| Methylene blue,malachite green and crystal violet have anti-inflammatory and antibacterial effects.Because of their high efficiency and low cost,they are used as fungicides and parasitic agents in aquaculture industry or applied in medical treatment of fungi and burn.At the same time,these three substances also belong to the common basic dyes,in textile,printing and dyeing,cosmetics,leather and many other industries as colorants.However,these three substances can be teratogenic,carcinogenic,mutagenic,and easily interact with negatively charged cell membrane surface,then enter cells and concentrate in the cytoplasm,causing harm to human body.Therefore,removal and detection of these three substances is of great significance to human health and environmental protection.In this paper,MOFs/COFs porous material was used as adsorbent to study the adsorption properties of methylene blue,malachite green and crystal violet,and the adsorption mechanism was discussed.In addition,MALDI-TOF MS was used to detect these three substances.The details about this research contents are as follows:1.Cd（Ⅱ）-MOF was synthesized by hydrothermal method through ligand bis（4’-methylene-（1,1’biphenyl）-2’-formicacid）amino benzoicacid and Cd（CH3COO）2·2H2O.It was characterized by single crystal X-ray diffratometer（XRD）,and Zeta potential.The results show that Cd（Ⅱ）-MOF is stepped three-dimensional pore structure,with negative charge on the surface.Therefore,the enrichment of methylene blue,malachite green and crystal violet can realized by electrostatic action andπ-πaction with Cd（Ⅱ）-MOF.The adsorption isothermal equation,thermodynamic and kinetic characteristics of Cd（Ⅱ）-MOF for methylene blue,malachite green and crystal violet were studied on the basis of static adsorption experimental data.The Langmuir and Freundlich isothermal models were used to fit the isothermal experimental data and the qseudo-first-order,qseudo-second-order,Elovich and intra-particle diffusion kinetic data.The model parameters were calculated and the adsorption mechanism was further discussed.The results showed that the adsorption capacity of methylene blue,malachite green and crystal violet were 220 mg·g-1,305 mg·g-1and 161 mg·g-1,respectively.The adsorption of methylene blue,malachite green and crystal violet on Cd（Ⅱ）-MOF conforms to Freundlich model and is endothermic.The adsorption kinetics of Cd（Ⅱ）-MOF on malachite green and crystal violet can be described by qseudo-second-order kinetic equation,and that of methylene blue can be described by qseudo-first-order kinetic equation.In addition,Cd（Ⅱ）-MOF has the potential to absorb laser energy and transfer it to analytes due to its strong ultraviolet light absorption capacity and good thermal stability.In this paper,a Cd（Ⅱ）-MOF-assisted LDI MS method was constructed to realize the detection of these three substances.The detection limits were 4 ng/m L,4 ng/m L and 0.4ng/m L,respectively,and the method was successfully applied to the detection and analysis of fishponderwater,tank water and industrial wastewater.2.The covalent organic framework Dp-COFs and Tp Pa-1 were synthesized by hydrothermal method,using turonic phloroglactil and 3,5-diaminobenzoic acid（DABA）,turonic phloroglactil（Tp）and p-phenylenediamine as raw materials,respectively.Through the characterization of material information such as microstructure,porous properties and thermal stability,it is proved that the surface of Dp-COFs is negatively charged,has a large specific surface area（390.63 m~2/g）and excellent thermal stability.The adsorption behavior of Dp-COFs on methylene blue,malachite green and crystal violet was studied by adsorption isothermal equation,adsorption kinetics and adsorption thermodynamics with the help of UV spectrophotometer.The adsorption experimental data show that the adsorption of malachite green by Dp-COFs conforms to Langmuir model and pseudo-second-order kinetics,while the adsorption of methylene blue and crystal violet by Dp-COFs can be described by Freundlich model and pseudo-second-order kinetics,and the adsorption process is endothermic reaction.The adsorption capacity of Tp Pa-1 on methylene blue,malachite green and crystal violet was 48 mg·g-1,30 mg·g-1 and 27 mg·g-1,respectively.Compared with Tp Pa-1,which lack of carboxyl group,the adsorption rate and adsorption capacity of Dp-COFs were much higher than Tp Pa-1.At the same time,in a certain concentration range,the UV data showed that the maximum adsorption capacity of Dp-COFs for the three dyes reached 255 mg·g-1,97 mg·g-1 and 293mg·g-1,respectively.In addition,Dp-COFs was used as substrate for the detection of the three substances,and the detection limits were 0.7 ng·L-1,0.5 ng·L-1 and 0.1 ng·L-1,respectively. |
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