Surfactant assisted Ce–Fe mixed oxide decorated multiwalled carbon nanotubes and their arsenic adsorption performance

Abstract

In this study, a novel mixed Ce-Fe oxide decorated multiwalled carbon nanotubes (CF-CNTs) material was prepared through a surfactant assisted method. The CF-CNTs material was characterized by various methods, including BET surface area analysis, transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). It was found that the Ce-Fe oxide was uniformly dispersed on the surface of CNTs with a mean size of 7.0 nm. The obtained CF-CNTs material was used as an adsorbent to remove arsenic from aqueous solutions. The adsorption experimental results showed that this CF-CNTs material had an excellent adsorption performance for As(V) and As(III). The adsorption processes of As(V) and As(III) could be well described by the pseudo-second-order model. The mechanistic study showed that different interactions were involved in As(V) adsorption, including electrostatic attraction and surface complexation. For As(III) adsorption, partial As(III) was oxidized to As(V) followed by the simultaneous adsorption of As(V) and As(III). It was also found that intra-particle diffusion existed in the process of adsorption on CF-CNTs, but that it was not the only rate-limiting step. The resulting CF-CNTs material can be used in a broad pH range, which suggests its great potential for the decontamination of arsenic-polluted water.

High-performance iron oxide–graphene oxide nanocomposite adsorbents for arsenic removal

“…The results suggest that As(III) is adsorbed onto FeO x -GO-80 through a surface complexation mechanism, rather than electrostatic interactions [23]. The adsorption capacity increase with increasing pH may be attributed to the enhanced surface hydroxyl groups at higher pH values for complexation [37]. Similar patterns of dependence have been noted in the literature [37].…”

“…the decrease of pH from 7 to 2. Similar trends of the effects of pH have commonly been observed with iron oxide-based adsorbents and can be explained by the changes in surface charge of the adsorbents and the arsenic speciation [7][8][9]12,[21][22][23][24]26,32,34,37,38]. Figure 9(b) shows the dependence of surface charge of FeO x -GO-80 on pH.…”

“…Typical substrates include low-cost abundant ones, such as naturally occurring minerals [21], activated carbons [22], graphene oxide (GO) [23][24][25][26][27][28][29][30][31][32][33], and cellulose [34], as well as some specially synthesized costly ones, such as mesoporous carbons [35,36], carbon nanotubes [37], macroporous silica [38], etc. Such nanocomposite adsorbents facilitate their more convenient separation following adsorption.…”

Electrospun chitosan–polyvinyl alcohol composite nanofibers loaded with cerium for efficient removal of arsenic from contaminated water

“…The nd-ings of the present study were applied to Langmuir isotherm model, which is based on the assumption that interactive force between the adsorbed molecules is negligible and once the active site is lled, no more adsorption occurs. The Langmuir isotherm equation 27,48 used for calculation is expressed as:…”

Surfactant‐Free One‐Pot Synthesis of Low‐Density Cerium Oxide Nanoparticles for Adsorptive Removal of Arsenic Species

“…The figure clearly indicated the effective adsorption within first minute of reaction and equilibrium at 2.5 min. Such a low equilibrium time has not been reported earlier using ceria-based adsorbents for removal of arsenic species (Table 3) [22,[46][47][48][49][50][51].…”