Removal of Patent Blue Dye Using Ananas comosus-Derived Biochar: Equilibrium, Kinetics, and Phytotoxicity Studies

Patent Blue (PB) dye removal from an aqueous medium was investigated using pineapple fruit peel biochar (PFPB). The presence of functional groups and surface characteristics of PFPB was studied using Fourier transform infrared spectra (FTIR) and scanning electron microscopy (SEM). A study was conducted to assess the pH effect, contact time, concentration of dye, biochar dose, speed of agitation, and temperature on removal of PB (Patent Blue) dye from an aqueous medium by PFPB. The highest 95% elimination of PB dye was reported at pH 2 by PFPB with 600 mg/L concentration of PB dye. Equilibrium studies divulged the favorable adsorption that followed the Langmuir isotherm with a monolayer uptake potential of 10.29 mg/g. Findings of kinetics disclosed that adsorption results were properly explained by the pseudo second-order model. The adsorption phenomenon was exothermic and spontaneous, as observed by thermodynamic variables. PFPB reflected a 37% uptake capacity of PB dye for up to five consecutive cycles in the adsorption and desorption study. A phytotoxicity study exhibited that PFPB-treated PB dye solution enhanced the growth of seedlings and biochemical constituents of lentils. The findings of the present study indicate the immense potential of pineapple fruit peel biochar for anionic dye removal from wastewater systems. Thus, pineapple fruit peel biochar can be utilized as a promising green sorbent for the elimination of Patent Blue dye in industrial effluents, as it is widely available and converts wastewater into reusable assets.