0. 05μm; the content of carboxyl groups on the surface was 190. 5μmol/g (dry solids). The results indicate that it would be possible to obtain monodisperse and colored large polymer microspheres by this reported method.

Highly Hydrolysis-Resistant Polyimide Fibers Prepared by Thermal Crosslinking with Inherent Carboxyl Groups

Easy hydrolysis in alkaline environments limits the use of polyimide fibers in environmental protection. The hydrolysis resistance levels of polyimide fibers can be improved by crosslinking of the macromolecular chains. In this work, crosslinked polyimide fibers(CPI fibers) were produced by intrinsic carboxyl decarboxylation for the first time. The thermal stability of the polyimide fibers containing the intrinsic carboxyl groups(PIC fibers) was studied, and the temperature of the decarboxylation-crosslinking reaction was determined to be 450 ℃. The PIC fibers were hotdrawn to initiate thermal crosslinking of the carboxyl groups and molecular chain orientation at high temperature. The CPI fibers had high tensile strengths(0.72-1.46 GPa) and compressive strengths(401-604 MPa). The oriented macromolecules and chemically crosslinked structure improved the tightness of the molecular chains and endowed the CPI fibers with excellent hydrolytic resistance. The CPI-50 fiber did not dissolve in a 0.5 wt% NaOH solution during heating at 90 ℃ for 10 h, and the tensile strength retention reached 87% when treated in 0.5 wt% NaOH solutions at 90 ℃ for 1 h, providing a guarantee for its application in alkaline corrosive environments.

Carboxylic bacterial cellulose fiber-based hydrogel electrolyte with imidazole-type ionic liquid for dendrite-free zinc metal batteries

Aqueous zinc metal batteries are regarded as the most promising energy storage system due to their advantages of high safety,low cost,and high theoretical capacity.However,the growth of dendrites and the occurrence of side reactions hinder the development of zinc metal batteries.Despite previous attempts to design advanced hydrogel electrolytes,achieving high mechanical performance and ionic conductivity of hydrogel electrolytes has remained challenging.In this work,a hydrogel electrolyte with an ionic crosslinked network is prepared by carboxylic bacterial cellulose fiber and imidazole-type ionic liquid,following by a covalent network of polyacrylamide.The hydrogel electrolyte possesses a superior ionic conductivity of 43.76 mS cm^(−1),leading to a Zn^(2+)migration number of 0.45,and high mechanical performance with an elastic modulus of 3.48 GPa and an elongation at breaking of 38.36%.More importantly,under the anion-coordination effect of the carboxyl group in bacterial cellulose and[BF4]−in imidazole-type ionic liquid,the solvation sheath of hydrated Zn^(2+)ions and the nucleation overpotential of Zn plating are regulated.The results of cycled testing show that the growth of zinc dendrites is effectively inhibited and the generation of irreversible by-products is reduced.With the carboxylic bacterial cellulose-based hydrogel electrolyte,the Zn||Zn symmetric batteries offer good cyclability as well as Zn||Ti batteries.

Carboxyl groups trigger the activity of carbon nanotube catalysts for the oxygen reduction reaction and agar conversion

Ozone treatment is a common way to functionalize commercial multi-walled carbon nanotubes （CNTs） with various oxygen functionalities like carboxyl, phenol and lactone groups, in order to enhance their textural properties and chemical activity. In order to detail the effect of each functional group, we correlated the activity with the surface density of each group, and found that the carboxyl groups play a pivotal role in two important catalytic reactions, namely the electrochemical oxygen reduction reaction （ORR） and agar conversion to 5-hydroxymethylfurfural （HMF）. During the processes, the hydrophilic surface provides a strong affinity for reaction substrates while the improved porosity allows the efficient diffusion of reactants and products. Furthermore, the activity of functionalized CNTs for agar conversion remained almost unchanged during nine cycles of reaction. This work highlights a strategy for improving the activity of CNTs for electrochemical ORR and agar conversion reactions, as well a promising application of carboxyl-rich CNTs as a solid acid catalyst to produce high-purity HMF--an important chemical intermediate.

