Biosorption of Crystal Violet, a Cationic Dye onto Alkali Treated Rauvolfia tetraphylla Leaf: Kinetics, Isotherm and Thermodynamics

The leaves of Rauvolfia tetraphylla (RTL), an abundantly grown woody shrub, have been modified with mild alkali and exercised for remarkable uptake of crystal violet dye from simulated and industrial wastewater. FESEM and FTIR characterize the material, whereas BET surface area indicates porosity. The stability of NRTL has been tested by TGA.FTIR proposes the presence of amine and polyphenolic functionalities which are capable of crystal violet binding through electrostatic and hydrogen bonding. As identified from FESEM images, surface texture displays well-defined channels with heterogeneous pore openings ideal for dye attachment. The NRTL’s zero-point charge (pH_ZPC) is 7.5, an ideal pH for dye removal from wastewater. The uptake process follows the Langmuir adsorption isotherm model (R² = 0.998) and pseudo-second-order kinetic model (R² = 0.999). Satisfactory regeneration (68%) has been achieved with 1:1 methanol/water solution and the material is capable of three-cycle use. Industrial effluent treatment was mapped to assess the field applicability of the present protocol. The activated leaves of Rauvolfia tetraphylla could be a future choice for small-scale dye removal from colored effluent with a maximum uptake competency of 109.99 mg/g.