具有超高阳离子染料去除能力的磺酸功能化球形共价有机框架

通过三醛基间苯三酚(TFP)与2,2′-联苯胺二磺酸(BDSA)的席夫碱反应, 合成了β-酮烯胺连接的磺酸功能化球形共价有机框架(TFP-BDSA COF). 所得阴离子型TFP-BDSA可迅速吸附如亚甲基蓝(MLB)、 结晶紫(CV)和罗丹明B(RhB)等阳离子染料, 而对如甲基橙(MO)和荧光素钠(FS)等阴离子染料则难以吸附, 该COF可实现基于电荷模式的阴离子、 阳离子染料的分离. TFP-BDSA对阳离子染料的吸附动力学均遵循拟二级吸附动力学模型, 吸附过程符合Langmuir吸附模型, 其对MLB, CV和RhB的最大吸附容量分别高达1116, 1429和1638 mg/g. 与其它COFs材料相比, TFP-BDSA对CV和RhB的吸附容量最高. 该工作可为开发功能COFs材料实现对废水中有机污染物的快速吸附和有效去除提供参考.     

阴离子型有机化合物在LDHs上的动力学和热力学研究

考察了水滑石焙烧产物MgAl-LDO吸附3种阴离子染料Acid Red 88(AR88)、Acid Orange 3(AO3)、Acid Violet 90(AV90)过程中的热力学和动力学机理,并在不同温度下探究该吸附过程的热力学参数。实验结果表明:MgAl-LDO对染料阴离子的吸附过程复合Langmuir吸附等温模型,且为自发、放热的过程。3种染料在MgAl-LDO上的吸附过程均符合准二级反应动力学模型,且该吸附过程是由MgAl-LDO与阴离子染料之间的反应速率控制而不是两者之间的扩散作用。计算所得的吉布斯自由能绝对值在7~15 kJ·mol-1,这主要是由染料阴离子与MgAl-LDHs层板的氢键作用产生,结合Materials Studio 5.5软件模拟染料分子在MgAl-LDHs上的排列分布,推测MgAl-LDO对阴离子染料的吸附机理是表面吸附(占优势)与层间插层的协同作用。     

柱芳烃基多孔聚合物的制备及其吸附性能

将柱[5]芳烃与1,3,5-三乙炔苯(TEB)通过Sonogashira偶联反应制备了一类新型多孔有机聚合物P[5]-TEB,进而通过脱甲基反应对其进行改性得到多羟基的多孔聚合物P[5]OH-TEB,对二者的物理化学性质和吸附性能进行研究。 氮吸附测试表明,羟基的引入使P[5]OH-TEB的比表面积变大,同时引入微孔结构。 染料吸附实验表明,两聚合物对亚甲基蓝吸附过程符合Langmuir模型,P[5]OH-TEB对亚甲基蓝有更大的吸附量;吸附动力学试验表明,吸附过程更符合拟二级动力学模型,属于化学吸附过程,改性之后P[5]OH-TEB有更快的吸附速率;选择性吸附实验表明,羟基引入聚合物后聚合物对阳离子染料的吸附性能提升,对阴离子染料的吸附效果变差。     

阴离子型有机化合物在LDHs上的动力学和热力学研究

本文考察水滑石焙烧产物MgAl-LDO吸附3种阴离子染料AcidRed88（AR88）、AcidOrange 3（AO3）、AcidViolet90（AV90）过程中的热力学和动力学机理,并在不同温度下探究该吸附过程的热力学参数。实验结果表明：MgAl-LDO对染料阴离子的吸附过程复合Langmuir吸附等温模型,且为自发、放热的过程。3种染料在MgAl-LDO上的吸附过程均符合准二级反应动力学模型,且该吸附过程是由MgAl-LDO与阴离子染料之间的反应速率控制而不是两者之间的扩散作用。计算所得的吉布斯自由能绝对值在7~15kJ·mol^-1,这主要是由染料阴离子与MgAl-LDHs层板的氢键作用产生,结合MaterialsStudio 5.5软件模拟染料分子在MgAl-LDHs上的排列分布,推测MgAl-LDO对阴离子染料的吸附机理是表面吸附（占优势）与层间插层的协同作用。     

