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羊毛固化单宁的制备及其对水溶液中六价铬的吸附

Preparation of Tannin Immobilized Goat Hair and its Adsorption of Hexavalent Chromium from Aqueous Solution

  • 摘要: 将荆树皮单宁固载于羊毛纤维上,得到一种羊毛固化单宁吸附材料,并用于水溶液中六价铬(Cr6+)的吸附。结果表明,该材料对Cr6+的吸附属于氧化还原吸附,Cr6+先被还原为Cr3+,然后被吸附。当温度为313 K、pH为2.0、Cr6+初始质量浓度为300 mg/L时,该材料对Cr6+的平衡吸附量为117.3 mg/g;温度升高,吸附量增加。pH对吸附容量影响明显,pH为2.0时,该材料对Cr6+的吸附能力最强,原因在于该条件下有利于氧化还原反应。该材料对Cr6+的吸附平衡符合Freundlich方程,吸附动力学可用拟二级速率方程描述。模拟电镀废水的吸附实验结果表明,采用该吸附剂,通过调节pH可实现水溶液中Cr6+的有效脱除。

     

    Abstract: Mimosa tannins were immobilized on goat hair to prepare a sorbent for the adsorption of hexavalent chromium (Cr6+) in aqueous solution. The results indicate that the redox reaction occurs during the adsorption process. Cr6+ is firstly reduced to Cr3+ and then adsorbed on the sorbent. The adsorption capacity is 117.3 mg/g at pH 2.0 and 313 K with the initial Cr6+ concentration of 300 mg/L. Increasing temperature can promote the adsorption capacity. The solution pH can affect the adsorption capacity significantly because the redox reaction is dependent on pH value, and the optimal pH for the adsorption is 2.0. The adsorption isotherms of the sorbent to Cr6+ can be well described by the Freundlich model, and the adsorption kinetic data of Cr6+ fit the pseudo-second-order model. The results of adsorption experiments for the simulated electroplating wastewater indicate that Cr6+ can be effectively removed using the sorbent when adjusting pH of the solution.

     

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