Preparation of adsorbent for phosphate recovery from aqueous solutions based on condensed tannin gel.
Preparation of adsorbent for phosphate recovery from aqueous solutions based on condensed tannin gel.
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DOI：
10.1016/j.jhazmat.2011.05.073
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发表时间：
2011-08
影响因子：
13.6
通讯作者：
Takeshi Ogata;Shintaro Morisada;Yasumi Oinuma;Y. Seida;Y. Nakano
中科院分区：
文献类型：
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作者：
Takeshi Ogata;Shintaro Morisada;Yasumi Oinuma;Y. Seida;Y. Nakano
我们合成了一种载铁单宁凝胶作为水溶液中磷酸盐回收的吸附剂。由缩合单宁制备的单宁凝胶是一种普遍存在的廉价天然聚合物，使用这种凝胶不仅成本低、环境友好，而且有趣，因为这种吸附磷酸盐的凝胶有望直接用作肥料。硝酸氧化单宁凝胶的载铁量远大于未氧化单宁凝胶的载铁量。这种载铁量的增加导致了磷酸盐在凝胶上的吸附量显著增加。穆斯堡尔谱分析表明，铁在凝胶中的形态为一元络合物，该络合物是Fe(III)与氧化单宁发生化学反应的结果。在较宽的初始pH范围内，载铁单宁凝胶对磷酸盐表现出对其它阴离子的选择性吸附，对磷酸盐的吸附具有pH无关性。载铁单宁凝胶对磷酸盐的吸附等温线符合Freundlich方程，其吸附常数分别为Kf=2.66和1/n=0.31，而不符合朗缪尔方程。载铁单宁凝胶对磷酸盐的铁质量吸附量为31.3 mg-P/g-Fe，与氢氧化铁等其他磷酸盐吸附剂相比，凝胶中的铁可有效地用于磷酸盐的吸附。
We have synthesized an iron-loaded tannin gel as an adsorbent for phosphate recovery in aqueous solutions. The use of the tannin gel prepared from condensed tannin, which is a ubiquitous and inexpensive natural polymer, is not only cost effective and environment-friendly, but interesting because the phosphate-adsorbed gel can be expected to use directly as a fertilizer. The amount of iron loaded into the tannin gel oxidized by nitric acid was much larger than that into the non-oxidized tannin gel. This increase in the amount of the loaded iron resulted in the significant increase in the adsorption amount of phosphate onto the gel. Mössbauer spectroscopy indicated that the morphology of iron in the gel is a mono-type complex, which is formed as a result of the reaction between Fe(III) and the oxidized tannin gel with carbonyl groups. The iron-loaded tannin gel showed the adsorption selectivity for phosphate over other anions and the pH independence of phosphate adsorption in the wide range of initial pH 3–12. The phosphate adsorption isotherm for the iron-loaded tannin gel followed the Freundlich equation with constants of KF=2.66 and 1/n=0.31, rather than the Langmuir equation. The adsorption amount of phosphate on iron weight basis for the iron-loaded tannin gel is 31.3mg-P/g-Fe, which indicates that iron in the gel was efficiently used for the phosphate adsorption compared with other phosphate adsorbents, such as iron hydroxides.