| 钙掺杂四氧化三铁回收水中磷的实验 |
| 摘要点击 2545 全文点击 636 投稿时间：2019-02-02 修订日期：2019-03-20 |
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| 中文关键词 过氧化钙(CaO2) 四氧化三铁(Fe3O4) 磷酸盐 吸附 废水 |
| 英文关键词 CaO2 Fe3O4 phosphate adsorption wastewater |
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| 中文摘要 |
| 吸附法是回收水中磷酸盐经济有效的方法之一，为提高四氧化三铁（Fe3O4）对磷酸盐的吸附能力，且保证其在外加磁场的作用下仍易于从水中分离，本研究选取过氧化钙（CaO2）作为氧化剂部分氧化Fe2+制备了磷回收吸附剂——Ca掺杂Fe3O4（CMIO），并利用XRD、XRF和VSM等技术对CMIO进行表征.结果表明，CMIO为嵌入Ca2+的Fe3O4晶型结构，其饱和磁化强度为38.82 emu·g-1，在外加磁场作用下易从水中分离.CMIO对磷的吸附容量随pH增加而降低，在pH=2，T=25℃时达到最大吸附容量24.10 mg·g-1，几乎是纯Fe3O4吸附容量的5倍.CMIO对磷的吸附符合Langmuir等温吸附模型，其吸附过程遵循准二级动力学模型.磷酸盐在CMIO内表面发生络合反应，形成了≡Fe-Ca-P三元复合物，从而吸附磷.与水中其他阴离子相比，CMIO对PO43-有良好的选择吸附性，且吸附的PO43-可用NaOH溶液解吸；CMIO每循环利用一次质量减少不超过4%，可多次循环利用. |
| 英文摘要 |
| Adsorption is an economical and effective method for recovering phosphate from wastewater. In order to improve the adsorption capacity of Fe3O4 for phosphate and for easy separation from water under the action of an external magnetic field, CaO2 was used in this study as an oxidant to partially oxidize Fe2+. A phosphorus recovery adsorbent, Ca doped Fe3O4 (CMIO), was prepared and was characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF) and vibrating sample magnetometer (VSM) techniques. The results showed that CMIO had a Ca2+ doped Fe3O4 crystal structure with a saturation magnetization of 38.82 emu·g-1, which was easily separated from water by using an external magnetic field. The phosphorus adsorption capacity of the CMIO decreased with an increase of pH value. When pH=2 and T=25℃, the maximum adsorption capacity was 24.10 mg·g-1, which is almost five times the adsorption capacity of pure Fe3O4. The phosphorus adsorption of CMIO was in accord with the Langmuir isotherm adsorption model, and the adsorption process followed the pseudo-second order kinetic model. The complexation of phosphate occurred on the inner surface of the CMIO to form a ≡Fe-Ca-P ternary complex, which can adsorb phosphorus. Compared with other anions in the aqueous solution, CMIO had good adsorption selectivity to PO43-, and the adsorbed PO43- could be desorbed by NaOH solution.The quality loss of the CMIO was less than 4% once, and multiple recycling was possible. |
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