Surface complexation sorption and ligand-promoted dissolution of enrofloxacin on aluminum hydroxide and iron hydroxide
恩诺沙星在含水氧化铝和含水氧化铁上的配位吸附及配位增溶效应

Batch equilibrium experiments were used to reveal enrofloxacin(ENR) adsorption on two different hydrous oxides:aluminum hydroxide(HAO) and iron hydroxide(HFO).The results showed that the adsorption isotherms of ENR on the two hydrous oxides were both well described by Langmuir model when KL(HFO) >KL(HAO).The adsorption capacity(Qm) of enrofloxacin to HAO/HFO decreased with the increase of ion strength if NaCl concentrations were at a range between 0.01 mol · L-1 and 0.5 mol · L-1.However,the ion strengths in the solution had little effect on the adsorption at the low concentrations of enrofloxacin,which indicated that adsorption of enrofloxacin on the two different hydrous oxides was essentially based on ligand reaction.However,the adsorption efficiency apparently decreased in the strong acidic or alkaline environment.The coordination adsorption mainly occurred at pH 5~8 in the environment.It was found that the coordination point occurred at the C-3 carboxyl site,and the soluble complexes of 1:1 ENR:M(Metal ions) were formed in the solution,which was measured by UV spectrometry,ATR-FTIR difference spectrometry and atomic absorption spectrometry.Meanwhile,the formed complex between ENR and HAO/HFO could increase the solubility of ENR in aqueous solution.