钙铝黄长石陶粒改性及处理含锰废水效能

以工业固体废弃物造纸白泥和粉煤灰为原料,通过煅烧制备钙铝黄长石陶粒,再经NaOH溶液水热反应法改性,用于含锰废水的吸附处理。利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)等方法对改性前后的陶粒进行表征,探讨陶粒水热改性机制。检测不同NaOH溶液浓度以及水热反应温度改性后陶粒的静态吸附除锰效能,并与改性前陶粒对比,确定最佳水热改性条件,并探索改性陶粒吸附除锰机理。结果表明:改性后陶粒的主矿物相仍为钙铝黄长石,但部分Ca元素被活化,生成新物相Ca(OH)₂,提高了陶粒本身碱性,继而使锰去除率显著提高,吸附平衡时间明显缩短。4,3 mol/L的NaOH溶液浓度以及160 ℃的水热温度分别为2种陶粒的最佳改性条件;改性后陶粒除锰可以在10~15 min内达到吸附平衡,锰去除率接近100%。吸附过程中,Mn2+与OH-生成白色Mn(OH)₂沉淀,然后被氧化为黑褐色的MnO(OH)₂,最终被陶粒表面均匀吸附,实现了固体废弃物资源化利用,达到以废治废的目的。

MODIFICATION OF GEHLENITE CERAMSITE AND ITS TREATMENT EFFICIENCY ON MANGANESE-CONTAINING WASTEWATER

Gehlenite ceramsites were prepared through calcination, with industrial solid wastes lime mud and fly ash as the raw materials. Then, the ceramsites were modified by hydrothermal reaction of NaOH solution and finally applied to the adsorption of manganese-containing wastewater. The ceramsites before and after the modification were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), to explore the modification mechanism. Under different modification conditions, such as the concentration of NaOH solution and the temperature of the hydrothermal reaction, the adsorption efficiency of Mn2+ by the ceramsites was detected. Thus, the optimum modification conditions and the adsorption mechanism of Mn2+ were determined. The results showed that after modification, the main mineral phase of the ceramsites was still gehlenite, but a new phase, Ca(OH)₂ was generated because of the activation of the partial calcium element. Accordingly, the alkalinity of the ceramsites was increased, significantly improving the removal rate of Mn2+ and shortening the adsorption equilibrium time. The concentrations of NaOH solution of 4, 3 mol/L and the temperature of 160 ℃ were the optimum modification conditions of the two ceramsites, respectively. For the adsorption of Mn2+ by the modified ceramsites, the adsorption equilibrium was achieved at 10~15 min, and the removal rate was close to 100%. During the adsorption process, Mn2+ in solution was reacted with OH- released from the ceramsites to form white Mn(OH)₂ and then quickly oxidized to brown MnO(OH)₂, which was evenly adsorbed on the surface of the ceramsites. This technology not only realized the utilization of solid wastes, but also achieved the purpose of Treating Waste with Waste.