Binding Characteristics Of Copper To Natural Humin Fractions Sequentially Extracted From The Lake Wuliangsuhai Sediments

Humin?HM?has the largest proportion in humus and contains many acidic groups,which has a strong complexation and adsorption to Cu²⁺,but the HM fractions have different element composition and structural characteristics,etc.There are differences in the mechanism of the interaction between HM fractions and Cu²⁺.This work was based on the extraction,grouping and purification of HM fractions from the surface sediments of Wuliangsuhai,which combined with spectroscopy and topography,in order to study the adsorbent characteristics of HM fractions absorbed Cu²⁺under various conditions include pH and ion competitive adsorption.It is important in providing evidence for monitoring and controlling the heavy metal pollution such as Cu.The main findings are listed below:?1?The types of functional groups in DMSO-HM and HF-HM were basically similar,but the contents of functional groups were different.The aromaticity of DMSO-HM was smaller than HF-HM where as aliphatic content of DMSO-HM was larger than HF-HM.The results of acid functional group titration showed that the contents of carboxyl and phenolic hydroxyl in DMSO-HM were higher than those in HF-HM.?2?According to the isotherms results,the adsorption capacity of Cu²⁺on DMSO-HM higher than that of HF-HM.?3?When the pH value was lower than the critical pH value,the adsorption capacity of Cu²⁺to HM fractions increased,and when the pH value exceeded the critical pH value,the adsorption capacity of Cu²⁺to HM fractions decreased due to the hydrolytic precipitation of Cu²⁺.?4?The existence of competitive ions can decrease the adsorption capacity of Cu²⁺and Pb²⁺on HM fractions,and the competitive power of Cu²⁺and Pb²⁺on DMSO-HM and HF-HM was Cu²⁺>Pb²⁺.?5?Under different pH conditions,comparing with the changes of peak in the FTIR spectrum on HM fractions pre-and post-adsorption,hydroxyl groups and carboxyl functional groups contributed greatly to the adsorption capacity of Cu²⁺by HM fractions.The results of EEM showed that carboxyl groups and quinone groups participate in the adsorption process,which accompanied the breaking of ?-?*.