| 不同沉淀pH值条件下制备的水合氧化锆对水中磷酸盐的吸附作用 |
| 摘要点击 1908 全文点击 864 投稿时间：2016-11-09 修订日期：2016-12-08 |
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| 中文关键词 水合氧化锆 沉淀pH值 磷酸盐 吸附 配位体交换 |
| 英文关键词 hydrous zirconium oxide precipitated pH values phosphate adsorption ligand exchange |
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| 中文摘要 |
| 研究了沉淀pH值分别为4.8、8.0和10.6条件下制备的水合氧化锆对水中磷酸盐的吸附作用，结果表明，共存的Na+仅仅略微促进了沉淀pH值为4.8和8.0时所得水合氧化锆对水中磷酸盐的吸附，却明显促进了沉淀pH值为10.6时所得水合氧化锆对磷酸盐的吸附.共存的Ca2+仅仅略微促进了沉淀pH值为4.8时水合氧化锆对磷酸盐的吸附，却极大地促进了沉淀pH值为8.0和10.6时水合氧化锆对磷酸盐的吸附.共存的HCO3-和SO42-抑制了水合氧化锆对磷酸盐的吸附，且它们对沉淀pH值为4.8时水合氧化锆吸磷的抑制作用明显大于对沉淀pH值为8.0和10.6时水合氧化锆的抑制作用.不同沉淀pH值条件下制备的水合氧化锆对水中磷酸盐的吸附能力均随着溶液pH值的增加而降低.不同沉淀pH值条件下所得水合氧化锆对水中磷酸盐的吸附平衡数据可以采用Langmuir、Freundlich和Dubinin-Redushckevich（D-R）等温吸附模型加以描述.存在Na+而不存在Ca2+情况下，3种不同沉淀pH值条件下所得水合氧化锆对中性溶液中磷酸盐的最大单层吸附容量差别不大；存在Ca2+情况下，沉淀pH值为8.0和10.6时所得水合氧化锆对中性溶液中磷酸盐的最大单层吸附容量远远高于沉淀pH值为4.8时制备的水合氧化锆.沉淀pH值为4.8和8.0时所得水合氧化锆的吸磷机制主要是表面氯和羟基基团与磷酸盐之间的配位体交换作用，而沉淀pH值为10.6时所得水合氧化锆的吸磷机制主要是表面羟基基团与磷酸盐之间的配位体交换作用.以上研究结果显示，与沉淀pH值为4.8时制备的水合氧化锆相比，沉淀pH值为8.0和10.6时制备的水合氧化锆更加适合作为吸附剂去除废水中的磷酸盐. |
| 英文摘要 |
| In this study, hydrous zirconium oxide (HZO) samples precipitated at different pH values were prepared, characterized and used as adsorbents to remove phosphate from aqueous solution. The adsorption characteristics and mechanisms of phosphate on these HZO samples were investigated. The results showed that the presence of Na+ slightly enhanced the adsorption of phosphate on HZO samples prepared at precipitation pH of 4.8 and 8.0, but it greatly enhanced the adsorption of phosphate on HZO prepared at precipitation pH of 10.6. The presence of Ca2+ slightly enhanced the adsorption of phosphate on HZO prepared at precipitation pH of 4.8, but it significantly enhanced the adsorption of phosphate on HZO samples prepared at precipitation pH of 8.0 and 10.6. The presence of HCO3- or SO42- inhibited phosphate adsorption onto HZO, and the inhibitory effect of these anions on phosphate adsorption onto HZO precipitated at pH 4.8 was much higher than that on phosphate adsorption onto HZO samples precipitated at pH 8.0 and 10.6. The phosphate adsorption was dependent upon solution pH, and it decreased with increasing solution pH. The Langmuir, Freundlich and Dubinin-Redushckevich (D-R) isotherm models fitted well to the adsorption equilibrium data of phosphate on HZO samples precipitated at pH 4.8, 8.0 and 10.6. In the presence of Na+ but in the absence of Ca2+, there was no significant difference of the maximum phosphate monolayer adsorption capacity derived from the Langmuir isotherm model among HZO samples prepared at precipitation pH of 4.8, 8.0 and 10.6. In the presence of Ca2+, the maximum phosphate monolayer adsorption capacity derived from the Langmuir isotherm model for HZO precipitated at pH 8.0 or 10.6 was much higher than that for HZO precipitated at pH 4.8. The mechanism for phosphate adsorption onto HZO mainly obeyed the inner-sphere complexing mechanism. The surface chloride and hydroxyl groups played the key role in the adsorption of phosphate on HZO precipitated at pH 4.8 or 8.0, while only the surface hydroxyl groups played the key role in the adsorption of phosphate on HZO precipitated at pH 10.6. Results of this work demonstrated that the HZO precipitated at pH 8.0 or 10.6 was a more promising adsorbent for removing phosphate from wastewater than the HZO precipitated at pH 4.8. |
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