微波辅助羧基改性黄麻吸附材料的制备工艺优化

在突发水污染应急处置过程中,纤维状吸附材料形态自由度大,应用灵活且便于回收,但现有的纤维状材料制备时间较长,严重限制其在实际中的应用.为此,以价廉易得的黄麻为基体,采用微波辅助对其进行快速预处理和接枝改性.在单因素实验的基础上,采用响应曲面法对黄麻预处理工艺的参数进行优化,并与高温碱煮法进行对比;而后在预处理黄麻上接枝羧基,通过对微波辅助与水浴加热法下的接枝反应速率进行比较,揭示微波在接枝反应中的作用;最后,考察改性黄麻对水中重金属离子的吸附效果.结果表明,与高温碱煮工艺相比,微波辅助碱预处理工艺缩短了反应时间(缩短约70%),降低了碱液质量分数(由20%降至16%);微波辅助下的初始接枝反应速率约为水浴加热下的18.6倍.这是因为微波提高了接枝反应的指前因子,降低了表观活化能,促进了反应的发生.与原麻相比,改性黄麻对水中重金属离子的吸附效果有明显提高.

Optimization of the microwave-assisted preparation process for the carboxyl modified jute fiber adsorbent

The morphology of fibrous adsorbents possessed the large degree of freedom so that they can be used flexibly and recycled easily in emergency water treatment. Traditionally, long time preparation of the fibrous adsorbents severly limited their wide application. To solve the above mentioned problem, the microwave-assisted method was applied to prepare a new adsorbent which was derived from the low-cost and available jute. The pretreatment process was optimized with the response surface methodology (RSM) method based on single factor experiments, and the performance of microwave-assisted method was compared with the control test by alkali boiling under water-bath heating. The above pretreated jute was then grafted with carboxyl groups, and the contribution of microwave during graft reaction was clarified. Finally, the adsorption behaviors of modified jute toward heavy metal ions removal were studied. Compared to alkali boiling under water-bath heating, the pretreatment time was reduced 70% and alkaline mass fraction was declined from 20% to 16% under microwave-assisted method. Initial microwave-assisted grafting reaction rate was about 18.6 times higher than that under water-bath heating, because the microwave heightened the pre-exponential factor and lowered the apparent activation energy of graft reaction. Modified jute exhibited a higher removal efficiency of heavy metal ions than raw jute.