Synthesis, Characterization Of Bifunctional Mesoporous Zirconium Phosphonates And Their Adsorption Behaviors Of Silmon Spermary DNA

Mesoporous zirconium phosphonatess with both the basic characters of mesoporous materials and tailored structure of phosphonates, exhibit various chemical composition, diverse framework properties and biological compatibility from phosphonic acid. It have attracted much attaentions to the potential applications in the immobilization of biological macromolecules such as protein and nucleic acid.In this dissertation, bifunctional mesoporous zirconium phosphonates were synthesized through through one-pot co-condensation of 1.4-bis(phosphomethyl)piperazine (BPMP), 1-phosphomethylproline (H3PMP) and ZrCl4 in the presence of anionic surfactant (sodium dodecyl sulface, SDS) under weak acidic conditions. These materials were characterized using N2 adsorption–desorption isotherms, scanning electron microscopy (SEM), 31P and 13C MAS NMR as well as element analysis. The bifunctional mesoporous zirconium phosphonates exhibits high surface areas and large pore volume. And the mesopores of these mesoporous materails can be controlled in the range of 2.4 to 14 nm by adjusting the amount of anionic surfactant SDS. The two functions of bifunctional mesoporous zirconium phosphonates, one was derived from the reversible protonation-deprotonation of piperazine groups in 1.4-bis(phosphomethyl)piperazine under different pH values, which endows mesoporous zirconium phosphonates with reversible cationic-neutral surface properities, namely pH-senstivity; the other was arised from the chiral L-proline of 1-phosphomethylproline, which causes mesoprous zirconium phosphonates with chirality.We have investigated the adsorption of salmon spermary DNA onto bifunctional mesoporous zirconium phosphonates in details. The mesopore size directely affected the adsorptive capacity of salmon spermary DNA. When the mesopore size was 4.7 nm, the adsorptive capacity of bifunctional mesoporous zirconium phosphonates for salmon spermary DNA can reach as high as 239 mg/g. It can be observed that the Langmuir isotherms can accurately describe the adsorption of these mesoporous materials for salmon spermary DNA from the fit of the experimental data using Langmuir model and Freundlich model. So, the adsorption of salmon spermary DNA onto four mesoporous samples can be attributed to single-layer sorption. From the kinetics of adsorption of bifunctional mesoporous zirconium phosphoantes for salmon spermary DNA, all samples almost reach equilibrium with 6 h. Salmon spermary DNA can be slowly adsorbed onto four samples. The adsorption of salmon spermary onto bifunctional mesorporous zirconium phosphonates can be well represented by pseudo-second-order kinetics, which indicates that the adsorption mechanism depends on the physisorption through the strong electrostatic interactions between cationic frameworks of mesoporous materials and anionic salmon spermary DNA. The investigation of the effects of chirality of these materials on the double helix of salmon spermary DNA is ongoing. Thus, bifunctional mesoporous zirconium phosphonates are promising carriers for nucleic acid.In addition, HRP@CNTs were obtained through covalent bonding to immobilize horseradish peroxidase (HRP) on carbon nanotubes (CNTs). The immobilization conditions of HRP and the efficiency of phenol removal of HRP@CNTs were investigated in details. The high stability and the efficiency in phenol remove of HRP@CNTs make this new HRP@CNTs very good potential application prospect in treatment of wastewater containing phenol.