Bai Run-Ying, Liu Jian-Ming, Hao Jun-Feng, Xu Hui, Hu Wen-Bin, Song Lei, Liu Yu-Hong, Li Hui-Dong, Zhou Qi-Shan
College of Civil Engineering, Inner Mongolia University of Technology, Hohhot 010051, China.
Huan Jing Ke Xue. 2019 Sep 8;40(9):4098-4104. doi: 10.13227/j.hjkx.201902014.
Adsorption is an economical and effective method for recovering phosphate from wastewater. In order to improve the adsorption capacity of FeO for phosphate and for easy separation from water under the action of an external magnetic field, CaO was used in this study as an oxidant to partially oxidize Fe. A phosphorus recovery adsorbent, Ca doped FeO (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 Ca doped FeO crystal structure with a saturation magnetization of 38.82 emu·g, 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 =25℃, the maximum adsorption capacity was 24.10 mg·g, which is almost five times the adsorption capacity of pure FeO. 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 PO, and the adsorbed PO could be desorbed by NaOH solution.The quality loss of the CMIO was less than 4% once, and multiple recycling was possible.
吸附是一种从废水中回收磷的经济有效方法。为了提高FeO对磷的吸附能力，并便于在外部磁场作用下与水分离，本研究使用CaO作为氧化剂对Fe进行部分氧化。制备了一种磷回收吸附剂Ca掺杂FeO（CMIO），并通过X射线衍射（XRD）、X射线荧光（XRF）和振动样品磁强计（VSM）技术对其进行了表征。结果表明，CMIO具有Ca掺杂FeO晶体结构，饱和磁化强度为38.82 emu·g，利用外部磁场可轻松将其与水分离。CMIO的磷吸附容量随pH值升高而降低。当pH = 2且温度为25℃时，最大吸附容量为24.10 mg·g，几乎是纯FeO吸附容量的五倍。CMIO对磷的吸附符合Langmuir等温吸附模型，吸附过程遵循准二级动力学模型。磷酸盐的络合发生在CMIO的内表面，形成≡Fe-Ca-P三元络合物，从而能够吸附磷。与水溶液中的其他阴离子相比，CMIO对PO具有良好的吸附选择性，吸附的PO可用NaOH溶液解吸。CMIO单次质量损失小于4%，可以进行多次循环利用。
