VNU Journal of Science Mathematics – Physics, Vol 37, No 3 (2021) 9 21 9 Original Article Highly Selective Separation of CO2 and H2 by MIL 88A Metal Organic Framework Do Ngoc Son1,2, Nguyen Thi Xuan Huynh3,*, Nam Thoai1,2, Pham Trung Kien1,2 , 1Ho Chi Minh City University of Technology, 268 Ly Thuong Kiet, District 10, Ho Chi Minh City, Vietnam 2Vietnam National University, Ho Chi Minh City, Quarter 6, Linh Trung, Thu Duc, Ho Chi Minh City, Vietnam 3Quy Nhon University, 170 An Duong Vuong, Ngu[.]