聚苯胺-氧化铁磁性复合材料的制备及其对甲基橙吸附性能的应用

用"化学一步法"制备了聚苯胺-氧化铁(PANI@Fe_2O_3)磁性复合材料,并用红外光谱和X射线衍射对其进行了表征。为验证此复合材料作为处理染料废水的吸附剂的性能,选择了甲基橙(MO)作为染料模型化合物,对其在不同的酸度、吸附时间、温度以及盐度等条件下的吸附情况进行试验。结果表明:PANI@Fe_2O_3对MO的吸附经30min已达到平衡;根据相关参数,可确定此吸附过程符合准二级动力学模型。在试验的温度范围(293～313K)内,温度升高,PANI@Fe_2O_3对MO的吸附量增大。染料废液在弱酸性条件下(如pH 5)有利于此吸附剂对染料的吸附。此外盐度(以氯化钠进行试验)的增大,使MO的吸附量显著降低。热力学试验结果表明:上述吸附符合Freundlich等温吸附模型,为自发吸热过程的多层吸附。此外,由于PANI@Fe_2O_3为磁性材料,经吸附处理后在外磁场的作用下易于与水体分离。     

羧甲基-β-环糊精功能化的四氧化三铁磁性纳米复合物对罗丹明B的吸附性能

基于S_N2取代反应制备了羧甲基-β-环糊精(CM-β-CD),采用层层组装法将其成功修饰在Fe₃O₄磁性纳米粒子表面(MNPs),得到了CM-β-CD功能化的磁性纳米复合物(CM-β-CD-MNPs),通过透射电子显微镜(TEM)、傅里叶变换红外光谱(FTIR)及振动样品磁强计(VSM)等技术手段进行了表征,考察了其对染料罗丹明B(RhB)的吸附性能。 结果表明,CM-β-CD-MNPs呈球形,分散均匀,平均粒径为16 nm,饱和磁化率为54 emu/g,呈超顺磁性。 吸附动力学符合准二级动力学模型,且吸附1 h达到平衡。 吸附等温线符合Langmuir等温吸附模型,最大吸附量为135.1 mg/g。     

聚乙烯亚胺功能化磁性纳米颗粒制备及其吸附分离蒽醌类阴离子染料性能研究

在室温下,采用戊二醛化学交联法制备聚乙烯亚胺功能化的磁性纳米吸附剂(Fe3O4-PEI).利用TEM、XRD、FT-IR、VSM和TGA等手段对其进行结构表征,并以茜素红、核固红及茜素绿3种蒽醌类染料为目标吸附质,通过静态吸附实验考察了pH值、吸附时间、染料初始浓度、操作温度等因素对吸附的影响,同时进行了吸附动力学和吸附等温线模拟研究.结果表明,在pH=3和温度303 K的条件下,茜素红、核固红和茜素绿的最大吸附量分别为256.1,138.8和134.6 mg/g;初始浓度和吸附时间对染料吸附效率有明显的影响,吸附可在60 min内达到平衡,且吸附过程符合准二级动力学模型;Langmuir等温线模型能更好地描述染料的吸附;蒽醌类染料在Fe3O4-PEI上的吸附是一个自发的吸热过程.另外,Fe3 O4-PEI良好的稳定性和重复使用性,使其可作为一种潜在的水处理吸附剂.     

氧化石墨：制备及去除阳离子染料的性能

以石墨粉为原料按Hummers氧化法制备氧化石墨,借助X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅里叶变换红外光谱法(FTIR)和低温氮吸附-脱附对氧化石墨的结构和形貌进行了表征。结果表明,氧化石墨是不平整的、具有一定层状结构的褶皱片状,在其表面存在着许多含氧的官能团如:环氧基、羟基、羧基。此外还研究了氧化石墨对阳离子染料的吸附性能,结果表明:吸附过程的等温模型符合Langmuir等温式,对甲基紫、甲基绿、中性红这3种阳离子染料的最大饱和吸附量分别为:741,446和368 mg.g-1;对阳离子染料的吸附过程符合二级动力学方程。氧化石墨作为一种吸附剂能有效的去除阳离子染料与其较高的比表面积和与阳离子染料的静电吸引有关。     

