title: Preparation, characterization, and phosphate removal and recovery of magnetic MnFe2O4 nano-particles as adsorbents.
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, MnFe2O4, was prepared through the improved co-precipitation method and investigated in terms of phosphate removal. MnFe2O4 was characterized by scanning electron microscopy, vibrating sample magnetometry, X-ray diffraction, and Fourier transform infrared spectroscopy. Phosphate adsorption by MnFe2O4, desorption of adsorbed MnFe2O4 with the regeneration of desorbed MnFe2O4, and phosphate recovery were researched. Experimental results showed that adding the appropriate amount of polyethylene glycol to MnFe2O4 precursors during preparation inhibited the agglomeration of MnFe2O4 between particles because of the magnetic property of MnFe2O4 etc. High crystallinity and strong magnetism were achieved by MnFe2O4 at low temperatures. Average particle size was 5.1 nm. The hysteresis loops confirmed the ferrimagnetic behaviour of MnFe2O4 with a high saturation magnetization (i.e. 26.27 emu/g). The adsorption mechanism of phosphate was mainly physical. The prepared MnFe2O4 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 MnFe2O4 in 15 w/v% NaOH solution. The adsorption capacity of the desorbed MnFe2O4 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 MnFe2O4 could be a promising adsorbent for efficient phosphate removal.
authors: a College of Materials Science and Chemical Engineering , Harbin Engineering University , Harbin , People's Republic of China.|b Key Laboratory of Superlight Material and Surface Technology of Ministry of Education, College of Materials Science and Chemical Engineering , Harbin Engineering University , Harbin 150001 , People's Republic of China.
authors: Shumei
authors: S
authors: Xia
authors: a College of Materials Science and Chemical Engineering , Harbin Engineering University , Harbin , People's Republic of China.
authors: Xiaoming
authors: X
authors: Xu
authors: c College of Power and Energy Engineering , Harbin Engineering University , Harbin , People's Republic of China.
authors: Changsong
authors: C
authors: Xu
authors: d Tianjin Port Free Trade Zone , Environmental Monitoring Station , Tianjin 300308 , People's Republic of China.
authors: Hongshuai
authors: H
authors: Wang
authors: e Chongqing Wangjiang Industry Co., Ltd ., Chongqing , People's Republic of China.
authors: Xiaowei
authors: X
authors: Zhang
authors: a College of Materials Science and Chemical Engineering , Harbin Engineering University , Harbin , People's Republic of China.|b Key Laboratory of Superlight Material and Surface Technology of Ministry of Education, College of Materials Science and Chemical Engineering , Harbin Engineering University , Harbin 150001 , People's Republic of China.
authors: Guangmin
authors: G
authors: Liu
mesh_terms: D000327:Adsorption; D005290:Ferric Compounds / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D010710:Phosphates / Q000032:analysis / Q000302:isolation & purification*; D062065:Wastewater; D018508:Water Purification
chemical_list: D005290:Ferric Compounds; D017895:Manganese Compounds; D010710:Phosphates; D062065:Wastewater; C551151:manganese ferrite
keywords: Magnetic MnFe2O4 nano-adsorbent; adsorbent desorption; adsorbent regeneration; phosphate recovery; phosphate removal