Abstract
Nitrogen-doped biochar is considered as a renewable, cost-effective, and promising SO2 adsorbent. However, it is difficult to improve the physicochemical properties of biochar synergistically and clarify the adsorption mechanism. Therefore, in this study, a one-step high-temperature CO2-NH3 modification method was proposed for biochar to improve its SO2 adsorption, and the in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (in situ DRIFTS) was used to reveal the interface reaction mechanism between SO2 and nitrogen-doped biochar. The results showed that when the modification temperature exceeded 700 °C, CO2 and NH3 exhibited significant thermal activation and nitrogen doping on biochar simultaneously. Under a modification temperature of 800 °C (BCAN-800), the microporous surface area and nitrogen content of modified biochar reached the highest value of 563.83 m2/g and 6.63 wt%. The SO2 adsorption capacities of BCAN-800 were up to 201.89 mg/g and 145.68 mg/g at 30 °C and 120 °C, respectively. The results of in situ DRIFTS showed that dimeric and bridge hydrogen bonds were the main SO2 adsorption sites on nitrogen-doped biochar at 30 °C. With the increase of adsorption temperature, nitrogen-containing groups as the main adsorption site could combine with SO2 to form sulfamide (60 °C), which eventually existed in a more stable form of SO42−/R-O-SO2-OR′ (120 °C).
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
