Background

Excessive nitrate and phosphate in water is a major cause for eutrophication.

Methods

Carboxymethyl β-cyclodextrin immobilized on hydrated lanthanum oxide (LaCD) composite was fabricated, using carboxymethyl β-cyclodextrin (CM-β-CD) to immobilize hydrated lanthanum oxide (HLO). LaCD can efficiently and simultaneously adsorb nitrate and phosphate.

Significant findings

Results disclosed that the adsorption capacity in sole system reached 37.50 mg N/g and 66.98 mg P/g, whereas the adsorption capacity in binary system reached 31.62 mg N/g and 64.05 mg P/g. LaCD can also maintain high and stable adsorption efficiency within a wide pH range (4–11). Characterizations indicated excellent adsorption efficiency of LaCD for nitrate and phosphate. This finding may be due to electrostatic interaction, hydrogen bonding of abundant oxygen-containing groups on CM-β-CD surface and host-guest interaction in β-cyclodextrin (β-CD) cavity. HLO on LaCD had specific adsorption to phosphate through Lewis acid-base interaction and ligand exchange. Ten cycles verified LaCD had excellent reusability in adsorption-desorption experiments. This study may provide a supplementary method for synchronous and efficient removal for nitrate and phosphate to solve water eutrophication problem.

中文翻译：

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羧甲基β-环糊精固定在水合氧化镧上同时吸附硝酸盐和磷酸盐

背景

水中过量的硝酸盐和磷酸盐是造成富营养化的主要原因。

方法

采用羧甲基β-环糊精（CM-β-CD）固定水合氧化镧（HLO），制备了固定在水合氧化镧（LaCD）复合材料上的羧甲基β-环糊精。LaCD 可以高效同时吸附硝酸盐和磷酸盐。

重要发现

结果表明，单一体系的吸附量分别达到37.50 mg N/g和66.98 mg P/g，而二元体系的吸附量分别达到31.62 mg N/g和64.05 mg P/g。LaCD 还可以在较宽的 pH 范围 (4-11) 内保持高而稳定的吸附效率。表征表明 LaCD 对硝酸盐和磷酸盐具有出色的吸附效率。这一发现可能是由于静电相互作用、CM-β-CD 表面上丰富的含氧基团的氢键作用以及 β-环糊精 (β-CD) 腔中的主客体相互作用。LaCD上的HLO通过路易斯酸碱相互作用和配体交换对磷酸盐具有特异性吸附作用。十次循环验证 LaCD 在吸附-解吸实验中具有出色的可重复使用性。