Hughes D L, Afsar A, Harwood L M, Jiang T, Laventine D M, Shaw L J, Hodson M E
Soil Research Centre, Department of Geography and Environmental Science, University of Reading, RG6 6DW, UK.
Department of Chemistry, University of Reading, RG6 6AD, UK.
Chemosphere. 2017 Sep;183:519-527. doi: 10.1016/j.chemosphere.2017.05.146. Epub 2017 May 26.
The ability of diethylenetriaminepentaacetic acid (DTPA)-functionalised, silica-coated magnetic nanoparticles to adsorb Pb and Zn from single and bi-metallic metal solutions and from solutions containing dissolved organic carbon was assessed. In all experiments 10 mL solutions containing 10 mg of nanoparticles were used. For single metal solutions (10 mg L Pb or Zn) at pH 2 to 8, extraction efficiencies were typically >70%. In bi-metallic experiments, examining the effect of a background of either Zn or Pb (0.025 mmol L) on the adsorption of variable concentrations (0-0.045 mmol L) of the other metal (Pb or Zn, respectively) adsorption was well modelled by linear isotherms (R > 0.60; p ≤ 0.001) and Pb was preferentially adsorbed relative to Zn. In dissolved organic carbon experiments, the presence of fulvic acid (0, 2.1 and 21 mg DOC L) reduced Pb and Zn adsorption from 0.01, 0.1 and 1.0 mmol L solutions. However, even at 21 mg DOC L fulvic acid, extraction efficiencies from 0.01 to 0.1 mmol L solutions remained >80% (Pb) and >50% (Zn). Decreases in extraction efficiency were significant between initial metal concentrations of 0.1 and 1.0 mmol L indicating that at metal loadings between c. 100 mg kg and 300 mg kg occupancy of adsorption sites began to limit further adsorption. The nanoparticles have the potential to perform effectively as metal adsorbents in systems containing more than one metal and dissolved organic carbon at a range of pH values.
评估了二乙烯三胺五乙酸（DTPA）功能化的二氧化硅包覆磁性纳米颗粒从单金属和双金属溶液以及含有溶解有机碳的溶液中吸附铅和锌的能力。在所有实验中，均使用了含有10 mg纳米颗粒的10 mL溶液。对于pH值为2至8的单金属溶液（10 mg L铅或锌），萃取效率通常>70%。在双金属实验中，研究了锌或铅（0.025 mmol L）背景对另一种金属（分别为铅或锌）可变浓度（0 - 0.045 mmol L）吸附的影响，吸附情况通过线性等温线得到了很好的模拟（R > 0.60；p ≤ 0.001），并且相对于锌，铅优先被吸附。在溶解有机碳实验中，富里酸（0、2.1和21 mg DOC L）的存在降低了0.01、0.1和1.0 mmol L溶液中铅和锌的吸附。然而，即使在21 mg DOC L富里酸的情况下，0.01至0.1 mmol L溶液的萃取效率仍保持>80%（铅）和>50%（锌）。在初始金属浓度为0.1和1.0 mmol L之间，萃取效率的降低是显著的，这表明在金属负载量约为100 mg kg至300 mg kg时，吸附位点的占据开始限制进一步的吸附。这些纳米颗粒有潜力在一系列pH值下，在含有多种金属和溶解有机碳的系统中有效地作为金属吸附剂发挥作用。
