Removal of crystal violet dye from wastewater using Chitosan green peas peel powder composite as a biosorbent

Dye containing wastewater generated from industrial sectors such as textile, printing, leather, food, and cosmetics necessitates efficient treatment to prevent environment and human health risks. In present study, Green peas peel powder (GPP), Chitosan hydrogel particles (CHP) and composite of Chitosan-Green peas peel powder (CHGP) were utilized as an effective biosorbent for the removal of crystal violet (CV) dye from aqueous medium. The influence of various factors viz. adsorbent dosage, initial dye concentration and contact time on dye removal efficiency was examined. The CV dye removal efficiency was investigated using UV-Visible spectroscopy, while Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Thermogravimetric analysis (TGA) were employed for structural, morphological, thermal stability analysis of synthesized biosorbent. The maximum removal efficacy using CHGP composite of greater than 96% in first 30 mins and with 99.4% after 120 mins of contact time was achieved at pH 6. The nonlinear kinetic and isotherm studies revealed that adsorption process is better characterized by both Langmuir and Freundlich and pseudo-first and pseudo-second order model and showed a maximum adsorption capacity of 9.996 mg/g. Additionally, CHGP biosorbent was able to remove the 98% of CV dye after three regeneration cycles. Compared to single component CHP and GPP, CHGP composite exhibited enhanced adsorption performance as a result of its enriched active functional groups. Thermodynamic analysis revealed that the adsorption process is endothermic, spontaneous and favorable. TGA analysis of CHGP and CHP showed reduced thermal stability of composite. Overall findings of present study indicate that bio-composite of Chitosan-Green peas peel powder can be used as low-cost, environmentally friendly and circular-economy aligned solution for efficient removal of crystal violet dye from contaminated wastewater.