熔盐裂解玉米芯制备活性炭及其对Pb(Ⅱ)的吸附性能研究

Preparation of activated carbon by cracking corn cob in molten salt and its absorption performance for Pb(Ⅱ)

以玉米芯为生物原料、ZnCl_(2)/KCl熔盐为介质,采用熔盐热裂解法制备活性炭。通过X射线衍射(XRD)、扫描电子显微镜(SEM),N_(2)吸附-脱附等手段对不同裂解温度下所制得的玉米芯活性炭进行了结构和形貌表征,并研究了活性炭在不同溶液温度条件下对水中Pb(Ⅱ)的吸附性能。结果表明:玉米芯活性炭呈现为多孔隙结构,裂解温度为650℃时制得的活性炭比表面积最大,为605.2m^(2)/g。玉米芯活性炭对Pb(Ⅱ)的吸附量以及去除率随着溶液温度的升高而增加。在323K条件下,当铅离子的初始浓度为5mg/L时,铅离子去除率可以达到98.72%。吸附过程更适合用Freundlich等温模型来描述,吸附为非均匀吸附。可为废弃生物质在环境保护中的应用提供借鉴思路。

Using corn cob as biomass material and ZnCl_(2)/KCl molten salt as medium,the activated carbon(AC)was prepared through molten salt pyrolysis.The structure and morphology of the AC obtained at different pyrolysis temperatures were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD)and N;adsorptiondesorption.The absorption performance of the biochar for Pb(Ⅱ)at different solution temperatures was investigated.The results showed that the AC exhibited a multi-pore structure,and the AC obtained at 650℃ had the largest specific surface area of 605.2 m^(2)/g.The absorption capacity and removal rate for Pb(Ⅱ)by the activated carbon increased with the increase of solution temperature.The removal rate of Pb(Ⅱ)reached to 98.72% under 323 K and the initial concentration of 5 mg/L.The absorption process was more suitable to be described by Freundlich isothermal model,and the absorption was non-uniform.An idea to utilization of biomass waste into environmental protection was provided.