Studies On The Adsorption Performance Of The Modified Synthetic Fiber And Plant Fiber

As one of the three synthetic fibers, the para aramid fiber(PPTA) has a wide range of applications because of the excellent performance. With the development of the further research on the properties of PPTA, the higher quality and yield of the aramid fiber is also required in the process of expanding application. The advantages of high modulus and corrosion resistance of PPTA are becoming a difficulty in the process of degradation process. The study showed that, the composite materials could be received from the modified waste aramid fibers, having the excellent adsorption performance under the harsh conditions. The oxidized porous silica with narrow pore size distribution and neat structure could be obtained from the waste aramid fibers going through a series of operations of modification and calcination. Then put the organic phosphonic acid and L-proline grafted onto the porous silicon oxide to prepare a new kind of materials, and studied on their adsorptive property. The plant fiber contains a lot of compounds which are cellulose, lignin, wood ester, and phenylpropanoids. These compositions are advantageous to the chemical reaction due to a large number of active sites inside. In the nature, the rich sources of plant fiberprovides are convenient conditions for experiments going smoothly. The modified fibers had become used widely in the aspect of metal ions adsorption. During my graduate school, the main work of all I have done includes the following three aspects:1. The PPTA as raw materials, going through metalized reaction and making the3-Chloropropyltriethoxysilane(CPTS) grafted onto its suface, could be used to prepare the PPTA-CPTS. These two kinds of adsorption material of PPTA-CP-AT and PPTA-CP-L could be prepared by using nitrilotrimethylene triphosphonic acid(ATMP)and L-proline to modify the PPTA-CPTS. Then the as-prepared samples were characterized by TG and SEM, and applied to the metal ions adsorption and separation.The TG result revealed that the obvious weight loss occurs of the two modified materials; The SEM showed that there are folds on the surface of the modified materials; These results indicated that the modified experiments were successful,which were laid the foundation for next adsorption experiments. Because PPTA had high temperature resistance, so that as the results of the TG experiment showed that the materials based on PPTA substrate within high performance of adsorption could satisfythe condition of adsorptions of metal ions at 200℃. The kinetics adsorption process conformed to the pseudo-second order kinetics, and the thermodynamics adsorption process conformed to the Langmuir adsorption equation, and the adsorption effect was better with the temperature increased.2. The PPTA as raw materials, going through metalized reaction and making the CPTS grafted onto its suface, could be used to prepare the PPTA-CPTS. Made by calcination at high temperature and activation process, silicon oxide(SG) possessed both narrow pore-size distribution and larger specific surface area. These two kinds of adsorption material of SG-ATMP and SG-L could be prepared by using ATMP and L-proline to modify the SG. Then the as-prepared samples were characterized by TG,BET and SEM, and applied to the metal ions adsorption and separation. The experiments showed that the modified materials possess both high ratio of weight loss and large specific surface area, which were beneficial to the adsorption of expensive and heavy metal ions. The kinetics adsorption process conformed to the pseudo-second order kinetics, and the thermodynamics adsorption process conformed to the Langmuir adsorption equation. The adsorption experiments of dualistic system showed that the material had good adsorption selectivity of Au( Ⅲ), and the elution experiments showed that the adsorbent to Au(Ⅲ) still had good adsorption and the stripping ability after recycling three times, which could be used for the separation and enrichment of metal ions.3. In order to make the hydroxyls of the compounds including cellulose, wood ester and phenylpropanoids in the active statein, we based on the biological eucommia ulmoides oliver and used hydrochloric acid and sodium hydroxide respectively to treat the surface of it. Then the adsorption material of DZ-L could be prepared by using L-proline to modify the surface of the material. After that we applied the two as-prepared samples to the metal ions adsorption and separation. As the results showed that we put the L-proline grafted onto the surface of eucommia ulmoides oliver with esterification method at low temperature, and the modified material for Au( Ⅲ)adsorption performance was the best. We did a further research to the adsorption for Au( Ⅲ) of the DZ-L. The research showed that the adsorption process of DZ-L for Au(Ⅲ) was mainly due to film diffusion, which conformed to the pseudo-second orderkinetics and was belong to spontaneous endothermic reaction. DZ-L had good selective adsorption for Au(Ⅲ) and relatively good elutropic effect, which could be used for the separation and enrichment of metal ions.