Investigating adsorption mechanism and surface complex formation modeling for aqueous sulfadiazine bonding on Fe/Mn binary oxides.

In aquatic environment, the existence of antibiotics including sulfadiazine (SDZ) has gain a huge attention. It is suggested that hydrous metal oxides have large potential to remove contaminants in water. The SDZ removal capability by ferric and manganese binary oxides (FMBO) was investigated, and the SDZ removal performance was compared with the ferric hydroxide (HFO) and manganese dioxide (HMO). Our results showed that SDZ removal was highly pH-dependent, but pH has less effect on uptake of SDZ on FMBO than that of the other two adsorbents. The surface acidity constant of FMBO was first calculated to be 6.31 and 8.48, respectively. The uptake process was successfully fitted for according to surface complex formation models (SCFM) and the results of modern surface analytical methods, such as FTIR and XPS, were also consistent with the surface complex uptake mechanism. The uptake of SDZ by FMBO ascribed to specific chemical interaction between the aniline group of SDZ and the hydroxyl groups from FMBO.