以玉米秸秆为原料,采用浸渍-热解法制备了铁锰改性生物炭(FMBC),以Pb(Ⅱ)、Cd(Ⅱ)为目标污染物,通过批量吸附实验考察了铁锰离子摩尔比、溶液初始pH对FMBC吸附性能的影响,并结合扫描电子显微镜、傅里叶变换红外光谱仪、X射线衍射仪等表征手段探究其吸附机理。结果表明:当铁锰离子摩尔比为1:10时,FMBC对Pb(Ⅱ)和Cd(Ⅱ)的去除率分别达到97.05%和93.17%,显著优于原始生物炭;在溶液初始pH=6条件下,FMBC对Pb(Ⅱ)和Cd(Ⅱ)的吸附量达到最佳,吸附过程符合准二级动力学模型和Langmuir等温吸附模型,吸附以化学吸附和单层吸附为主。吸附机理研究表明,FMBC通过物理吸附、络合作用、共沉淀作用协同实现对Pb(Ⅱ)和Cd(Ⅱ)的高效固定。
Iron-manganese modified biochar (FMBC) was prepared via an impregnation-pyrolysis method using corn straw as the raw material.Taking Pb(Ⅱ) and Cd(Ⅱ) as the target pollutants,batch adsorption experiments were conducted to systematically investigate the effects of iron-manganese molar ratio and solution initial pH on the adsorption performance of FMBC.Additionally,characterization techniques such as scanning electron microscopy (SEM),Fourier transform infrared spectroscopy (FT-IR),and X-ray diffraction (XRD) were employed to deeply explore the underlying adsorption mechanism.The results demonstrated that when the molar ratio of iron to manganese was 1:10,the removal efficiencies of FMBC for Pb(Ⅱ) and Cd(Ⅱ) reached 97.05% and 93.17%,respectively,which were significantly superior to those of raw biochar.The adsorption capacities of FMBC for Pb(Ⅱ) and Cd(Ⅱ) achieved the optimal level under the condition of initial solution pH=6.The adsorption process conformed to the pseudo-second-order kinetic model and Langmuir isotherm model,indicating that the adsorption was dominated by chemical adsorption and monolayer adsorption.Mechanistic studies revealed that FMBC realized the efficient immobilization of Pb(Ⅱ) and Cd(Ⅱ) through the synergistic effects of multiple mechanisms,including physical adsorption,complexation,and co-precipitation.
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基金资助
吉林省教育厅科学研究项目资助(JJKH20240160HT)
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