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以无机材料硅胶为基体,利用有机硅烷偶联剂KH550、乙二醛和戊二醛为原料进行希夫碱反应,分别合成含有C=N的硅胶键合醛基型吸附材料(乙二醛修饰的为SG-1、戊二醛修饰的为SG-2),并采用红外光谱、热重、扫描电子显微镜和孔结构等分析手段对吸附材料进行了表征。结果表明:(1)从微观上看,硅胶表面较光滑;SG-1、SG-2表面的粗糙度、孔隙率都较硅胶明显增加,有利于吸附实验的进行。(2)拟二级动力学方程更适合描述SG-1、SG-2对重金属离子的吸附行为,吸附过程由化学吸附过程决定。SG-1、SG-2对4种重金属离子的吸附热力学过程适合用Langmuir等温吸附方程解释,其过程是单分子层吸附。(3)SG-1、SG-2对4种重金属离子的静态饱和吸附量均表现为Cu(Ⅱ)>Ni(Ⅱ)>Pb(Ⅱ)>Cr(Ⅵ)。SG-1、SG-2对Cu(Ⅱ)静态饱和吸附量分别达到9.401、9.738mg/g。(4)SG-1、SG-2对4种重金属离子解吸率与解吸液(5%(质量分数)硫脲+0.1mol/L盐酸)体积并不呈现正相关,解吸率基本可达到90%,再生性能良好,当解吸液体积为6mL时解吸率最大。
Using inorganic material silica gel as matrix, the organic silane coupling agent KH550, glyoxal and glutaraldehyde were used as raw materials to make Schiff base reaction to synthesize silica-bonded aldehyde adsorption materials with C = N (glyoxal modification Of SG-1 and glutaraldehyde modified SG-2) were synthesized and characterized by IR, TG, SEM and pore structure analysis. The results show that: (1) Microscopically, the surface of silica gel is smooth; the surface roughness and porosity of SG-1 and SG-2 are obviously increased compared with that of silica gel, which is favorable for the adsorption experiment. (2) The pseudo-second-order kinetic equation is more suitable for describing the adsorption behavior of heavy metal ions by SG-1 and SG-2. The adsorption process is determined by the chemisorption process. The adsorption thermodynamic processes of SG-1 and SG-2 for four kinds of heavy metal ions are suitable to be explained by the Langmuir isothermal adsorption equation. The process is monolayer adsorption. (3) The static adsorption capacities of SG-1 and SG-2 on four kinds of heavy metal ions all show Cu (Ⅱ)> Ni (Ⅱ)> Pb (Ⅱ)> Cr (Ⅵ). The static adsorption capacities of Cu (Ⅱ) on SG-1 and SG-2 reached 9.401 and 9.78 mg / g, respectively. (4) There was no positive correlation between the desorption rate of desorption solution (5% thiosemicarbazone + 0.1 mol / L hydrochloric acid) and the desorption rate of SG-1 and SG-2 to 90% , Regeneration performance is good, when desorption volume of 6mL, the maximum desorption rate.