欢迎访问《环境科学学报》编辑部网站！

快速检索			高级检索

研究报告

杨春平
1. 浙江省固体废物处理与资源化重点实验室, 浙江工商大学环境科学与工程学院, 杭州 310012;2. 环境生物与控制教育部重点实验室, 湖南大学环境科学与工程学院, 长沙 410082

摘要：研究了裂解温度分别为500℃和700℃的两种水稻秸秆生物炭(分别标记为W500、W700)对有机染料日落黄和亚甲基蓝的吸附作用及机制.同时,针对实际印染废水的特点,考察了反应温度、pH和硫酸盐对吸附去除效率的影响.结果显示,生物炭对两种染料的吸附均符合准二级动力学方程,等温吸附曲线均可用Freundlich模型较好地描述,但其对两种染料的吸附机制显著不同.生物炭对阳离子染料亚甲基蓝的吸附主要通过离子交换作用,随着生物炭裂解温度升高,其极性基团减少,离子交换作用减弱.生物炭对阴离子染料日落黄的吸附则主要通过生物炭芳香结构与日落黄分子芳环之间的π-π相互作用,随裂解温度升高,生物炭芳香化程度增大,π-π作用随之增大;生物炭对两种染料的吸附去除效率均随反应温度的升高(5~45℃)而增大,且在3< pH< 11、硫酸盐浓度25~2500 mg·L^-1的变化范围内,吸附去除效率均保持稳定.

Abstract：The sorption of two organic dyes, methylene blue and sunset yellow by biochar with two different pyrolytic temperatures (500℃ and 700℃) was studied. The effective factors such as reaction temperature, pH and sulfate concentration were also discussed. The kinetic data fitted well by pseudo second-order model and the equilibrium sorption data were best described by the Freundlich model for both dyes. However, the sorption mechanisms of biochar for methylene blue and sunset yellow were different. The cationic methylene blue was mainly sorbed onto the biochar surface by cationic exchange, and the sunset yellow was mainly sorbed to the biochar by the π-π interaction between its aromatic ring and the aromatic structure of biochar. As the increase of pyrolytic temperature, more aromatic structure formed in biochar was accompanied by loss of H-and O-containing groups, so that the ionic electrostatic attraction from methylene blue and biochar decreased while the π-π interaction from sunset yellow and biochar increased. The removal efficiency of the two organic dyes by biochar can be enhanced by increasing the reaction temperature from 5℃ to 45℃. The variation of pH from 3 to 11 and sulfate from 25 mg·L^-1 to 2500 mg·L^-1 did not show obvious effect on the removal of the two organic dyes by biochar from aqueous solution.