Chemically treated Lawsonia inermis seeds powder (CTLISP): An eco-friendly adsorbent for the removal of brilliant green dye from aqueous solution

Abstract

The present paper deals with the preparation of a novel low-cost and eco-friendly chemically treated lawsonia inermis seed powder (CTLISP) as adsorbent and was further explored for the removal of brilliant green (BG) dye (93%) from aqueous solution. The adsorbent was characterized by various techniques such as FTIR, EDX, SEM and TEM. Effects of various parameters such as concentration, pH, doses, contact time was carried out. The maximum adsorption capacity 34.96 mgg−1 was found to be at 50 °C. The equilibrium was attained in 180 mints and the experimental data were elucidated for isotherms and kinetic studies. The results exhibited that the data is best fitted for the Langmuir isotherm with maximum (R2) value of 0.990 and pseudo-second order kinetics with maximum (R2) value of 0.998. The thermodynamic parameters such as ΔH0, ΔG0 and ΔS0 were also evaluated and the results showed the process to be endothermic, spontaneous in nature. The desorption study showed that 84% of the adsorbed BG could be desorbed by using 1 M oxalic acid as eluting agent. The breakthrough and exhaustive capacities were found to be 12.5 and 45.0 mg g−1, respectively. In order to make the process more economical and feasible the regeneration studies were also carried out and the adsorbent can be reused up to fifth cycle successfully. Therefore, the present low-cost adsorbent (CTLISP) has excellent regenerative capability and gives high monolayer adsorption capacity as compared to others various adsorbent reported in literature. Moreover, the material has been proved to be a promising adsorbent for treatment of BG dye from aqueous solution.