Konstantinos Simeonidis

Aristotle University of Thessaloniki | AUTH · Department of Solid State Physics

Minimizing food wastes and finding a second life use for industrial residuals have become some of the top priorities of modern society. This work considers the use of spent eggs and mussels shells, as well as marble dust, as raw sources to develop nanoparticles involving renewable resources in both their preparation and adoption in technological ap...

Tin oxide nanoparticles optimized to capture low concentrations of hexavalent chromium from water were developed through a facile, scalable, and low-cost one-step solar vapor deposition methodology. Considering the preservation of high electron donation capacity as the key to support the reduction of mobile Cr(VI) into insoluble forms, the growth o...

This work introduces a continuous flow process for the implementation of magnetic nanoadsorbents in drinking water treatment practices based on their complete recovery using a rotary separation setup with an arrangement including the use of permanent magnets. Magnetostatic analysis and computational fluid dynamics were combined to simulate the gene...

Correction for ‘Enhanced detoxification of Cr ⁶⁺ by Shewanella oneidensis via adsorption on spherical and flower-like manganese ferrite nanostructures’ by Diana S. Raie et al. , Nanoscale Adv. , 2023, https://doi.org/10.1039/d2na00691j.

Maximizing the safe removal of hexavalent chromium (Cr6+) from waste streams is an increasing demand due to the environmental, economic and health benefits. The integrated adsorption and bio-reduction method can be applied for the elimination of the highly toxic Cr6+ and its detoxification. This work describes a synthetic method for achieving the b...

This research examined a scenario for the recovery of a high-capacity Cr(VI) adsorbent, consisting of Sn6O4(OH)4, after reaching its operational lifetime. To accomplish this target, a sequence of processes involving the spent adsorbent’s decomposition, the separation of Sn/Cr ions, and Sn6O4(OH)4 reconstruction was investigated. Characterization of...

A new class of inorganic/biobased nanocomposites is introduced for the efficient removal of hexavalent chromium from drinking water in compliance to the new concentration levels described by European Union legislation as safe (25 μg/L). Studied nanocomposites are based on the combination of Sn(II) oxy-hydroxides which serve as a reductant of Cr(VI)...

Magnetic nanoparticles remain in the focus of intense research since they exhibit a rich variety of magnetic phenomena when compared to their bulk counterparts, giving rise to a novel set of applications with great importance to everyday human activities in the fields of information technology, environmental protection, and biomedicine. This chapte...

Proper tuning of hydroxyl excess offers multiple options for the implementation of monodisperse magnetically responsive nanoparticles in drinking water technology. Results concerning Cr(VI) uptake indicate that a small increase in hydroxyl excess features synthesized nanoparticles with an uptake capacity of 2.5 mg/g owing to the decrease in particl...

The impact of hydroxyl excess as defined by the Fe(II)/hydroxide ratio during the synthesis of Fe3O4 nanoparticles by oxidative precipitation of FeSO4 was examined as a critical parameter determining the potential for Cr(VI) uptake from polluted water. Various samples were prepared by varying the OH− excess in the range of −0.10 up to +0.03 M and c...

This chapter summarizes the recent advances in the development and evaluation of biomass-derived nanocomposites consisting of a carbon-based network and inorganic nanoparticles distributed on it. The preparation routes and the typical properties of the raw, thermally treated, and modified biomass substances are first described and then, extended to...

The use of magnetic nanoparticles (MNPs) to locally increase the temperature at the nanoscale under the remote application of alternating magnetic fields (magnetic particle hyperthermia, MHT) has become an important...

this link https://www.sciencedirect.com/science/article/pii/S0013935121013499 provides free access. This work attempts to shed light on whether the COVID-19 pandemic rides on airborne pollution. In particular, a two-city study provides evidence that PM2.5 contributes to the timing and severity of the epidemic, without adjustment for confounders. T...

A magnetic nanocomposite, consisting of Fe3O4 nanoparticles embedded into a Mg/Al layered double hydroxide (LDH) matrix, was developed for cancer multimodal therapy, based on the combination of local magnetic hyperthermia and thermally induced drug delivery. The synthesis procedure involves the sequential hydrolysis of iron salts (Fe 2+ , Fe 3+) an...

