Adsorption characteristics of beta-lactam cefixime onto nanosilica fabricated from rice husk with surface modification by polyelectrolyte
Adsorption characteristics of beta-lactam cefixime onto nanosilica fabricated from rice husk with surface modification by polyelectrolyte
复制标题
聚电解质表面修饰稻壳纳米二氧化硅对β-内酰胺头孢克肟的吸附特性
DOI：
10.1016/j.molliq.2019.111981
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发表时间：
2020
影响因子：
6
通讯作者：
Adachi Yasuhisa
中科院分区：
文献类型：
--
作者：
Pham Tien Duc;Bui Thu Thuy;Truong Thi Thuy Trang;Hoang Thu Ha;Le Thanh Son;Duong Viet Dung;Yamaguchi Atsushi;Kobayashi Motoyoshi;Adachi Yasuhisa
研究了聚二烯丙基二甲基氯化铵（PDADMAC）改性纳米二氧化硅（PMNS）对β-内酰胺头孢克肟（CEF）的吸附性能。通过X射线荧光（XRF）光谱法证实了从稻壳制造的纯度大于99.6%的纳米二氧化硅，而通过透射电子显微镜（TEM）测定的粒径为20 nm。BET法测得纳米SiO2的比表面积为160.5m2/g.在pH 10和100 mM KCl下，通过预吸附PDADMAC对纳米二氧化硅的表面进行改性，以增强PMNS的高度正电荷。PMNS去除CEF的有效条件为接触时间90 min、pH 4和吸附剂投加量10 mg/mL。在最佳吸附条件下，CEF去除率从24.55%显著提高到93.51%。不同盐浓度下PMNS对CEF的吸附等温线均符合两步吸附模型，吸附动力学符合准二级动力学模型。CEF在PMNS上的吸附随离子强度的增加而减少，说明CEF在PMNS上的吸附主要受阴离子CEF分子与带正电荷的PMNS表面之间的静电引力控制。PMNS经4次再生后，CEF的去除率仍达90%。PMNS对实际医院废水中CEF的去除率高于75%。我们的研究结果表明，PMNS是一种新型的吸附剂，从水溶液中去除抗生素。
The present study aims to investigate adsorption of beta-lactam cefixime (CEF) onto strong polycation, polydiallyldimethylammonium chloride (PDADMAC) modified nanosilica (PMNS). Nanosilica fabricated from rice husk with purity greater than 99.6% was confirmed by X-ray fluorescence (XRF) spectroscopy while a particle size of 20 nm was determined by transmission electron microscopy (TEM). The specific surface area of nanosilica by Brunauer - Emmett – Teller (BET) method was 160.5 m2/g. The surface of nanosilica was modified by pre-adsorption of PDADMAC at pH 10 and 100 mM KCl in order to enhance highly positive charge of PMNS. The effective conditions for removal CEF using PMNS were found to be contact time 90 min, pH 4 and adsorbent dosage 10 mg/mL. Under the optimum adsorption conditions, CEF removal from aqueous solution increased significantly from 24.55% to 93.51%. Adsorption isotherms of CEF onto PMNS at different salt concentrations were fitted well by two-step model while adsorption kinetics agreed well with the pseudo-second-order kinetic model. Adsorption of CEF onto PMNS decreased with an increase of ionic strength, demonstrating that adsorption of CEF onto PMNS is mainly controlled by electrostatic attraction between anionic CEF molecules and positively charged PMNS surface. After four regenerations of PMNS, the removal of CEF still reached to 90%. The removal of CEF from an actual hospital wastewater using PMNS was higher than 75%. Our results suggest that PMNS is a novel adsorbent to remove antibiotics from aqueous solutions.