The kinetics of Fe2+ heavy metal adsorption by microalgae Desmodesmus sp. beads

Abstract

Industrial waste that contains high concentration of iron heavy metal (Fe2+) needs to be reduced into a safer limit for water ecosystem using an environmental-friendly, sustainable and low cost technology. This literature study was aimed to gather information on Fe2+ metal ion removal with biosorption method by mobilized beads-shaped Desmodesmus sp. green microalgae. Biosorbent beads are made of Desmodesmus sp. green microalgae powder binded with Na-alginate polymer. Desmodesmus sp. microalgae were cultivated in an Erlenmeyer flask with wastewater contains Fe2+ and Beijerinck growth media controlled in batch system. Analysis was conducted to study the influence of pH, size, beads, beads concentration, and Na-alginate concentration towards Fe2+ heavy metal removal efficiency on biosorption process. Research results revealed that Fe2+ heavy metal was effectively adsorbed by 1 mm beads up until 46% at maximum capacity on pH level of 6. These beads contain 8% gr/L of microalgae powder and 9% gr/L of Na-alginate. The involved function groups in Fe2+ sorption and the beads biosorbent morphology changes were analyzed by using FTIR and SEM. This biosorption research was following by analysis of Freundlich isotherm and reaction kinetics order two with linear approach. This was to shows the beads possess adsorption kinetics with optimum Fe2+ absorption capacity. Desmodesmus sp. beads are highly potential to be used as biosorbent since the heavy metal removal process was selectively conducted on wide pH level and temperature ranges, fast adsorption kinetics, and low operational cost. The smaller the beads size the wider the surface area, which leads to higher removal efficiency rate.