Abstract
Elemental mercury (Hg(0)) removal from a hot gas is still challenging since high temperature influences the Hg(0) removal and regenerable performance of the sorbent. In this work, a facile yet innovative sonochemical method was developed to synthesize a thermally stable magnetic tea biochar to capture the Hg(0) from syngas. A sonochemically synthesized magnetic sorbent (TUF(0.46)) exhibited a more prodigious surface area with developed pore structures, ultra-paramagnetic properties, and high dispersion of Fe(3)O(4)/γ-Fe(2)O(3) particles than a simply synthesized magnetic sorbent (TF(0.46)). The results showed that TUF(0.46) demonstrated strong thermostability and attained a high Hg(0) removal performance (∼98.6%) at 200 °C. After the 10th adsorption/regeneration cycle, the Hg(0) removal efficiency of TUF(0.46) was 19% higher than that of TF(0.46). Besides, at 23.1% Hg(0) breakthrough, TUF(0.46) achieved an average Hg(0) adsorption capacity of 16.58 mg/g within 24 h under complex syngas (20% CO, 20% H(2), 5% H(2)O, and 400 ppm H(2)S). In addition, XPS results revealed that surface-active components (Fe(+), O(2-), O*, C=O) were the key factor for high Hg(0) removal performance over TUF(0.46) from syngas. Hence, sonochemistry is a promising practical tool for improving the surface morphology, thermal resistance, renewability, and Hg(0) removal efficiency of a sorbent.