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首页> 外文期刊>Journal of Environmental Science and Health >Boron removal by a composite sorbent: Polyethylenimine/tannic acid derivative immobilized in alginate hydrogel beads
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Boron removal by a composite sorbent: Polyethylenimine/tannic acid derivative immobilized in alginate hydrogel beads

机译：通过复合吸附剂去除硼：固定在藻酸盐水凝胶珠粒中的聚乙烯亚胺/鞣酸衍生物

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摘要

A novel composite material was prepared by the grafting of tannic acid on polyethylenimine (PEI), which allows an efficient sorption of boron (sorption capacity close to 0.89mmol B g(-1)). The encapsulation of this chelating sorbent (finely crushed) facilitates its use (readily solid/liquid separation, use in fixed-bed columns) at the expense of a loss in sorption capacity (proportionally decreased by the introduction of alginate having poor efficiency for boron uptake). Sorption isotherms are modeled using the Langmuir equation, while the kinetic profiles are presented a good fit by pseudo-second order rate equation. In addition, the encapsulating matrix introduces supplementary resistance to intraparticle diffusion, especially when the resin is dried without control: freeze-drying partially limits this effect. The stability (at long-term storage) of the sorbent is improved when the sorbent is stored under nitrogen atmosphere. The presence of an excess of NaCl was investigated. The degradation of the hydrogel (by ion-exchange of Ca(II) with Na(I)) leads to a decrease in the sorption performance of composite material but the action of Ca(II) ions in the solutions re-stabilizes the hydrogel.
机译：通过将鞣酸接枝到聚乙烯亚胺（PEI）上制备了一种新型复合材料，该材料可有效吸附硼（吸附量接近0.89mmol B g（-1））。这种螯合吸附剂的包封（细碎）有利于其使用（易于固/液分离，在固定床色谱柱中使用），但以吸附能力的损失为代价（由于引入了硼吸收效率低的藻酸盐而成比例降低） ）。使用Langmuir方程对吸附等温线进行建模，而动力学曲线通过伪二阶速率方程式很好地拟合。另外，包封基质对颗粒内扩散引入了附加的抵抗力，尤其是在无控制的情况下干燥树脂时：冷冻干燥部分地限制了这种作用。当吸附剂在氮气气氛下储存时，吸附剂的稳定性（长期储存）得到改善。研究了过量NaCl的存在。水凝胶的降解（通过将Ca（II）与Na（I）进行离子交换）导致复合材料的吸附性能下降，但溶液中Ca（II）离子的作用使水凝胶重新稳定。

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