ADSORPTION OF Cd AND Pb USING BIOMASS OF MICROALGAE SPIRULINA PLATENSIS

Abstract

Microalgae is one of the most common sources of biomass for heavy metal removal from wastewater.
Spirulina platensis is one of Indonesia's blue-green algae species found in Indonesian waters and has the ability to
adsorb heavy metals, but very little is used for metal adsorption. As a cost-effectiveness approach, S. platensis was
selected in this study which aimed to determine the effectiveness of Cd and Pb uptake by S. platensis for 10 days
experiment, using Dutatonic solution as microalgae growth medium. The method used was complete random
sampling with 3 concentration variations and 3 repetitions on each metal. The concentration variations for Cd were
0.1, 1, 5 mg/L, and 1, 2, 4 mg/L for Pb. The optimum adsorption concentration was tested by AAS. Biomass and cell
size (length and width) were also measured to understand the physiological effects of Cd and Pb exposure on S.
platensis. The results showed that Cd was more effectively adsorbed by S. platensis than Pb which reached 91.8%
(day 5) at concentrations of 1 mg/L Cd and 84.3% (day 5) at concentrations of 1 mg/L Pb. The biomass and cell size
of S. platensis were not influenced by the variation of Cd concentration (p>0.05), while Pb was significantly at the
5% significance level (p <0.05). It can be assumed that Pb was more toxic than Cd for S. platensis because the
weight of biomass decreased in increasing Pb concentration.