側鏈含羥基與雙胺基之螯合樹脂吸附水中Cu2+ 的研究

Adsorptions of Cu2+ by a Chelating Resin Containing Hydroxyl and Diamino Groups

本研究先以懸浮聚合法製備具孔洞的交聯聚縮水甘油丙烯酸甲酯(cPGMA)後，再以N,N-二甲基乙二胺和cPGMA反應而得到簡稱為PGD2N的螯合樹脂。經顯微鏡觀察得知PGD2N的粒徑大約在150～250 μm之間。當PGD2N吸附水中的Cu2+ 時，約60分鐘達到0.911 mmol/(g PGD2N)的最大吸附容量。而隨著Cu2+ 濃度的增加，PGD2N的吸附容量亦上升並在Cu2+ 濃度超過12 mM時達最大值。當Cu2+ 溶液的pH值大於4時，PGD2N對Cu2+ 的吸附容量保持在最高值；而pH值從4降到3時，吸附容量僅出現極些微的減少現象；但pH＜3.0時，PGD2N的吸附能力卻急劇下降並在 pH 1時失去吸附Cu2+ 的能力。以0.3 M的HNO3溶液進行5次連續脫附／再吸附實驗，確定PGD2N對Cu2+ 的吸附容量仍可維持在最初值的92%以上，證實PGD2N吸附Cu2+ 時，具有良好的重複使用特性。

Crosslinked poly(glycidyl methacrylate) (cPGMA) was synthesized via a suspension polymerization of Glycidyl methacrylate with Polyethylene glycol diacrylate. It was then reacted with N,N-Dimethylethylenediamine to form a chelating resin (PGD2N) for adsorbing Cu(II) from aqueous solutions. The size of PGD2N observed by optical microscope was found to be 150-250 μm in diameter. The adsorption of Cu2+ tended toward equilibrium at 60 min and the equilibrium adsorption capacity was 0.911 mmole/(g PGD2N). The adsorption isotherms of Cu2+ by PGD2N followed the Langmuir isotherm. When the pH of Cu2+ solutions were 4-5, the adsorption capacities retained the maximum value. As the pH of the solutions decreased from 4 to 3, the adsorption capacity decreased slightly. However, the adsorption capacity decreased dramatically from pH 3 to 2. In addition, PGD2N could not adsorb Cu2+ at pH 1. After 5 cycles of desorption-adsorption operations, the re-adsorption capacities of Cu2+ could attain 92% of initial values. This confirms that PGD2N is a good reusable adsorbent for the adsorptions of Cu2+ from aqueous solution.