羧基化石墨烯对4种离子型染料的吸附脱色

合成的羧基化石墨烯（G-COOH）用FT-IR进行表征,并对G-COOH用于水溶液中甲基紫、中性红、灿烂黄和茜素红4种离子型染料的吸附性能进行了研究。 考察了吸附剂用量、吸附时间、初始浓度以及溶液pH值等条件对吸附效果的影响。 同时,研究了甲基紫染料的脱附性能,结果表明,用NaOH/EtOH混合溶液洗脱甲基紫,洗脱率可达88.2%,洗脱后的G-COOH可再利用。 从热力学角度探讨得出,G-COOH对阳离子染料甲基紫和中性红的吸附行为能够较好的符合Langmuir等温吸附模型,而对阴离子染料灿烂黄和茜素红的吸附行为则能够较好的符合Freundlich等温吸附模型,计算的吸附参数表明,G-COOH对4种染料的吸附过程容易进行。 动力学研究表明,G-COOH对4种离子型染料的吸附行为均能较好的符合准二级吸附模型。 该实验研究表明,在处理染料废水时,G-COOH为相当优异的吸附剂。     

粉煤灰磁性吸附剂的制备及磷吸附机理

通过化学沉淀法制备了CMS@La_2O_3磁性磷吸附剂。结构及磁性表征显示,氧化镧较均匀的包覆在粉煤灰磁珠表面;样品的比磁化强度达20.35 emu·g~(-1),可实现高效磁分离。利用钼酸铵分光光度法对所得磁性吸附剂的磷吸附性能进行了试验研究。研究表明,其最高磷比饱和吸附量可达19.50 mg·g~(-1),吸附时间、pH值、共存阴离子等因素对磷吸附效果均具有显著影响。吸附动力学拟合表明,CMS@La_2O_3对含磷离子的吸附符合准二级动力学方程,以化学吸附为主,磁性吸附剂对含磷离子的吸附反应过程可由La_2O_3表面羟基化-离子交换模型解释。吸附磷后的CMS@La_2O_3吸附剂经处理后可多次循环使用。     

阳离子共价有机框架对水中非甾体药物的强化去除

以三醛基间苯三酚(TFP)和溴化乙锭(EB)为单体, 在溶剂热条件下合成了一种二维β-酮烯胺类阳离子型共价有机框架(COF)材料. 所得TFP-EB COF呈现出良好的结晶度、 高的比表面积和丰富的溴化乙锭单元, 故可将其应用于水中非甾体抗炎药(NSAIDs)的去除.阳离子TFP-EB COF对双氯芬酸钠(DCF-S)和对氨基水杨酸钠(PAS-S)两种非甾体抗炎药表现出高的吸附能力和快的吸附动力学, 其饱和吸附容量分别可达350.4和145.3 mg/g. 而采用TFP与4,4'-二氨基联苯(BND)在类似条件下合成的中性TFP-BND COF则表现出较差的吸附性能, 其对DCF-S和PAS-S的饱和吸附容量分别仅有59.7和13.6 mg/g. TFP-EB COF的吸附性能比TFP-BND COF更优异, 这主要归因于TFP-EB COF孔道中存在的大量阳离子EB单元与NSAIDs中的羧基间存在强烈的静电作用. 此外, 竞争离子干扰和循环再生实验表明阳离子型TFP-EB COF在NSAIDs污染物的去除方面具有良好的应用前景.     

Selective adsorption of the cationic dye rhodamine-6G from aqueous solution by phosphotungstic acid@MOF-199 composites

