Using Adsorption Material Based on the Residual Biomass of Chlorella Sorokiniana Microalgae for Wastewater Purification to Remove Heavy Metal Ions

A method for obtaining adsorption material based on the residual biomass of Chlorella sorokiniana microalgae, thermally expanded graphite, and chitosan is presented. Investigations of the microstructure of the developed adsorbent have been conducted; it is shown that the adsorption material has a porous surface due to thermally expanded graphite and a layered structure due to chitosan. The IR spectrum of the sorbent showed the following functional groups (-C-O; -NH; -C=O; -OH; -CH2); due to their presence, it is possible to presume a chemisorption mechanism for extraction of heavy metal ions from aqueous solutions. The obtained adsorbent was used for purification of model solutions to remove Cu2+ and Pb2+ ions in static and dynamic conditions. The maximum sorption capacity for Pb2+ ions is equal to 18.35 mg/g, and for Cu2+ ions is 8.59 mg/g. Purification efficiency exceeds 90% at low concentrations of heavy metal ions (from 5 to 20 mg/Liter). While an increase in the concentration for Cu2+ ions leads to a decrease in the purification efficiency to 42.0%, for Pb2+ ions its values remain at 90% in the concentration range of 5-200 mg/Liter.