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采用Na_2S化学再生法对吸附Fe~(2+)、Mn~(2+)、Cu~(2+)和Zn~(2+)饱和的膨润土-钢渣复合颗粒吸附剂分别进行重金属离子的固定及其再生实验研究,探究该吸附剂吸附的重金属离子的固定问题及其再生的可能性和多次再生后的吸附效果,同时根据SEM图进一步揭示固定、再生机理。结果表明:在对Fe~(2+)的固定、再生实验中,可形成Fe S沉淀而实现固定,但再生后再吸附时,膨润土复合颗粒中蒙脱石结构改变使得颗粒坍塌变成粉末状,因此,吸附Fe~(2+)饱和的膨润土复合颗粒吸附剂不适合用Na_2S再生;而对Mn~(2+)、Cu~(2+)和Zn~(2+)的固定、再生实验中,均可形成S化物沉淀而实现固定,颗粒结构未改变,经过3次再生后,吸附剂对Mn~(2+)、Cu~(2+)和Zn~(2+)的去除率还可达到94.22%、83.2%和76.30%,远比未经再生的吸附剂吸附效果好,同时,由SEM表征分析进一步揭示:Na_2S再生溶液既可使重金属离子形成MS沉淀固定,又可使复合颗粒吸附剂获得再生,实现了同步固定、再生的目的,且吸附剂经多次再生后吸附效果保持良好。
Adsorption of bentonite-slag composite adsorbent adsorbing Fe 2+, Mn 2+, Cu 2+ and Zn 2+ by Na 2 S chemical regeneration method were respectively used to immobilize heavy metal ions The regeneration experiments were carried out to investigate the immobilization of heavy metal ions adsorbed on the adsorbent, the possibility of its regeneration and the adsorption effect after repeated regeneration. Meanwhile, the mechanism of immobilization and regeneration was further revealed according to SEM images. The results show that during the experiment of Fe2 + fixation and regeneration, FeS precipitates can be formed and fixed, but when the particles are regenerated and then adsorbed, the structure of montmorillonite in bentonite composite particles is changed into powder Therefore, the bentonite composite particle adsorbent with saturated Fe 2+ is not suitable for regeneration with Na 2 S, while the immobilization and regeneration experiments of Mn 2+, Cu 2+ and Zn 2+ , The precipitate of S can be formed and fixed, the structure of the particles has not changed. After 3 times of regeneration, the removal rates of Mn ~ (2 +), Cu ~ (2+) and Zn ~ (2+) Which can reach 94.22%, 83.2% and 76.30%, which is much better than that of the adsorbent without regeneration.At the same time, the characterization by SEM reveals that the regeneration solution of Na2S can not only immobilize heavy metal ions to form MS precipitate, but also make the composite particles The adsorbent is regenerated to achieve the purpose of simultaneous fixation and regeneration, and the adsorption effect of the adsorbent after being regenerated for many times is well maintained.