The Study On The Preparation Of Metal Coordination Fiber And Its Adsorption Properties Of CO

In this thesis, some new metal complexes, such as Au(0)/AOCF, Ag(0)/AOCF, Pt(0)/AOCF, Pd(0)/AOCF and other composite materials were synthesized by using amidoxime-oriented polyacrylonitrile fiber (AOCF) as the base material, and Au (III), Ag (I), Pt (IV), Pd (II), Cu (II), Ni (II) to form complexes, by selecting the appropriate reducing agents and reaction conditions. A variety of different morphologies of nano-metal (M)/AOCF particles obtained through controlling the process conditions, such as the initial concentration of metal ions, reaction time and reductant concentration. The particle morphology, structure, bonding and other aspects of the characterization have been characterized by means of IR, SEM, EDS, XRD, and XPS. The metal ion complexes fiber (Mn+/AOCF, Mn+=Cu2+, Pt4+, Ni2+, Pd2+) and metal complexes fiber (M/AOCF, M=Ag, Pt, Pd) removal of CO adsorption, as well as organic dye photocatalytic degradation was studied by using Ag(0)/AOCF fiber. In all of those works published so far, various ways had been used for synthesis of nano-metal particles, but the synthesized product are usually simply dispersed in the solution, or simply load on other carriers through these methods. While in our research group, metal ions through the "coordination" to the amidoxime fiber surface at first, then the ionized metal will be "restore" a zero price of metals by using chemical reduction method, and different morphologies of nano-metal particles would be obtained by controlling the experimental conditions. As the "coordination-Restore" Preparation of nano-particles and the carrier through the coordination bonds between the fibers connection, is a chemical bonding, so a more stable material properties, application prospects are very broad, but also for the metal load on the fiber surface to find new approach.(1) Through the test, the optimum conditions on preparation of Au(0)/AOCF were defined:Gold acid chloride concentration of 0.003mol/L, adsorption for 30min under room temperature, and then restore for 30min with 0.2mol/L of hydroxylamine. The gold flowers obtained are composed of several pieces of gold prisms. Typical gold flowers are about 500 nm in diameter, and prisms are about 100 nm in width. The addition of Fe(III) can help gold flower's growth. The reducing agent (NH2OH) concentration is essential for the growth of gold crystals. When the reductant concentration lower from 0.2mol/L to 0.075mol/L, the fiber surface only the spherical crystals exist, and this implies that morphology of gold nanocrystals controled by the dynamics. The as-obtained gold flowers exhibited better stability than previous works. It was proved that the product is indeed of nano-crystal Au(0) through IR, SEM, EDS, XRD and XPS characterization.(2) It was found that, AgNO3 concentration of 2.95mmol/L, adsorption for 30min under room temperature, and then restore for 60min with N2H4·H2O concentration of 5.16mmol/L, the product obtained in the Ag(0) nanoparticles was flaky. Remaining the other conditions, be to restore the time of 30min, the product of the Ag(0) nanoparticles was cube-shaped. As AgNO3 concentration of 5.90mmol/L, adsorption for 30min under room temperature, and then restore for 30min with N2H4·H2O concentration of 1.03mmol/L, the product obtained in the Ag(0) spherical nano-particles are presented. The IR, SEM, EDS, XRD and XPS characterization results show that the product of the sheet, cube-shaped and spherical nano-crystals are indeed Ag(0). This experiment also examined the three different morphologies of nano-Ag particles by photocatalytic degradation of methyl orange. The results showed that the catalyst has better photocatalytic effect of methyl orange, And the three kinds of different morphologies of the catalyst have different ability on the degradation of methyl orange which sphere the best, followed by the cube, flake the worst. Higher levels of catalyst, the same time, the higher the rate of degradation, and the catalyst can be used repeatedly.(3) Through the test, the optimum conditions on preparation of Pt(0)/AOCF were defined:the concentration of chlorine platinum acid solution 7.723mmol/L, adsorption for 30min at. room temperature, and then restore for 60min with 3.44mmol/L of hydrazine hydrate. Nano-particles obtained with spherical shape was evenly distributed in the fiber surface, the IR, SEM, EDS, XRD and XPS characterization results show that the product of the spherical nano-crystals are indeed Pt(0).(4) The optimum conditions on preparation of Pd(0)/AOCF were: reaction for 15min with FeCl3 solution, then immersed into 0.001mol/L of PdCl2 solution, adsorption for 30min at room temperature, and then restore for 60min with 0.0344mol/L of hydrazine hydrate at room temperature. Characterization results showed that the nano-particles obtained as "flower" shape evenly distributed in the fiber surface. Fe(III) ion in presence of Pd(0) was the key pattern, but, Fe(III) ion content in too high will easily lead to reunion. In addition, it will cause the reduction accelerated destruction of flower-shaped crystals forming if the reductant concentration is too large or the temperature is too high.(5) Both metal ion complexes fiber (Mn+-AOCF, Mn+=Cu2+, Pt4+, Ni2+, Pd2+) and metal complexes fiber (M-AOCF, M=Ag,Pt,Pd) have a good adsorption capacity for CO, blank fiber does not have the ability to adsorption CO. Metal ion complexes fiber, normal temperature and pressure approach to the physical adsorption. Experimental conditions, the purge two minutes better, and the saturation adsorption time of AOCF-Cu(II), AOCF-Ni(II), AOCF-Pt(IV), AOCF-Pd(II) Complexes fiber was 90min,120min,30min and 60min. Complex fiber re-use of good performance, the adsorption capacity remain around 90% after re-use for five times, and do not need to have a complex activation process before the re-use. Metal complexes fiber (Ag(0)-AOCF, Pt(0)-AOCF and Pd(0)-AOCF fibers) has better effect of removal the CO.