Enhanced cationic/anionic dyes removal in wastewater by green nanocomposites synthesized from acid-modified biomass and CuFe2O4 nanoparticles: Mechanism, Taguchi optimization and toxicity evaluation

Abstract

This article addresses the nanoadsorption mechanisms of rhodamine B (RB), crystal violet (CV), and Congo red (CR) using acid-treated C.edulis (ATCE)/CuFe₂O₄ (ATCE@CuFe₂O₄) from an aqueous solution. The physical and chemical characterizations of nanobiomass were studied using different techniques. The specific surface areas of the ATCE and ATCE@CuFe₂O₄ composites were 15.88 and 337.81 m²/g, respectively, indicating a significant specific surface area of ​​the ATCE@CuFe₂O₄ nanocomposite. A number of functional groups were determined, which promote the binding of the dye to the adsorbent. The SEM also shows that the adsorbent has a homogeneous texture with deep voids and significant porosity, which likely explains the retention and binding of dye ions on the surface of the adsorbent. In fact, the Langmuir isotherm with a correlation coefficient of 99 % for CV, RB and CR, respectively, represents the most suitable model to explain the adsorption mechanism. The maximum adsorption amount is 666.6 mg/g for CV, 645.16 mg/g for RB and 434.71 mg/g for CR at 308 °K. The adsorption kinetic processes were predicted by the pseudo-second order kinetic model. The thermodynamic properties showed that the adsorption on ATCE@CuFe₂O₄ was possible and spontaneous. The ATCE@CuFe₂O₄ recycling and elimination CV, RB, and CR were 74.23 %, 72.75 %, and 67.84 %, respectively, after seven cycles. The design, modeling and optimization of the adsorption parameters were carried out using the Taguchi experimental design. The maximum removal efficiency of CV, RB and CR dyes in optimal operating conditions were 99.96, 98.29 and 97.76 %, respectively. Which at the optimal conditions of 1 g/L, 90 min, 20 mg/L, 298 ^°K, pH 10 for CV and RB dyes and 1 g/L, 90 min, 20 mg/L, 308 ^°K, pH 4 for CR. This research demonstrated the performance of ATCE@CuFe₂O₄ in bean seed germination test and its effectiveness in removing dyes from wastewater.