化学淋洗法是常用的污染场地修复方法, 其经济性、 简便性、 安全性等指标较其他方法有较大优势。 化学淋洗法存在的弊端之一是淋洗过程土壤伴存养分的同步淋失, 若能在此瓶颈问题上有所突破, 将会大大促进淋洗法场地修复的应用进程。 本文研究的目标在于揭示合成秸秆基阴离子吸附剂对养分淋失的减缓机制, 采用吸附平衡模式(等温线和动力学)与光谱分析技术(SEM和FT-IR)相结合, 力图从微观层面验证宏观研究结果。 Langmuir和准二级动力学方程能更好地描述硝酸根和磷酸根的吸附行为, 由Langmuir方程计算得出qm分别为7.507　5和4.194　6 mg·g-1, 吸附反应为单层吸附和优惠吸附过程, 主要控速步骤为化学吸附。 阴离子吸附剂对硝酸根和磷酸根的吸附活化能(298 K)Ea分别为42.25和39.38 kJ·mol-1, 吸附反应自发、 吸热。 纯净水和KOH能够实现阴离子吸附剂的再生, 超声辅助和延长解吸时间对于解吸效果略有促进作用。 吸附后阴离子吸附剂表面被点状分布的细微颗粒物覆盖, 解吸后仅有少量枝状物零星分布。 吸附前后FTIR图谱的主要波峰红移或蓝移, 证实阴离子吸附剂表面及内部官能团通过静电作用与硝酸根和磷酸根结合。 阴离子吸附剂对硝酸根和磷酸根的吸持固定是物理吸附和化学吸附共同作用的结果。

The soil washing technology is commonly used to remediate contaminated soils because of its advantages of low cost, ease handling and environmental-friendly. However, it should be noticed that the nutrient might leach simultaneously from soil in the washing process, and the technical solution of the issue will greatly accelerate the application process of washing technology in site remediation. This paper aims to reveal the regulating mechanism of synthesized anion adsorbent from straw on nutrient leaching potential through approaches of adsorption equilibrium models (isotherms and kinetics) and spectral analysis instruments (SEM and FTIR). The results showed: the Langmuir isotherm and pseudo second order kinetic equation fit better the adsorption behavior of nitrate and phosphate. The maximum adsorption capacity (qm), calculated with Langmuir isotherm, are 7.507 5 and 4.194 6 mg·g-1, respectively, and the reaction belongs to the monolayer and favorable adsorption with chemical adsorption the rate-determining step. The activation energy of adsorption for nitrate and phosphate at 298 K are 42.25 and 39.38 kJ·mol-1, respectively, and the reaction is spontaneous and endothermic. The purified water and KOH solution are effective for the regeneration of anion adsorbent, the desorption effect is better for the assistance of ultrasonic sound and longer desorption time. The surface of anion adsorbent after adsorption is covered with particles, while less spray-like component appears after desorption with purified water. The movement of vibration peaks in FTIR spectra indicates the effect of electrostatic interaction in the reaction. The adsorption of nitrate and phosphate on anion adsorbent involves simultaneously the effects of physical and chemical adsorption.