Preparation Of Thiacalixarene Modiifed Resin And Research On The Adsorption Performance

A novel thiacalixarene modified resin had been prepared by loading ananion-exchange resin with the active components, which is the third supramolecularcompound named thiacalixarene. Thiacalixarene modified resin was characterized by themeans of IR spectrum, and it proved that thiacalixarene had been combined with resin. Wefound that thiacalixarene was not broken away from the resin by oscillation experiment.Adsroption experiment showed that the adsorption ability of thiacalixarene modified resinto heavy metal ions is better than blank resin.The influence factors of static adsorption experiments are investigated in adsorptionprocess. For example, the pH value, initial concentration of heavy metal ion, the dosage ofthiacalixarene modified resin, time of the reaction and adsorption temperature. The resultsindicated that thiacalixarene modified resin had best adsorption ability to heavy metal ionswhen the pH value is6.0, initial concentration of heavy metal ion10mg/L, dosage ofthiacalixarene modified resin4g/L, time of the reaction120min, and adsorptiontemperature35℃. According to the soft and hard acids and bases, the alkali andalkaline-earth metal ions of hard acides, like K+, Na+, Ca2+and Mg2+, are hardly adsorbedby thiacalixarene modified resin, while the metal ions of soft acides such as Cu2+, Zn2+,Cd2+and Pb2+are easily adsorbed. In compound solution of heavy metal ions, the priorityof adsorption is Cu2+>Zn2+>Cd2+>Pb2+. The results of adsorption kenetic analysisdemonstrated that pseudo-second-order kinetics model was coincidence with adsorptionprocess, and the chemical adsorption could be the rate-limiting step in the process. Thedata of apparent activation energy showed that the diffusion mechanism was dominated inthe adsorption process. The internal diffusion of particle was not the only rate-limiting stepby calculation of equation, the adsorption process was controlled by many adsorption mechanisms. Freundlich isotherm model was fitted well with the adsorption process ofthermodynamics, which illustrated that there was chemical adsorption in the process. Theenthalpy change ΔH°>0proved that the rise of temperature was favorable for adsorptionprocess, the entropy change ΔS°>0showed that entropy increased in the adsorptionprocess, the Gibbs free energy change ΔG°<0indicated that the adsorption is spontaneous,|TΔS°|>|ΔH°|revealed the reaction was driven by the entropy.Many times of adsorption experiments were preliminary discussed for theregeneration ability of the thiacalixarene modified resin. It’s confirmed that thethiacalixarene modified resin could be reused several times after regeneration.