Construction of Safety and Non-flammable Polyimide Separator Containing Carboxyl Groups for Advanced Fast Charing Lithium-ion Batteries

With the wide applications of lithium-ion batteries(LIBs)in electronic devices and electric vehicles,it is of great importance to improve their safety and electrochemical performance.Herein,soluble polyimides(PI)containing carboxyl groups(―COOH)were synthesized by a simple one-step method and PI separators with sponge-like,interpenetrating porous structures were prepared via non-solvent induced phase separation(NIPS).The obtained PI separators exhibited excellent thermal stability and fire-resistance properties,with the electrolyte uptake of 344%and good dimensional integrity in air at 200℃.The results showed that the lithium-ion transference number of the obtained PI separator could reach 0.48,which was much higher than that of the Celgard-2400 separator(0.38).The Li/LiFePO_(4) half-cell with the PI separator showed excellent cycle capability and high-rate performance with a high capacity of 121.80 mA·h·g^(-1) at 5 C,which was better than that of the cell with the Celgard-2400 separator(54.3 mA·h·g^(-1)),demonstrating the promising applications of this PI separators in LIBs.

Synthesis of Polycaprolactone with Two Carboxyl End Groups

At 225℃. caprolactone has been polymerized in the presence of succinic acid under dry nitrogen atmosphere. Characterizations of the polymer through IR and molecular weight measurements by 1H-NMR and end group titration have shown that the polycaprolactone obtained is of two carboxyl end groups. The molecular weight of it increases with decreasing of the acid content in the reaction mixture under the same polymerization conditions. With a certain ratio of acid to caprolactone. the maximum of molecular weight of the polymer will be reached at the reaction time of 3h.

Synthesis and characterization functionalized poly(ether ether ketone)s with carboxylic groups

A novel type of aromatic poly（ ether ether ketone） s with carboxyl groups were prepared by polycondensation of 4,4-bis（4-hydroxyphenyl）pentanoic acid with difluoro-monomers. Their mo- lecular structures were determined by ^1H-NMR and IR, respectively. Their molecular weights were measured by gel permeation chromatography （ GPC ）, which showed that all the polymers had high molecule weights （ 〉 42 000）. Due to the long side chains of polymers, all the polymers had good solubility （soluble in NMP, DMAc, THF, etc. ）. The differential scanning calorimeter （DSC） detected their excellent glass transition temperatures （ Tg ） up to 195 ℃. The Tg increased with the content of carboxylic units in the polymer chains, because the interactions of H bonds increased with increasing content of carboxylic. The polymers could form transparent and flexible films, which make them a candidate for membrane materials.

羧基化柚子皮吸附Cd^(2+)的性能与机制

为探索利用食品加工废弃物柚子皮制备一种重金属离子吸附材料的可行性,通过NaOH将柚子皮中甲酯化的羧基水解成羧酸,再利用TEMPO/次氯酸钠/溴化钠体系将柚子皮中C-6位伯羟基氧化成羧酸,制备出一种羧基化柚子皮吸附材料,同时采用FTIR、SEM-EDS和XPS对柚子皮和吸附Cd^(2+)前后的羧基化柚子皮进行表征,研究其吸附机制。结果表明羧基化柚子皮中羧基含量为2.34 mmol/g,是改性前的10.64倍,且可以有效地去除水溶液中Cd^(2+)。羧基化柚子皮吸附Cd^(2+)更符合Langmuir和伪二阶动力学模型,属于单层化学吸附,对Cd^(2+)的最大吸附量为76.16 mg/g,是改性前的5.81倍。羧基化柚子皮中羧基(-COO^(-))是吸附Cd^(2+)的功能性基团,吸附后形成羧酸镉,其中镉以Cd^(2+)的形式存在,与-COO^(-)的配位方式主要是双齿桥式,该吸附过程是一个阳离子(Na^(+)和Cd^(2+))交换的过程。

聚酰胺纳滤膜表面羧基密度调控及其抗污染性能

采用均苯三甲酰氯(TMC)、对苯二甲酰氯(IPC)与哌嗪进行界面聚合反应,制备了不同羧基密度的聚酰胺纳滤膜.研究了羧基密度对膜污染的影响,并对纳滤膜的镁-锂分离选择效果进行评估.结果表明,TMC纳滤膜的羧基密度是IPC纳滤膜的3倍,水通量分别为81.9 L/(m^(2)·h·MPa)和56.5 L/(m^(2)·h·MPa).TMC纳滤膜对硫酸镁、氯化钠的截留效果优于IPC纳滤膜,对卤水镁的截留率达82.66%,对锂的截留率为-27.82%,具有较好的镁-锂分离选择效果.膜污染结果显示,TMC纳滤膜的不可逆通量衰减指数是IPC纳滤膜的3倍,抗污染能力与膜面羧基密度成反比.结果证实了膜面羧基官能团在膜污染中的关键作用,为制备具备抗污染性和高镁-锂分离比的纳滤膜提供了新思路.

