Arthrospira platensis nanoparticle-based approach for efficient removal of methyl orange dye from aqueous solutions: isotherm, kinetic, and thermodynamic analysis

Abstract

AbstractBlue-green algae Arthrospira platensis, strain NIOF 17/003, is an ecologically friendly were tested as adsorbents for the removal of methyl orange dye (MO) from aqueous solution. The surface deposition of A. platensis was investigated utilizing a variety of techniques, including Fourier-transform infrared spectroscopy (FT-IR), Brunauer–Emmett–Teller (BET), and scanning electron microscopy (SEM). FTIR analysis demonstrated the contribution of carbonyl and carboxylic groups to MO dye adsorption. Different initial concentrations of MO dye (5–30 mg L–1) at contact time (5–180 min.), adsorbent doses (0.05–0.4 g), temperature (20–60 °C), and pH (1–11) were conducted in batch conditions. The results revealed that MO sorption in aqueous solutions increased with contact time and concentration. Temperature also affects MO adsorption. The elimination of MO from the solution augmented as the mass of A. platensis increased. The maximum MO dye sorption onto A. platensis was achieved at 15 mg L−1, 20 °C, 0.4 g, pH 1, for 30 min. A significant quantity of dye can be removed with just 0.1 g of A. platensis, with a removal efficiency of 18.1% and 28.35% for seawater and real wastewater, respectively. Many isotherm equations were used to analyze the experimental results (including Freundlich, Langmuir, Dubinin-Radushkevich, and Temkin models). The maximum adsorption capacity of MO onto A. platensis was 156.25 mg g−1. The fractionary-order kinetic model provided the best fit to experimental data compared with other models. Moreover, the thermodynamic parameters of ΔH° and ΔG° factors showed exothermic as well as spontaneous sorption processes. Additionally, A. platensis can be used more than once for economic gain, and it was found that the percent removal decreased to 89.28% of regeneration after three cycles for synthetic wastewater. These investigations indicate the effectiveness of the blue-green algae A. platensis, which may have significant potential for methyl orange dye applications in wastewater treatment.