Search

This study aimed to extract pectin from local Majiayou pomelo (Citrus grandis (L.) Osbeck) peel in Jiangxi province with distilled water, hydrochloric acid and citric acid, respectively, and analyze the physicochemical components of pectin and its adsorption properties on Pb(II), and explicit the effect of adsorption parameters (initial pH value, initial ion concentration, adsorption time) on Pb (II) and its adsorption mechanism by adsorption isotherms and adsorption kinetics. The results showed that the yield of pectin by citric acid extraction (CEP) was highest (28.62%), followed by hydrochloric acid extraction (HEP) and distilled water extraction (WEP). In addition, the esterification degree (58.20%) and molecular weight (598.40 ku) of CEP were significantly lower than those of WEP and HEP (P<0.05), indicating that CEP had more carboxyl and higher solubility. The three pectins showed optimal adsorption of Pb (II) at initial pH 5.0, and reached equilibrium after 120 min adsorption. In addition, the adsorption capacity of CEP on Pb (II) was significantly higher than that by WEP and HEP. The adsorption isotherms of the three pectins were in accordance with Langmuir monolayer adsorption model, and the adsorption kinetics of the three pectins was consistent with pseudo first-order kinetics model. The adsorptions of three pectins on Pb (II) were the result of physical and chemical adsorption. Conclusion: The physicochemical properties of pectin and its adsorption capacity on Pb (II) were closely related to the extraction method, and CEP has a high adsorption capacity on Pb (II), which could be used as a low-cost, efficient, natural and environmental friendly adsorbent for removal of Pb (II). [ABSTRACT FROM AUTHOR]