ZIF-8/改性聚丙烯腈电纺纳米纤维的制备及其高效去除水中孔雀石绿

通过原位生长方法，将最常见的金属有机骨架（MOFs）——沸石咪唑酯骨架材料（ZIF‐8）固定到羧甲基化聚丙烯腈静电纺丝纳米纤维（PAN‐COOH NFs）表面，得到ZIF‐8/PAN‐COOH NFs。通过扫描电子显微镜（SEM）、能量色散光谱（EDS）、X射线粉末衍射（XRD）和傅里叶变换红外光谱（FTIR）对合成的ZIF‐8/PAN‐COOH NFs形貌和结构进行表征，并深入研究ZIF‐8/PAN‐COOHNFs从废水中去除孔雀石绿（MG）的性能。研究发现： ZIF‐8/PAN‐COOH NFs对MG的吸附符合拟二级动力学方程，吸附过程可采用Langmuir等温线模型拟合，其对MG的最大吸附容量可达3 604 mg·g^-1。此外，ZIF‐8/PAN‐COOH NFs在染料吸附实验中表现出良好的分离功能和重复利用性。     

基于ZIF-8的新型复合吸附材料及从水中吸附孔雀石绿的应用

近年来,ZIFs型金属-有机骨架材料被发现可作为吸附剂应用于吸附分离水中有机污染物。但由于ZIFs的非球形型粉末形态及强的疏水性使其在水溶液中分散性差,不利于充分发挥吸附性能。针对这一不足,本文以聚丙烯酸酯羧基微球(PC-SMM)为载体,通过原位生长法在其表面生长一层ZIF-8纳米粒子外壳层,制备既具备ZIF-8粒子的结构特性又呈现出微球形态的ZIF-8/PC-SMM复合微球。以MG水溶液为分离体系来评价ZIF-8/PC-SMM复合微球的吸附分离性能,结果显示,ZIF-8/PC-SMM复合微球对MG的吸附量高达101.2mg/g,与ZIF-8及PC-SMM微球相比,其吸附性能得到明显提高。     

不同尺寸ZIF-8对U(VI)的吸附性能

以经典的金属有机骨架(MOFs)材料ZIF-8为吸附剂,研究尺寸效应对铀吸附性能的影响。 通过3种方法合成不同粒径的ZIF-8,利用扫描电子显微镜(SEM)、X射线粉末衍射仪(XRD)、表面积与孔隙度分析仪等对其进行了表征,测试了相同条件下不同尺寸的ZIF-8对硝酸铀酰溶液中U(VI)吸附,分别对其吸附过程的动力学和吸附等温线进行了考察,并测试了材料的可重复利用性。 结果表明,成功制备了高结晶性、高纯度的ZIF-8,产物形貌呈菱形十二面体,颗粒均匀,粒径分别为约50 nm、150 nm及2 μm;3种ZIF-8具有单一均匀的微孔结构和与粒径高度相关的比表面积;不同尺寸的ZIF-8均能快速吸附溶液中的U(VI),在室温pH=3下,在70 min左右时即可吸附初始质量浓度为200 mg/L的U(VI)溶液中90%以上U(VI);其中较小尺寸(约50 nm)的ZIF-8吸附性能最好,单位质量ZIF-8吸附U(VI)的饱和吸附量达到520.26 mg/g;ZIF-8对U的吸附动力学上符合二级动力学方程,吸附等温线符合Langmuir模型,说明ZIF-8对U(VI)的捕获属于化学单层吸附;经过4个吸附-解吸循环后,3种尺寸的ZIF-8均依然保持了70%以上的去除率。     

用于高效去除水中孔雀石绿的三层结构磁性复合材料Fe3O4@聚丙烯酸@ZiF-8的制备

设计并合成了一种以磁性纳米粒子为核,聚合物为中间层,金属有机骨架材料为外层的三层结构磁性复合材料(Fe₃O₄@PAA@ZIF-8)。首先利用溶剂热法制备Fe₃O₄纳米粒子,然后通过蒸馏沉淀聚合法在Fe₃O₄纳米粒子表面包覆聚丙烯酸(PAA)层,最后通过原位沉积法在PAA外部包覆ZIF-8。在对Fe₃O₄@PAA@ZIF-8的组成和结构进行表征的基础上,深入研究其对孔雀石绿(MG)的吸附性能。透射电子显微镜(TEM)显示Fe₃O₄@PAA@ZIF-8具有明显的三层结构,Fe₃O₄的平均粒径为117nm,PAA层厚度约为17 nm,ZIF-8层的厚度约为14 nm。Fe₃O₄@PAA@ZIF-8对MG的吸附量随着p H的升高而增大,吸附过程符合准二阶动力学模型和Langmuir等温吸附模...     

