氧化改性生物炭对水体中阳离子和阴离子染料的吸附研究

以HNO3和H2O2为改性剂,对玉米秸秆和甘蔗屑在不同温度下制备的生物炭进行改性。研究了氧化改性生物炭对水体中阳离子染料(MB)和阴离子染料(KN-R)的吸附效果。结果表明,氧化改性生物炭对染料的吸附效果与氧化剂的强度、染料性质和浓度、生物炭制备条件关系密切。HNO3氧化改性生物炭对阳离子染料和阴离子染料的吸附效果明显优于H2O2氧化改性生物炭;其中HN4YM和HN4GZ对阳离子染料各浓度均表现出极高的吸附效果;而HN8YM更适合处理中、低浓度的阴离子染料。再生实验结果一方面表明,KCl再生后的HN4YM和HN4GZ对阳离子染料仍保持极高的吸附效果;其去除效率占再生前90%,有很好的利用潜力,阳离子交换作用可能在吸附中发挥重要作用。HN8YM再生后对阴离子的吸附效果虽然只约占再生前的50%,但考虑到其制备简单且成本低廉,也可用于处理较低浓度阴离子染料,其吸附机制除与阴离子交换有关外,其他吸附机制也发挥了重要作用。

Study on biochar modified by oxidation for removal of cationic and anionic dye from aqueous solutions

Biochar produced in different temperature was modified by HNO3 and H2O2, which was evaluated for its ability of adsorption for cationic (MB) and anionic dye (KN-R) from aqueous solutions. The results showed that the ability of adsorption of the biochar modified by oxidation was closely related with oxidation strengthen, characterization and concentration of dye and the produced method of biochar. For cationic dye , biochar modified by HNO3 indicated higher ability of adsorption than that modified by H2O2, and both HN4YM and HN4GZ had the greatest ability of adsorption in high-, mid- and low-concentration. However, HN8YM merely showed high ability of adsorption in mid- and low-concentration for anionic dye. In addition, findings from regeneration experiment with KCl indicated that HN4YM and HN4GZ still had a good performance for the adsorption of cationic dye after several generation and cycles, and its average removal rate accounted for about 90% cationic dye sorption from pre-generation, which confirmed that HN4YM and HN4GZ can be recycled and reused after cationic dye adsorption, and cationic exchange might play an important role in adsorption. For HN8YM after regeneration, although its average removal rate accounted for roughly 50% anionic dye sorption from pre-generation, it can be reused to remove anionic dye in mid- and low concentration if considering the simple produced method and low-cost materials. Furthermore, the result could confirm that besides anionic exchange other sorption mechanisms also might play an important role in anionic dye adsorption.