富G海藻酸钠聚氨酯泡沫对亚甲基蓝的吸附

Adsorption of methylene blue by polyurethane foam based on G-rich sodium alginate

利用低分子量富G海藻酸片段(LG-HA)与六亚甲基二异氰酸酯(HDI)之间的交联作用,制备了富G海藻酸钠聚氨酯泡沫(PF-SA)。采用红外光谱和扫描电子显微镜对PF-SA结构进行了表征,并系统研究了其对水相中亚甲基蓝(MB)的吸附性能。结果表明,PF-SA具有三维网络结构,吸附时间、溶液的p H值、吸附温度、MB溶液的初始浓度等因素都会对吸附效果造成影响。在优化条件下,PF-SA对MB初始浓度低于2 000 mg/L的溶液,去除率可达99%以上。对于更高浓度的MB溶液,吸附量可达到1 000 mg/g。准二级吸附动力学模型更能真实地反映吸附过程。吸附热力学函数的计算结果表明,吸附是一个自发的吸热过程。

Polyurethane foams based on G-rich sodium alginate（ PF-SA） were prepared by cross-linking low-molecular-weight G-rich alginic acid（ LG-HA） with hexamethylene diisocyanate（ HDI）. The obtained PFSA was characterized by scanning electron microscopy（ SEM） and Fourier transform infrared（ FTIR） spectroscopy,and its adsorption efficiency for Methylene Blue（ MB） in aqueous solution was investigated systematically.PF-SA showed a three-dimensional network structure. The contact time,the adsorbent dosage,the p H of MB solution,the temperature,and the initial concentration of MB had notable effects on the adsorption behavior of the PF-SA. Under optimal experimental conditions,the removal efficiency of MB could be as high as 99% for a MB solution with a concentration lower than 2 000 mg / L. The maximum adsorption capacity could reach about1 000 mg / g for a MB solution at higher concentrations. The adsorption data conformed well to the pseudo-second-order kinetics model. The calculated values of ΔG^0,ΔH^0,and ΔS^0at different temperatures indicate that the adsorption was a spontaneous,endothermic process.