ZIF-8的制备及其作为杀菌药物载体的研究

采用室温搅拌法制备了金属有机骨架材料ZIF-8.通过X射线粉末衍射(XRD)、红外光谱(IR)、N2吸附-脱附、透射电子显微镜(TEM)和扫描电子显微镜(SEM)对所得样品进行了表征分析,并以苯扎氯铵为杀菌药物模型,研究了ZIF-8对苯扎氯铵这种药物的载药及体外释药性能.表征结果显示,制备的ZIF-8是一种具有规则十二面体方钠石结构的晶体,BET比表面积为2 643m2/g.载药及体外释放实验表明,ZIF-8对浓度为4mmol/L苯扎氯铵的载药量为43g/100g ZIF-8,载药后的ZIF-8在释放90h后,释放率达84.82%,说明ZIF-8对苯扎氯铵有较好的缓释性能.     

ZIF-8的合成、表征及正己烷吸附性能

以甲醇为溶剂,硝酸锌六水合物为锌源,2-甲基咪唑为有机配体,通过溶剂热法合成了金属有机骨架材料ZIF-8;采用X射线衍射(XRD)、氮气吸附、热重-差热分析(TG-DSC)和扫描电子显微镜(SEM)等方法对ZIF-8样品进行了表征;研究了正己烷在ZIF-8上的液相吸附动力学和动态选择性吸附性能.结果表明,合成的ZIF-8晶体具有方钠石结构,结晶度较高,孔结构主要为0.37~1.10 nm的微孔,BET比表面积为1836 m2/g,孔体积为0.65 cm~3/g.TG-DSC和高温原位XRD分析结果表明,合成的ZIF-8具有良好的热稳定性能.283~313 K时,正己烷在ZIF-8上液相吸附的扩散系数为(2.53~8.88)×10-12cm~2/s,扩散活化能为31.11 k J/mol;308 K时,ZIF-8对正己烷的动态饱和吸附量为187.3 mg/g,由吸附穿透曲线计算得出Thomas速率常数为2.17×10~(-3)m L·min~(-1)·mg~(-1).与5A分子筛相比,ZIF-8对正己烷的吸附容量高出约1倍,液相吸附表观扩散时间常数高出约70%.     

ZIF-8吸附剂上CH4/N2的吸附分离性能与热力学性质

将沸石咪唑酯骨架结构材料应用于抽放煤层甲烷的浓缩净化研究。以三乙胺(TEA)为导向剂,ZnSO₄为金属离子源,水为溶剂,采用水热合成法进行了ZIF-8吸附剂的制备。采用XRD、物理吸附、动态吸附分离和反相气相色谱(IGC)等方法对ZIF-8的物理结构、化学稳定性、吸附分离性能和热力学性质进行了研究。结果表明,ZIF-8具有良好的化学稳定性,能够在强酸、强碱和强极性的溶剂中保持结构的稳定性;在298 K时,ZIF-8对CH₄/N₂的分离因子达到3.4,与活性炭相当,但CH₄、N₂在ZIF-8上的吸附热比在活性炭上低20%左右。     

三氮唑修饰ZIF-67材料的制备及其对碘的捕获研究

采用2-甲基咪唑为主配体、1,2,4-三氮唑(3NIM)为修饰配体,与钴离子反应制备三氮唑修饰ZIF-67材料,通过配体修饰调节其表面形貌,得到了一种具有与ZIF-67相同晶体结构的金属-有机骨架材料ZIF-67 (3NIM)。红外光谱结果显示三氮唑配体进入ZIF-67的骨架中;热重分析表明,该材料具有良好的热稳定性;场发射扫描电镜结果表明,其粒径较3NIM修饰前增大,但随着修饰配体浓度的升高团簇现象变得更为严重。将ZIF-67 (3NIM)材料应用于碘单质的气相和液相吸附中,在75℃下对碘蒸气的吸附量可达到6.66g/g,较未修饰的ZIF-67 (碘吸附量5.16g/g)提高了29%;在环己烷溶液中的碘去除率也有显著提高,去除率最高可达97.5%。结果表明,氨基配体修饰的ZIF-67系列材料有望用于放射性碘的高效去除。     

