Absorbent cotton-templated manganese oxide nanocomposites for methylene blue promote isothermal adsorption

The public is still concerned about the effectiveness and efficiency of wastewater treatment. Investigating a better material to contribute to water purification is the objective of this research. Absorbent cotton-templated manganese oxide nanocomposites (AC/MnO2) were facilely synthesized by immersing adsorbent cotton into a potassium permanganate (KMnO4) solution through an in situ reduction with a biological template strategy. AC/MnO2 is attracted to hydration hydroxyl in aqueous solutions and has an excellent adsorption capacity for dye wastewater degradation in aqueous solutions. The morphology, structure, composition, and thermostability of AC/MnO2 were characterized by FE-SEM, XPS, XRD, FTIR, and TGA. This as-prepared nanomaterial was applied to degrade methylene blue. The factors that affected the degradation performance, including soaking time, initial methylene blue concentration, the amount of AC/MnO2, pH, and temperature, were investigated. The experiments indicated that the optimal conditions for adsorption were achieved at pH 5 using three wads of AC/MnO2 in 15 min, which were synthesized by soaking for 60 h. The isothermal adsorption behavior and kinetics were studied by measuring the absorbance intensities in reaction time to fit Langmuir and Freundlich's adsorption isotherms, pseudo-first-order kinetic models, and pseudo-second-order kinetic models. The correlation coefficient comparisons demonstrated that methylene blue degradation conformed to the Langmuir isotherm, indicating that the superficial behavior was like the monolayer and pseudo-second-order models, elucidating that this process contained both physical diffusion and chemical adsorption. The regeneration capability was assessed to demonstrate that AC/MnO2 can be recycled. The degradation in efficiency persisted at about 40% after five cycles.

Automated summary

This research aims to investigate a better material for water purification and successfully synthesized absorbent cotton-templated manganese oxide nanocomposites (AC/MnO2). The AC/MnO2 showed excellent adsorption capacity for dye wastewater degradation in aqueous solutions, and the optimal conditions for adsorption were determined. The results also demonstrated that the AC/MnO2 can be regenerated and reused.