典型铁氧化物对Cu(Ⅱ)的吸附性能研究

Study on Adsorption Properties of Typical Iron Oxides on Cu(Ⅱ)

为研究针铁矿、赤铁矿、磁铁矿和水铁矿对模拟Cu(Ⅱ)污染废水中的Cu(Ⅱ)去除性能,采用XRD、FTIR、BET比表面积及电位滴定对4种铁氧化物进行表征分析,通过静态和动态迁移试验对4种铁氧化物吸附Cu(Ⅱ)的性能进行综合比较。结果表明:(1)投加量为1 g/L,Cu(Ⅱ)初始浓度为50 mg/L时,4种铁氧化物对Cu(Ⅱ)的吸附饱和时间为30 min,在弱酸性条件下对Cu(Ⅱ)的吸附效果较为显著,针铁矿、赤铁矿、水铁矿和磁铁矿对Cu(Ⅱ)平衡吸附率分别为61.02%、50.72%、70.58%、46.65%。(2)针铁矿和水铁矿对Cu(Ⅱ)吸附过程为单分子层化学吸附,赤铁矿和磁铁矿则更符合Freundlich方程,以非均匀多分子层化学吸附为主。(3) Cu(Ⅱ)在迁移过程中,主要在含吸附剂的土柱表层和中层累积,且远大于深层,水铁矿对Cu(Ⅱ)的阻滞和吸附能力优于针铁矿。(4) 4种铁氧化物对Cu(Ⅱ)的吸附性能由好到差依次为水铁矿、针铁矿、赤铁矿、磁铁矿。

In order to study the removal performance of goethite,hematite,magnetite and ferrihydrite on Cu(Ⅱ)in simulated Cu(Ⅱ)contaminated wastewater,four kinds of iron oxides were characterized by XRD,FTIR,BET specific surface area and potentiometric titration.The adsorption performance of four kinds of iron oxides on Cu(Ⅱ)was compared by static and dynamic migration tests.The results showed that:①When the dosage was 1 g/L and the initial concentration of Cu(Ⅱ)was 50 mg/L,the adsorption saturation time of Cu(Ⅱ)by four iron oxides was 30 min.The adsorption effect of Cu(Ⅱ)was significant under weak acidic conditions.The equilibrium adsorption rates of Cu(Ⅱ)by goethite,hematite,ferrihydrite and magnetite were 61.02%,50.72%,70.58%and 46.65%,respectively.②The adsorption process of goethite and ferrihydrite on Cu(Ⅱ)is monolayer chemical adsorption,while hematite and magnetite are more in line with Freundlich equation,which is dominated by non-uniform multi-layer chemical adsorption.③During the migration process,Cu(Ⅱ)mainly accumulated in the surface and middle layers of the soil column containing adsorbents,and was much larger than that in the deep layer.The retardation and adsorption capacity of ferrihydrite to Cu(Ⅱ)was better than that of goethite.④The adsorption performance of four kinds of iron oxides on Cu(Ⅱ)from good to bad was ferrihydrite,goethite,hematite and magnetite.