PAN Min¹, HUANG Xiao-ming¹, CHEN Tian-hu², XIE Jing-jing², WU Guang-xue³

(1. Environmental Science and Technology, Xiamen University of Technology, Xiamen 361024, China;
2. School of Resource and Environmental Engineering, Hefei University of Technology, Hefei 230009, China;
3. Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China)

Abstract: In this study, three kinds of nano-adsorbents were prepared by supporting aluminum hydroxide, iron hydroxide, and aluminum/iron hydroxide onto palygorskite in hydrolysis processes (named PNCMⅠ, PNCMⅡand PNCMⅢ) to remove phosphate from aqueous solution. They were characterized by using X-ray diffraction (XRD) and X-ray fluorescence (XRF). The adsorption behaviour and adsorption capabilities of phosphate were investigated in batch experiments. Results show that the preparation processes do not change palygorskite’s crystal structure. Temperature has no obvious effects on thethree kinds of nano-adsorbents adsorbing phosphate, while the adsorption capacities and initial adsorption rates increase with increasing initial phosphate concentrations. Compared with PNCMⅡ and PNCMⅢ, PNCMⅠshows the highest phosphate adsorption capacity of 18.18 mg/g. The initial adsorption rate of PNCMⅠincreases from 0.125 mg/g·min to 1.425 mg/g·min with increasing initial phosphate concentrations from 5 mg/L to 50 mg/L. The adsorption rates of phosphate on the three kinds of nano-adsorbents fit pseudo-second-order kinetic models, indicating that chemisorption mechanism plays an important role and that the initial adsorption rate may be controlled by a chemical reaction between Al(OH)3 and Fe(OH)3 on adsorbents and phosphate.

Keywords: palygorskite; adsorption; phosphate; kinetics

E-mail: chentianhu168@vip.sina.com

ACTA MINERALOGICA SINICA Vol. 35, No. 1, 2015, Page 29-34