Facile and Economical Synthesis of Large Hollow Ferrites and Their Applications in Adsorption for As(V) and Cr(VI)

Abstract

Unlike the previous ferrites (MFe2O4; M=Fe, Co, Zn, and Mn) solid nanospheres/nanoparticles, which were prepared by polluted solvothermal (glycol) approaches, here controllable monodisperse porous ferrites hollow nanospheres are promptly synthesized by a nontemplate hydrothermal method which has introduced an addition agent, polyacrylamide. The hollow nanospheres with different size can be prepared by varying the synthetic compositions. Scanning/transmission micros-graphs show the outside diameters of ferrite nanospheres are 180-380 nm and the shell thicknesses of that are only 20-45 nm, which could be adjusted by controlling CH3COONa concentration. X-ray diffraction (XRD) and X-ray photoelectron (XPS) spectroscopy, scanning electron (SEM) and transmission electron (TEM) microscopy, energy-dispersive spectrometer (EDS), the measurement of N2 adsorption-desorption isotherms and Brunauer-Emmett-Teller (BET) surface area, and superconducting quantum interference device (SQID) magnetometer were adopted to analyze their phase composition, morphology, porosity, and magnetic properties, respectively. The results of controlled experiments show that citrate and polyacrylamide are vital for the phase purities and morphology of ferrites. In particular, the as-obtained samples exhibit a large adsorption capacity for the toxic solution containing As(V) and Cr(VI) ions, and the calculated result of the maximum adsorption capacity is 340 mg/g based on Langmuir model, which shows excellent As(V) and Cr(VI) ions uptake capacity in contrast to other solid nanosphere materials.

Enhanced removal of hexavalent chromium from aqueous media using a highly stable and magnetically separable rosin-biochar-coated TiO2@C nanocomposite

“…51 The reections of Fe 2 O 3 and the crystal planes of TiO 2 , indexed to (101), (105), (111), (200), (220) and (310), conrmed the successful preparation of the biocharcoated magnetic RBC-TiO 2 @C nanocomposite. 52 The magnetic property of the RBC-TiO 2 @C nanocomposite was measured by VSM at room temperature in an applied magnetic eld sweeping from À5000 to 5000 G (Fig. 2) and the hysteresis loop indicates that the RBC-TiO 2 @C nanocomposite sample possesses superparamagnetic behavior with no remanence or coercivity.…”

Effective adsorption of Cr(VI) on mesoporous Fe-functionalized Akadama clay: Optimization, selectivity, and mechanism

“…The contribution of the interaction 15 effects (X 1 X 2 , X 1 X 3 , X 1 X 4 , X 2 X 3 , X 2 X 4 , X 3 X 4 ) on the Cr(VI) adsorption capacity are the 16 following: 0, 0, 0.04%, 0.37%, 0.02%, and 0.02%, respectively. The results indicated that M a n u s c r i p t 18 percentage effects of X 2 , X 3 , and X 4 (1.12%, 45.15%, and 53.17%,) are much more than 1 The presence of co-existing ions leads to high ionic strength, which may greatly affect 2 the adsorption process. Therefore, selectivity is a very important factor for an adsorption 3 material, and it will influence the application in real wastewater treatment.…”

Effect of a pH-controlled co-precipitation process on rhodamine B adsorption of MnFe2O4 nanoparticles

“…Moreover, MnFe 2 O 4 provides an advantage for repeating magnetic separation with good stability. [23][24][25][26][27][28][29] It has been shown that MnFe 2 O 4 nanoparticles can be prepared via several methods such as hydrothermal, 30,31 solgel, 29,32 and co-precipitation. [33][34][35] Among these methods, coprecipitation has been widely utilized for the preparation of magnetic ferrite.…”