keywords: Acid red 1, isotherms, kinetics, tamarind, thermodynamics, waste water
Activated tamarind kernel powder (ATKP) was prepared from tamarind fruit (Tamarindus indica) and utilized for the removal of Acid Red 1 (AR 1) from its aqueous solution. The powder was activated using 4N HNO3. The adsorbent was characterised using infrared spectroscopy, bulk density, Ash content, pH, moisture content and dry matter content measurements. The effect of various parameters which include; temperature, pH, adsorbent dosage, ion concentration, and contact time were studied. Four different equilibrium Isotherm models were tested on the experimental data but the Temkin isotherm model (R2 values ranging between 0.913-0.987) was best-fitted into the experimental data. The pseudo-second order was best fitted into the experimental data with R2 value of 0.999. The values of the activation energy (E) obtained indicated that the adsorption of AR1, on ATKP is a physical process. The negative free energy (ΔG) indicated that the adsorption process is feasible and spontaneous, the negative enthalpy (ΔH) indicated that the reaction is exothermic in nature and the negative entropy (ΔS) indicated that there is decreased randomness at the solid/solution interphase during the adsorption process. Therefore, activated tamarind kernel powder has proven to be a very good adsorbent (with removal efficiency ranging from 54 – 95%) for the removal of Acid Red 1 from industrial waste water.