Новый гидрогелевый комплекс с иммобилизованными клетками микроводорослей для удаления аммоний и фосфат-ионов из сточных вод

Abstract

The aim of the work was to create a stable hydrogel complex containing microalgae cells to remove ammonium and phosphate ions from an experimental solution simulating domestic wastewater. A new polymer matrix based on sodium alginate and carboxymethyl cellulose, polyacrylic acid, retained the integrity of the structure in a solution with a high content of ammonium and phosphate ions, and also proved to be resistant to alkali metals. To increase the stability of hydrogel complexes, we proposed an increase in the number of chemical bonds in the polymer environment due to the crosslinking of alginate and carboxymethyl cellulose with Ca2+ and Fe3+ ions, as wellпа as the introduction of an additional external stabilizer – cationic polyacrylamide. Due to the combination of several polymers, only slight swelling was observed and, as a result, the preservation of the hydrogel matrix in integrity for a long time. The two most commonly used algae in biotesting were selected for the experiment: Tetradesmus obliquus and Chlorella vulgaris from the live microalgae strains collection of the Institute of Biology (Syktyvkar, Russia). The formation conditions of the hydrogel complex made it possible to preserve the viability, reproduction and development of the microalgae cells in the polymer matrix. The cell viability of both cultures was over 95%. It was found that living cells of microalgae are mainly involved in the process of nitrogen uptake. Microalgae immobilized cells, in the presence of carbonate ions, provided the best degree of removal of ammonium nitrogen, which reached 90%. The greatest contribution to the phosphorus removal (> 95%) was made by the polymer component of the hydrogel complex.