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选用石英砂填充柱模拟土壤体系,通过测量纳米羟基磷灰石(Nano-HAP)ζ电位、出流比等来考察不同环境因素(腐殖酸浓度、pH和离子强度)对其在饱和石英砂柱中迁移规律的影响.结果表明,随着腐殖酸浓度的增加,Nano-HAP胶体的ζ电位相应增加(绝对值增加),吸附效率(α)相应降低,当溶液中腐殖酸浓度由0增加为10 mg/L时,Nano-HAP胶体的ζ电位由-15mV增加至-55 mV,吸附效率由1.0减小为0.012,迁移能力增加;此外,随着本体溶液pH增加,Nano-HAP胶体的ζ电位亦随之增加,吸附效率相应降低,因此有利于其在饱和体系中的迁移.然而,随着本体溶液离子强度增加,Nano-HAP胶体的双电层被压缩,ζ电位逐渐减小,吸附效率相应增加,且二价阳离子对Nano-HAP迁移能力的影响要远大于单价阳离子的影响.当本体溶液离子强度(支持电解质为单价阳离子Na+)由1 mmol/L增加至100 mmol/L时,吸附效率由0.030增加至0.13,而当本体溶液离子强度(支持电解质为二价阳离子Ca2+)由0.2 mmol/L增加至10 mmol/L时,吸附效率由0.030增加至1.0,更多的Nano-HAP胶体被滞留在多孔介质中,阻碍其迁移.该研究结果将有助于从机制上深入地了解纳米羟基磷灰石在土壤-地下水环境中的迁移行为及其归趋.
Quartz sand packed columns were used to simulate the soil system. The effects of different environmental factors (humic acid concentration, pH and ionic strength) on the saturated quartz sand were investigated by measuring the zeta potential and outflow ratio of nano-hydroxyapatite (Nano-HAP) The results showed that with the increase of humic acid concentration, the zeta potential of Nano-HAP colloid increased correspondingly (absolute value increased) and the adsorption efficiency (α) decreased correspondingly. When the concentration of humic acid in solution 0 increased to 10 mg / L, the zeta potential of Nano-HAP colloid increased from -15 mV to -55 mV, the adsorption efficiency decreased from 1.0 to 0.012, and the migration ability increased. In addition, with the increase of bulk solution pH, Nano-HAP The zeta potential of the colloid also increases and the adsorption efficiency decreases correspondingly, which is in favor of its migration in a saturated system. However, as the ionic strength of the bulk solution increases, the electrical double layer of the Nano-HAP colloid is compressed and the zeta potential decreases And the adsorption efficiency increased correspondingly, and the effect of divalent cation on the migration ability of Nano-HAP was far greater than that of monovalent cation.When the ionic strength of support solution (monovalent cation Na +) increased from 1 mmol / L to 100 mmol / L, the adsorption efficiency increased from 0.030 to 0.13 When the ionic strength of the bulk solution (supporting electrolyte is divalent cation Ca2 +) increased from 0.2 mmol / L to 10 mmol / L, the adsorption efficiency increased from 0.030 to 1.0. More Nano-HAP colloids were retained in the porous media, hindering The results of this study will help to understand in depth the mechanism of migration of nano-hydroxyapatite in soil-groundwater environment and its trend.