Regulated adsorption sites using atomically single cluster over biochar for efficient elemental mercury uptake

Carbon-based materials have been widely used in gaseous pollutant removal because of their sufficient surface functional groups; however, its removal efficiency for elemental mercury (Hg-0) is low. In this study, we fabricated biomass using a chelated coupled pyrolysis strategy and further constructed the regulated adsorption sites for gaseous Hg-0 uptake. A series of Mn-delta-N2O2/BC with different manganese cluster sizes demonstrated that manganese clusters anchored on biochar acted as highly active and durable adsorbents for Hg-0 immobilization, which increased the adsorption efficiency of Hg-0 by up to 50%. Shrimp- and crab-based biochar adsorbents exhibited excellent Hg-0 removal because of their chitosan-like structure. In particular, small Mn clusters and oxygen species around the defect led to a boost in the Hg-0 adsorption by carbon. The results of density functional theory calculation revealed that the presence of oxygen in the carbon skeleton can tune the electrons of small-sized Mn clusters, thereby promoting the affinity of mercury atoms. The newly developed Mn-delta-N2O2/BCshrimp had an adsorption capacity of 7.98-11.52 mg g(-1) over a broad temperature range (50-200 & DEG;C) and showed a high tolerance to different industrial flue gases (H2O, NO, HCl, and SO2). These results provide novel green and low-carbon disposal methods for biomass resource utilization and industrial Hg-0 emission control.

Automated summary

In this study, biomass with regulated adsorption sites for gaseous Hg-0 uptake was fabricated using a chelated coupled pyrolysis strategy. Manganese clusters anchored on biochar were found to act as highly active and durable adsorbents for Hg-0 immobilization, increasing its adsorption efficiency by up to 50%. Shrimp- and crab-based biochar adsorbents showed excellent Hg-0 removal due to their chitosan-like structure.