ZIF-8材料中CH4/H2吸附与扩散的分子模拟

采用平衡分子动力学和巨正则系综蒙特卡洛模拟方法对多孔沸石咪唑酯骨架材料(ZIF-8)中CH4和H2分子的吸附与扩散特性进行了比较研究.结果表明,采用柔性力场能够很好地复制ZIF-8在不同压力或温度条件下的晶体结构,也能准确地计算不同温度下CH4和H2分子在ZIF-8中的扩散系数,特别是高温下CH4分子因能够摆脱ZIF-8骨架笼口的空间限制而使其扩散系数出现大幅提升.同时,该力场也能粗略地模拟CH4和H2分子在ZIF-8中的等温吸附曲线,通过自编程序得到吸附和扩散平衡时CH4和H2分子在ZIF-8单元晶胞内的几率密度分布数据,并利用VMD软件可视化.结果显示CH4和H2分子在ZIF-8中的优先吸附位置均在大孔中心靠近咪唑环的区域,但CH4分子的优先吸附位置有两个不同层次,而H2分子的优先吸附位置只有一个层次,说明CH4和H2分子在ZIF-8中存在着不同的吸附机理.     

金属有机骨架材料/聚酰亚胺混合基质膜的制备及气体分离性能

合成了3种不同结构、 粒径和气体吸附性能的金属有机骨架材料(MOFs): 微米级Cu₃(BTC)₂、 亚微米级ZIF-8和S-Cu₃(BTC)₂. 氮气吸附等温线分析结果表明, ZIF-8和Cu₃(BTC)₂具有较大比表面积(1653和1439 m²/g), S-Cu₃(BTC)₂的比表面积为171.4 m²/g. 用共混法将MOFs直接引入聚酰亚胺中制备了MOFs/聚酰亚胺混合基质膜(MMMs). X射线衍射(XRD)和全反射红外光谱(FTIR-ATR)分析结果表明, MOFs在混合基质膜中保持物理和化学稳定. 气体渗透测试结果表明, MOFs的加入使膜的气体渗透分离性能明显提高, S-Cu₃(BTC)₂使渗透系数增加了1.75倍; ZIF-8和Cu₃(BTC)₂使渗透系数增加了3倍左右; 同时, 膜的气体分离系数变化很小.     

用于高效去除水中孔雀石绿的三层结构磁性复合材料Fe3O4@聚丙烯酸@ZiF-8的制备

设计并合成了一种以磁性纳米粒子为核，聚合物为中间层，金属有机骨架材料为外层的三层结构磁性复合材料(Fe₃O₄@PAA@ZIF 8)。首先利用溶剂热法制备Fe₃O₄纳米粒子，然后通过蒸馏沉淀聚合法在Fe₃O₄纳米粒子表面包覆聚丙烯酸(PAA)层，最后通过原位沉积法在PAA外部包覆ZIF 8。在对Fe₃O₄@PAA@ZIF 8的组成和结构进行表征的基础上，深入研究其对孔雀石绿(MG)的吸附性能。透射电子显微镜(TEM)显示 Fe₃O₄@PAA@ZIF 8 具有明显的三层结构，Fe₃O₄的平均粒径为 117nm，PAA 层厚度约为 17 nm，ZIF 8层的厚度约为 14 nm。Fe₃O₄@PAA@ZIF 8对 MG 的吸附量随着 pH 的升高而增大，吸附过程符合准二阶动力学模型和 Langmuir等温吸附模型。此外，Fe₃O₄@PAA@ZIF 8还表现出良好的重复利用性能，8次循环利用后对MG(500 mg·L^-1)的最大吸附量仍可达982 mg·g^-1。     

ZnO-rich CdS-ZIF-8 catalyst for enhanced visible-light photocatalytic degradation of methylene blue

