Abstract Removal of phosphate is necessary to prevent eutrophication and remediate other environmental issues. In this study, branched polyethyleneimine (bPEI) was grafted onto rice husk porous silica (RSi-bPEI) to enhance the selective adsorption of phosphate. The adsorption tests for phosphate were performed at various conditions to assess the effects of pH, dose, initial concentration, and contact time. As confirmed by FTIR-spectra, it was proposed that phosphate species anchored onto RSi-bPEI through ion-exchange and hydrogen bonding. The increase in positive charge of RSi-bPEI, which was due to the presence of protonated amine, played a key role in offering more adsorption sites to augment the adsorption by means of electrostatic attraction. Consequently, RSi-bPEI exhibited qm of 123.46 mg g-1, which was two-fold better than that of RSi. The adsorption behavior was best described by Langmuir isotherms and the pseudo-second-order kinetics model. Based on the competitive study, the co-existing anions did not interfere with adsorption due to the fact that phosphate could form both inner and outer sphere complexes. In addition to the high performance, high efficiency in wide pH range as well as good stability and easy recyclability are the other promising criteria of RSi-bPEI that promote its practcal usage in treating phosphate-induced eutrophication of water bodies.

中文翻译：

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通过支化聚乙烯亚胺接枝吸附磷酸盐提高多孔稻壳二氧化硅的性能

摘要 去除磷酸盐对于防止富营养化和修复其他环境问题是必要的。在这项研究中，支化聚乙烯亚胺 (bPEI) 接枝到稻壳多孔二氧化硅 (RSi-bPEI) 上以增强磷酸盐的选择性吸附。在各种条件下对磷酸盐进行吸附试验，以评估 pH 值、剂量、初始浓度和接触时间的影响。正如 FTIR 光谱所证实的那样，有人提出磷酸盐物质通过离子交换和氢键固定在 RSi-bPEI 上。由于质子化胺的存在，RSi-bPEI 正电荷的增加在提供更多吸附位点以通过静电吸引增加吸附方面发挥了关键作用。因此，RSi-bPEI 的 qm 为 123.46 mg g-1，比​​ RSi 好两倍。Langmuir 等温线和准二级动力学模型最好地描述了吸附行为。根据竞争研究，共存的阴离子不会干扰吸附，因为磷酸盐可以形成内外球复合物。除了高性能、在宽 pH 范围内的高效率以及良好的稳定性和易回收性之外，RSi-bPEI 的其他有希望的标准促进了其在处理磷酸盐引起的水体富营养化方面的实际应用。