Assoc. Prof. Guozhao Ji

Dalian University of Technology，China 

Dr. Guozhao Ji is an associate professor of environmental engineering at Dalian University of Technology, P. R. China. He obtained Bachelor degree (2008) and Master degree (2010) in Northeastern University, P. R. China, and received PhD degree in the University of Queensland, Australia. He worked as a postdoctoral research fellow in School of Chemical Engineering and School of Mining and Mechanical Engineering at the University of Queensland from Sept. 2014 to Mar. 2016. With the fellowship of International Postdoctoral Exchange Program, he joined School of Environment at Tsinghua University for two year and three month from April 2016. In July 2018, Dr. Ji joined School of Environmental Science and Technology at Dalian University of Technology as an associate professor. His research focuses on resource recovery from solid waste via thermochemical conversions, modeling kinetics of thermochemical conversions, computational fluid dynamics simulation, carbon capture and storage and gas separation by inorganic membrane. He has published 50+ SCI papers in high-impact international journals such as Energy & Environmental Science, Environmental Science & Technology, Energy, Chemical Engineering Science, Chemical Engineering Journal, Industrial & Engineering Chemistry Research, Dalton Transactions and Energy & Fuels. He is the guest editor of the SCI journal-Processes in a special issue: Transport of Fluids in Nanoporous Materials. 

Speech Title: Kinetic analysis for cyclic CO2 capture using lithium orthosilicate sorbents derived from different silicon precursors

Abstract: A series of Li4SiO4 was synthesized using LiNO3 and 6 different silicon precursors. The precipitated-silica-derived Li4SiO4 presented the highest CO2 capacity in a 10-h sorption test, and ZSM-5-derived Li4SiO4 demonstrated the most rapid CO2 sorption. The CO2 sorption kinetics predominently followed the nucleation mode and could be accurately described by Avrami-Erofeev model. Avrami-Erofeev model previded an in-depth analysis of correlation between sorption performance and material property. Both nucleation speed and nucleation dimensionality affected the overall sorption kinetics. The kinetics and pore-size distribution suggest that the sorption kinetics was dependent on the quantity of ~4-nm-pores which favors nucleation dimensionality. For the cyclic tests, precipitated-silica-derived sample presented the poorest performance with a capacity decreasing from 31.33 wt.% at the 1st cycle to only 11.52 wt.% at the 30th cycle. However the sample made from fumed silica displayed the opposite trend with a capacity increasing from 19.90 wt.% at the 1st cycle to 34.23 wt.% at the 30th cycle. The radically distinct behaviour of samples during cycles was on account of the alternation of sorption kinetics. The decrease in ~4-nm-pores after cycles was responsible for the decrease of nucleation dimensionality for precipitated-silica-derived sample. The rearrangement during cycles could enrich the pores of ~4-nm for the fumed silica-derived sample, which improved the nucleation growth, thus enhancing the kinetics with cycles.