Synthesis and characterization of adsorbent derived from pandan leaves for methylene blue removal

Abstract

Dyes are an important type of pollutants that come in a large amounts which originated from industries such as textile, paper and pulp making, and petroleum. The elimination of dyes from wastewater is challenging as they have a synthetic origin and possess complex aromatic molecular structures which caused them to structurally inert and difficult to biodegrade, and unfortunately, the industries have overlooked this aspect in the treatment of wastes. Adsorption is known to be the superior technique compared to all other chemical for dye treatment. In this study, adsorbent was synthesized through chemical activation process by NaOH. The pandan leaves adsorbent was characterized by Fourier Transform Infrared (FTIR) and Brunauer-Emmett-Teller (BET). Results revealed that the pandan leaves adsorbent was successfully synthesized. The BET surface area for the adsorbent is 6.79 m^2/g. The adsorption capacity was found to be dependent on reaction time, pH, adsorbent dosage and initial dye concentration. The highest amount of adsorption capacity is 24.113 mg/g that was found at the adsorbent dosage of 0.02 g. The adsorption data for MB dye were well fitted Langmuir isotherm model and obeyed the pseudo-second order kinetics model. The value of standard Gibbs free energy for temperature 303.15 K is -1.895, temperature 323.15 K is -5.228 and temperature 333.15 K is -5.581. The negative value of standard Gibbs free energy indicated the feasibility and spontaneity of the adsorption processes and the positive value of enthalpy change confirmed the endothermic nature of overall process.