羧基对聚硫脲介电储能特性的影响研究

引入极性羧基被认为是提高聚合物介电性能的有效方法,但羧基对聚硫脲(Polythiourea,PTU)介电储能特性的影响尚不清楚。本文采用实验和理论相结合的方法,深入开展了羧基、偶极极化和电荷输运特性与PTU电学性能之间的关联研究,揭示了羧基对PTU介电常数和击穿场强的影响机理,最终建立了储能密度与羧基侧链结构的关联机制。结果表明,分子链引入极性羧基作为侧链结构,可以扩大分子链间距,促进羧基转向,进而增强偶极极化强度,增大介电常数;但羧基电离产生的本征氢离子会增大体系的电导和损耗,造成击穿场强降低;在PTU中引入少量羧基可以实现高介电常数、高击穿场强和高储能密度。

丙烯酸酯类两亲性共聚物超滤膜的制备及性能

为探索环保型高性能水处理超滤膜材料,设计、合成了仅含碳、氢、氧元素的丙烯酸酯类两亲性共聚物-聚(甲基丙烯酸甲酯-co-丙烯酸丁酯-co-甲基丙烯酸)[P(MMA-co-BA-co-MAA),简写为PMBM],研究了PMBM超滤膜的制备、结构和性能.研究发现,通过非溶剂诱导相转化法(NIPS)制备的PMBM超滤膜具有良好的亲水性和抗污染性,不同羧基含量的PMBM膜在不同pH下的性能差别较大.其中MAA质量分数为11%的PMBM-11膜在中性条件下纯水通量为1310 L/(m^(2)·h·MPa),对BSA的截留率为98%,BSA污染后的通量恢复率(FRR)达到79%.

黄原胶改性及对活性染料印花性能的影响

为了改善黄原胶在棉织物上的印花性能,以过氧化氢为氧化剂将黄原胶分子结构中的羟基氧化成羧基,对黄原胶进行氧化改性。结果表明:当过氧化氢用量为1.5%,反应温度为60℃,反应时间为1.5 h时,改性后的黄原胶可以获得与海藻酸钠接近的印花效果;傅里叶变换红外光谱仪和Zeta-电位仪的测定结果表明,氧化反应使得黄原胶结构中的羟基被氧化成了羧基。

聚酯生产过程端羧基含量控制的浅析

介绍了聚酯生产工艺流程和工艺调整方向,重点分析了熔体中端羧基含量的影响因素和控制方法。端羧基含量是衡量聚酯生产的一个重要指标,它直接影响聚酯熔体的加工稳定性和下游产品的品质。根据酯化反应和缩聚反应的原理,从原料、反应条件、真空系统等方面,探讨了造成熔体中端羧基含量偏高的原因和解决对策,以及针对性工艺调整后的效果和特点。结合生产实践,提出了分类检查和应对方法,以保障聚酯装置长期稳定运行。

聚酯工艺指标对纺丝断头的影响及解决对策

在中纺院年产30万t四釜聚酯装置上,研究第一酯化酸值、端羧基含量和特性黏度对纺丝断头的影响。研究数据表明:第一酯化酸值控制在58~60 mg/g、端羧基含量控制在37~40 mol/t、熔体特性黏度控制在0.622~0.630 dL/g时,纺丝断头次数为最少。同时,得出影响第一酯化酸值、端羧基含量和熔体特性黏度的因素为液位、回用乙二醇、反应温度、压力、搅拌速度、真空度以及添加的催化剂含量等,通过优化这些因素,使聚酯工艺指标最佳。

Synthesis, Structure and Properties of a Strontium(Ⅱ) Complex with 2, 3-Pyrazinedicarboxylic Acid

Complex [Sr2（pdc）2（H2O）7]·H2O （1, H2pdc = 2,3-pyrazinedicarboxylic acid） has been synthesized and characterized by single-crystal X-ray diffraction studies and FT-IR. Structural determination reveals that there are two crystallographically independent strontium ions in 1. The coordination geometry of Sr（1） is a nine-coordinated distorted monocapped tetragonal antiprism, while Sr（2） is a nine-coordinated distorted monocapped tetragonal prism. The ligand pdc2- takes two different connecting modes and links St（If） centers to generate a 2D layer structure. The 2D layers are linked through O-H...O and O-H...N hydrogen bonds to form a 3D framework structure. Thermal stability and luminescent properties of complex 1 are investigated. 1 belongs to the monoclinic system, space group P21/n with a = 10.7182（10）, b = 7.0377（6）, c = 29.225（3） A, β = 95.7170（10）°, Z = 4, V = 2193.5（3） A3, Mr = 651.56, Dc = 1.973 g/cm3, F（000） = 1296,μ = 4.951 mm-1, the final R = 0.0318 and wR = 0.0726 for 3938 observed reflections with I 〉 2σ（/）.

