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合成了四乙烯五胺功能化纳米高分子材料(TEPA-NP),采用傅里叶变换红外光谱分析(FTIR)、有机元素分析(EA)、X射线光电子能谱分析(XPS)等手段对其进行了表征,重点考察了其对水中Cr(VI)与磷酸根离子共存时的吸附机理.结果表明,溶液p H对TEPA-NP的吸附性能影响较大.对于Cr(VI)或磷酸盐单一体系,p H 2.5时TEPA-NP的吸附效果最佳;吸附热力学均符合Langmuir模型,吸附动力学均符合准二级速率方程.TEPA-NP对Cr(VI)的饱和吸附量为123.5 mg/g;吸附过程为吸热熵增的自发过程,ΔH为16.06 k J/mol,ΔS为59.02 J/(mol K),308 K时ΔG为-2.10 k J/mol;吸附活化能为30.28 k J/mol.TEPA-NP对磷酸盐的饱和吸附量为149.2 mg/g;吸附过程为放热熵增的自发过程,ΔH为-1.74 k J/mol,ΔS为1.91J/(mol K),308 K时ΔG为-2.32 k J/mol;吸附活化能为18.85 k J/mol.当磷酸盐的共存浓度小于100 mg/L时,磷酸盐对TEPA-NP吸附Cr(VI)几乎没有影响;而当Cr(VI)的共存浓度大于5 mg/L时,Cr(VI)对TEPA-NP吸附磷酸盐的影响已较为明显,可使TEPA-NP吸附磷酸盐的饱和吸附量减小17.3%;结合红外和XPS表征可以推测TEPA-NP对Cr(VI)的吸附涉及静电与配位相互作用,而对磷酸盐以静电吸附为主;Cr(VI)与磷酸盐共存时,TEPA-NP优先吸附Cr(VI).Cr(VI)可以通过竞争取代吸附在TEPA-NP上的磷酸根,且随着Cr(VI)初始浓度增大,TEPA-NP上吸附的总磷脱附的比例增大;而磷酸根对Cr(VI)的竞争吸附较难实现.
The tetraethylenepentamine functionalized nano-polymer (TEPA-NP) was synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), organic elemental analysis (EA) and X-ray photoelectron spectroscopy (XPS) The adsorption mechanism of Cr (VI) and phosphate ions in water was investigated emphatically. The results showed that the adsorption of pEP on TEPA-NP had a great effect on the adsorption of Cr (VI) or phosphate The adsorption kinetics of TEPA-NP was the best at p H 2.5. The adsorption thermodynamics accorded with Langmuir model and the adsorption kinetics were in accordance with quasi-second rate equation. The saturated adsorption capacity of TEPA-NP to Cr (VI) was 123.5 mg / g ; ΔH was 16.06 kJ / mol, ΔS was 59.02 J / mol K, and ΔG was -2.10 kJ / mol at 308 K. The adsorption activation energy was 30.28 kJ / The saturated adsorption capacity of phosphate to phosphate was 149.2 mg / g. The adsorption process was a spontaneous process of exothermic entropy increase, ΔH was -1.74 kJ / mol, ΔS was 1.91J / mol K, 308 K When ΔP was -2.32 kJ / mol, the adsorption activation energy was 18.85 kJ / mol. Phosphate had little effect on the adsorption of Cr (VI) to TEPA-NP when the coexistence of phosphate was less than 100 mg / L. A total of Cr (VI) The effect of Cr (VI) on the adsorption of phosphate on TEPA-NP was obvious when the concentration was more than 5 mg / L, which could decrease the saturated adsorption capacity of TEPA-NP on phosphate by 17.3%. Combining infrared and XPS characterization, -NP adsorption on Cr (VI) involves the interaction of electrostatic and coordination, while the adsorption of phosphate is mainly electrostatic; TEPA-NP preferentially adsorbs Cr (VI) when Cr (VI) and phosphate coexist. ) Could replace the phosphate adsorbed on TEPA-NP by competition, and the proportion of total phosphorus adsorbed on TEPA-NP increased with the initial concentration of Cr (VI) The competitive adsorption is more difficult to achieve.