对不同pH、电解质强度条件下氧化铁对腐殖酸的吸附量、解吸量和腐殖酸可见光谱(E4/E6)进行测定和分析,从而探讨氧化铁对腐殖酸的吸附机理。采用批量平衡震荡法进行氧化铁对腐殖酸的吸附实验,并用分光光度计对吸附前后的E4/E6进行检测。结果表明:酸性环境中物理吸附、物理化学吸附和化学吸附并存,其中物理吸附占了近一半;中性和弱碱性环境中氧化铁对腐殖酸的吸附以化学吸附为主。吸附过程中,吸附在矿物表面的腐殖酸的分子量大、芳构化度大,芳香环的缩合度较大;解吸过程中,中性条件解吸出来的HA的分子量大、芳构化大、芳香环的缩合度较大,碱性条件解吸出的腐殖酸的分子量小、芳构化度小、芳香环的缩合度较小。三氧化二铁和四氧化三铁与不同电解质强度的不同组合条件下,其吸附机制基本相同。
This paper mainly studied on the adsorption of humic acid(HA) on ferric oxide mineral under different conditions.Moreover,the adsorption mechanism of humic acid and ferric oxide mineral was investigated by using desorption and the visible spectrum analysis.The adsorption of humic acid on ferric oxide mineral was performed by using batch equilibrium techniques,whereas the E4/E6 ratio was measured by Spectrophotometers.It was found that,the physisorption and the chemical adsorption coexists,and nearly one half was occupied by physisorption under the meta-acid environmental condition.On the other hand,under neutral and weak basic environmental condition,the ionic exchange adsorption was the dominant type.In the process of adsorption HA on the mineral surface characterized by lighter molecular weight,weaker aromatization process,and shrinked properly small aromatic nucleus.While under neutral condition,the characteristic of HA on the mineral surface was the same except for the lower ratio of E4/E6 and higher t value.The adsorption mechanism for both Fe2O3 and Fe3O4 with different electrolyte strength almost remains the same.