Preparation, characterization, and phosphate removal and recovery of magnetic MnFe2O4 nano-particles as adsorbents. Issue 7 (2nd April 2016)

• Record Type: Journal Article
• Authors: Xia, Shumei; Xu, Xiaoming; Xu, Changsong; Wang, Hongshuai; Zhang, Xiaowei; Liu, Guangmin
• Is Part Of: Environmental technology. Volume 37:Issue 7(2016)
• Page Start: 795
• Page End: 804
• Publication Date: 2016-04-02
• Subjects: Magnetic MnFe2O4 nano-adsorbent -- phosphate removal -- adsorbent desorption -- adsorbent regeneration -- phosphate recovery; Environmental engineering -- Periodicals; Environmental protection -- Periodicals; 628.05
• DOI: 10.1080/09593330.2015.1085099
• Languages: English
• ISSNs: 0959-3330

Abstract

ABSTRACT: Phosphate removal is an important method for controlling eutrophication in bodies of water. Adsorption is an effective phosphate removal approach. In this research, the adsorbent, namely, MnFe2 O4, was prepared through the improved co-precipitation method and investigated in terms of phosphate removal. MnFe2 O4 was characterized by scanning electron microscopy, vibrating sample magnetometry, X-ray diffraction, and Fourier transform infrared spectroscopy. Phosphate adsorption by MnFe2 O4, desorption of adsorbed MnFe2 O4 with the regeneration of desorbed MnFe2 O4, and phosphate recovery were researched. Experimental results showed that adding the appropriate amount of polyethylene glycol to MnFe2 O4 precursors during preparation inhibited the agglomeration of MnFe2 O4 between particles because of the magnetic property of MnFe2 O4 etc. High crystallinity and strong magnetism were achieved by MnFe2 O4 at low temperatures. Average particle size was 5.1 nm. The hysteresis loops confirmed the ferrimagnetic behaviour of MnFe2 O4 with a high saturation magnetization (i.e. 26.27 emu/g). The adsorption mechanism of phosphate was mainly physical. The prepared MnFe2 O4 had a spinel structure. The proposed technique achieved a phosphate removal rate of 96.06%. A considerable amount of phosphate was desorbed from the adsorbed MnFe2 O4 in 15 w/v% NaOH solution. The adsorption capacity of the desorbed MnFe2 O4 could be restored to 96.73% in 10 w/v% NaNO3 solution through ion exchange. A sustainable phosphate source was recovered via hydroxyapatite crystallization in the desorption solution, which contained an abundant amount of phosphate as seed for suitable recovery condition. This finding suggested that MnFe2 O4 could be a promising adsorbent for efficient phosphate removal.