Adsorption of Eriochrome Black-T(EBT) using tea waste as a low cost adsorbent by batch studies: A green approach for dye effluent treatments

The potential of using tea waste as a low-cost adsorbent for the removal of Eriochrome Black-T (EBT), an anionic dye from aqueous solution was studied. Batch sorption studies were conducted to study the effect of adsorbent dosage, initial dye concentration, pH and contact time. The equilibrium EBT adsorption data on tea waste was best described by Langmuir isotherm model. It was found that the amount of dye adsorbed at batch equilibrium studies was 95% using 11 ​g/L acid treated tea waste. The adsorption kinetics of EBT on tea waste followed a pseudo-second order model. More over data obtained that diffusion intraparticle diffusion model is the rate controlling step. The nature of the adsorbent and adsorbate interactions was examined by Brunauer–Emmett–Teller (BET) analysis, Fourier-transform-infrared (FTIR) spectroscopy, and scanning-electron-microscopy (SEM). The mechanism for the adsorption of EBT on the surface of tea-waste includes hydrophobic interaction, van der waals interaction, π-π stacking and electrostatic interaction.