In this paper, H₃[ P(W₃O₁₀)₄]@MOF-199 composites ([email protected]) were successfully synthesized by a simple one-step reaction under solvothermal conditions and characterized by XRD, SEM, FT-IR and N₂ adsorption–desorption isotherms. Additionally, rhodamine-6G (Rh6G, a cationic dye) and methyl orange (MO, a anionic dye) as model dyes were employed to assess its adsorption performance. The adsorption capacity of MOF-199 towards Rh6G and MO were enhanced and weakened respectively after the introduction of PTA (from 8.6 mg/g to 41 mg/g; 11.4 mg/g to 2.6 mg/g) proving that the selective adsorption capacity for the cationic dye of porous MOF-199 could be improved through the modification of PTA. Moreover, in diverse initial concentrations of single Rh6G and MO aqueous solutions (10 mg/L, 25 mg/L, 50 mg/L and 100 mg/L), [email protected] exhibited much higher adsorbing capacity towards Rh6G (about 25, 30, 11 and 16 times higher than that of MO). In mixed dyes adsorption studies, the adsorption capacity of [email protected] towards Rh6G (2.871 mg) are nearly five times larger than that of MO (0.437 mg) even in a solution with a higher concentration of MO than Rh6G (5 mg/L of Rh6G and 10 mg/L of MO). The kinetic study indicated that the adsorption of the Rh6G and MO onto [email protected] followed the pseudo second-order model well. The isotherm obtained from experimental data fitted the Freundlich model (the linearly dependent coefficient are 0.99839 and 0.94845 for Rh6G and MO respectively) indicating multilayer adsorption mechanism. In summary, all these results implied that the as-prepared [email protected] is of great potential to be used as a cationic pollutants adsorbent with high efficiency and selectivity.     

Tailoring Pore Structure and Morphologies in Covalent Organic Frameworks for Xe/Kr Capture and Separation

As a rising star among porous solid materials, covalent organic frameworks(COFs) with excellent properties including but not limit to facilely controllable structure, high porosity, and multi-chemical functionality represent significant potential for efficient ¹²⁷Xe/⁸⁵Kr capture and separation. In this study, through tuning the length of the organic ligands, two-dimensional(2D) COF mate-rials with identical connection group but different pore properties, denoted as ATFG-COF and TpPa-COF with AA-stacking model and TpBD-COF with AB-stacking model were synthesized and tested for Kr and Xe adsorption for the first time. Adsorption measurements indicate that the narrower pore apertures and higher porosity are conducive for COF materials to capture Xe and Kr. Furthermore, the Henry's constant, isosteric heat of adsorption(Q_st), and ideal adsorbed solution theory(IAST) selectivity of ATFG-COF, the pore size of which is closest to the kinetic diameter of the Xe atom(0.41 nm) among 2D COF materials, were carried out based on the single component sorption isotherms. The results illustrate that the high isosteric heat values of Xe/Kr adsorption on ATFG-COF are 25 and 16 kJ/mol at room temperature, respectively. Henry's law predicts that the selectivity factor of Xe to Kr is 6.07, consistent with the adsorption selectivity(ca. 6) calculated based on the IAST.     

Decorating Covalent Organic Frameworks with High-density Chelate Groups for Uranium Extraction

The extraction of uranium from aqueous solution is highly desirable for sustaining the increasing demand for environmental safety and nuclear fuel. Herein, we report a strategy using a two-step covalent modification for the synthesis of covalent organic frameworks(COFs) with high-density amidoxime chelate groups at periphery. The introduction of dense amidoxime groups plays a pivotal role in uranium adsorption. The resulting COF exhibits strong affinity with the distribution coefficient of 5.2×10⁴ mL/g and a high adsorption capacity of 319.9 mg/g. The strategy could be expanded to identify and remove different contaminants by introducing special functional groups.     

具有染料选择吸附性的衍生于沸石咪唑酯骨架-67的NiCo-层状双氢氧化物设计与合成

以沸石咪唑类金属有机骨架(ZIF-67)为模板合成了一种新型的中空吸附剂NiCo-LDH@ZIF-67,该吸附剂对甲基橙具有良好的选择吸附性以及可循环性。 通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线粉末衍射仪(XRD)、红外光谱、电子能谱和氮气吸附-脱附等手段对样品进行了表征。 研究了溶液的pH值、甲基橙的初始浓度以及染料与吸附剂作用时间对NiCo-LDH@ZIF-67吸附性能的影响。 结果表明,该吸附剂对甲基橙的吸附动力学符合准二级动力学模型,且吸附等温线符合朗缪尔方程。 当pH值等于4, 吸附时间15 min,吸附剂用量为2400 mg/L时,该吸附剂对甲基橙的最大吸附量可达1766 mg/g,高于之前文献报道的类似吸附剂。 此外,NiCo-LDH@ZIF-67能从甲基橙和亚甲基蓝的混合溶液中选择性吸附甲基橙。     

