Influence of the drying method on the sorption properties the biomass of Chlorella sorokiniana microalgae

Abstract

In this paper, it is proposed to use the biomass of microalgae Chlorella sorokiniana as a biosorbent for wastewater treatment, as well as an oral sorbent. Biosorbents are capable of adsorbing both organic and inorganic compounds, including heavy metals. The sorption capacity depends on the type of aquatic plant and microalgae strain. The use of microalgae and aquatic plants as biosorbents for pollutant treatments is discussed in the introduction part. The biomass of microalgae Chlorella sorokiniana was chosen as the object of this study. The cultivation conditions (temperature, light, pH and aeration) and the optimal biomass harvesting parameters are presented. Dehydration of biomass was carried out in two ways: IR-drying and freeze-drying. The obtained samples were tested for the ability of the biomass to extract heavy metal ions (zinc, cadmium, zinc, copper) from standard solutions. The initial concentration of heavy metal ions in the working solutions was 10 mg/l. Results show that the lyophilized samples demonstrated up to 99.9% of heavy metal removal efficiency. The paper also presents the composition of Chlorella sorokiniana biomass, in which up to 40.97–41.87% are proteins. The analysis of the amino-acid composition showed a ratio of essential to non-essential amino-acids higher than 0.8. All the above results confirm the possibility of using microalgae biomass as an oral sorbent and as an additive in the production of functional foods.