Removal of 2,4-Dichlorophenoxyacetic Acid Using Fe(OH)3 Based Complex Adsorbent

Abstract

The herbicide 2,4-dichlorophenoxyacetic acid with molecular formula C 8 H 6 O 3 Cl 2 and mole mass of 221.04 g/mol has been widely applied to control broad-leaved weeds in farming. However, 2,4-dichlorophenoxyacetic acid is considered as moderately toxic and its allowable concentration is 100 ppb in drinking water. The International Agency for Research on Cancer (IARC) concluded that the phenoxy acid herbicides including 2,4-dichlorophenoxyacetic acid, 2-methyl-4cholorophenoxy acid, 2,4,5-tricholorophenoxyacetic acid as a group were classified as a class 2B carcinogen-possibly carcinogenic to humans. On the other hand, 2,4-dichlorophenoxyacetic acid is a poorly biodegradable chemical that may persist for long time in the soil and groundwater. In Vietnam war, the herbicide agent orange contained 2,4-dichlorophenoxyacetic acid has been used extensively 1 . The 2,4-dichlorophenoxyacetic acid concentrations in the soils in some zones are much higher than allowable concentration. Based on these reasons many technologies have been developed for the removal of 2,4-dichlorophenoxyacetic acid from water, including photo catalytic degradation, ultrasound with photo-Fenton treatment, advanced oxidation processes, aerobic degradation, ozonation and adsorption [2][3][4][5] . In this article an adsorbent used for the removal of 2,4-dichlorophenoxyacetic acid from water based on the new complex adsorbent containing Fe(OH) 3 , SiO 2 and Fe (0) is presented. The study goal is focused on the main