活性炭表面含氧官能团对二噁英吸附的影响机制研究

Study on the mechanism of adsorption of dioxins by oxygen-containing functional groups on activated carbon surface

以分子结构和性质与二噁英相似的二苯并呋喃为模型化合物,椰壳炭为吸附剂,在120℃条件下进行了吸附实验。将硝酸改性后的样品分别在300、500、800℃进行热处理,比较了原始样品和改性后的椰壳炭对二苯并呋喃的吸附能力。并利用BET、TPD-MS、元素分析等手段对改性前后椰壳炭的物理化学性质进行了表征。结果表明,硝酸改性后椰壳炭表面含氧官能团增多,抑制了其对二苯并呋喃的吸附,其中,内酯基对二苯并呋喃吸附的影响最大,通过热处理,减少含氧官能团的含量,可提高椰壳炭对二苯并呋喃的吸附容量。

The adsorption behaviors of the model molecule dibenzofuran(DBF)with similar molecule structure and size to dioxins on the activated carbon was elucidated.The activated carbon adsorbent was coconut shell-based.The adsorption experiments were conducted at 120℃.The activated carbon samples were modified by nitric acid at 300,500,and 800℃,and their DBF adsorption capacities were compared.The physico-chemical properties of samples were characterized by BET,TPD-MS,elemental analysis,and other instruments.The results demonstrated that nitric acid treatment could inhibit the adsorption of DBF on activated carbon.The DBF adsorption capacity of activated carbon was related to its surface oxygen-containing functional groups.Lactone groups on activated carbon had the biggest influence on the DBF adsorption.Heat treatment reduced the content of surface oxygen-containing functional groups,and improved the adsorption capacity of DBF.