CdS-ZIF-8 photocatalyst was prepared by introducing a ZnO-rich zeolitic imidazolate framework-8 (ZIF-8) during synthesis of CdS by a facile solvothermal method, using ZnO-rich ZIF-8 and cadmium acetate [Cd(Ac)₂] as support and CdS precursor, respectively. The introduction of ZnO-rich ZIF-8 and the photodegradation performance of the catalyst for methylene blue (MB) organic dye were systemically investigated. The CdS-ZIF-8 catalysts were also characterized using X-ray diffraction analysis, transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy, N₂ adsorption–desorption measurements, Fourier-transform infrared (FT-IR) spectroscopy, ultraviolet–visible (UV–Vis) diffuse reflectance spectroscopy (DRS), and photoluminescence spectroscopy. The results indicated that CdS-ZIF-8 contained ZIF-8, CdS, and ZnO phases. The CdS in CdS-ZIF-8 catalysts exhibited smaller particle size compared with pure CdS. Furthermore, compared with pure CdS, CdS-ZIF-8-30 with introduction of ZnO-rich ZIF-8 exhibited higher surface area (77.3 m²/g) and pore volume (0.103 cm³/g). EDX and FT-IR results suggested that a CdS/ZnO heterostructure was formed, which effectively reduced recombination of photogenerated electron–hole pairs. Radical trapping experimental data and band edge position analysis revealed that Z-scheme behavior also played a role in the system. Relying on the combined effect of their structure, the photodegradation efficiency of all the CdS-ZIF-8 catalysts was obviously superior to that of pure CdS for degradation of MB under visible-light irradiation. Photodegradation results illustrated that CdS-ZIF-8 with introduction of 30 mg ZnO-rich ZIF-8 (denoted as CdS-ZIF-8-30) exhibited optimal photodegradation activity.     

Effect of acid and alkali treatments of a forest waste,Pinus brutia cones,on adsorption efficiency of methyl green

The removal of methyl green (MG) dye from aqueous solutions using acid- or alkali-treated Pinus brutia cones (PBH and PBN) waste was investigated in this work. Adsorption removal of MG was conducted at natural pH, namely, 4.5 ± 0.10 for PBH and near 4.8 ± 0.10 for PBN. The pseudo-second-order model appeared to be the most appropriate to describe the adsorption process of MG on both PBN and PBH with a correlation coefficient R² > 0.999. Among the tested isotherm models, the Langmuir isotherm was found to be the most relevant to describe MG sorption onto modified P. brutia cones with a correlation factor R² > 0.999. The ionic strength (presence of other ions: Cl^?, Na⁺, and SO₄^2?) also influences the adsorption due to the change in the surface properties; it had a negative impact on the adsorption of MG on these two supports. A reduction of 68.5% of the adsorption capacity for an equilibrium dye concentration Ce of 30 mg/L was found for the PBH; while with PBN no significant influence of the ionic strength on adsorption was observed, especially in the presence of NaCl for dye concentrations superior to 120 mg L^?1.     

Synthesis and characterization of CDs/Al2O3 nanofibers nanocomposite for Pb2+ ions adsorption and reuse for latent fingerprint detection

This study reports a new approach of preparation of carbon dots coated on aluminum oxide nanofibers (CDs/Al₂O₃NFs) nanocomposite and reusing the spent adsorbent of lead (Pb²⁺) ions loaded adsorbent (Pb²⁺-CDs/Al₂O₃NFs) nanocomposite for latent fingerprint detection (LFP) after removing Pb²⁺ ions from aqueous solution. CDs/Al₂O₃NFs nanocomposite was prepared by using CDs and Al₂O₃NFs with adsorption processes. The prepared nanocomposite was then characterized by using UV–visible spectroscopy (UV–visible), Fourier transforms infrared spectroscopy (FTIR), Fluorescence, X-ray diffraction pattern (XRD), scanning electron microscope (SEM), Transmission electron microscopy (TEM), Energy-dispersive X-ray spectroscopy (EDS), Zeta potential, X-ray photoelectron spectroscopy (XPS). The average size of the CDs was 51.18 nm. The synthesized CDs/Al₂O₃NFs nanocomposite has proven to be a good adsorbent for Pb²⁺ ions removal from water with optimum pH 6, dosage 0. 2 g/L. The results were best described by the Freundlich Isotherm model. The adsorption capacity of CDs/Al₂O₃NFs nanocomposite showed the best removal of Pb²⁺ ions with q_m = (177. 83 mg/g), when compared to the previous reports. This adsorption followed the pseudo-second order kinetic model. ΔG and ΔH values indicated spontaneity and the endothermic nature of the adsorption process. CDs/Al₂O₃NFs nanocomposite therefore showed potential as an effective adsorbent. The data were observed from adsorption–desorption after 6 cycles which showed good adsorption stability and re- usability of CDs/Al₂O₃NFs nanocomposite. Furthermore, the spent adsorbent of Pb²⁺-CDs/Al₂O₃NFs nanocomposite has proven to be sensitive and selective for LFP detection on various porous substrates. Hence Pb²⁺-CDs/Al₂O₃NFs nanocomposite can be reused as a good fingerprint labelling agent in LFP detection so as to avoid secondary environmental pollution by disposal of the spent adsorbent.     

