Control of disinfection by-product derived from humic acid using MIEX process: optimization through response surface methodology

Abstract

This work investigated the removal of humic acid (HA) as the precursor of disinfection by-product (DBP) using a magnetic ion exchange (MIEX) resin. The Box–Behnken design of response surface methodology (RSM) was used to evaluate the effect of process variables (initial pH, MIEX dose and reaction time) and their interaction for HA removal. Specific ultraviolet absorbance (SUVA) removal was selected as the response value. The analysis of variance (ANOVA) of the quadratic model demonstrated that the model was significant, and the optimum conditions were obtained as pH 2.3, MIEX resin dosage 0.95 mL L⁻¹, and reaction time 59.18 min. At these applied optimum conditions, 39.74% SUVA removal from an initial SUVA value of 10.06 L mg⁻¹ m⁻¹ was achieved. Also the reduction in DBP (chloroform, dichloroacetic acid and trichloroacetic acid) formation potentials was about 76%, 73% and 80%, respectively. The MIEX process was effectively optimized by RSM with a desirability value of 1.0. After the process optimization, the MIEX treatment was proven to be a good option for controlling the DBP derived from HA.