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.