Quartzite an efficient adsorbent for the removal of anionic and cationic dyes from aqueous solutions

Quartzite obtained from local source was investigated for the removal of anionic dye congo red (CR) and cationic dye malachite green (MG) as an adsorbent from aqueous solution in batch experiment. The adsorption process was studied as a function of dye concentration, contact time, pH and temperature. Adsorption process was described well by Langmuir and Freundlich isotherms. The adsorption capacity remained 666.7 mg/g for CR dye and 348.125 mg/g for MG dye. Data was analyzed thermodynamically, ΔH⁰ and ΔG⁰ values proved that adsorption of CR and MG is an endothermic and spontaneous process. Adsorption data fitted best in the pseudo-first order kinetic model. The adsorption data proved that quartzite exhibits the best adsorption capacity and can be utilized for the removal of anionic and cationic dyes.     

Preparation of unsaturated polyester Ce(IV) phosphate by plastic waste bottles and its application for removal of Malachite green dye from water samples

In this paper, recycling of polyethyleneterephthalate (PET), a non-biodegradable plastic, was carried out by preparing unsaturated polyester Ce(IV) phosphate (USPECe(IV)P) composite cation exchanger. Various samples of USPECe(IV)P was prepared by mixing different volume ratios of unsaturated polyester in an inorganic Ce(IV) phosphate gel and characterized by TGA/DTA, XRD, SEM, Fourier transform infra-red spectroscopy (FTIR) instrumental methods. The composite has been employed as adsorbents for the removal of Malachite green dye from waste water. The nature of possible adsorbent and dye interaction was examined by the FTIR technique. The adsorption of MG was found to be maximum (98%) at pH 8. The extent of removal of MG was found to be dependent on adsorbent dose, temperature and time. The equilibrium data for adsorption was best represented by the Friendlich isotherm. Thermodynamic parameters (ΔH⁰ and ΔG⁰) suggest an endothermic and spontaneous process. Kinetic studies show better applicability of an intraparticle diffusion kinetic model.     

Host-Guest Interaction in Ethylene and Ethane Separation on Zeolitic Imidazolate Frameworks as Revealed by Solid-State NMR Spectroscopy

The separation of ethane/ethylene mixture by using metal-organic frameworks (MOFs) as adsorbents is strongly associated with the pore size-sieving effect and the adsorbent-adsorbate interaction. Herein, solid-state NMR spectroscopy is utilized to explore the host-guest interaction and ethane/ethylene separation mechanism on zeolitic imidazolate frameworks (ZIFs). Preferential access to the ZIF-8 and ZIF-8-90 frameworks by ethane compared to ethylene is directly visualized from two-dimensional ¹H-¹H spin diffusion MAS NMR spectroscopy and further verified by computational density distributions. The ¹H MAS NMR spectroscopy provides an alternative for straightforwardly extracting the adsorption selectivity of ethane/ethylene mixture at 1.1∼9.6 bar in ZIFs, which is consistent with the IAST predictions.     

基于医用纱布负载的二氧化锰纳米颗粒用于亚甲蓝染料的去除

以医用纱布（medical gauze,MG）同时作为模板和还原剂,通过原位氧化还原反应,简便地制备了MG负载的MnO₂纳米颗粒（MnO₂ NPs/MG）,并对其形貌、成分进行表征。结果表明,MnO₂ NPs均匀地分散于MG纤维表面。结合MnO₂纳米材料的吸附性能和MG复合材料的操作便捷性,将MnO₂ NPs/MG进一步应用于亚甲蓝染料的去除。结果表明,在中性条件下,通过简单的浸泡搅拌,MnO₂ NPs/MG对亚甲蓝的去除率可达85.09%,并且可以通过增大吸附材料用量与染料初始浓度的比例提高去除率。等温吸附和动力学研究证明,MnO₂ NPs/MG对亚甲蓝的吸附符合Langmuir吸附等温模型和拟二级动力学模型。