Ab Initio Studies on Hematite Surface and the Adsorption of Phosphate

Chaudhury, Swati; Varadachari, Chandrika; Ghosh, Kunal

doi:10.1155/2014/312921

Cited by 5 publications

(5 citation statements)

References 23 publications

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“…However, it is generally accepted that larger particles (>500 nm) are predominantly taken up via nonspecific energy-dependent membrane-tangled internalization and macropinocytosis 91 . Moreover, the observed uptake may be possibly due to the high adsorption of phospholipid head groups on the plasma membranes to surface hydroxyl groups (Fe-OH) via a proven Fe–O–H–O–P mechanism 92 . We, thus, anticipate the internalization to occur by a combination of mechanisms, most notably non-selective macropinocytosis 93 , where internalization of upper-size-limit particles up to 3-μm was elegantly demonstrated 90 .…”

Section: Resultsmentioning

confidence: 99%

Preparation of iron oxide mesoporous magnetic microparticles as novel multidrug carriers for synergistic anticancer therapy and deep tumor penetration

El‐Boubbou

Ali

Alzahrani

et al. 2019

Sci Rep

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The preparation of mesoporous iron oxides with controllable physiochemical properties for effective therapeutic drug delivery remains a formidable challenge. Herein, iron oxide mesoporous magnetic microparticles (IO-MMMs) were prepared by a modified reverse hard-templating approach using, for the first time, acid-prepared mesoporous spheres (APMS) as the hard silica template. The obtained mesostructures exhibited remarkably high surface area and large pore volumes ( S BET = 240 m 2 /g and V pore = 0.55 cm 3 /g), controllable average sizes, generally uniform morphologies, and excellent biocompatibilities, allowing them to achieve optimal drug release in cancer cells and tumor tissues. IO-MMM carriers were able to co-load high amounts of hydrophilic chemotherapeutic drugs (Dox or Daun) and/or hydrophobic hormonal anticancer drugs (Tam), and release them sustainably in a pH-dependent manner, utilizing the fluorescence of Daun to real-time trace the intracellular drug distribution, and employing Daun/Tam to treat cancer by combined chemo/hormonal therapy. Cytotoxicity assays against different types of cancerous cells showed that the combinatory Daun/Tam@IO-MMM formulation significantly reduced the viability of metastatic MCF7 and KAIMRC1 breast as well as HCT8 colorectal cancer cells, with the least potency towards non-cancerous normal primary cells (up to 10-fold). Electron, flow, and live confocal microscopy imaging confirmed that the loaded vehicles were successfully and differentially uptaken by the different tested cells, gradually releasing their payloads, and causing apoptotic cell death. Importantly, compared to free drugs, Daun/Tam@IO-MMMs displayed enhanced drug accumulation in patient breast primary tumor tissues, deeply penetrating into the tumor region and killing the tumor cells inside. The designed carriers described here, thus, constitute a novel promising magnetic mesoporous smart system that entraps different kinds of drugs and release them in a controlled manner for combinatorial chemo/hormonal cancer theranostics. This multifactorial platform may open new avenues in cancer therapy as efficient synergistic antitumor system through overcoming limitations of conventional cancer therapy.

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Section: Resultsmentioning

confidence: 99%

Preparation of iron oxide mesoporous magnetic microparticles as novel multidrug carriers for synergistic anticancer therapy and deep tumor penetration

El‐Boubbou

Ali

Alzahrani

et al. 2019

Sci Rep

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“…In addition, GGA calculations usually underestimate the band gap for transition metals like iron . Meanwhile, Hubbard U correction usually provides more accurate electronic descriptions of frontier orbitals, which are the key to understanding chemical reactions . A GGA + U with U eff = 4 eV ( U = 5 eV and J = 1 eV) was used in electronic structure calculations (DOS, charges), since those values have been indicated to provide comparable bulk lattice parameters and band gap to experimental measurements …”

Section: Computational Detailsmentioning

confidence: 99%

Chemical Origin of Sodium Phosphate Interactions on Iron and Iron Oxide Surfaces by First Principle Calculations

