【摘要】 以碱木质素、谷氨酸钠及甲醛为原料,依据Mannich反应制备谷氨酸—木质素吸附剂(GA-L)。采用FT-IR和凯氏定氮表征其化学结构,并分析了吸附时间、吸附剂用量、pH值及反应温度对Pb2+吸附性能的影响。研究结果表明,谷氨酸已接枝到木质素上,产物氮质量分数为2.62%;GA-L在3h达到饱和状态,最佳吸附剂用量为0.2g/L;对酸性介质中的Pb2+具有良好的吸附性能,吸附容量随初始重金属离子质量浓度和温度的增加而增大;引入的胺基和羧基明显提高了木质素的络合能力,GA-L对Pb2+的吸附容量可达87.28mg/g,与未改性木质素(35.07mg/g)相比提高了148.87%。25℃时初始Pb2+质量浓度在20～200mg/L范围内,吸附规律符合Langmuir平衡模型,吸附机理以单分子层化学吸附为主。更多还原

【Abstract】 Glutamic acid-lignin adsorbent (GA-L) was synthesized from alkali lignin modified with sodium glutamate and formaldehyde via Mannich reaction. Chemical changes were analyzed using FT-IR and Kjeldahl,and the effects of adsorption time,usage,pH value,and temperature on the adsorption properties of GA-L to Pb2+ were investigated. Results indicated that glutamic acid had been grafted into lignin,and the nitrogen content of the resulting product was 2.62 percent. GA-L reached saturation within 3 hours,and the optimum usage was 0.2g/L. The material exhibited desirable adsorption property to Pb2+ existed in acidic medium,and the adsorption capacity enhanced as both initial ionic concentration and temperature increasing. Owing to the introduction of amidocyanogen and carboxyl,the adsorption capacity of GA-L to Pb2+ reinforced significantly,and the maximum reached 87.28mg/g,increasing by 148.87 percent compared with the unmodified GA-L (35.07mg/g). The adsorption data followed Langmuir model within the concentrations of Pb2+ ranging from 20 to 200mg/L at 25 degrees C,and the chemical monolayer adsorption was dominant.更多还原