Simultaneous elimination of diethyl phthalate, butylated hydroxy toluene and butylated hydroxy anisole from aqueous medium by an adsorption process on pretreated waste material; investigation of isotherms and neural network modeling

Simultaneous removal of three pollutants (diethyl phthalate, butylated hydroxy anisole and butylated hydroxy toluene) that appear in plastic industries' wastewater was the aim of this study. These compounds have harmful effects on human health. The adsorbent, Sesamum indicum seeds' waste, is a natural adsorbent which was obtained freely and abundantly from a local market after being oil-pressed. For performing the treatment process, the pretreated adsorbent was put in contact with a solution of the compounds of interest. The effect of variable parameters like the type of pretreatment solvent, pretreatment time, pH of solution, dosage of adsorbent, adsorption time and the concentration of solution containing the pollutants was investigated. The equilibrium isotherm data were analyzed too. Moreover, an artificial neural network model was progressed to anticipate the adsorption efficiency of the pollutants. The results indicated that the obtained data have a good predictive capability (R-2 = 0.9940). The optimum pretreatment organic solvent was found to be ethyl acetate, and the optimum pretreatment time was 10 min. Furthermore, when the adsorbent dosage and adsorption time increased, the adsorption efficiency enhanced and reached a constant limit. The optimum pH was found to be 9 and the decrease in pollutants' concentration resulted in an increase in wastewater treatment efficiency. The isotherm data for all studied pollutants were fitted well with Langmuir isotherm.