Column Study of the Effect of Modified Zeolite with Different Concentrations of Surfactant on the Removal of Phosphorus and Its Simulation with the Kinetic Models and ANFIS

Phosphorus is not only the main nutrient of living organisms and the basic materials of many industries, but also it is one of the important parameters affecting the environment. In this study, the effect of different levels of Hexa decyl tri methyl ammonium surfactant concentration on modification of clinoptilolite zeolite was investigated in order to remove phosphate using column tests. For this purpose, the effect of modified zeolite with 0, 10, 20 and 25 mg/L concentrations were investigated using columns with height of 30 cm, diameter of 32 mm and with upward flow. Three common models; Bohart-Adams, Thomas and modified dose-response, with an artificial intelligence model of adaptive neuro-fuzzy inference system (ANFIS) were investigated in terms of modeling the breakthrough curve in the adsorption column,. The results of this study showed that the amount of equilibrium absorption capacity increases from 0.08 to 0.23 mg/L with increasing surfactant concentration. The concentration of 25 mg/L with a breakthrough and saturation time of 15 and 225 minutes and an adsorption capacity of 0.23 mg/g was the best level for modification of zeolite in order to remove phosphorus. The modified dose-response model versus the Thomas and Bohart-Adams models is the most accurate adsorption math model to predict a column breakthrough curve for phosphorus removal. Also, the results of this study indicate that ANFIS is more capable and accurate than the conventional kinetics models in estimating the output concentration from phosphorus adsorption column which results a reduction of 44, 32 and 20% of the average relative error, root mean square error and chi-square, relative to the best mathematical adsorption model.