Rapid removal of trace haloacetic acids from drinking water by a continuous adsorption process using graphene oxide

Significant health risks are caused by trace levels of haloacetic acids (HAAs) in drinking water. We used graphene oxide (GO), a high-performance absorbent, to remove monochloroacetic acid (MCAA), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA). 31.6%, 27.1% and 30.2% of MCAA, DCAA and TCAA in drinking water could be rapidly removed within 2 min by the interaction of intermolecular hydrogen bonds between GO and HAAs. On the other hand, as a type of weak interaction, intermolecular hydrogen bonds are easy to fracture, which leads to the recovery of GO. The removal efficiency of MCAA, DCAA and TCAA monotonously decreased with increasing pH from 3 to 11. Temperature was not an important influence on the removal efficiency of HAAs, and only affected the interaction of intermolecular hydrogen bonds between GO and HAAs. A continuous adsorption process was used for further improving the removal efficiency of HAAs, and the concentration of total HAAs decreased from 436 to 52.5 μg L^-1 after five adsorption processes. The total contact time was just 2.25 min, which was faster than other reported adsorbents, and total HAAs could be decreased by 88%. The innovative process in this study provides an effective method for application of GO to rapidly remove HAAs in drinking water.