| 锆改性硅藻土吸附水中磷的研究 |
| 摘要点击 2600 全文点击 865 投稿时间：2016-09-18 修订日期：2016-11-01 |
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| 中文关键词 锆 硅藻土 磷 吸附 表面交联 |
| 英文关键词 zirconium diatomite phosphate adsorption surface cross-linking |
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| 中文摘要 |
| 采用锆对硅藻土进行改性所得锆改性硅藻土，其氧化锆质量分数占12.39%，经XRD鉴定为无定形.SEM结果显示，改性后硅藻土表面出现粗糙多孔的絮状物.相比硅藻土，锆改性硅藻土的比表面积由14.00 m2·g-1扩大到75.22 m2·g-1.XPS谱图显示，氧化锆与硅藻土之间以化学键方式，而非物理沉积方式结合.锆改性硅藻土对磷的等温吸附线更符合Langmuir模型，拟合得到最大吸附量为10.56 mg·g-1.锆改性硅藻土的吸附量按照氧化锆的质量分数计算为81.67 mg·g-1 ZrO2，高于文献报道的纯氧化锆吸附剂.锆改性硅藻土对磷的吸附随pH的上升而下降，结合吸附前后材料的Zr3d高分辨XPS图谱，确定锆改性硅藻土对磷的吸附为配体交换过程.氯离子、硫酸根离子和硝酸根离子共存不会抑制磷的吸附，而碳酸氢根离子具有一定的抑制作用.对磷浓度为2 mg·L-1的富营养化湖水，锆改性硅藻土投加量大于1.25 g·L-1时，反应后磷浓度即可满足《地表水环境质量标准》规定的湖库Ⅲ类标准. |
| 英文摘要 |
| Zirconium modified diatomite was obtained by modifying raw diatomite with zirconium and the mass fraction of zirconia was 12.39% in the obtained material, which was proved to be amorphous via XRD. SEM images showed that porous floccules covered the surface of diatomite after modification and the specific surface area of the zirconium modified diatomite was 75.22 m2·g-1, larger than that of raw diatomite (14.00 m2·g-1). XPS spectra indicated that zirconia and diatomite were bonded together through chemical linkage, rather than physical deposition. The adsorption isotherm of phosphate by zirconium modified diatomite was fitted better to the Langmuir model with a calculated maximum adsorption capacity reaching 10.56 mg·g-1. The adsorption amount of zirconium oxide component in the material was estimated to be 81.67 mg·g-1 ZrO2, which was higher than that of pure zirconium oxides reported in previous studies. The adsorption amount of phosphate by zirconium modified diatomite decreased with the increase of pH. The adsorption was proved to be a ligand exchange process, supported by the XPS spectra of Zr3d region before and after adsorption. Chloride ion, sulfate ion and nitrate ion did not inhibit the adsorption of phosphate on the material, whereas coexistence of bicarbonate ions competed with phosphate ions to a certain extent. When treating eutrophic lake water with a phosphate concentration of 2 mg·L-1, the phosphate concentration level could meet the Ⅲ rank of Surface Water Environment Quality Standard of China by adopting the dosage of zirconium modified diatomite ≥1.25 g·L-1. |
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