Enhanced adsorption performance of a novel Fe‐Mn‐Zr metal oxide nanocomposite adsorbent for anionic dyes from binary dye mix: Response surface optimization and neural network modeling

A novel adsorbent, Fe‐Mn‐Zr metal oxide nanocomposite was synthesized and investigated for removal of methyl orange (MO) and eosin yellow (EY) dyes from binary dye solution. The magnetic nanocomposite has shown surface area of 143.01 m²/g and saturation magnetization of 15.29 emu/g. Optimization was carried out via response surface methodology (RSM) for optimizing process variables, and optimum dye removal of 99.26% and 99.55% were obtained for MO and EY dye, respectively with contact time 62 min, adsorbent dose 0.45 g/l, initial MO concentration 11.0 mg/l, and initial EY concentration 25.0 mg/l. A feed forward back propagation neural network model has shown better prediction ability than RSM model for predicting MO and EY dye removal (%). Adsorption process strictly follows Langmuir isotherm model, and enhanced adsorption capacities of 196.07 and 175.43 mg/g were observed for MO and EY dye, respectively due to synergistic effects of physicochemical properties of trimetal oxides. Surface adsorption and pore diffusions are the mechanisms involved in the adsorption as revealed from kinetic studies.     

A Two-dimensional Covalent Organic Framework for Iodine Adsorption

Radioactive iodine is a notorious pollutant in gas radioactive nuclear waste due to its radiation hazard, volatility, chemical toxicity, and high mobility. Therefore, developing a material with high efficiency-specific iodine capture is significant. Covalent organic framework(COF) has attracted significant attention as a new crystalline porous organic material. Due to its large specific surface and high chemical stability, it is an excellent alternative to adsorbents. Herein, we report a chemically stable two-dimensional COF(termed JUC-609) with specific adsorption of iodine. Adsorption experiments show that JUC-609 has an excellent iodine adsorption capacity as high as 5.9 g/g under 353 K and normal pressure condition, and iodine adsorption after multiple cycles is still maintained. Our study thus promotes the potential application of COFs in the field of environment-related applications.     

偶氮苯功能化的光响应共价有机框架材料

通过后修饰的方法, 在共价有机框架(COFs)材料JUC-500的孔道中引入光敏性的偶氮苯小分子, 合成了具有光热刺激响应的共价有机框架材料JUC-501. 在紫外线和加热作用下, 孔道中的偶氮苯会发生可逆的顺-反异构变化, 对染料污染物甲基橙(MO)表现出优异的可逆吸附与释放性能.     

三聚氰胺功能化多孔有机聚合物的合成及其对甲基橙的吸附性能

首先以对三联苯(TP)和对苯二甲酰氯(TC)为单体合成了酮基聚合物前体(TP-TC),而后基于席夫碱反应将三聚氰胺(MA)与之交联得到胺功能化的多孔有机聚合物TP-TC-MA。通过扫描电镜(SEM)、透射电镜(TEM)、傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)、氮气吸附-脱附(BET)以及零电荷点(pH_pzc)的测定等手段对合成的多孔有机聚合物进行表征。以染料废水中典型的阴离子染料甲基橙为研究对象,研究了TP-TC-MA对其吸附行为,并探讨了吸附机制。利用紫外-可见分光光度计(UV-Vis)得出目标污染物的紫外吸收光谱标准曲线,标准曲线拟合相关系数(R²)为0.999。结果表明,TP-TC-MA由于具有高比表面积(708.5 m²/g)和总孔体积(0.556 cm³/g)以及丰富的含氮基团,对阴离子染料甲基橙表现出优异的吸附性能。TP-TC-MA对水中甲基橙的吸附动力学符合准二级动力学方程,吸附平衡数据可以采用Langmuir等温吸附模型描述。经由Langmuir等温吸附模型计算得到的理论最大吸附容量为156.3 mg/g。选择性实验结果表明,TP-TC-MA对阴离子染料甲基橙具有更强的吸附作用,吸附作用机理可归结为静电相互作用、氢键和π-π相互作用等。在重复使用5次之后,TP-TC-MA对甲基橙仍保持90%以上的去除率,表明材料具有良好的稳定性和重复利用性,在染料废水处理中具有很好的应用前景。