Abstract：
Effective removal of phosphate from water is essential for preventing the eutrophication and worsening of water quality. This study aims to enhance phosphate removal by synthesizing starch-stabilized ferromanganese binary oxide (FMBO-S), discover the factors, and investigate adsorption mechanisms. FMBO and FMBO-S properties were studied using Scanning Electron Microscopy, BET analysis, Polydispersity Index (PDI), Fourier Transform Infrared Spectroscopy, and X-ray Photoelectron Spectroscopy (XPS). After starch loading, the average pore diameter increased from 14.89 Å to 25.16 Å, and significantly increased the pore volume in the mesopore region. FMBO-S showed a PDI value below 0.5 indicating homogeneous size dispersity and demonstrated faster and higher adsorption capacity: 61.24 mg g-1 > 28.57 mg g-1. Both FMBO and FMBO-S adsorption data fit well with the pseudo-second-order and Freundlich models, indicating a chemisorption and multilayered adsorption process. The phosphate adsorption by FMBO was pH-dependent, suggesting electrostatic attraction as the dominant mechanism. For the FMBO-S, phosphate adsorption was favored in a wide pH range, despite the weaker electrostatic attraction as evident from the point of zero charge and zeta potential values, indicating ligand exchange as a main mechanism. Moreover, the XPS analysis shows a significant change in the proportion of Fe species for FMBO-S than FMBO after phosphate adsorption, indicating significant involvement of Fe. Meanwhile, phosphate adsorption was almost unaffected by the presence of Cl-, NO3-, and SO42- anions, whereas CO32- significantly reduced the adsorption capacity. This study revealed that FMBO-S could be a promising, low-cost adsorbent for phosphate removal and recovery from water.
摘要：
有效去除水中的磷酸盐对于防止水体富营养化和水质恶化至关重要。本研究旨在通过合成淀粉稳定的锰铁二元氧化物（FMBO-S）来提高磷酸盐的去除，发现因素，并研究吸附机理。使用扫描电子显微镜研究了FMBO和FMBO-S的性质，BET分析,多分散指数(PDI),傅里叶变换红外光谱,和X射线光电子能谱(XPS)。淀粉加载后，平均孔径从14.89µ增加到25.16µ,并显着增加了中孔区域的孔体积。FMBO-S显示低于0.5的PDI值,表明均匀的尺寸分散性,并显示更快和更高的吸附容量:61.24mgg-1>28.57mgg-1。FMBO和FMBO-S吸附数据均与伪二阶和Freundlich模型拟合良好，表明化学吸附和多层吸附过程。FMBO对磷酸盐的吸附具有pH依赖性，表明静电吸引是主导机制。对于FMBO-S来说,在宽pH范围内有利于磷酸盐的吸附，尽管从零电荷和zeta电位值的角度来看静电吸引力较弱，表明配体交换是主要机制。此外，XPS分析表明，在磷酸盐吸附后，FMBO-S的Fe物种比例比FMBO显著变化，表明Fe的显著参与。同时,磷酸盐吸附几乎不受Cl-存在的影响，NO3-,和SO42-阴离子，而CO32-显著降低了吸附容量。这项研究表明，FMBO-S可能是一个有希望的，从水中去除和回收磷酸盐的低成本吸附剂。
