Sawdust Preparation And Adsorption For U(â…¥) In The Waste Water Of Quaternary Ammonium Salt Chelate Adsorbent

With the advance of nuclear technology, there are more need for uranium, and at the same time, it produces large amouts of uranium wastewater through mining. There are many ways to treating uranium wastewater at present, each way has its own advantage and disadvantage. But the adsorption has the advantage of high efficiency of removing, simple technology, low cost, and simple adsorbent processing after the adsorption, less damaging(burning or heat treatment). The characteristic of the sawdust adsorbent is low cost, large amount of material, easy to obtain, environment friendly and no secondary pollution and so on, but the adsorption rate of the adsorption is not high when it is directly applicated, so we can improve its adsorption rate by modifying. MS improved its adsorption rate, chemical and ph stability for its quaternary ammonium groups, and it is a kind of chelating adsorbent but also a kind of cationic and anion adsorbent. At present, it is rare literature reports for synthesizing MS by using sawdust.In this paper, the MS of high adsorption rate was prepared by modifying sawdust through physical and chemical modification, then its porosity increased and the functional group with special adsorption performance was introduced, and the adsorption was used to removal U(VI) in wastewater. The adsorption performance of the MS to U(VI) was studied through the static adsorption experiment, and then its adsorption mechanism was studied. The main research contents and research results are as follows:1. The MS was prepared by using of epichlorohydrin as etherifying agent, diethylenetriamine as crosslinking agent and triethylamine graft copolymerization agent. The effects of epichlorohydrin dosage, diethylenetriamine dosage, etherification reaction time, grafting reaction time on adsorbent were studied to choose the best way of modifying sawdust. The optimum technological condition of preparing MS was obtained by doing single factor test and orthogonal test.The MS making under the best conditions was characterized and discussed the modification mechanism of the adsorbent. The experimental results show that the adsorption capacity had improved much than the original sawdust. Characterization results show that the surface is more smooth, the structure is more loose, the aperture is larger, crystallinity decreased, and the sawdust surface groups structure had changed, the quaternary ammonium group successful introducted.2. The MS was prepared to strengthen the effect of adsorbing uranium at the uranium milling plant. The presence of functional groups and surface morphology of the adsorbent were characterized and the presence of functional groups and surface morphology of the adsorbent were characterized. The effect of MS dosage, reaction time, p H and the reaction temperature to adsorption property was explored. The rule of isothermal adsorption and the isothermal adsorption was analyzed in adsorption processes, and the adsorption mechanism was also analyzed based on the rule. The experimental results were fitted with Langmuir equations well and the maximum adsorption teached 63.69 mg/g under the condition of 313 K. The adsorption was an endothermic process, and the increase of temperature did benefit the process. The adsorption kinetics data were well described by pseudo-second-order equation. The adsorption mechanism of U(VI) was main complexation reaction. Afrer adsorption the surface morphology of the MS has changed.