Abstract:

A composite of cross-linked starch supported magnesium hydroxide ISt-Mg（OH）₂ was synthesized with cross-linked starch and MgSO₄·7H₂O as raw material and NaOH as alkalizing agent. It was characterized by FTIR，SEM，EDS and XRD，and used for the adsorption removal of Cu²⁺ in simulated wastewater. The effects of factors such as dosage，pH，initial concentration of Cu²⁺ on the adsorption properties of ISt-Mg（OH）₂ were investigated. The results showed that when the mass concentration of Cu²⁺ was 20 mg/L，pH=5.45，the dosage of ISt-Mg（OH）₂ was 300 mg/L，and the adsorption temperature was 25 ℃，the removal rate of Cu²⁺ could reach 91.7%. The fitting results of adsorption isotherm showed that the adsorption process of Cu²⁺ in water by ISt-Mg（OH）₂ conformed to the Langmuir adsorption model and belonged to monolayer adsorption. At 25 ℃，the fitting saturated adsorption capacity was 82.78 mg/g. The fitting results of adsorption kinetic datas showed that the adsorption process conformed to the quasi second order kinetic model and belonged to chemical adsorption. When ISt-Mg（OH）₂ was applied to treat the electroplating wastewater with Cu²⁺ mass concentration of 15.20 mg/L and pH=5.45，the removal rate of Cu²⁺ could reach more than 90%，and it was a promising adsorbent for heavy metal ions.

Key words: cross-linked starch, magnesium hydroxide, heavy mental ions, adsorption, adsorption mechanism

摘要：

以交联淀粉和MgSO₄·7H₂O为原料，NaOH为碱化剂，制备了交联淀粉负载氢氧化镁复合材料ISt-Mg（OH）₂，采用FTIR、SEM、EDS、XRD对其进行了表征，并将其用于对模拟废水中Cu²⁺的吸附去除，考察了ISt-Mg（OH）₂投加量、pH、Cu²⁺初始浓度等因素对ISt-Mg（OH）₂吸附Cu²⁺性能的影响。结果表明，当Cu²⁺质量浓度为20 mg/L，pH=5.32，ISt-Mg（OH）₂投加量为300 mg/L，吸附温度为25 ^oC时，Cu²⁺的去除率可达91.7%。吸附等温线拟合结果表明，ISt-Mg（OH）₂对水中Cu²⁺的吸附过程符合Langumir吸附模型，为单分子层吸附过程，在25 ^oC时，拟合饱和吸附量为82.78 mg/g。吸附动力学数据拟合结果表明，吸附过程符合准二级动力学模型，属于化学吸附。将ISt-Mg（OH）₂应用于处理Cu²⁺质量浓度15.20 mg/L、pH=5.45的电镀废水时，在其投加量为100 mg/L时，Cu²⁺去除率可达90%以上，具有良好的应用前景。

关键词: 交联淀粉, 氢氧化镁, 重金属离子, 吸附, 吸附机理

CLC Number: 

• X52

• TQ424