A new valorization of faba bean waste: Fabrication of a low-cost adsorbent for efficient removal dyes from textile wastewater

Abstract

Abstract As part of the effort to extract more value from agri-food waste, innovative adsorbents have been prepared from faba bean waste (FB: Vicia Faba L) using a physical activation process at a moderate temperature of 350°C. This process, developed by the authors of the study, yields effective adsorbent materials known as HTFB. Due to the favorable physico-chemical properties of these materials, they are suitable for treating water that is contaminated with two different groups of dyes: anionic (orange G (OG)) and cationic dyes (crystal violet (CV) and methylene blue (MB)). The adsorption was carried out in batch mode to examine the influence of different operating conditions (pH, initial dye concentration, temperature, contact time, etc.) on the percentage of the removal dye. According to the experiment results, the materials developed have demonstrated a remarkable efficiency for the elimination of cationic dyes (66.86% for the crystal violet and 58.20% of the methylene blue) and a limited efficiency for anionic dyes (7.05% of the orange G) at natural pH. Kinetic studies showed that the pseudo-second-order model better described the adsorption of dyes onto the HTFB. Besides, Langmuir isotherm model fit better the equilibrium data of dyes adsorption. The maximum adsorption capacities determined from the Langmuir equation were 43.48, 32.68, and 3.51 mg/g, for CV, MB and OG, respectively.