改性木质素胺吸附剂对废水中Pb2+的吸附

Adsorption of Lead Ions in Effluent onto Lignin Amines Adsorbents from Modified Kraft Lignin

中文关键词:  木质素  木质素胺  吸附  Pb²⁺

Key Words:lignin  lignin amine  adsorption  Pb²⁺

中文摘要:

      以木质素、二乙烯三胺和甲醛为原料，通过Mannich反应合成改性木质素胺吸附剂，考察了不同吸附条件对Pb²⁺吸附效果的影响。实验结果表明：n(木质素)∶n(二乙烯三胺)∶n(甲醛)=1∶1.5∶4.5条件下,改性木质素胺吸附剂对Pb²⁺吸附效果最好；在吸附温度为45℃、吸附剂用量为1.2 g/L、溶液pH值为5.0、吸附时间为24 h的最佳吸附条件下，合成的吸附剂对Pb²⁺的去除率为59.82%，吸附量为49.85 mg/g。该吸附过程为慢性吸附，动力学模型符合McKay二级吸附动力学。改性木质素胺对Pb²⁺吸附过程是受颗粒内扩散和液膜扩散的共同影响，其中颗粒内扩散是主要的控制步骤。

Abstract:

      Lignin amine adsorbents were synthesized from kraft lignin, diethylenetriamine and formaldehyde via Mannich reaction. The effect of different conditions on the adsorption of Pb2+ was investigated. The results showed that the lignin amine with n(lignin)∶n(diethylenetriamine)∶n (formaldehyde) = 1∶1.5∶4.5 had the best adsorbing efficiency among three different lignin absorbents. The optimum adsorption conditions were as follows: adsorption temperature was 45℃, the amount of adsorbents was 1.2 g/L, pH was 5.0 and the adsorption time was 24 hours. Under these conditions the removal of Pb2+ reached 59.82%, the adsorption capacity was 49.85 mg/g. This adsorption process was chronic adsorption, the dynamic model was consistent with McKay secondary adsorption kinetics. The adsorption of Pb2+ on lignin amine was affected by the intraparticle diffusion and liquid film diffusion, and the intraparticle diffusion was the main rate-controlling step.