苯胂酸化合物在金属氧化物和氢氧化物及粘土矿物上的吸附和解吸。
Adsorption and desorption of phenylarsonic acid compounds on metal oxide and hydroxide, and clay minerals.
机构信息
MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China; College of Resources and Environment, Hunan Agricultural University, Changsha 410128, China.
MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.
出版信息
Sci Total Environ. 2021 Feb 25;757:143765. doi: 10.1016/j.scitotenv.2020.143765. Epub 2020 Nov 16.
Adsorption and desorption of p-arsanilic acid (p-ASA) and roxarsone (ROX) on six soil minerals, including hematite (α-FeO), goethite (α-FeOOH), ferrihydrite (Fe(OH)), aluminum oxide (α-AlO), manganese oxide (γ-MnO), and kaolinite, were studied, and the impact of solution matrices on their adsorption was systematically evaluated. Adsorption of p-ASA/ROX on the metal (hydro)oxide and clay minerals occurred quickly (mostly within 2 h), and could be well described by the pseudo second-order kinetic model. The apparent maximum adsorption capacities of α-FeO, α-FeOOH, Fe(OH), α-AlO, γ-MnO, and kaolinite (at an initial pH of 7.0) for p-ASA were 1.7, 0.9, 2.5, 0.08, 1.1, and 0.02 μmol/m, while those for ROX were 1.6, 0.7, 2.4, 0.1, 0.5, and 0.05 μmol/m, respectively. Besides adsorbing p-ASA/ROX, γ-MnO also caused their oxidation. Experimental results suggest that formation of inner-sphere complexes through the arsonic acid group is the primary mechanism for adsorption of p-ASA/ROX on iron (hydro)oxides and γ-MnO, while outer-sphere complexation plays a critical role in their adsorption on α-AlO and kaolinite. Adsorption of p-ASA/ROX on the metal (hydro)oxide and clay minerals was affected by solution pH, co-existing metal ions (Ca, Mg, Al, Cu, Fe, and Zn), oxyanions (HPO, HCO, and SO), and humic acid. The solid-to-liquid partition coefficients of p-ASA during the desorption from α-FeO, α-FeOOH, Fe(OH), α-AlO, γ-MnO, and kaolinite were 0.47, 2.69, 4.38, 0.03, 30.4, and 0.1 L/g, while those of ROX were 0.28, 1.68, 3.48, 0.02, 4.0, and 0.02 L/g, respectively. Agricultural soils with lower contents of organic carbon exhibited higher adsorption capacities towards p-ASA/ROX, which indicates that soil minerals play a key role in the adsorption of phenylarsonic acid compounds while organic matter could have strong inhibitory effect. These findings could help better understand and predict the transport and fate of p-ASA/ROX in surface soils with low contents of organic matter.
研究了 6 种土壤矿物质（包括赤铁矿（α-FeO）、针铁矿（α-FeOOH）、水铁矿（Fe(OH)）、氧化铝（α-AlO）、氧化锰（γ-MnO）和高岭石）对对氨基苯砷酸（p-ASA）和洛克沙胂（ROX）的吸附和解吸作用，并系统评估了溶液基质对其吸附的影响。p-ASA/ROX 在金属（氢）氧化物和粘土矿物上的吸附速度很快（大多在 2 小时内），可用伪二级动力学模型很好地描述。在初始 pH 值为 7.0 时，α-FeO、α-FeOOH、Fe(OH)、α-AlO、γ-MnO 和高岭石对 p-ASA 的表观最大吸附容量分别为 1.7、0.9、2.5、0.08、1.1 和 0.02 μmol/m，而对 ROX 的吸附容量分别为 1.6、0.7、2.4、0.1、0.5 和 0.05 μmol/m。除了吸附 p-ASA/ROX 外，γ-MnO 还导致了它们的氧化。实验结果表明，通过胂酸基团形成内圈络合物是 p-ASA/ROX 吸附在铁（氢）氧化物和 γ-MnO 上的主要机制，而在外圈络合作用在其吸附在α-AlO 和高岭石上起着关键作用。p-ASA/ROX 在金属（氢）氧化物和粘土矿物上的吸附受溶液 pH 值、共存金属离子（Ca、Mg、Al、Cu、Fe 和 Zn）、含氧阴离子（HPO、HCO 和 SO）和腐殖酸的影响。从α-FeO、α-FeOOH、Fe(OH)、α-AlO、γ-MnO 和高岭石解吸 p-ASA 的固液分配系数分别为 0.47、2.69、4.38、0.03、30.4 和 0.1 L/g，而 ROX 的固液分配系数分别为 0.28、1.68、3.48、0.02、4.0 和 0.02 L/g。有机碳含量较低的农业土壤对 p-ASA/ROX 的吸附能力较高，这表明土壤矿物质在苯胂酸化合物的吸附中起着关键作用，而有机质可能具有很强的抑制作用。这些发现有助于更好地理解和预测低有机质含量地表土壤中 p-ASA/ROX 的迁移和归宿。
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