ZIF-8/玉米芯吸附功能材料的制备及性能研究

采用亚氯酸钠脱木素、TEMPO氧化改性处理玉米芯原料,并在改性玉米芯表面原位负载锌系金属有机框架物(ZIF-8),制备出ZIF-8/玉米芯吸附功能材料。探讨了改性处理对不同粒径玉米芯结构与性能的影响,对比了块状和粒状改性玉米芯对ZIF-8负载及吸附功能材料性能的影响。结果表明,脱木素与氧化处理可提高玉米芯纤维素及羧基含量,促进纳米ZIF-8晶体在玉米芯上的配位结合与原位锚定。相比块状玉米芯,粒状玉米芯改性后的比表面积更大、Zeta电位更高和羧基含量更多,更有利于ZIF-8的负载与分布,因而具有更好的吸附能力(对甲基橙最大吸附能力:3.5 mg/g比1.0 mg/g)。上述两种吸附功能材料均具有较好的回用性能,循环使用6次后,两种吸附功能材料对甲基橙的去除率仍高于90%。

Preparation of ZIF-8/ Corncob Adsorbent and Its Dye Adsorption Performance

The ZIF-8/ corncobs adsorbing composite was prepared by treating raw corncob material with sodium chlorite for delignification and TEMPO for oxidation, and followed by in-situ loading zinc metal-organic framework (ZIF-8) on the surface of the modified corncobs. The effects of modification on the structure and properties of corncobs with different particle sizes were discussed. Besides, the effects of block corncobs (B-CBs) and particle corncobs (P-CBs) on the ZIF-8 loading and the adsorption properties of composite materials were also compared. The results showed that delignification and oxidation treatment could increase the content of cellulose and carboxyl groups in the corncob, and promote the coordinated binding and in-situ anchoring of nano-ZIF-8 crystals on the corncob. Compared with the B-CBs, the modified P-CBs had a higher specific surface area, Zeta potential and carboxyl content, which was more conducive to the loading and distribution of ZIF-8, thus leading to a better dye adsorption capacity of methyl orange 3.5 mg/g vs. 1.0 mg/g. Both composite materials above mentioned have good reusability (more than 90% of dye removal efficiency after 6 cycles).