玉米秸秆生物炭活化过硫酸盐催化降解罗丹明B的性能研究

The Catalytic Performance of Persulfate for aqueous Rhodamine B Activated by Corn Stalk Biochar

以玉米秸秆为原料,制备了不同温度的生物炭材料,以罗丹明B(RB)为目标有机污染物,研究了过硫酸盐种类和浓度、生物炭热解温度、RB浓度以及小分子酸等对生物炭活化过硫酸盐降解RB性能的影响,并开展了模拟水样中RB的降解实验。结果表明:生物炭能够有效活化过一硫酸盐(PMS)和过二硫酸盐(PDS),进而促进RB的降解,其中生物炭-PMS体系的催化活性更强;热解温度影响生物炭活化PMS的催化活性,较低热解温度制备生物炭的催化性能更好;生物炭-PMS体系的催化活性随着PMS浓度的增加或RB浓度的降低而增加;3种小分子酸(柠檬酸、抗坏血酸、草酸)能显著促进体系的催化能力;RB的初始浓度与初始降解速率符合Langmuir-Hinshelwood动力学模型,说明在RB降解过程中,吸附作用发挥着重要作用;生物炭-PMS体系降解人工地下水中RB的效果有所降低。

Biochar materials at different temperature were prepared from corn stalk. With rhodamine B(RB) as the target organic pollutant, the effects of persulfate species and concentration, calcination temperature of biochar, RB concentration, and small-molecule acids on the catalytic efficiency were studied. Besides, the degradation of RB was also performed in simulated water. The results showed that the as-prepared biochar can effectively activate persulfate(peroxymonosulfate(PMS) and perodisulfide(PDS)) to promote the degradation of RB, among which the biochar-PMS system had a stronger catalytic activity. Calcination temperature affected the catalytic activity of biochar, that is, the activated efficiency of biochar prepared at a lower calcination temperature is better. The catalytic activity of biochar increased with the increase of PMS concentration or the decrease of RB concentration. Three small molecule acids(citric acid, ascorbic acid and oxalic acid) significantly promoted the catalytic capacity of biochar. The initial concentration and the initial degradation rate of RB were consistent with the Langmuir-Hinshelwood(L-H) kinetic model, indicating that adsorption played an important role in the degradation of RB. The degradation performance of RB in actual water bodies was lower than that of in aqueous solution.