Tieu

Zhu

et al. 2017

J. Phys. Chem. C

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Density functional theory calculations of chemical interactions of lubricant additives sodium pyrophosphate (Na4P2O7) and orthophosphate (Na3PO4) on nascent iron Fe(110) and iron oxide Fe2O3(0001) surfaces have been carried out. Comparisons of adsorption behaviors of the two lubricant additives on different surfaces have been implemented on the basis of the thermodynamics of adsorption and electronic structure analyses. The results indicate that sodium phosphates chemically adsorb on iron and iron oxide surfaces by forming Fe–O bonds and stick on the surfaces through Fe–O–P linkages. The stronger binding of Na3PO4 than that of Na4P2O7 on both Fe(110) and Fe2O3(0001) surfaces is consistent with its better antiwear performance observed by the experiments. It is found that Fe–O bonds formed during the phosphate adsorption are stable covalent bonds that are as strong as P–O bonds of the Fe–O–P linkages. However, the binding of Fe–O–P on Fe surface is caused by a donor–acceptor mechanism; in contrast, the donation/back-donation interaction mechanism on the Fe2O3 surface. This study provides an in-depth understanding of the early stage of the tribochemical reaction between polyphosphates and metal/oxide surfaces.

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“…This indicated a possible electrostatic attraction between FAU-X and NaH 2 PO 4 . This interaction plays an important role in the catalytic activity [49,50].…”

Section: Adsorption On the Fau-x Modelmentioning

confidence: 99%

“…This indicated a possible electrostatic attraction between FAU-X and NaH2PO4. This interaction plays an important role in the catalytic activity [49,50]. The adsorption energy can be used as a criterion to describe the interaction mechanism between two systems [4].…”

Section: Adsorption On the Fau-x Modelmentioning

confidence: 99%

Computational Study of the Adsorption of Phosphates as Wastewater Pollutant Molecules on Faujasites

2021

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The adsorption of sodium dihydrogen phosphate (NaH2PO4) onto X- and Y-type faujasite zeolites was computationally studied using the Density Functional Theory (DFT) method. The structures were modeled using the Materials Studio software. The Si/Al ratios for the X- and Y-type zeolite models were 1.2 and 2.5, respectively. The central pore of the zeolite provided a more favorable coordination for adsorbing NaH2PO4. Full molecular optimization and adsorption energy calculations were performed using the VASP code. The adsorption was more effective on zeolite Y, with an adsorption energy of 161 kJ/mol, compared to the zeolite X system, with an adsorption energy of 31.64 kJ/mol. This calculated value for X-type faujasite was found in the interval of the adsorption energy of H2PO4− on hydrated Fe oxide (94.4 kJ/mol) and modified polyether sulfone (22.5 kJ/mol), and the calculated adsorption energy of the molecule on Y-type faujasite coincides with the reported value for this adsorbate on Mg/Ca-modified biochar structures. The molecular conformations of the adsorbate on the two studied models are very different, so the difference between the adsorption energy values of each type of zeolite model is comprehensible. On the one hand, the oxygen atoms of the molecule formed a bidentate complex with the hydrogen atoms of the pore in the X-type faujasite model, and the O-H distance was 1.5 Ǻ. On the other hand, an adsorbed oxygen atom of the phosphate was placed on a hydrogen atom at site II of the Y-type faujasite zeolite, and two of the hydrogen atoms of the phosphate were placed on the oxygen atoms. The Bader analysis results indicated that the negative charge of the phosphate anions was delocalized on the zeolites protons. The hydroxy groups of the phosphate form bonds between their hydrogen atoms and the oxygen atoms of the zeolite porous structure; therefore, we concluded that these sites have an alkaline character. The aim of this study was to include a computational analysis of possible phosphate adsorption mechanisms in faujasite zeolites that can be confirmed by experimental tests, and hence contribute to the generation of new technologies for capturing pollutant molecules in wastewater. The results are in agreement with the experimental information concerning the influence of pH on the adsorption activity of phosphate adsorption on zeolites.

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Ab Initio Studies on Hematite Surface and the Adsorption of Phosphate

Cited by 5 publications

References 23 publications

Preparation of iron oxide mesoporous magnetic microparticles as novel multidrug carriers for synergistic anticancer therapy and deep tumor penetration

Preparation of iron oxide mesoporous magnetic microparticles as novel multidrug carriers for synergistic anticancer therapy and deep tumor penetration

Chemical Origin of Sodium Phosphate Interactions on Iron and Iron Oxide Surfaces by First Principle Calculations

Computational Study of the Adsorption of Phosphates as Wastewater Pollutant Molecules on Faujasites

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