活性炭和分子筛对甲醛气体吸附性能的比较

Comparative Study on Adsorption Behavior of Activated Carbon and Zeolites on Formaldehyde

目的寻求一种经济有效去除室内甲醛污染的处理方法,探索活性炭和分子筛对甲醛气体的吸附性能及影响机理.方法利用固定吸附床考察活性炭及不同类型分子筛对甲醛的吸附性能.以低温氮气(77.4 K)吸附法测定各样品吸附等温线,用密度函数理论计算出各样品的孔径分布.结果钴离子改性的13X分子筛吸附效果优于其他吸附剂,甲醛质量浓度为30mg/m3,气体流量为150 mL/min的条件下,Co-X穿透时间370 min,吸附量18.9 mg/g.结论分子筛作为极性吸附剂对甲醛的吸附性能优于活性炭.分子筛对甲醛分子的吸附是其晶体结构和骨架中阳离子共同作用的结果.通过水溶液离子交换法得到的Co-X型分子筛对甲醛的吸附性能最好.

The purpose of this paper is to provide an economic and effective removal way of indoor formalde-hyde.The adsorption capability of formaldehyde on activated carbon、ZSM-5、13X、Cocontaining 13X zeolites are examined by the adsorption measurements in a fixed bed flow adsorption apparatus.The porous structure parameters of the samples under study are investigated using nitrogen adsorption at the low temperature 77.4 K.The pore size distributions of the samples under study are calculated by density functional theory.Compared with other samples,the Cocontaining 13X showes the optimum capability.When the formaldehyde concentra-tion is 30 mg/m3 and flow is 150 mL/min,the breakthrough time and adsorption amount of Cocontaining 13X is 370 minutes and 18.9 mg/g respectively.Results indicate that zeolite has better adsorption capacity on removing of formaldehyde than activated carbon as polar adsorbent.It is found that the adsorption capacity of formaldehyde on zeolites is related to the pore structure and cations on molecular sieves framework.