Vegetable residue of fenugreek (Trigonella Foenum-Graecum), waste biomass for removal of Basic Violet 14 from wastewater: Kinetic,equilibrium, and reusability studies

The present work has focused on the utilization of vegetable residue of Fenugreek (VRF), sustainable and novel adsorbent for sequestration of Basic Violet 14 (BV 14) dye. Effect of various batch operating parameters on BV 14 adsorption has been studied in detail and optimum values were reported as pH of 7.2, adsorbent loading of 0.125 g, shaking time of 105 min and temperature of 323 K. VRF was characterized based on various techniques as FTIR, DLS, zeta potential, SEM-EDS, and BET analysis. Kinetic and equilibrium data have been well exemplified by pseudo 1^st order and Freundlich model, respectively. The maximum uptake capacity was reported to be significant as 177.78 mg/g. Mechanism of BV 14 adsorption on VRF was reported to involve steps as pore diffusion and film diffusion based on reported data fitting to Boyd model. Thermodynamic investigation affirmed adsorption as spontaneous, endothermic and physical in nature. Recovery of adsorbed BV 14 from VRF was conducted using ethanol as an elution media and regenerated VRF was applied for fresh BV 14 adsorption in five cycles. Recovery values were reported to be significant as 98.92% for first cycle and 84.41% for fifth cycle. Similarly, uptake capacity values were reported to be significant as 39.34 mg/g for first cycle and 32.47 mg/g for fifth cycle, which has proved the recovery potential and thus the applicability of VRF for subsequent cycles of BV 14 adsorption. Overall, the present work proved VRF as a promising adsorbent for successful remediation of BV 14 dye.