IMPROVING BIOSORPTION OF CU(II)-ION ON ARTIFICIAL WASTEWATER BY IMMOBILIZED BIOSORBENT OF TROPICAL MICROALGAE

Abstract

This research purposes to study the role of microalgae in tropical environment – isolated
from Wastewater Treatment Plant (WWTP) Setiabudi, Jakarta, Indonesia – on biosorption of Cu(II) ion in
heavy metal wastewater. The effects of pH and contact time on the rate of metallic biosorption were
examined to reach the greatest biosorption efficiency. Microalgae diversity analysis through phenotypic
approaches showed that the microalgae community was comprised of 3 species of Chloropyceae i.e
Ankistrodesmus braunii, Chlorella sp., and Scenedesmus quadricauda var quadrispina. Immobilized
biosorbent from microalgae was prepared by oven-drying, grinding, and entrapping the microalgae biomass
into polymeric matrix of alginate. The sorption properties of biosorbent was characterized by using infrared
spectroscopy and SEM micrograph analysis. The optimization of sorption parameters was conducted in batch
systems using Cu(II)-artificial wastewater of 300 ppm with pH arrangement of 2-7 and the contact time
arrangement of 60, 90, 120, 180, 240 minutes. During the experiment, the Chlorophyceae free and Na-alginat
immobilized biomass were added. The research showed that either free and immobilized biomass could
adsorb Cu(II) metal ion and reduce its concentration into 25-50 ppm. A maximum biosorption by the
alginate-immobilized biosorbent obtained at pH 3,0 and contact time of 180 minutes with 43% absorption
efficiency. Sorption properties of microalgae biomasses were indicated by various functional groups presence
on biosorbent that could bind heavy metals compared to others. The research proved that the alginate-
immobilized biosorbent was highly effective for the treatment of Cu(II)-artificial wastewater and that tolerant
cholorophyceae could act as an effective biosorbent in further optimization.