Synthesis And Adsorption Properties Of Trimesic Acid-based MOFs

With the ever-changing human society,the development of social civilization,science and technology,a large number of chemicals used in various fields have been synthesized,unreasonable production and abuse of the global environment has brought great harm,environmental pollution has become a human health and ecological balance and the biggest challenge facing the social and economic development,environmental pollution problems without delay,in urgent need of a new class of materials to solve these problems.Should these requirements,a number of new materials have been synthesized to meet the needs and solve the traditional materials cannot solve the problem,the metal organic framework materials(MOFs)is one of the more popular of a class.Compared with conventional sorbent materials,MOFs has unparalleled advantages,mainly reflected in its wide range of organic ligands,can form different types of structures,adjustable pore size,large specific surface area,as well as special metal center(saturated or unsaturated metal sites).These features make the application of MOFs great potential in adsorption related fields.Currently on the enrichment of MOFs removing hazardous substances,environmental contaminants particularly water contaminants adsorbed reports,there are already a lot.Current material has the largest surface area and the lowest crystal density of the metal-organic framework materials(MOFs)has great potential applications in the treatment of environmental pollution problems.In this paper,the oxygen-containing aromatic carboxylic acid(trimesic acid)and nitrogen-containing heterocyclic organic ligands,the choice of copper ion to metal skeleton design and synthesis of MOFs.First synthetic methods,classification and characteristics of the ligand and the potential application of MOFs reviewed,described the significance of this study.The hydrothermal synthesis of MOFs by the trimesic acid and copper,to optimize experimental select n(CuSO4·5H2O): n(H3BTC)=2:1 ratio,pH 3.0,reaction temperature 140 ?,reaction time 72 h,Cu2+ concentration of 50mmol/L,were the optimum conditions.The MOFs synthesized samples were analyzed in detail various characterization and single crystal structure,determine the composition of C18H20Cu2O18.MOFs material grains hydrothermal synthesis of relatively complete and good thermal stability.Based on the design and synthesis of trimesic acid and 2-methylimidazole double ligand and copper,the expected composition of [Cu(H3BTC)(C4H6N2)];synthetic conditions were optimized,selected n(Cu(NO3)2·3H2O): n(H3BTC): n(2-methylimidazole): n(NaOH)= 2: 2: 2: 1.5 ratio,pH 4.0,temperature 160 ?,50 mmol/L Cu2+ in the optimum conditions.The MOFs synthesized samples were characterized by infrared spectroscopy and scanning electron microscopy characterization.The synthesis and characterization data analysis showed that the product MOFs had been expected.The yield of product was 73.3 %,and product MOFs had the grain more complete,good thermal stability.The nitrogen adsorption desorption curves show that the synthesized MOFs material has a specific surface area and pore structure,and the adsorption of methylene blue on organic dye provides the basis for the application of this material.Finally,nine polycyclic aromatic hydrocarbons(PAHs)were extracted by solid phase extraction with the preparation of successful trimesic acid and copper ion MOFs as adsorbents,and the extraction time,ionic strength and extraction solvent of solid phase extraction were optimized.(250×4.6 mm,5 ?m);mobile phase,acetonitrile-water(55/45,v / v);flow rate,1.0 m L?min-1;detection wavelength,254 nm;temperature: 25 ?,injection volume: 10 m L.The standard curves of 9 PAHs were established under the condition of liquid chromatography.The detective limitations of the 9 PAHs were 4-15 ng?m L-1,and the average recoveries of those were in the range of 85.1%-97.3%.The content of nine PAHs in a river sample was determined by external standard method,and naphthalene was detected.This method has the advantages of simple preparation,low cost and small sample size.The experimental results also show that the method has high recovery and precision,and is suitable for enrichment and extraction of trace analytes.