Phenol adsorption on surface-functionalized iron oxide nanoparticles: modeling of the kinetics, isotherm, and mechanism

Abstract

Phenol adsorption from aqueous solution was carried out using uncoated and methyl acrylic acid (MAA)-coated iron oxide nanoparticles (NPs), having size \10 nm, as adsorbents. Batch adsorption studies revealed that the phenol removal efficiency of MAAcoated NPs (950 mg g -1 ) is significantly higher than that of uncoated NPs (550 mg g -1 ) under neutral to acidic conditions. However, this improvement disappears above pH 9. The adsorption data under optimized conditions (pH 7) were modeled with pseudo-first-and pseudo-second-order kinetics and subjected to Freundlich and Langmuir isotherms. The analysis determined that pseudo-second-order kinetics and the Freundlich model are appropriate for both uncoated and MAA-coated NPs (all R 2 [ 0.98). X-ray photoelectron spectroscopy analysis of pristine and phenoladsorbed NPs revealed core-level binding energy and charge for Fe(2s) and O(1s) on the NP surfaces. The calculations suggest that phenol adsorption onto MAAcoated NPs is a charge transfer process, where the adsorbate (phenol) acts as an electron donor and the NP surface (Fe, O) as an electron acceptor. However, a physisorption process appears to be the relevant mechanism for uncoated NPs.

Green synthesis, characterization of biomaterial-supported zero-valent iron nanoparticles for contaminated water treatment

“…Freundlich model assumes that adsorptions occur at heterogeneous binding sites and formation of multilayer takes place due to interactions among adsorbed molecules on the surface of adsorbent (Soon et al 2016). The expression for Freundlich adsorption isotherm is as follows:…”

Adsorptive Removal of Carbamazepine and Diatrizoate in Iron Oxide Nanoparticles Amended Sand Column Mimicing Managed Aquifer Recharge

“…Use of XPS analysis to interpret adsorption mechanism of pharmaceutical compounds over Fe 3 O 4 nanoparticle surface has not been reported earlier. However, slight peak shift for Fe(2p) and O(1s) core level spectra with magnetite and MAA-magnetite has been observed following phenol adsorption in batch studies [11]. In other words, changes in binding energies are evident when organics are adsorbed to magnetite and MAA-magnetite.…”

“…The specific surface area of magnetite and MAA-coated magnetite, as measured in nitrogen adsorption-desorption BET method, were 113.29 and 117.66 m 2 ·g −1 , respectively. Further characterization of MAA-magnetite using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) can be found elsewhere [10,11].…”

“…The Fe and O present on the samples were identified from the survey spectra. The survey scans started at 1400 eV and ended at 0 eV, with a step size of 1 eV and dwell time of 200 ms [11].…”

The Use of Modified Fe3O4 Particles to Recover Polyphenolic Compounds for the Valorisation of Olive Mill Wastewater from Slovenian Istria

“…The removal of polyphenolic compounds from OMWW with bare Fe 3 O 4 attraction is mainly controlled by chemisorption combined with π-π interactions, along with water-bridged H-bonds, according to Dehmani et al [ 52 ], or physiosorption, according to Yoon et al [ 53 ]. Coating the Fe 3 O 4 particles can lead to better efficiency in removing polyphenolic compounds from aqueous solutions [ 52 ]; this can also be seen in our results.…”