Experimental investigation of Luffa cylindrica as a natural sorbent material for the removal of a cationic surfactant

The efficiency of a potentially low-cost Luffa cylindrica as sorbent in removing cationic surfactant (CS) by adsorption process was evaluated in this study. 1-Cetylpyridinium bromide (CPB) was used as a representative member of CS. Effect of process variables such as initial concentration, adsorbent dosage, solution pH, and adsorption temperature had been studied. The sorption data were analyzed by using Langmuir, Freundlich and Dubinin–Radushkevich equations. The results indicate that the Langmuir model provides the best correlation of experimental data. Sorption kinetic was also evaluated by pseudo-first-order, pseudo-second-order, Elovich rate equations and intraparticle diffusion models. It was inferred that sorption follows pseudo-second-order kinetic model better. Activation energy value of 34.09 kJ/mol is in the range of 5–40 kJ/mol, indicating physical sorption. FTIR was also conducted to confirm the sorption of 1-cetylpyridinium bromide (CPB) onto L. cylindrica.

► Luffa cylindrica as sorbent in removing cationic surfactant was evaluated.
► The sorption follows the Langmuir model.
► The sorption follows pseudo-second-order kinetic model better.
► The process is a physical sorption with the activation energy of 34.09 kJ/mol.