Abstract Title: | Regeneration Mechanism of Biochar Mercury Adsorbent Directionally Modified by Multi-Metal Multilayer Loading |
Presenter Name: | Li Jia |
Company/Institution: | Taiyuan University of Technology |
Session: | Mercury Treatment / Abatement |
Day and Session: | Monday 25th July - Session One |
Start Time: | 0600 UTC |
Co-Authors: | Li Jia,Yue Yu |
Abstract Information :
To solve the current problems of the low adsorption efficiency of biochar directly obtained by pyrolysis and the ineffective recycling of adsorbents, conventional chemical coprecipitation, sol-gel, multi-metal multilayer loading and biomass pyrolysis coking processes have been integrated. Upon selection of specific components for the structural design, a novel high-performance biochar adsorbent was obtained. The effects of O2 concentration and temperature on the regeneration characteristics were explored. An isothermal regeneration method was proposed to repair the deactivated adsorbent in a specific atmosphere, and the optimal regeneration mode and conditions were obtained. In addition to the microscopic characteristics of regenerated samples, the mechanism of Hg0 removal and regeneration was revealed by using temperature-programmed desorption technology and adsorption kinetics. The results show that the doping of multiple metals can reduce the pyrolysis reaction barrier of the modified biomass. The doped metals form aggregated oxides on the modified sample surface, and the synergistic effect produced can enhance the oxidative activity of biochar carriers and the threshold effect of Ce oxide. The optimal regeneration conditions of 5% O2 and 600øC can not only effectively coordinate the competitive relationship between the deep carbonization process and the adsorption/oxidation site repair process, but also establish an excellent structure-activity relationship between the physicochemical characteristics and Hg0 removal performance of the regenerated samples. Hg0 adsorption by the regenerated samples is a multi-layer mass transfer process involving the coupling of physical and chemical effects, and the surface adsorption sites play a leading role.