• 关键词：凤眼莲  金属离子  吸附  机理

• 基金项目：福建省环境保护厅资助项目(No.FJHK200912)

• 韩永和
• 福建师范大学生命科学学院,福州 350108

• 章文贤
• 福建师范大学生命科学学院,福州 350108

• 周志华
• 福建师范大学生命科学学院,福州 350108

• 李敏
• 福建师范大学生命科学学院,福州 350108

• 摘要：利用凤眼莲根、茎、叶粉末吸附水溶液中的Fe²⁺、Mn²⁺,并通过一系列的条件优化,确定了最佳的吸附条件.同时,采用等温吸附模型与动力学模型拟合研究了吸附特性. 结果表明,凤眼莲根、茎、叶对Fe²⁺的吸附能力依次为根>叶>茎,对Mn²⁺的吸附能力依次为茎>叶>根;在Fe²⁺、Mn²⁺起始浓度分别为45 mg·L^-1和75 mg·L^-1,pH分别为4.0和5.0,吸附剂添加量为0.4 g,摇床转速为180 r·min^-1,温度为50 ℃的条件下,根对Fe²⁺的最大吸附量为(21.73±0.38) mg·g^-1,茎对Mn²⁺的最大吸附量为(15.55±0.58) mg·g^-1,去除率分别达到96.58%和82.93%. Langmuir模型和准二级动力学模型能够较好地拟合Fe²⁺、Mn²⁺的吸附过程,吸附活化能与傅立叶红外光谱等表明该过程为物理化学吸附.与现有的Fe²⁺、Mn²⁺吸附生物质相比,凤眼莲粉末吸附水溶液中Fe²⁺、Mn²⁺的能力较突出,是一种极具潜力的吸附材料.

• Abstract：In this paper, dry powders of root, stem and leaf of Eichhornia crassipes were used to adsorb divalent iron and manganese ions from aqueous solution. With batch experiments, the optimum adsorbing conditions were determined. Also, the adsorption characteristics were studied by Isothermal Adsorption Model (IAM) and Kinetic Model (KM). According to the results, the dry powders of root and stem were the best for removing Fe²⁺ and Mn²⁺, respectively. The maximum adsorption capacity of Fe²⁺ and Mn²⁺ was observed at initial concentration of Fe²⁺ as 45 mg·L^-1 and Mn²⁺ as 75 mg·L^-1, respectively. The optimum pH was 4.0 for Fe²⁺ and 5.0 for Mn²⁺. Besides, an enhanced metal adsorption on 0.4 g of biomass with an agitation time of 120 min for Fe²⁺ and 60 min for Mn²⁺ was recorded. The optimum rotate speed for removing Fe²⁺ and Mn²⁺ was both confirmed at 180 r·min^-1. It was also observed that the adsorptions of two metal ions correlated with temperature. Maximum adsorption of Fe²⁺[(21.73±0.38) mg·g^-1] and Mn²⁺ [(15.55±0.58) mg·g^-1] were obtained under the above optimum conditions, with the removal rate of 96.58% for Fe²⁺ and 82.93% for Mn²⁺. The adsorption process fit well with Langmuir model and pseudo-second order kinetic model, and activation energy of adsorption and FT-IR experiments confirmed that the adsorption of Fe²⁺ by root and Mn²⁺ by stem were a physiochemical process. Compared with the existing biomass for removing Fe²⁺ and Mn²⁺, the powder of E. crassipes is a good adsorption material to remove heavy metals from aqueous solution.

• Key words：Eichhornia crassipes  metal ion  adsorption  mechanism

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