Adsorption of phosphate from aqueous solution using iron-zirconium modified activated carbon nanofiber: Performance and mechanism

• Published in: Journal of colloid and interface science 2017-05, Vol.493, p.17-23
• Main Authors: Xiong, Weiping, Tong, Jing, Yang, Zhaohui, Zeng, Guangming, Zhou, Yaoyu, Wang, Dongbo, Song, Peipei, Xu, Rui, Zhang, Chen, Cheng, Min
• Format: Article
• Language: English
• Subjects: Activated carbon nanofiber; Adsorption; Iron; Phosphate; Zirconium
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2017.01.024

[Display omitted] Phosphate (P) removal is significant for the prevention of eutrophication in natural waters. In this paper, a novel adsorbent for the removal of P from aqueous solution was synthesized by loading zirconium oxide and iron oxide onto activated carbon nanofiber (ACF-ZrFe) simultaneously. The adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The results showed that P adsorption was highly pH dependent and the optimum pH was found to be 4.0. The isotherm of adsorption could be well described by the Langmuir model and the maximum P adsorption capacity was estimated to be 26.3mgP/g at 25°C. The kinetic data were well fitted to the pseudo-second-order equation, indicating that chemical sorption was the rate-limiting step. Moreover, co-existing ions including sulfate (SO42−), chloride (Cl−), nitrate (NO3−) and fluoride (F−) exhibited a distinct effect on P adsorption with the order of F−>NO3−>Cl−>SO42−. Further investigations by FT-IR spectroscopy and pH variations associated with the adsorption process revealed that ligands exchange and electrostatic interactions were the dominant mechanisms for P adsorption. The findings reported in this work highlight the potential of using ACF-ZrFe as an effective adsorbent for the removal of P in natural waters.