Feasibility of naphthol green-B dye adsorption using microalgae: thermodynamic and kinetic analysis

• Published in: Desalination and water treatment 2020-07, Vol.192, p.358-370
• Main Authors: Gunasundari, E., Kumar, P. Senthil, Rajamohan, N., Vellaichamy, Parthasarathy
• Format: Article
• Language: English
• Subjects: Equilibrium; Exothermic; Kinetics; Multilayer adsorption; Naphthol green-B; Spirulina platensis
• ISSN: 1944-3986; 1944-3986
• DOI: 10.5004/dwt.2020.25777

The usage of ultrasonic-assisted Spirulina platensis (UASP) algal powder for the adsorption of Naphthol green-B (NGB) dye was analyzed within environmental conditions. The batch removal investigations were done with various operational conditions including UASP dose, contact time, initial NGB dye concentration and the NGB solution pH to eliminate NGB dye molecules in the aqueous solution. The optimal working conditions for the removal of NGB dye by UASP was showed that contact time (60 min), dose (3 g/L), initial NGB dye concentration (100 mg/L), pH (3), and temperature (30°C). The dye removal data were inspected by utilizing four adsorption isotherm models like Langmuir, Freundlich, Toth, and Hill isotherm models. The experimental data generated best fits within the following isotherm order: Freundlich > Hill > Toth > Langmuir isotherm model. The maximum monolayer adsorption capacity was 137.9 mg/g. The pseudo-first-order, second-order kinetic, and intraparticle diffusion models were probed and the outcomes show that the pseudo-first-order fitted with the adsorption of NGB dye molecules by UASP. Thermodynamic parameters like ΔG°, ΔH°, and ΔS° were determined and the results prove that the NGB adsorption was exothermic, spontaneous, and feasible. The results specify that the UASP has actually been utilized as an inexpensive biosorbent for the removal of NBG dye from aqueous solution.