The results showed that both of OAC-Fe and OAC-Mn have good adsorption capacities for As(III) but OAC-Fe has a greater removal capacity for As(V) than OAC-Mn. OAC-Mn was identified as a good material for the of As(III) removal, because of its oxidation efficiency of As(III) to As(V) during adsorption process. | Vietnam Journal of Science and Technology 56 (2C) (2018) 80-87 MODIFICATION OF OXIDIZED ACTIVATED CARBON SURFACE BY Fe AND Mn FOR ARSENIC REMOVAL FROM AQUEROUS SOLUTION Pham Thi Hai Thinh1, 2, *, Tran Hong Con3, Phuong Thao3 1 Institute of Environmental Technology, VAST, 18 Hoang Quoc Viet, Cau Giay, Ha Noi 2 Graduate University of Science and Technology, VAST, 18 Hoang Quoc Viet, Cau Giay, Ha Noi 3 VNU, University of Science, 19 Le Thanh Tong, Ha Noi * Email: phamhaithinh1979@ Received: 3 May 2018; Accepted for publication: 21 August 2018 ABSTRACT Carboxylate groups on oxidized activated carbon surface were transformed to the forms of Mn2+ and Fe3+ (signed as OAC-Mn and OAC-Fe respectively) through multi-step procedure. This modified activated carbon then was used as an adsorption material for arsenic removing from aqueous solution. Synthetic water containing As(III) and As(V) was used for study of arsenic adsorption capacities of OAC-Fe and OAC-Mn. The similar study had also been done with original granular activated carbon for comparison. The effects of modified metals onto oxidized activated carbon, metals doses and initial arsenic concentration on the removal of As(III), As(V) have been surveyed and discussed. Batch adsorption experiments were carried out with arsenic concentration in the range of 1 – 50 mg/l. Langmuir models were used for the adsorption isotherm screening. The results showed that both of OAC-Fe and OAC-Mn have good adsorption capacities for As(III) but OAC-Fe has a greater removal capacity for As(V) than OAC-Mn. OAC-Mn was identified as a good material for the of As(III) removal, because of its oxidation efficiency of As(III) to As(V) during adsorption process. Keywords: oxidized activated carbon, Fe and Mn modificaton, arsenic removal. 1. INTRODUCTION Activated carbons (AC) have been proven to be effective adsorbents for the removal of a wide variety of organic and inorganic pollutants. However, AC is relatively less .
