ABSTRACT
The cyanobacterium Arthrospira (Spirulina) platensis was used to study the process of silver biosorption. Effects of various parameters such as contact time, dosage of biosorbent, initial pH, temperature, and initial concentration of Ag(I) were investigated for a batch adsorption system. The optimal biosorption conditions were determined as pH 5.0, biosorbent dosage of 0.4 g, and initial silver concentration of 30 mg/L. Equilibrium adsorption data were analyzed by the Langmuir and Freundlich models – however, the Freundlich model provided a better fit to the experimental data. The kinetic data fit the pseudo-second-order model well, with a correlation coefficient of 0.99. The analysis of thermodynamic parameters (ΔG°, ΔH° and ΔS°) revealed that the adsorption process of silver ion by spirulina biomass was exothermic and spontaneous (ΔG° < 0), and exothermic (ΔH° < 0) process. The biosorption capacity of biomass A. platensis serves as a basis for the development of green technology for environmental remediation.
Associated content
*S Supporting Information
Linear representation of the Langmuir and Freundlich isotherm models for the biosorption of silver ions on A. platensis biomass is reported in additional figures (Figures S1 and S2). Comparison of Langmuir and Freundlich parameters obtained in the present work with the results from other research is presented in Table S1.
Funding
This work was supported by the Russian Foundation for Basic Research under Grant No. 16-33-00434.
Conflict of interest
The authors confirm that they have no conflicts of interests.
Ethical approval
This article does not contain any studies with human participants or animals performed by any of the authors.