Influence of Acid and Heat Treatment on the Removal of Fluoride by Red Mud

Kang, Ku; Nyakunga, Expedito; Kim, Young-Kee; Park, Seong-Jik; Kang, Ku; Nyakunga, Expedito; Kim, Young-Kee; Park, Seong-Jik

doi:2015.37.4.210

The Korean text of this paper can be translated into multiple languages on the website of http://jksee.or.kr through Google Translator.

J Korean Soc Environ Eng > Volume 37(4); 2015 > Article

Original Paper

J Korean Soc Environ Eng 2015;37(4): 210-217. doi: https://doi.org/10.4491/KSEE.2015.37.4.210

Red Mud의 산처리 및 열처리가 불소 제거에 미치는 영향

강구¹, Expedito Nyakunga², 김영기³, 박성직⁴

¹한경대학교 미래융합기술대학원
²한경대학교 국제협력개발대학원
³한경대학교 화학공학과
⁴한경대학교 지역자원시스템공학과

Influence of Acid and Heat Treatment on the Removal of Fluoride by Red Mud

Ku Kang¹, Expedito Nyakunga², Young-Kee Kim³, Seong-Jik Park⁴

¹Graduate School of Future Convergence Technology, Hankyong National University
²Graduate School of International Development and Cooperation, Hankyong National University
³Department of Chemical Engineering, Hankyong National University
⁴Department of Bioresources & Rural systems Engineering, Hankyong National University

Corresponding author

Seong-Jik Park ,Tel: 031-670-5131, Fax: 02-873-2087, Email: parkseongjik@hknu.ac.kr

Received: March 9, 2015; Revised: April 15, 2015; Accepted: April 23, 2015. Published online: April 30, 2015.

ABSTRACT

Fluoride removal by acid and heat treated red mud were studied in batch and column system regarding contact time, initial concentration, pH, adsorbent dose, and filter depth. The results showed that acid treated with 0.8 M HCl, had highest adsorption capacity of fluoride and adsorption capacity decreased as heat treatment temperature increased. Sorption equilibrium reached in 30 min at a initial concentration of 50 mg-F/L but 1 h was required to reach the sorption equilibrium at the initial concentration of 500 mg-F/L by 0.8 M acid treated red mud (0.8 M-ATRM). Equilibrium adsorption data were fitted well to Langmuir isotherm model with maximum fluoride adsorption capacity of 23.162 mg/g. The fluoride adsorption decreased as pH increased due to the fluoride competition for favorable adsorption site with OH^- at higher pH. Removal percentage was increased but the amount of adsorption per unit mass decreased by adding the amount of 0.8 M-ATRM. It was concluded that the 0.8 M- ATRM could be used as a potential adsorbent for the fluoride removal from aqueous solutions because of its high fluoride adsorption capacity and low cost.

Key Words: Red Mud, Fluoride, Acid Treatment, Heat Treatment, Adsorption