Sorption of Heavy Metal Pollutant in Aquatic Environment by Microalgae Desmodesmus sp.
D A Widyaningrum1, R Hadisoebroto2, A Rinanti3*

Environmental Engineering Department, Faculty of Landscape Architecture and Environmental Technology, Universitas Trisakti, Jakarta, Indonesia

Abstract

Gold mining has increased environmental issues due to constant resource utilization and side product generation in form of dangerous wastes. Wastes that enter water contain high concentration of iron (Fe) heavy metal, which require sustainable and low cost technology to lower toxic heavy metal concentration to reach environmentally acceptable level. The objective of this paper is to acknowledge the ability of green tropical microalgae as biosorbent to absorb Fe heavy metal on water. Beads produced from Desmodesmus sp. green microalgae powder were bind with Na-alginate polymer has the potency as biosorbent. Biosorption by Desmodesmus sp. beads can become an interesting alternative technology because Fe heavy metal removal performed selectively on broad pH and temperature ranges, with a rapid adsorption kinetics, and low operational cost. Variables that affect biosorption process are light, carbon dioxide (CO2), pH level, contact time, beads size, beads concentration, and NA-alginate concentration. The result of this research revealed that beads with size of 1 mm are the most effective ones to absorb Fe metal (II), with maximum biosorption rate of 46% on pH level of 6. The 1 mm beads that contain 8% w/v of microalgae powder and 6% w/v of Na-alginate perform the broadest absorption, which leads to higher Fe metal binding ability than 2, 3, and 4 mm beads. Beads possess efficient Fe (II) metal adsorption performance- at the first 5 minutes, it can absorb 22% of Fe metal. Based on the results, mobilized Desmodesmus sp. has the potency to be utilized as biosorbent and can be regenerated up to several heavy metal sorption cycles.

Keywords: Heavy metal, beads, biosorption, adsorption kinetics, Desmodesmus sp.

Topic: Symposium on Energy and Environmental Science and Engineering