Adsorption and removal of diethyl phthalate from aqueous media with poly(hydroxyethyl methacrylate) nanobeads

In this study, poly (hydroxyethyl methacrylate) (PHEMA) nanobeads with an average size of 115 nm were prepared by emulsion polymerization. The nanobeads were characterized with infrared spectroscopy, scanning electron microscopy, and zeta size analysis. The surface area of the PHEMA nanobeads was calculated as 541.4 m2/g. Then, diethyl phthalate (DEP) removal efficiency of the PHEMA nanobeads from aqueous media was investigated. At a fixed adsorbent/solution ratio, various factors affecting the adsorption of DEP from aqueous solution such as pH, initial concentration, contact time, temperature, and adsorbent dosage were analyzed. The maximum DEP adsorption capacity of the PHEMA nanobeads was determined as 265.1 mg/g at pH 4.0, 25°C. The Sips isotherm model fits the experimental data in the wide range of DEP concentration tested (1–300 mg/L). The pseudo-first-order, pseudo-second-order, modified Ritchie’s-second-order kinetic models were used to test the adsorption kinetics. The DEP adsorption capacity of the nanobeads did not change after five batch successive usages. DEP removal efficiency of the PHEMA nanobeads from different water media such as saliva, sweat, and tap water was also evaluated. The removal efficiencies in the range from 82.4 to 100.0% demonstrate the usability of PHEMA nanobeads for DEP removal from real samples.