Insight into the biosorptive removal mechanisms of hexavalent chromium using the red macroalgae Gelidium sp

Hexavalent chromium (Cr(VI)) is a highly toxic form of chromium, which can be found in industrial effluents from various sectors, such as the metallurgical, tanning, and pigment industries. The presence of Cr(VI) in the environment is a concern due to its negative effects on human health and the ecosystem since it is carcinogenic, mutagenic, and can cause damage to the respiratory, renal, hepatic, and dermatological systems. Adsorption is a sustainable alternative for the removal of Cr(VI) from the environment since it is an efficient, low-cost technique and can be adjusted according to specific environmental conditions. The use of algae biomass activated with chemical agents can be a promising solution to improve the adsorption capacity of the material and contribute to the mitigation of contamination by Cr(VI) and the protection of human health and the environment. The results of the study indicate that the activation of the red macroalgae Gelidium sp. with zinc chloride (ZnCl2) resulted in improvements in the adsorbent properties of the material for the removal of Cr(VI) in aqueous solutions. The physical characteristics of the material were analyzed, and it was observed that the surface area increased from 2.90 to 3.12 m2 g−1 after activation with ZnCl2. Furthermore, changes in the surface structure of the material were observed, with the presence of irregularities, mainly after the adsorption of Cr(VI). The analysis of functional groups indicated that the main groups present in the native biomass remained after activation with zinc, and new diffraction peaks also appeared, indicating the chemical modification of the material. The adsorption experiments were carried out under different conditions, such as pH, dosage, temperature, Cr(VI) concentration, and contact time. It was observed that the adsorption was favored under acidic conditions, with a dose of 0.05 g L−1 of activated biomass. Equilibrium was reached quickly in the first few minutes, and the general kinetic model best fitted the experimental data. The kinetic adsorption capacity was higher for the activated material (226 mg g−1) compared to the native material (114 mg g−1). Increasing the concentration of Cr(VI) in the solution resulted in an increase in the adsorption capacity, indicating that the driving force gradient was greater at higher concentrations of the contaminating ion. The isothermal data were well fitted by the Koble-Corrigan heterogeneous surface model, and the maximum adsorption capacities were estimated at 126 mg g−1 and 240 mg g−1 for native and activated biomass, respectively, at the highest Cr(VI) concentration studied (150 mg L−1). The results indicate that the activation of the red macroalgae Gelidium sp. with zinc chloride improved its adsorbent properties for the removal of Cr(VI) ions, with high adsorption capacity and efficiency, demonstrating a high potential for application in the removal of Cr(VI) metal ions in aqueous solutions

• Autores: Narayanan, Ishvarya; Kumar, P. Senthil; Franco, Dison; georgin, jordana; Meili, Lucas; Selvasembian, Rangabhashiyam
• Tipo de recurso: Article of investigation
• Fecha de publicación: 2023
• Institución: Corporación Universidad de la Costa
• Repositorio: REDICUC - Repositorio CUC
• Idioma: eng
• OAI Identifier: oai:repositorio.cuc.edu.co:11323/14243
• Acceso en línea: https://hdl.handle.net/11323/14243; https://repositorio.cuc.edu.co/
• Palabra clave: Adsorption; Chemical activation; Heavy metals; Seaweed
• Rights: closedAccess
• License: Atribución 4.0 Internacional (CC BY 4.0)