The mechanochemical (MC) brominated fly ash is a cost-effective mercury removal adsorbent, in which unburned carbon (UBC) plays an important role. The MC bromination mechanism of UBC and its mercury removal mechanism were completely studied through the density functional theory (DFT) method. Various defects on zigzag and armchair edge models were constructed at the micro-scale to simulate the MC effect on UBC at the macro-scale. The results reveal that the intact surface of zigzag and armchair can be constructed into abundant defective structures by MC action. Compared with the complete surface, bromine is more favorable to bind on the defective surface, resulting in more and stronger C-Br covalent bonds and more active sites. These defective structures also have a promoting effect on mercury adsorption. For the bromine-embedded structure, although the appropriate defective structure accounts for less, it not only can promote the adsorption and oxidation of mercury by improving adsorption ability or decreasing the oxidation energy barrier but is also easier to generate. Due to defect types formed by MC interaction on the UBC surface are much more diverse and complex, this study provides the theoretical basis for further research.

机械化学（MC）溴化粉煤灰是一种经济高效的除汞吸附剂，其中未燃碳（UBC）发挥着重要作用。通过密度泛函理论（DFT）方法对UBC的MC溴化机理及其脱汞机理进行了全面研究。在微观尺度上构建了锯齿形和扶手椅边缘模型上的各种缺陷，以在宏观尺度上模拟 MC 对 UBC 的影响。结果表明，锯齿形和扶手椅的完整表面可以通过MC作用构建成丰富的缺陷结构。与完整表面相比，溴更有利于结合在缺陷表面上，从而产生更多更强的C-Br共价键和更多的活性位点。这些有缺陷的结构对汞的吸附也有促进作用。对于溴嵌入结构，适当的缺陷结构虽然所占比例较小，但不仅可以通过提高吸附能力或降低氧化能垒来促进汞的吸附和氧化，而且更容易生成。由于MC相互作用在UBC表面形成的缺陷类型更加多样化和复杂，本研究为进一步研究提供了理论基础。