Controllable synthesis of mesoporous magnetite/activated carbon composites as efficient adsorbents for hexavalent chromium removal

Abstract

Controllable synthesis of mesoporous magnetite/activated carbon composites as efficient adsorbents for hexavalent chromium removalEq. S1-S4, Figure S1-S3 and Table S1-S3 are included in this supporting information.

High Dispersion FeFe2O4 nanoparticles synthesis and its Oxygen Reduction Reaction catalytic performance

“…The specific surface areas of pyrolytic Na 2 CO 3 , FeFe 2 O 4 , FeFe 2 O 4 ‐0.25, FeFe 2 O 4 ‐0.50 and FeFe 2 O 4 ‐0.75 were 0.50, 9.00, 10.01, 10.16, and 9.52 m 2 g −1 , respectively. The corresponding pore size allocation was assessed by NL‐DFT method and the calculated results indicated that the synthesized products had a mesoporous structure (Figure 4c), [56,57] which verified the results from N 2 adsorption‐desorption isotherms and SEM images.…”

“…But after the FeSO 4 ⋅ 7H 2 O content over 0.50 mmol, the diffraction peak intensity of FeFe 2 O 4 -0.75 was weakened, which might attribute by the agglomeration lowering the crystallinity. [54,55] The specific surface area as well as pore size distribution were measured by nitrogen adsorption-desorption measurement and was shown in Figure 4b and 4c ChemistrySelect structure (Figure 4c), [56,57] which verified the results from N 2 adsorption-desorption isotherms and SEM images.…”

Smart Adsorbents for Aquatic Environmental Remediation

“…For instance, an adsorption reduction from 385 mg g −1 of Cr 6+ by PAC (SSA: 936 m 2 g −1 , M s : 3 emu g −1 ) to 179 mg g −1 by Fe 3 O 4 /PAC (SSA: 464 m 2 g −1 , M s : 38 emu g −1 ). [170] However, SSA rise after magnetization has also been reported for a coconut shell based AC, with an increase from 417 to 952 m 2 g −1 (with increasing adsorption capacity from 20 to 24 mg g −1 for phenol) due to the release of micropores and mesopores previously covered by minerals that dissolved during magnetization. [175] Other authors reported average pore size increasing with , respectively, than on the original PAC (SSA: 1360 m 2 g −1 ).…”

“…Due to their comparatively low price, great availability, and large magnetizing capacity, [162,163] ferrites such as manganese ferrite (MnFe 2 O 4 ), [164] cobalt ferrite (CoFe 2 O 4 ) [165] nickel ferrite (NiFe 2 O 4 ), [166] and iron oxides, namely maghemite (γ-Fe 2 O 3 ) and, especially, magnetite (Fe 3 O 4 ), are most commonly used. [167] Co-precipitation, either by in situ (one-step with simultaneous formation and impregnation of magnetic NPs in AC framework [168,169] ) or ex-situ (two-step involving the synthesis of magnetic NPs followed by their dispersion with AC [170,171] ), are the most conventional MAC synthesis owing to their simplicity, productivity, and cost-effectiveness. [167] Saturation magnetization (M s ) is a very important parameter when considering magnetic separation of magnetized PAC, [172] and M s values are usually reported to support magnet responsiveness.…”

“…M s values of MAC are usually lower due to the presence of PAC composited with these NPs but still allow for magnetic separation. [170] During magnetization, surface magnetic NPs may block pores in PAC, leading to a decrease in specific surface area (SSA), [170,173,174] which may reduce its maximum adsorption capacity. For instance, an adsorption reduction from 385 mg g −1 of Cr 6+ by PAC (SSA: 936 m 2 g −1 , M s : 3 emu g −1 ) to 179 mg g −1 by Fe 3 O 4 /PAC (SSA: 464 m 2 g −1 , M s : 38 emu g −1 ).…”