Biodegradable polymeric green adsorbent for the highly efficient removal of crystal violet dye from aqueous solution

Abstract

In this study, we fabricated a novel membrane from breadfruit peel (Artocarpus altilis), a biowaste, to quickly and effectively remove the toxic crystal violet (CV) dye from aqueous solutions. The membrane was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), water contact angle, thermogravimetric analysis (TGA), and Fourier transform infrared spectra (FTIR) techniques. SEM results confirmed that the breadfruit peel particles are well dispersed on the membrane surface. Furthermore, the breadfruit peel improved the mechanical and thermal stability of the membrane. The membrane exhibited a maximum adsorption capacity of 176.25 mg/g at a pH of 11 and a contact time of 150 min. The adsorption capacity of the membrane could be tailored by operational parameters like initial concentration of CV, equilibrium time, adsorbent dosage, and temperature. The adsorption mechanisms responsible for the efficient elimination of CV dye is discussed in terms of electrostatic attraction. The adsorption kinetic results indicate that the adsorption of CV was more consistent with pseudo-second order model. Meanwhile, the adsorption data fitted to Freundlich model rather than Langmuir isotherm model. Furthermore, even after six adsorption-desorption cycles, no significant decrease in the removal efficiency was observed. The polymer membrane was therefore proposed as a potential candidate for water treatment.