Xiaoting Zhang,Ruize Zhang,Shanshan Chen,Kang Wen,Runping Han
ABSTRACT In this study, D751 resin (macroporous styrene chelated ion exchange resin, sodium form) was modified by FeCl 3 to enhance the adsorption performance of phosphate from solution. The modified resin (D751-Fe) was characterized by FTIR and XPS, and its adsorption property toward phosphate was presented. The results showed that it was favorable of phosphate adsorption with the increase in the temperature and acidity. The effect of coexisting ions (chloride and sulfate) was insignificant. When the solid–liquid ratio was 1.5 g L –1 , the unit adsorption amount of D751-Fe toward phosphate was to 14.1 mg g –1 (according to P element) with solution pH 3. The adsorption isotherms were well fitted by Langmuir model, Freundlich model, and Koble–Corrigan model while the kinetic curves were well described by pseudo-first-order kinetic model, double constant model, and intraparticle model. There were both physical adsorption and chemical adsorption between D751-Fe and phosphate. It was effective for 0.1 mol·L –1 sodium hydroxide solution as desorbent to regenerate phosphate-loaded adsorbent. It is concluded that that D751-Fe can be used well for the removal of phosphate from solution.
A highly effective adsorbent of lanthanum-modified D751 resin (D751 resin for macroporous styrene chelated resin, sodium form) was prepared to enhance the effect of removing phosphate from solution. FTIR, SEM were used to explore the functional groups and structural features on the surface of D751-La; XPS analyzed the action mechanism between phosphate and D751-La. The adsorption performance about D751-La toward phosphate was investigated by batch experiment. The results showed that Langmuir, Freundlich, Temkin, Koble-Corrigan as well as Redlich-Peterson models fitted well for the adsorption isotherms. The adsorption kinetics could be better fitted by Double Constant, Elovich, and Pseudo-second-order model. The effect of salinity was not significant, such as Cl − and SO 4 2− . When the solid-liquid ratio was 15 g·L −1 with setting the reaction time as 8 h, the unit adsorption quantity of D751-La to phosphate (calculated in P) reached up to 26.3mg·g −1 under the solution pH=3 at 293 K. The process was spontaneous and exothermic from thermodynamic analysis. It shows that D751-La has potential to remove phosphate from solution.
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