活性炭负载MnO2及其对甲醛的吸附

Activated carbon loaded MnO2 and its adsorption of formaldehyde

以椰壳活性炭为原料,采用单因素实验方法,考察高锰酸钾浓度、浸渍振荡时间、煅烧温度、煅烧时间对负载MnO2活性炭吸附甲醛(质量浓度3.5 mg/L)能力的影响,再将最佳条件下制备的负载MnO2活性炭(MnO2-AC)对一定质量浓度的甲醛溶液进行吸附,采用单因素实验方法,通过BET、XPS、FTIR以及XRD等分析手段,考察吸附时间、MnO2-AC投加量、初始甲醛质量浓度对MnO2-AC吸附甲醛能力的影响。结果表明,MnO2-AC(高锰酸钾浓度0.08 mol/L、浸渍振荡时间4 h、煅烧温度600℃、煅烧时间2.5 h)对质量浓度3.5 mg/L的甲醛吸附率达90.17%,较AC提高了240.26%。MnO2-AC吸附甲醛(质量浓度3.5 mg/L)4 h时,可认为吸附达到平衡;随着投加量的增加,甲醛吸附率增加趋势逐渐平缓;对低浓度甲醛溶液吸附过程符合Langmuir吸附等温模型,饱和吸附量Q∞为8.24 mg/g;负载MnO2的晶型为δ-MnO2且结晶度较好,本研究以期为研发一种吸附甲醛能力强的活性炭提供参考依据。

Coconut shell activated carbon was used as raw material and single factor experiment method was adopted to study the influence of the concentration of potassium permanganate,dipping oscillation time,calcining temperature,and calcining time on the formaldehyde(the mass concentration of formaldehyde solution is 3.5 mg/L)adsorption capacity of MnO2 loaded activated carbon.The adsorption performance of MnO2-AC samples which were prepared under optimized conditions was further investigated using formaldehyde solution with a certain mass concentration by single factor experiment method.The effects of adsorption time,dosing quantity of MnO2-AC,and the initial concentration of formaldehyde solution on the absorption performance of MnO2-AC were investigated through BET,XPS,FTIR and XRD.The results show that the adsorption efficiency of formaldehyde(the mass concentration of formaldehyde solution is 3.5 mg/L)solution by MnO2-AC(the concentration of potassium permanganate is 0.08 mol/L,and the dipping oscillation time is4 h,the calcination temperature and time are 600℃and2.5 h,respectively)is 90.17%,which increased by240.26%compared to that of AC.The adsorption equilibrium can be achieved after 4 h(the mass concentration of formaldehyde solution is 3.5 mg/L).With the dosage increasing,the increasing rate of adsorption efficiency becomes gradual.The adsorption process of formaldehyde solution with low concentration fits to the Langmuir adsorption isothermal model,and the adsorption capacity Q∞is 8.24 mg/g.The crystal pattern of MnO2 isδ-MnO2 with good crystalline.This study is expected to provide a reference for the development of an activated carbon with strong adsorption ability to formaldehyde.