Synthesis, Structure and Properties of a Two-dimensional Samarium(Ⅲ) Complex of 1,3-Benzenedicarboxylic Acid and 1,10-Phenanthrolin

The title complex [Sm2（bdc）3（phen）2]n （1, H2bdc = 1,3-benzenedicarboxylic acid, phen = 1,10-phenanthrolin）, a new samarium（III） complex based on ligand H2bdc and 1,10-phen- anthrolin, has been hydrothermally synthesized and characterized by elemental analysis, FT-IR, and single-crystal X-ray diffraction. The crystal structure reveals that the Sm（1） centre adopts an eight-coordinated distorted square anti-prism coordination geometry, while the Sm（2） centre adopts a nine-coordinated distorted monocapped square prism coordination geometry. The ligand bdc2- takes two different connecting modes and links the Sm（llI） centers to give rise to a 2D network structure. Further, 2D layers of 1 are connected together to form a 3D structure through C-H-O hydrogen bonding interactions. The luminescent property and thermal stability of complex 1 are studied. 1 belongs to the triclinic system, space group P1 with a = 10.7367（5）, b = 14.3750（7）, c = 13.7505（3）A, a = 92.8840（10）, β = 104.4010（10）, ）, = 98.1400（10）°, Z= 2, V= 2143.44（18） A3, Mr = 1153.44, Dc = 1.787 g/cm3, F（000） = 1128,μ= 2.784 mm-1, the final R = 0.0279 and wR = 0.0720 for 8226 observed reflections with 1 〉 2σ（I）.

Insights into the role of oxygen-containing functional groups on carbon surface in water–electricity generation

A deep understanding of the electricity generation mechanism from the interaction between water molecules and carbon material surfaces is attractive for next-generation water-based energy conversion and storage systems.Herein,an asymmetric generator was assembled based on functionalized carbon nanotubes films to investigate the relative contribution from various oxygen functional groups on carbon surface to the water-electrical performance.Experiments and calculations demonstrate that the electricity mainly originates from the water molecule adsorption by carboxyl groups and dissociation of functional groups on carbon surface,which leads to the formation of electrical double layers at interfaces.This device allows the electricity generation with a variety of water sources,such as deionized water,tap water,as well as seawater.In particular,the generator based on carboxyl carbon nanotubes can induce a voltage of over 200 mV spontaneously in natural seawater with the power density of about 0.11 mW·g^(−1).High voltages can be achieved easily through the series-connection strategy to power electronic products such as a liquid crystal display.This work reveals the dominant role of carboxyl groups in carbon-based water–electricity conversion and is expected to offer inspiration for the preparation of carbon materials with high electrical performance.

两性纤维素基吸附剂的制备及其吸附性能研究

本研究以蔗渣制备的微晶纤维素为基体,以含氨基和羧基的两性小分子为功能试剂,以环氧氯丙烷为交联剂,采用交联法制备了一种具有高羧基含量(5.11 mmol/g)和氨基含量(7.43 mmol/g)的两性纤维素基吸附剂,并解析了重金属离子在其表面的竞争吸附行为和吸附动力学。结果表明,该吸附剂可在120 min内将1.0 mg/L的Cr(Ⅵ)、Pb(Ⅱ)、Cd(Ⅱ)和2.0 mg/L的Cu(Ⅱ)同步去除至0.0030 mg/L以下,使溶液中重金属离子残余浓度符合国家安全饮用水标准GB 5749—2022,实现了低浓度多种重金属离子的同步高效去除;吸附剂对重金属离子的吸附吻合Langmuir吸附等温线模型,以单层化学吸附为主,对Cr(Ⅵ)、Cu(Ⅱ)、Pb(Ⅱ)和Cd(Ⅱ)的理论最大吸附容量分别为373.1、128.4、134.4和113.3 mg/g。