Heteroaggregation of Graphene Oxide with Minerals in Aqueous Phase
Heteroaggregation of Graphene Oxide with Minerals in Aqueous Phase
复制标题
氧化石墨烯与矿物质在水相中的异相聚集
DOI：
10.1021/es505605w
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发表时间：
2015
影响因子：
11.4
通讯作者：
Xing Baoshan
中科院分区：
文献类型：
--
作者：
Zhao Jian;Liu Feifei;Wang Zhenyu;Cao Xuesong;Xing Baoshan
在释放到沃茨、沉积物和土壤中时，氧化石墨烯（GO）可与细矿物颗粒相互作用。我们研究了GO与不同矿物（包括蒙脱石、高岭石和针铁矿）在水相中的异相聚集。GO通过异相聚集显著提高了带正电荷针铁矿的分散性（>50%），而GO与带负电荷的蒙脱石或高岭石之间没有相互作用。在pH 4.0-8.5范围内，静电引力是GO-针铁矿异质聚集的主导力，针铁矿中溶解的Fe离子（<0.16 mg/L）不能破坏GO悬浮液的稳定性。通过GO吸附研究，进一步定量研究了GO-针铁矿异质聚集。GO在不同pH值（4.0和6.5）下的吸附等温线均符合线性模型。对于所有吸附等温线观察到表观截距（1.0- 6.9mg/g），表明在测试条件下，吸附的GO的该部分难以从针铁矿解吸（这里定义为不可逆吸附）。脱附滞后现象，这可以解释为具有高构型稳定性的多层GO-针铁矿复合物的形成。这些发现有助于了解GO与矿物表面的相互作用，以及GO在自然条件下在水生环境以及土壤和沉积物中的潜在命运和毒性。
Upon release into waters, sediments, and soils, graphene oxide (GO) may interact with fine mineral particles. We investigated the heteroaggregation of GO with different minerals, including montmorillonite, kaolinite, and goethite, in aqueous phase. GO significantly enhanced the dispersion of positively charged goethite (>50%) via heteroaggregation, while there was no interaction between GO and negatively charged montmorillonite or kaolinite. Electrostatic attraction was the dominant force in the GO–goethite heteroaggregation (pH 4.0–8.5), and the dissolved Fe ions (<0.16 mg/L) from goethite were unable to destabilize GO suspension. The GO–goethite heteroaggregation was further quantitatively investigated through GO adsorption study. All adsorption isotherms of GO at different solution pH (4.0 and 6.5) followed the Linear model. The apparent intercept (1.0–6.9 mg/g) was observed for all the adsorption isotherms, indicating that this fraction of adsorbed GO was difficult to desorb from goethite (defined here as irreversible adsorption) under the tested conditions. Desorption hysteresis was observed, which could be explained by the formation of multilayered GO–goethite complex with high configurational stability. These findings are useful for understanding the interaction of GO with mineral surfaces, and potential fate and toxicity of GO under natural conditions in aquatic environments, as well as in soils and sediments.