Activated carbon (AC) has been proven to be an effective adsorbent for the removal of a variety of pollutants. AC is extensively used for adsorption because its high surface area is welldeveloped internal micro porosity. The objective of this study is to determine the optimal condition of the surface modification process of activated carbon from rice husk (ACRH) using HNO3. | Journal of Science and Technology 54 (4B) (2016) 19-26 SURFACE MODIFICATION OF ACTIVATED CARBON FROM RICE HUSK FOR ENHANCING THE NICKEL(Ni2+) AND CADMIUM (Cd2+) ADSORPTION CAPACITY Hoa Thai Ma1, 2, Van Thi Thanh Ho3, Hung Cam Ly3, Nguyen Bao Pham2, Tuan Dinh Phan3* 1 2 Vietnam National University, Hochiminh City University of Technology, 268 Ly Thuong Kiet street, Ward 14, District 10, HCMC, Vietnam Tra Vinh University, 126 Nguyen Thien Thanh street, Ward 5,Tra Vinh city, Vietnam 3 Hochiminh City of University of Natural Resources and Environment Vietnam, 236 Le Van Sy street, District Tan Binh, HCMC, Vietnam * Email: pdtuan@ Received: 15th August 2016 / Accepted for publication: 10th November 2016 ABSTRACT Activated carbon (AC) has been proven to be an effective adsorbent for the removal of a variety of pollutants. AC is extensively used for adsorption because its high surface area is welldeveloped internal micro porosity. The objective of this study is to determine the optimal condition of the surface modification process of activated carbon from rice husk (ACRH) using HNO3. That increase the functional group, and improve affinity towards certain contaminants of 2+ 2+ ACRH for increasing the adsorption capacity of Ni and Cd . Two factors were taken into account as: the concentration of HNO3 (1, 3, and 5 M), reaction time (1, 2, 3, 4 and 5 hours). The results showed that the optimal condition of the surface modification process was derived at the equilibrium concentration of HNO3 = 3 M and the equilibrium reaction time = 4 hour. Interestingly, in comparison with the control sample (ACRH not modified), the adsorption 2+ 2+ capacity of Ni and Cd increased from to mg/g and to mg/g, respectively. This adsorption capacity of modified ACRH shows the increase significantly. Keywords: surface modification, HNO3, activated carbon, rice husk. 1. INTRODUCTION Activated carbon (AC) has been proven to be effective for removal of a wide
