Research On The Assembly And Adsorption Performance Of Phosphonate Functionalized Hydrotalcite-like Materials

With the acceleration of industrialization,the contradiction between human civilization and the natural environment is becoming severe,and global environmental pollution has become a crucial factor threatening human health.Controlling heavy metal pollution caused by high-polluting industries has become a research focus and challenge globally.Various publications point out that the construction of layered two-dimensional nanomaterial based on intercalation assembly theory has shown promising application value in environment contamination control.In terms of liquid-phase adsorption,heavy metals can be effectively removed by hydrotalcite-like compounds.To this end,various phosphonate-functionalized anionic clays were designed by intercalation or surface modification,and used as adsorbents.Batch experiments,detection technologies,and simulation calculations were employed to study the interactions at the interface of clay/water.The main contents are as follows:（1）Preparation of ATMP-modified Zn/Al-LDH composite and its adsorption on Cu²⁺and Pb²⁺The ATMP-modified LDH adsorbent was prepared through a facile two-step approach,including co-precipitation and follow-up anion exchange methods,and employed to capture Cu²⁺and Pb²⁺.The intercalation characteristics and adsorption mechanism were explored by serial experiment,density functional theory and molecular dynamics simulation.The results show that the chemisorption ability of Cu²⁺and Pb²⁺onto composite could reach 42.02 mg/g and 84.06 mg/g,respectively.From molecular dynamics simulation and electrostatic potential conclusion,it reflected that electrostatic attraction is the main force between clay layers and guest anions,and anionic ATMP has a more favourable site for providing lone pair electrons in hybrid systems.（2）Preparation of HEDP-modified Ni/Al-LDH and its adsorption properties for Zn²⁺and Fe³⁺A layered cationic framework material loaded with HEDP was successfully prepared via a facile intercalation method to investigate the adsorption properties of the material in many respects.Materials characterization results indicate that the microstructure of the adsorbent did not change significantly before and after adsorption.Combined with adsorption kinetics,adsorption isotherm and adsorption thermodynamics studies,the high uptake capacities for Zn²⁺（281.36 mg/g）and Fe³⁺（206.03 mg/g）were governed by a monolayer chemical adsorption.Furthermore,dynamic features and wavefunction analysis results showed that electrostatic attraction and coordinate bond have a domain position in the adsorption process.Notably,the adsorption column test and acute toxicity analysis demonstrated that the synthesized material has immense potential in practice.（3）Study on the capture performance and mechanism of Cd²⁺and Cr³⁺onto DTPMP intercalated Mg/Al-LDHBased on the above research,the composite loaded with different phosphonate was constructed to capture hazardous metals.The data of kinetics and isotherm suggest that the chelating adsorption conforms to Langmuir isothermal model and pseudo-second-order model.Besides,the spent adsorbent showed good reusability after 6 cycles.Furthermore,dynamics characteristics of intercalated clay were described by CLAYFF-CVFF molecular simulation,indicating the binding affinity between clay layer and modifier was electrostatic interaction.In the end,detailed investigations on visual analyses of weak interactions and chelation mechanism studies provided a new path for properly designing novel materials.（4）Adsorption of Co²⁺and Ni²⁺on HPAA-modified Mg/Fe-LDH clay-composite materialCompared with intercalation construction,clay surface action is crucial in effectively removing heavy metals.In this chapter,HPAA molecules were used to modify the surface of hydrotalcite,and then the adsorption properties of the composites were investigated from multiple perspectives.The main results are as follows:the hydrotalcite prepared by the co-precipitation method has a flake structure,special surface area of the composite increases to 86.72 m²/g after being modified by HPAA.The adsorption reaction was a spontaneous and endothermic process.The application potential of the adsorbent was also explored by taking nickel-containing electroplating effluent.Moreover,Hirshfeld surface analysis and fingerprint plot were used to study noncovalent interactions.