Preparation Of Ionic Liquid Functionalized 2D Nanocomposites Based On Radziszewski Reaction And Their Environmental Adsorption Study

In recent years,nanomaterials have attracted extensive attention from scientific researchers with their unique physical and chemical properties.As an important member of the family of nanomaterials,two-dimensional layered materials have been widely used in many fields such as medical diagnosis,fluorescence sensing,and catalysis.In addition,they have high chemical stability and specific surface area,showing excellent adsorption performance for the treatment of environmental pollutants.However,the original two-dimensional layered materials still show some shortcomings,such as poor dispersion,limited active sites,and poor adsorption capacity.Ionic liquid is a kind of excellent surface modifier because of its unique properties.However,there are many problems in the previous researches on ionic liquid functionalized materials,such as complicated procedures,secondary contamination and so on.In order to solve the above problems,a novel adsorbent based on Radziszewski reaction functionalization route was proposed in this paper.Specifically,graphene oxide,two-dimensional transition metal carbonitride and layered Mg-Al bimetallic hydroxide were used as the substrate materials,and the Radziszewski reaction functionalization strategy was adopted to introduce the polyimidazole salt into the original materials to fabricate three kinds of composites.Then composite materials were characterized by hydrogen nuclear magnetic resonance spectroscopy（¹H NMR）,Fourier transform infrared spectrum（FT-IR）,thermogravimetric analysis（TGA）,transmission electron microscopy（TEM）and X-ray photoelectron spectroscopy.At the same time,Sunset yellow,Congo red and heavy metal chromium were used as pollutant models to explore the adsorption properties of the prepared composite materials under different influencing factors.Furthermore,the adsorption kinetics,isotherm and thermodynamic models were described according to the data obtained from the adsorption experiments,and the possible adsorption mechanism was explained.The research contents are as follows:（1）The polyimidazole salt functionalized LDH@PIL composite was successfully synthesized by hydrolysis coupling of amino acid salts on the LDH layered surface to generate a multi-component reaction between amino terminal LDH and pentaethylhexaamine,acetic acid,formaldehyde and pyruvaldehyde.Adsorption experiments showed that the modified LDH significantly enhanced the adsorption capacity of Sunset yellow in wastewater.The fitting results of adsorption data show that the adsorption process of LDH@PIL composite material for Sunset yellow is more combined with the pseudo-second-order kinetic model and Freundlich model.（2）PILGO composites functionalized with polyimidazole were successfully prepared by Radziszewski reaction between 1,6-hexanediamine,formaldehyde,pyruvic aldehyde,glacial acetic acid formed and CGO.The adsorption results showed that the functionalized GO significantly increased its ability to remove Congo red compared with the original GO.After fitting the adsorption experiment data,it is concluded that the adsorption process of Congo red in PILGO is more combined with pseudo-second-order kinetics and Freundlich isotherm model.The thermodynamic results show that the adsorption of Congo red to the surface of GO composites is a spontaneous and exothermic process.（3）The imidazole functionalized Ti₃C₂ adsorbent was successfully synthesized by Radziszewski reaction based on chitosan,formaldehyde,pyruval,glacial acetic acid and aminated MXene as raw marerials.Time-effect adsorption experiments showed that compared with the original Ti₃C₂,the adsorption capacity is increased by 4 times.With the change of p H in the range of strong acid to weak base,the adsorption capacity of the adsorbent gradually weakened,and the adsorption capacity decreased from 119.5to 19.7 mg g^-1.In addition,further analysis showed that the adsorption mechanism between Ti₃C₂ composites and chromium ions was mainly electrostatic interaction,and chelation/coordination also played an important role in the adsorption procedure.