Biomass Zilla spinosa Fruit Functionnalized Polyethyleneimine Polymer: Analysis and Application for the Elimination of Calmagite in Water

Abstract

The valorization of natural polymeric substrates has increased due to their uses and applications in several fields. The existence of many functional groups in their chemical structures allows them to be easily subjected to chemical modifications. This work focuses on the exploration of a new low-cost and abundant cellulosic biomass, Zilla spinosa fruit. The biomaterial was functionnalized with polyethyleneimine (1%, 3%, 5%, and 8%) in order to impart new reactive sites on its surface. The virgin and functionnalized biomaterials were analysed using several analytical methods; X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared (FT-IR), Scanning Electron Microscopy (SEM), and Thermogravimetric analysis (TGA). XPS spectrum of Zilla spinosa-polyethyleneimine exhibited the appearance of a new peak at 399 eV, which corresponds to N1s (5.07%). The adsorption characteristics of the prepared adsorbents were evaluated toward calmagite, an azoic and anionic dye. The adsorption capacity of Zilla spinosa-polyethyleneimine (5%) reached 114 mg/g at pH = 5, T = 20 °C, and time = 60 min conditions; though, it does not exceed 8.4 mg/g for the virgin Zilla spinosa under the same experimental conditions. The kinetic data followed both pseudo-first-order and pseudo-second-order kinetic equations suggesting a physicochemical process. The adsorption mechanism was found to be exothermic and non-spontaneous. Overall, Zilla spinosa-polyethyleneimine has demonstrated a high adsorption level which could be considered a promising candidate to remove synthetic dye molecules from contaminated water.