脱硫石膏吸附水体中重金属离子行为的研究

利用工业废弃物脱硫石膏(flue gas desulfurization gypsum,FGDG)作为吸附剂,在静态吸附条件下,从温度、pH值等方面考察了FGDG对多种重金属离子的吸附能力以及多种重金属离子共存在下的吸附过程.基于水合半径和带电量对于吸附过程的影响,初步提出一个传质模型.在多元重金属离子存在的体系中,水合半径和电荷大小对竞争吸附结果有显着影响,五种重金属离子竞争能力顺序表现为:Pb2+＞Cr3+＞Cd2+＞Mn2+＞Cu2+. Langmuir模型推测吸附模型中化学吸附主要属于单层吸附过程,Freundlich模型能够描述FGDG与重金属离子物理吸附属于多层吸附过. XRD定性分析后,FGDG与重金属离子可形成Cu-S,Cd-S,Cr-S,Mn-S,Pb-S.

Adsorption Behavior of Heavy Metal Ions by Desulfurization Gypsum in Water

The use of industrial waste desulfurization gypsum (flue gas desulfurization gypsum, FGDG) as a adsorbent, under the condition of static adsorption, the adsorption process of FGDG on various heavy metal ions and the coexistence of various heavy metal ions were investigated from the aspects of temperature, pH value.Based on the influence of the hydration radius and the electric charge on the adsorption process, a mass transfer model is proposed.In the system of the existence of multiple heavy metal ions, the hydration radius and charge size have a significant effect on the competitive adsorption results, the competitive ability of five heavy metal ions as the follows: Pb2+＞Cr3 +＞Cd2 +＞Mn2+＞Cu2+.The Langmuir model infers that chemical adsorption is mainly a single layer adsorption process in adsorption model, and Freundlich model can describe FGDG and heavy metal ions physical adsorption belongs to multilayer adsorption process.After XRD analysis, FGDG and heavy metal ions can form Cu-S, Cd-S, Cr-S, Mn-S, Pb-S.