锰铈改性铁基生物焦单质汞吸附特性研究

Adsorption Performance Study of Elemental Mercury on Iron-based Biochar Modified by Mn-Ce

通过结合溶胶凝胶法和共沉淀法在铁基改性生物焦的基础上,引入金属锰(Mn)、铈(Ce)制得双金属改性铁基生物焦,并考察改性后生物焦的汞吸附性能。研究了改性生物焦的孔隙结构、元素价态及表面官能团,探究其改性吸附机理,并结合Arrhenius方程获得了改性生物焦的表观活化能。结果表明:5%Ce1%Mn-FeBC样品的汞吸附性能最佳,3h累积汞吸附量达11926ng/g;Ce不仅直接参与汞吸附反应,还以提供晶格氧的方式与其他金属协同吸附单质汞;改性后生物焦含氧官能团丰富,汞吸附能力显著提高;汞在生物焦表面吸附控速步骤是化学吸附。

The iron-based biochar was modified by bimetals Mn and Ce using the combined sol-gel and coprecipitation methods.And its mercury adsorption performance was examined.The pore structure,element valence and surface functional groups of the biochar were characterized to explore its adsorption mechanism after modification.The apparent activation energy of modified biochar was obtained by Arrhenius equation.Results show that 5%Ce1%Mn-FeBC sample has the best mercury adsorption performance,and its cumulative mercury adsorption capacity in 3hours is achieved at 11926ng/g.Metal Ce not only participates in the mercury adsorption reaction directly,but also synergizes with other metals to adsorb elemental mercury by providing lattice oxygen.After modification,the biochar is abundant in oxygen functional groups,which improves the mercury adsorption performance significantly.Chemical adsorption is the rate controlling step of mercury adsorption on the biochar surface.