ABSTRACT

The porous polyvinyl alcohol (PVA)/Al₂O₃ composite by supporting activated alumina on the cross-linked network of PVA has been successfully prepared and its property for the removal of phosphate in aqueous solution was also evaluated. The structure of the PVA/Al₂O₃ was examined by scanning electron microscopy. It showed that the activated alumina particles with an average size of 1 μm were evenly dispersed and fixed in the cross-linked network structure of PVA. The effects of adsorption time, solution temperature, pH, initial concentration of phosphate, Al₂O₃ loading rate, dosage and coexisting ions on the phosphate removal were further studied. The results showed that the highest removal phosphate efficiency of 95% can be obtained with the Al₂O₃ loading rate of PVA/Al₂O₃ being 60 wt.% at pH of 4 at 30 °C. The maximum adsorption capacities of ${\mathrm{PO}}_4^{3-}$ by PVA/Al₂O₃ suggested by the Langmuir isothermal model was 10.12 mg/g. The adsorption process of phosphate can be fit well with a pseudo-second-order model (R² = 0.9900). The PVA/Al₂O₃ composite exhibited a high selective adsorption of phosphate in the presence of commonly coexisting anions except the obvious effect of ${\mathrm{CO}}_3^{2-}$ in water. Meanwhile, the PVA/Al₂O₃ composite can be easily separated and recovered due to the granulation of adsorbent. PVA/Al₂O₃ composite also shows the excellent properties of regeneration and recycling use with the removal efficiency of phosphate was 88.93%, 88.38% and 94.34% after three cycles, respectively. It can be proposed that the PVA/Al₂O₃ composite is a promising recyclable adsorbent for removing phosphate at low concentration from aqueous solution.

摘要

成功制备了在PVA交联网络上负载活性氧化铝的多孔聚乙烯醇(PVA)/Al ₂ O _{3复合材料，并对其去除水溶液中磷酸盐的性能进行了评价。}PVA/Al ₂ O ₃的结构通过扫描电子显微镜检查。结果表明，平均粒径为 1 μm 的活性氧化铝颗粒均匀分散固定在 PVA 的交联网络结构中。吸附时间、溶液温度、pH、磷酸盐初始浓度、Al ₂ O _3的影响进一步研究了负载率、用量和共存离子对除磷的影响。结果表明，在 30 ℃、pH 为 4 时，当PVA/Al ₂ O _{3的 Al 2} O ₃负载率为60 wt.% 时，可获得最高 95% 的磷酸盐去除率。最大吸附容量${\mathrm{采购订单}}_4^{3-}$由Langmuir 等温模型建议的PVA/Al ₂ O _{3为 10.12 mg/g。}磷酸盐的吸附过程可以很好地拟合准二级模型（R ²  = 0.9900）。PVA/Al ₂ O ₃复合材料在共存阴离子存在下表现出对磷酸盐的高选择性吸附。${\mathrm{一氧化碳}}_3^{2-}$在水里。同时，由于吸附剂的造粒，PVA/Al ₂ O ₃复合材料易于分离和回收。PVA/Al ₂ O ₃复合材料还表现出优异的再生和循环利用性能，三个循环后对磷酸盐的去除效率分别为88.93%、88.38%和94.34%。可以提出，PVA/Al ₂ O ₃复合材料是一种有前途的可回收吸附剂，用于从水溶液中去除低浓度的磷酸盐。