螯合树脂/SBA-15复合材料的制备及其对重金属的吸附研究

Preparation of Chelating Resin/SBA-15 Composite Materials for Adsorption of Heavy Metals

以三聚氰胺、甲醛、硫脲、正硅酸乙酯(TEOS)为前驱体,P123(EO_(20)PO_(70)EO_(20))为模板剂,通过共缩聚法合成了螯合树脂/SBA-15介孔氧化硅复合材料.着重考察树脂低聚物预聚合程度和TEOS预水解缩聚时间这两个合成参数对材料合成的影响.采用FT-IR和N2吸附-脱附对复合材料进行了表征,发现改变这两个合成参数会对材料的织构性能产生一定影响.通过对Cr(Ⅵ)的预吸附实验,挑选出了吸附性能最优的复合材料,并运用此种材料考察了其对水溶液中As(V)的吸附行为.发现复合材料对As(V)的吸附与准二级动力学模型和Langmuir等温吸附模型相符.用Arrhenius公式拟合得出吸附活化能Ea=12.13 k J/mol,说明该吸附反应较易发生.

A series of chelating resin/SBA-15 composite materials were synthesized via a co-condensation method by using melamine, formaldehyde, thiourea, and tetraethyl orthosilicate （ TEOS） as starting materials, and P123 （ EO20-PO70-EO20 ） as the template. Effects of pre-polymerization time of the chelating resin precursors and pre-hydrolysis time of TEOS on the resultant composite materials were systematically investigated. The composite materials were characterized by FT-IR and N2 adsorption-desorption techniques. It was found that the change of the above two synthesis parameters could affect textural properties of the composite materials. Based on the preliminary results for the adsorption of aqueous Cr （Ⅵ） species, the optimum composite material was selected to investigate the corresponding adsorption behavior for aqueous As（ V） species. The adsorption kinetics/thermodynamics results indicated that the composite materials follow pseudo-second-order model and Langmuir adsorption model. An Arrhe-nius formula fitting showed that the adsorption activation energy （Ea） equals 12. 13 kJ/mol, implying that the ad-sorption process can occur easily.