Decontamination of Cd2+ and Pb2+ from aqueous solution using a magnetic nanocomposite of eggshell/starch/Fe3O4

Peculiarities of adsorption of Cr (VI) ions on the surface of Chlorella vulgaris ZBS1 algae cells

“…After mixing the K 2 Cr 2 O 7 solution with a suspension of Chlorella vulgaris ZBS1 cells, samples of the solution were taken for analysis for the content of Cr (VI) ions every 20 min, for 120 min. The effect of temperature on the adsorption equilibrium was investigated by varying the temperature from 298 to 328 K. To study the kinetic behavior of the adsorption process of Cr(VI) from aqueous solutions, kinetic models of pseudo-first order, pseudo-second order, the Morris-Weber model describing intraporous diffusion, and the Elovich model were used; calculations were carried out according to formulas (3, 4, 5, and 6) [3,26,27,28,29,30,31,32,44]:…”

“…To study the adsorption of Cr (VI) ions on the surface of Chlorella vulgaris ZBS1 algae cells and obtain data on adsorption equilibrium, various models of adsorption isotherms were used: Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin one [24,25,26,27,28,29,30,31,32,33,48,49].…”

“…To study the thermodynamics of adsorption of Cr (VI) ions on the surface of Chlorella vulgaris ZBS1 cells, thermodynamic constants such as changes in enthalpy ΔH, free energy ΔG and entropy ΔS were calculated. The following equations were used for the calculation [24,25,26,27,28,29,30,31,32,33,44,53] (15,16,17):…”

“…Composite and modified nanosorbents show high efficiency in optimizing water purification conditions from heavy metal ions [24,25,26,27,28,29,30]. The use of biomass of brown algae Sargassum oligocystum, pre-modified CaCl 2 , for the treatment of water, containing Cr (VI) ions provides an adsorption value of 34.46 mg/g [3].…”

“…Under optimal conditions, the maximum degree of removal of Pb (II) and Cd (II) ions was 95.66% and 94.55%, respectively. To facilitate the process of separating sorbents from water, it is proposed to use the magnetic nanocomposite eggshell/starch/Fe 3 O 4 [28]. At a concentration of Cd (II) and Pb (II) ions in a solution of 10 mg/L, pH range 6-7, a temperature of 25 C, an adsorbate/adsorbent contact time of 60 min and a stirring speed of 500 rpm, the degree of removal of Cd (II) and Pb (II) ions was equal to 96.38% and 97.56%, respectively.…”