改性壳聚糖对Ni(Ⅱ)的吸附性能研究

Study on the Adsorption Performance of Modified Chitosan on Ni(Ⅱ)

为研究改性壳聚糖对水中Ni(Ⅱ)的吸附性能,以三聚磷酸钠为交联剂,对经过乙酸-双氧水体系氧化后的壳聚糖进行一步离子交联,制备改性壳聚糖吸附材料。通过扫描电子显微镜、傅里叶变换红外光谱仪、X射线衍射仪等对材料的微观形貌、分子结构及物相进行表征;采用条件实验探究改性壳聚糖吸附性能的影响因素,并对其吸附热力学进行分析。结果显示:改性后的壳聚糖呈纳米片状结构,成功实现了三聚磷酸钠中P—O与壳聚糖中—NH_(2)之间的交联;在三聚磷酸钠浓度为10 g/L、双氧水用量为5 mL、交联温度为40℃条件下制备的改性壳聚糖表现出较好的吸附性能,当pH为7、吸附时间为120 min、三聚磷酸钠改性壳聚糖投加量为50 mg时,其对Ni(Ⅱ)的去除率达到8371%;改性壳聚糖对Ni(Ⅱ)的吸附行为符合Langmuir等温吸附模型,吸附过程为自发吸热过程。

To investigate the adsorption performance of modified chitosan on Ni(Ⅱ)in water,sodium tripolyphosphate was used as a crosslinking agent to ionically crosslink chitosan oxidized by acetic acid-hydrogen peroxide system,and modified chitosan adsorbent was prepared.The micro morpholo-gy,molecular structure,and phase of the material were characterized by scanning electron microsco-py,Fourier transform infrared spectroscopy,and X-ray diffraction;the factors affecting the adsorption performance of modified chitosan were explored through conditional experiments,and the adsorption process was thermodynamically analyzed.The results showed that the modified chitosan presented a nanosheet structure,and the crosslinking between P—O in sodium tripolyphosphate and—NH_(2) on chi-tosan was successfully achieved;under the conditions of sodium tripolyphosphate concentration of 10 g/L,hydrogen peroxide volume of 5 mL,and crosslinking temperature of 40℃,the prepared modi-fied chitosan exhibited good adsorption performance.When the pH was 7,the adsorption time was 120 min,and the dosage of sodium tripolyphosphate-modified chitosan was 50 mg,the removal rate of Ni(Ⅱ)reached 8371%;the adsorption behavior of modified chitosan on Ni(Ⅱ)conformed to the Lang-muir isotherm adsorption model,and the adsorption process was a spontaneous endothermic process.