Studies on the Flocculation of Algae with Metal Ions

Park, Yeong Jae; Lee, Sang Soo; Cho, Hye Ryun; Park, Yeong Jae; Lee, Sang Soo; Cho, Hye Ryun

doi:2015.37.8.441

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(8); 2015 > Article

Original Paper

J Korean Soc Environ Eng 2015;37(8): 441-449. doi: https://doi.org/10.4491/KSEE.2015.37.8.441

금속이온에 의한 조류 응결에 관한 연구

박영재¹, 이상수², 조혜륜³

¹호서대학교 생명공학전공
²배재대학교 생명공학과
³한국원자력연구원 원자력화학연구부

Studies on the Flocculation of Algae with Metal Ions

Yeong Jae Park¹, Sang Soo Lee², Hye Ryun Cho³

¹Department of Biotechnology, Hoseo University
²Department of Life Science and Technology, Pai Chai University
³Nuclear Chemistry Research Division, Korea Atomic Energy Research Institute

Corresponding author

Yeong Jae Park ,Tel: 041-540-9641, Fax: 041-540-6231, Email: nyjpark@naver.com

Received: July 7, 2015; Revised: August 12, 2015; Accepted: August 24, 2015. Published online: August 31, 2015.

ABSTRACT

Studies on the flocculation of algae using various metal ions were carried out by measurements of optical density(OD) and zeta potential. Cyanobacteria were used as algaes. Flocculation efficiencies of cyanobacteria by an addition of metal ions were determined from OD values, and the effect of metal ions was greater in the order of Al³⁺ > La³⁺ > Ho³⁺ > Fe²⁺ > Ca²⁺. Especially for trivalent metal ions, percentages of metal removed from cyanobacteria solutions on flocculation were measured, showing the same order as in flocculation efficiencies. Zeta potentials of cyanobacteria alone were measured with increasing the concentration, found to be all negative voltages, and were increased with increasing the concentration. The effect of pH on zeta potential of cyanobacteria solution was investigated. Below pH 5.5, the zeta potentials were steeply decreased with increasing pH, whereas in the range of 5.5 ≤ pH ≤ 10 they were almost constant (-46±1 mV) even with increasing pH. At a constant concentration of cyanobacteria (A₇₃₀=0.25), an increase in concentration of metal ions caused an increase in zeta potential of cyanobacteria solution, showing that the effect was greater in the order of Al³⁺ > Ho³⁺ > La³⁺ ≫ Mg²⁺ ≥ Ca²⁺ ≫ K⁺. At a constant metal concentration, zeta potentials were measured with increasing cyanobacteria concentration, showing that zeta potentials for K⁺, Mg²⁺ and Ca²⁺ ions were negligibly changed, whereas those of Ho³⁺ and La³⁺ ions were decreased. Moreover, the effect of Ho³⁺ ion on decreasing zeta potential was smaller than that of La³⁺ ion. Al³⁺ ions showed quite a different behavior that with increasing cyanobacteria concentration the zeta potentials increased and decreased thereafter. Hydrolysis of Al³⁺ ions caused a difficulty to investigate coagulation or flocculation of cyanobacteria by measurement of zeta potentials.

Key Words: Algae, Cyanobacteria, Coagulation, Flocculation, Zeta Potential