Functional Modification Of Thiacalixarene And Its Application To Absoption Of Heavy Metal Ions

To manage the environment pollution is a significant and urgent task that our world has to confront. In recent years, as the rapid development of mining, metallurgy, chemical industry, electroplating and so on, a lot of heavy metal pollutants were let out, leading to a great destruction for ecological environment. In particular, severe harm and catastrophic effects would be resulted towards human production activities and daily life when the heavy metal ions were poured into the water in large quality. Such a harm and destruction arise from the nature of heavy metal ions, characterized in their properties in difficult degradation, high toxicity, biological enrichment. In view of the serious situation of water polluting by heavy metal ions, this thesis has done some work from thiacalix[4]arene(TCA) and its metal complexes. Detailed work mentioned below has been carried out.1. First, we prepared the starting compound, thiacalix[4]arene which is a member of the third generation of supramolecular host. This compound is able to form many new complexes with transition metal ions. Then, taking TCA as raw material, we obtained the thiacalix[4]arenetetrasulfonate via sulfonated reaction by a new method developed in our laboratory and such a method has not been reported so far. Using TCAS as active ingredient and loading it to717-anionic resin by electrostatic attraction, we got TCAS adsorption resin as the final product.2. The structures of TCA and TCAS were characterized by IR, UV-vis,1HNMR methods. For TCA, IR:2960cm-1which is characteristic absorption peak of tertiary butyl. UV-vis: λmax=320nm;1H NMR:at δ9.6, assigned as the signal of hydrogen on phenolic hydroxyl. At the same time, the ratio about the area of three kinds of hydrogen fits the number of hydrogen atom. For TCAS, IR:The peak at2960cm-1disappeared. At1180cm-1, the typical absorption peak of-SO3H appeared. UV-vis:λmax=301.4nm;1H NMR:at δ7.86, appears a single peak of aromatic hydrogen. 3. TCAS adsorption resin was tested by IR, UV-vis analysis methods. The results showed that TCAS can combine with anionic resin, while TCAS cannot fall off from the surface of the anion resin, TCAS adsorbted resin also has good stability in the water.4. With blank control experiment, we studied the adsorption removal rate of TCAS adsorption resin and blank resin for Pb2+, Cu2+. The results disclosed that TCAS adsorbed resin has a good adsorption effect for Pb2+and Cu2+in the water, The adsorption capacity of this adsorbed resin was14.26mg/g and29.78mg/g for Pb2+and Cu2+, respectively.5. By changing the resin content, the adsorption time, temperature and pH values of the heavy metal ions solution, we concluded the removal rate of adsorption resin for Pb2+, Cu2+in different conditions. Thereby, we found the best experimental conditions. The remove effect of the TCAS adsorption resin for Pb2+, Cu2+would be improved with the increase of the resin content; The period used for adsorption balance increased with the rise of temperature, but the removal rate reduced with the rise of temperature. When adsorption reached balance,[Cu2+] can reach state standards for drinking water, and the concentration of Pb2+reach the state industrial water discharge standards. During the range of pH4.0～8.0, the change of adsorption removal of TCAS adsorption resin for Cu2+was not large. That means, in a neutral or weak acid solution, removal rate for Cu2+reached the largest value. And for Pb2+, adsorption environmental needed more loose, neutral, weak acidity and weak alkaline environment.6. And finally, we have investigated the preferential absorption rules of TACS adsorbed resin towards several heavy metal ions, Pb2+, Cu2+and Cd2+, in the order as the follows:Cu2+>Cd2+>Pb2+in a coexistence system. We have found the removal rates of TCAS adsorbed for Pb2+, Cu2+under a background with the existence of Ca2+, Mg2+ions. More specifically, under an above-said situation, TCAS absorbed resin has an excellent effect in removing of Pb2+and Cu2+ions, at the same time the removal rate for Ca2+and Mg2+is very weak. This is a really satisfied result, for it would guarantee that, in the process of water treatment, we are hopeful to obtain the Holy Grail, that is, to realize the purpose of removal of harmful heavy metal ions, and at the meantime, retaining those necessary metal ions, Ca2+and Mg2+; which are good for human health.