聚乙烯亚胺改性麦秸秆对废水中磷酸根的吸附研究

Adsorption of phosphate in solution by polyethyleneimine modified wheat straw in batch mode

采用环氧氯丙烷(ECH)接枝法,将聚乙烯亚胺(PEI)引到麦秸杆(MWS)表面,制得改性阳离子吸附剂PEI-MWS。红外光谱(FT-IR)分析、定量元素分析显示,PEI负载在麦秸秆表面。研究了时间、温度以及溶液pH对PEI-MWS吸附性能的影响。结果表明:在pH为3.4,浓度为0.8g/L的条件下,吸附效果最好。303K时的吸附量达到30.0mg/g。吸附平衡过程符合Koble-Corrigan模型,吸附动力学可用准二级动力学模型来拟合。热力学结果表明,吸附过程是自发的、熵增的过程。改性麦秸杆在0.01mol/L NaOH中再生效果最好,可作为一种良好的吸附剂。

Polyethyleneimine(PEI) was introduced to the surface of wheat straw(MWS) by epichlorohydrin(ECH) grafting method to prepare modified cationic adsorbent PEI-MWS.FT-IR and quantitative element analysis results showed that PEI was successfully loaded on the surface of wheat straw.The effects of time, temperature and pH on the adsorption properties of PEI-MWS were studied.The results indicated that, when the pH was 3.4 and the concentration was 0.8 g/L,the adsorption effect was optimal and the adsorption capacity reached to 30.0 mg/g at 303 K.The adsorption equilibrium process conformed to the koble Corrigan model, and the adsorption kinetics could be fitted by the pseudo-second-order kinetic model.Thermodynamic results revealed that the adsorption process was a spontaneous and entropy increasing process.The regeneration effect of modified wheat straw reached to the maximum of 0.01 mol/L NaOH,which demonstrated that it could be used as a good adsorbent.