AMD铁絮体改性生物炭对重金属吸附机理研究——以Pb(Ⅱ)为例

The adsorption mechanisms of heavy metals by the biochar modified by AMD iron floc:Taking Pb(Ⅱ) as an example

以酸性矿山废水生成的铁絮体和秸秆生物炭为原料,采用化学改性和紫外辐射联用技术制备改性生物炭,并通过正交试验确定最佳改性条件,同时利用FTIR、SEM和BET等方法对吸附材料的形貌特征、孔隙结构及其表面化学性质进行表征.结果表明,通过改性使吸附材料比表面积增大,吸附位点增多,在25℃、pH为7时,吸附材料改性后比表面积为295.71 m^2·g^-1,对Pb(Ⅱ)的拟合吸附量可达278 mg·g^-1.改性材料对Pb(Ⅱ)的吸附过程符合Langmuir吸附等温线模型和准二级动力学模型,主要为单分子层吸附,受化学吸附控制.

In the manuscript,the biochar was fabricated by iron floc generated from acid mine drainage(AMD)and straw biochar by chemical modification and ultraviolet radiation.And the orthogonal experiments were used to determine the optimal modification conditions.Then the morphology,pore structure and surface chemistry properties of the obtained materials were characterized by FTIR,SEM and BET,etc.The results showed that the specific surface area and adsorption site of the modified adsorbent increased greatly after modification,and the specific surface area of the adsorbent is about 295.71 m2·g^-1,and the adsorption capacity of Pb(Ⅱ)could reach 278 mg·g^-1 at 25℃ and pH=7.In addition,the reaction process was fitted well with the Langmuir and pseudo-second-order kinetics models.The main reason was that the process was determined by monolayer adsorption and controlled by chemical adsorption.