The impact of solution chemistry of electrolyte on the sorption of pentachlorophenol and phenanthrene by natural hematite nanoparticles.
The impact of solution chemistry of electrolyte on the sorption of pentachlorophenol and phenanthrene by natural hematite nanoparticles.
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DOI：
10.1016/j.scitotenv.2013.07.072
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Fanfeng Zeng;Yan He;Z. Lian;Jianming Xu
中科院分区：
文献类型：
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作者：
Fanfeng Zeng;Yan He;Z. Lian;Jianming Xu
在自然环境条件下，通过专门设计的电解质对比溶液化学，研究了纳米赤铁矿（NPs）作为疏水性有机污染物（OC）的吸附剂。选择可电离的五氯苯酚（PCP）和不可电离的菲（PHE）作为代表性有机碳。五氯苯酚和菲的吸附量与pH值有关，当pH值低于其pKa值（4.75）时，吸附量较大。然而，PHE吸附容量在相对高或低的pH（例如低于4.0和高于10.0）下较高，这可能是由于赤铁矿NP的较大可用表面积，这是由较高的净电荷和电荷密度值引起的。因此，pH值的变化可能会影响吸附的有机碳的赤铁矿纳米颗粒，通过修改的吸附剂的表面特性和电子性质的山梨酸酯分子。不同离子强度对PCP和PHE吸附量的影响表明，不同类型离子（如Na+、K+、Mg2 +和Ca2 +）对PCP和PHE吸附量的影响呈浓度函数关系，其机理可能是由于氢键作用、环境离子竞争吸附、屏蔽效应和聚集效应等4种相互作用。结果证实，赤铁矿纳米颗粒的表面化学性质、PCP和PHE的化学性质以及电解液的溶液化学性质（如pH值和离子强度）都对赤铁矿纳米颗粒吸附PCP和PHE起着重要作用。通过比较吸附能力和生态优势，我们的研究结果表明，天然赤铁矿纳米颗粒将更有竞争力和更有效的PCP和PHE的吸附比工程纳米颗粒。这一发现增加了我们的知识，自然纳米粒子（如赤铁矿纳米粒子）的环境功能OC修复通过操纵他们的界面行为。
Hematite nanoparticles (NPs) were studied as a sorbent for hydrophobic organic contaminants (OCs) under natural ambient conditions through specially designed contrasting solution chemistry of electrolyte. Ionizable pentachlorophenol (PCP) and non-ionizable phenanthrene (PHE) were selected as representative OCs. The sorption capacities of PCP and PHE were pH-dependent, and a larger amount of PCP was sorbed at pH values below its pKa(4.75). However, the PHE sorption capacity was higher at relatively high or low pHs (e.g. below 4.0 and above 10.0), possibly due to the larger available surface area of the hematite NPs, caused by the higher values of net charges and charge density. Changes in pH might thus affect the sorption of OCs by hematite NPs, through modification of the surface characteristics of the sorbent and the electronic properties of the sorbate molecules. The influence of different ionic strengths indicated that the amounts of PCP and PHE sorbed by hematite NPs decreased as a concentration function of different types of ions (e.g. Na+, K+, Mg2 +and Ca2 +), with the underlying mechanism possibly being due to four interactions i.e. hydrogen-bonding, competitive sorption by ions in the ambient solution, screening effects and aggregation effects. The results confirmed that the surface chemistry of hematite NPs, the chemical properties of PCP and PHE, and solution chemistry (e.g. pH and ionic strength) of the electrolyte all played an important role in PCP and PHE sorption by hematite NPs. By comparison of both sorption capacity and ecologic advantages, our results suggested that natural hematite NPs would be more competitive and efficient for PCP and PHE sorption than engineered NPs. This finding increases our knowledge regarding the environmental function of natural NPs (such as hematite NPs) for OC remediation through manipulating their interfacial behavior.