檸檬酸及蘋果酸改質鎂鋁層狀複合金屬吸附重金屬之研究

A study on adsorption of heavy metal by Mg-Al LDHs intercalated with citrate and malate

楊凱閎(Kai-Hong Yang)

指導教授 ： 趙煥平

中原大學/工學院/生物環境工程研究所/碩士(2015年)

https://doi.org/10.6840/CYCU.2015.00490

摘要

本研究是使用水熱法合成層狀複合金屬Mg-Al LDHs，再利用有機酸陰離子(檸檬酸及蘋果酸)進行插層，並以合成之吸附劑吸附溶液中之重金屬(銅離子及鉛離子)。其中Mg-Al LDHs，Citrate Mg-Al LDH及Malate Mg-Al LDH則是使用共沉澱法合成。製備完成之吸附劑利用SEM、FTIR、Zeta Potential及XRD來鑑定其性質，再利用吸附平衡與動態吸附計算對選擇的重金屬離子之吸附容量與探討可能的吸附機制。
研究結果發現Mg-Al LDHs、Citrate Mg-Al LDH及Malate Mg-Al LDH可以迅速的從溶液中吸附銅離子及鉛離子。對於Mg-Al LDHs來說，其表面氫氧官能基會和溶液中銅離子形成不溶於水的金屬氫氧化物；鉛離子則除了金屬氫氧化物外，尚可與碳酸根離子形成碳酸鹽沉澱。Citrate Mg-Al LDH及Malate Mg-Al LDH插層中有機酸鹽類可與銅離子或鉛離子產生螯合作用去除這些金屬。對於溶液中銅離子和鉛離子之吸附量大小：Mg-Al LDHs

關鍵字

鎂鋁層狀複合金屬；檸檬酸；蘋果酸；吸附；重金屬離子

並列摘要

Mg-Al LDHs intercalated with the organic acid anions (citrate and malate) and adsorbed the heavy metal ions (copper and lead) from aqueous solution have been studied. Mg-Al LDHs was prepared by hydrothermal method and then citrate and malate were intercalated through a coprecipitation technique to form the citrate Mg-Al LDH and malate Mg-Al LDH. All of adsorbents were characterized by SEM, FTIR, zeta potential and XRD. The maximum adsorption capacities of adsorbents under the given conditions were estimated from Langmuir equation. Moreover, the dynamic data were fitted the pseudo-second order kinetic model well. The adsorption mechanisms of test adsorbents toward copper and lead ions were examined.
The results indicated the produced adsorbents could adsorb Cu2+ and Pb2+ rapidly from an aqueous solution. For Mg–Al LDHs, the adsorption capacities mainly result from the surface precipitation. For citrate Mg-Al LDH and malate Mg-Al LDH, the adsorption capacities were mainly attributable to the formation of the citrate–metal and malate–metal complexes in the interlayers of the Mg–Al LDHs. The uptake of Cu2+ and Pb2+ increased in the order Mg–Al LDH

並列關鍵字

Mg-Al layered double hydroxide ； Citrate ； Malate ； Adsorption ； Heavy metal ions

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