Abstract:In order to improve the adsorption capacity of attapulgite towards low concentration phosphorus in sewage, rare earth modified attapulgite (Nd-ATP, Ce-ATP, Y-ATP, La-ATP, Pr-ATP neodymium, cerium, yttrium, lanthanum, praseodymium) absorbents were prepared to treat low-concentration phosphorus-containing (TP=1 mg·L?1) wastewater. The phosphorus removal performance, adsorption kinetics and isotherm models of five adsorbents were compared, as well as the changes in the structure, composition and surface groups before and after modification. The results showed that at pH 3 the modified attapulgite had the best phosphorus removal effect, and the TP removal rate was 84%~98%; the coexisting ${\rm{HCO}}_3^ - $ had a strong inhibitory effect on the phosphorus removal, while ${\rm{SO}}_4^{2 - }$ and Cl? had almost negligible effects. The quasi-second-order kinetic model and Langmuir isotherm model could better describe the process of phosphorus removal process than other models. Among them, pH, dosage, and coexisting anions had the least influence on the phosphorus removal effect of Y-ATP yttrium modified attapulgite; Y-ATP yttrium modified attapulgite had the largest adsorption capacity for phosphorus TP, which was 12.94 mg·g?1. The phosphorus removal of rare earth modified attapulgite adsorbent mainly followed the intra-sphere complex mechanism, of which the surface hydroxyl groups on the adsorbent played a key role. Key words:attapulgite clay/ rare earth modification/ low-concentration phosphorus-containing wastewater/ phosphorus removal by adsorption.
图1稀土改性前后凹凸棒土SEM图谱 Figure1.SEM images of attapulgite before and after rare earth modification
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1.School of Environmental and Safety Engineering, Changzhou University, Changzhou 213000, China 2.Xuyi County Sinoma Attapulgite Clay Corporation, Xuyi 211700, China Received Date: 2021-06-25 Accepted Date: 2021-09-13 Available Online: 2021-11-18 Keywords:attapulgite clay/ rare earth modification/ low-concentration phosphorus-containing wastewater/ phosphorus removal by adsorption Abstract:In order to improve the adsorption capacity of attapulgite towards low concentration phosphorus in sewage, rare earth modified attapulgite (Nd-ATP, Ce-ATP, Y-ATP, La-ATP, Pr-ATP neodymium, cerium, yttrium, lanthanum, praseodymium) absorbents were prepared to treat low-concentration phosphorus-containing (TP=1 mg·L?1) wastewater. The phosphorus removal performance, adsorption kinetics and isotherm models of five adsorbents were compared, as well as the changes in the structure, composition and surface groups before and after modification. The results showed that at pH 3 the modified attapulgite had the best phosphorus removal effect, and the TP removal rate was 84%~98%; the coexisting ${\rm{HCO}}_3^ - $ had a strong inhibitory effect on the phosphorus removal, while ${\rm{SO}}_4^{2 - }$ and Cl? had almost negligible effects. The quasi-second-order kinetic model and Langmuir isotherm model could better describe the process of phosphorus removal process than other models. Among them, pH, dosage, and coexisting anions had the least influence on the phosphorus removal effect of Y-ATP yttrium modified attapulgite; Y-ATP yttrium modified attapulgite had the largest adsorption capacity for phosphorus TP, which was 12.94 mg·g?1. The phosphorus removal of rare earth modified attapulgite adsorbent mainly followed the intra-sphere complex mechanism, of which the surface hydroxyl groups on the adsorbent played a key role.
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