Removal of Humic Acid from Water by Magnetic Chitosan-Grafted Polyacrylamide

Abstract

For high-efficiency removal of humic acid (HA), a natural organic matter in the water source, an adsorbent named magnetically modified chitosan-grafted polyacrylamide (MC-g-PAM) was developed by using an in situ coprecipitation method. Analytical instruments, such as a Fourier transform infrared (FTIR) spectroscope, scanning electron microscope (SEM), vibrating sample magnetometer (VSM), and specific surface area tester (BET), were used to characterize and analyze this material. With the aid of batch tests, the removal efficiency and mechanism of humic acid in water samples were investigated. The results show that the specific surface area and specific saturation magnetization values of the prepared MC-g-PAM are 27.065 m2·g-1 and 9.63 emu·g-1, respectively. The adsorption of humic acid by MC-g-PAM is an endothermic process and the Langmuir isotherm model and the pseudo-second-order kinetic equation fit the adsorption process well. At 25℃, the equilibrium adsorption capacity of MC-g-PAM to humic acid reaches 120.77 mg·g-1.