Effect of pre-treatment of bentonite with sodium and calcium ions on phosphate adsorption onto zirconium-modified bentonite

JOURNAL OF ENVIRONMENTAL MANAGEMENT

卷:217

Article

Lin, Jianwei¹  Jiang, Bohui¹  Zhan, Yanhui¹ 

[1] Shanghai Ocean Univ, Coll Marine Ecol & Environm, 999 Hucheng Huan Rd, Shanghai 201306, Peoples R China

关键词: Water treatment;    Zirconium-modified bentonite;    Phosphate;    Adsorption;    Pre-treatment of bentonite with sodium ion;    Pre-treatment of bentonite with calcium ion;   

DOI  :  10.1016/j.jenvman.2018.03.079

来源: Elsevier

【 摘 要 】

To understand the influence of the pre-treatment of bentonite with Na+ and Ca2+ on the adsorption of phosphate on zirconium-modified bentonite, three kinds of adsorbent materials including zirconium modified raw, Na+-pretreated and Ca2+-pretreated bentonites were synthesized and characterized firstly, and afterward their adsorption performance and mechanism for phosphate were studied comparatively. The phosphate adsorption ability for zirconium-modified bentonite decreased after the pre-treatment of bentonite with Na+, but it increased after the pre-treatment of bentonite with Ca2+. The maximum phosphate adsorption capacity calculated from the Langmuir isotherm model for zirconium modified Ca2+-pretreated bentonites (13.4 mg P/g) was much higher than that for the zirconium modified raw bentonite (9.06 mg P/g). The pre-treatment of bentonite with Na+ and Ca2+ did not change the interaction type between zirconium-modified bentonite and phosphate, i.e., the coordination of phosphate to zirconium. The decreased phosphate adsorption capacity for zirconium-modified bentonite induced by the Na+ pre-treatment could be mainly attributed to the decrease of the specific surface area and the content of exchangeable Ca. The increased phosphate adsorption capacity for zirconium-modified bentonite induced by the Ca2+ pre-treatment could be mainly due to the increase in the amount of exchangeable Ca. Results of this work suggest that the zirconium-modified Ca2+-pretreated bentonite is more suitably used as an adsorbent for the removal of phosphate from wastewater than the zirconium-modified raw and Na+-pretreated bentonites. (C) 2018 Elsevier Ltd. All rights reserved.

【 授权许可】

Free