Kinetics, equilibrium and thermodynamic investigations of methylene blue dye removal using Casuarina equisetifolia pines

• Published in: Chemosphere (Oxford) 2021-12, Vol.285, p.131480-131480, Article 131480
• Main Authors: Chandarana, Helly, Senthil Kumar, Ponnusamy, Seenuvasan, Muthulingam, Anil Kumar, Madhava
• Format: Article
• Language: English
• Subjects: Biosorption; Casuarina equisetifolia; Endothermic; Methylene blue; Pseudo-first order
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2021.131480

Casuarina equisetifolia pines are degradable biopolymeric substance with dye-sequestering property was utilized as biosorbent to expel a cationic dye; methylene blue dye from simulated wastewater. The prepared adsorbent material was characterized for their structural, morphological and elemental features to understand their suitability in augmenting in dye-wastewater remediation. The results infer that 0.5 g/L biosorbent was proficient in removing 100 mg/L methylene blue (pH 7.0 ± 0.2) when agitated at 150 rpm for 120 min. Isothermal behavior were evaluated using non-linear isotherm models like Temkin, Langmuir and Freundlich models while the rate-limiting steps were found using kinetic models. Temkin isotherm and pseudo-first order model explained the removal mechanism among the models evaluated, which infers that the biosorption followed physisorption with the maximum adsorption capacity of 41.35 mg/g. Thermodynamic behavior of methylene blue removal by C. equisetifolia pines powder described the feasibility of biosorption as well as the type of heat involved. Equilibrium sorption capacities, rate constants and correlation coefficients explains that MB dye removal by C. equisetifolia pines is presumably physisorption, spontaneous and endothermic in nature. [Display omitted] •Biosorbent from Casuarina equisetifolia pine had affinity for Methylene Blue dye.•MB biosorption mechanism onto the adsorbent was explained.•Pseudo-first order and Temkin model governed the dye removal by prepared biosorbent.•Thermodynamics suggest that dye removal was feasible, spontaneous and endothermic.