Ethylenediamine And Beta - Cyclodextrin Modified Chitosan Microsphere Preparation And Its Adsorption Of T1 (â…¢) Experimental Study

Recently, the mining scale of thallium was expanding, the mental of thallium wasincreasingly used in various industries, the phenomenon that thallium was exposed tothe environment occurred frequently in the past several years. As a highly toxicelements, the mental of thallium and its compounds are like a “chemical time bomb”,which existed great threat to the future environment, besides, ecological effect andtoxicology has apparent lag, The potential threat were far more serious than theapparent effect. Therefore, it is urgent to develop an efficient and convenient, low costthallium pollutants treatment technology, solved the problem of thallium applicationlimited in various fields owing to the pollutions of thallium, make full use of theadvantages of our country thallium mine, drive and promote the development ofrelevant industries.As a polymer materials, chitosan are rich in natural resources and have goodenvironmental compatibility. In the present study, ethylenediamine modified chitosanchelating resin was synthesized and the application for the removal of thallium (III)was also investigated. It was found that resin showed a high uptake for thallium (III)with the initial pH of4within30min. All the kinetic data were fitted well to thepseudo second-order kinetic model with a high correlation coefficient. The Freundlich,Langmuir and Temkin adsorption models were applied to described isotherm, theisothermal data could be well interpreted by Langmuir models, the biggest adsorptiondosage can reach55.55mg/g at298K. Besides, the sorbents were regenerated fourtimes with0.1N NaOH and showed a high efficiency in the adsorption/desorptioncycle.We can saw that morphology and structure of modified chitosan chelating resinhad a obvious change from before and after the adsorption resin SEM map,resinsurface was loose and rough before adsorption, thus density level after adsorption.EDS chromatogram proved that adsorption reaction of Tl (III) by modified chitosanresin occurred, the stretching vibration peak of the-NH2and-OH before adsorption is stronger than resin adsorbed, indicating the-NH2and-OH combined with Tl (III)inadsorption process. The free energy of adsorptive reactions was negative, whichshowed that the adsorption processes was spontaneous.At the same time, through the comparison of the β-cyclodextrins solid chitosanprepared, the experimental results showed that when the dosage was0.7g, the biggestremoval percentage was only62.5%when applied to adsorb10mg/L of Tl (III) inwater, the biggest adsorption dosage reach2.154mg/g at298K, which is less effectivecompared to the ethylenediamine modified chitosan.