The optimum dose of MgO, in mining wastes/by-products of magnesite mine "Grecian Magnesite SA" (Chalkidiki, N. Greece), containing mainly serpentine ores, was calculated in order to maximize the formation of desirable olivine (forsterite) after thermal treatment at 1300 o C, aiming to upgrade their refractory properties and find alternative uses un...

The aim of the study was to investigate the effect of iron oxide (Fe) and silver (Ag) nanoparticles (NPs) on ram semen. A skim milk extender without antibiotics was used as a diluent of 21 ejaculates (8 rams; 2–3 ejaculates/ram). The groups of control (C; semen without NPs), Fe NPs (3.072 mg Fe3O4/mL semen), and Ag NPs (2.048 mg Ag-Fe/mL semen) wer...

Magnetic nanoparticles can generate heat when exposed to an alternating magnetic field. Their heating efficacy is governed by their magnetic properties that are in turn determined by their composition, size and morphology. Thus far, iron oxides (e.g., magnetite, Fe3O4) have been the most popular materials in use, though recently bimagnetic core-she...

Elevated concentrations of heavy metals in drinking water resources and industrial or urban wastewater pose a serious threat to human health and the equilibrium of ecosystems [...]

We report the synthesis of nanocomposites made of silica nanoparticles whose six surface dimples are decorated with magnetic maghemite nanoparticles and their use for detection and recovery of arsenic in aqueous media. Precursor silica nanoparticles have aminated polystyrene chains at the bottom of their dimples and the maghemite nanoparticles are...

Due to their small dimensions, airborne particles are able to penetrate through inhalation into many human organs, from the lungs to the cardiovascular system and the brain, which can threaten our health. This work establishes a novel approach of collecting quantitative data regarding the fraction, the composition and the size distribution of combu...

Objectives To examine the impact of concentrations of ambient fine particulate matter (PM2.5) air pollution on the incidence of COVID-19. Methods Publicly available data of COVID-19 deaths in March/October 2020 were compared with concentrations of PM2.5 measured in previous years at urban and suburban areas in Thessaloniki. Similar publicly availa...

This study examines the development of a nanocomposite consisting of iron oxy-hydroxides (FeOOH) embedded on magnetite (Fe 3 O 4) nanocarriers, towards its application for the simultaneous uptake of As(V) and Sb(V) ionic forms at concentrations below drinking water regulation and its magnetically-assisted recovery at the end of the process. Conside...

The importance of magnesite for the EU economy and industry is very high, making the understanding of their genesis for the exploration for new deposits a priority for the raw materials scientific community. Towards this direction, the study of the magnesite-hosting ultramafic rocks can be proved very useful. For the present study, ultramafic rock...

The purpose of the present work was to study the corrosion protection that relatively low-cost magnesium hydroxide coatings offer to concrete by stabilizing the surface pH. To facilitate the material’s adhesive ability, methyl-cellulose and carboxymethyl-cellulose were used as environmentally friendly additives in three different concentrations, 1,...

This study examined the effect of Fe3O4 nanoparticles on boar semen. Beltsville thawing solution without antibiotics was used to extend ejaculates from 5 boars (4 ejaculates/boar). Semen samples of control group (C) and group with Fe3O4 (Fe; 0.192 mg/mL semen) were incubated under routine boar semen storage temperature (17 °C) for 0.5 h and nanopar...

Magnetic particle hyperthermia, in which colloidal nanostructures are exposed to an alternating magnetic field, is a promising approach to cancer therapy. Unfortunately, the clinical efficacy of hyperthermia has not yet been optimized. Consequently, routes to improve magnetic particle hyperthermia such as designing hybrid structures comprised from...

The surface configuration of tetravalent manganese feroxyhyte (TMFx) was appropriately modified to achieve higher negative surface charge density and, hence, to improve its efficiency for the removal of dissolved Cd and Pb mostly cationic species from water at pH values commonly found in surface or ground waters. This was succeeded by the favorable...

Elevated concentrations of heavy metals in drinking water resources and industrial or urban wastewater pose a serious threat to human health and the equilibrium of ecosystems. During the last few decades, authorities have tended to set more strict regulations on acceptable limits challenging the improvement of conventional treatment technologies or...

Continuous processes are always preferred over batch ones when reproducible and scalable industrial procedures are needed. This work illustrates the production of magnetite nanoparticles by oxidative precipitation in aqueous media, following a continuous approach that offers additional advantages. Particularly, the developed reaction setup succeeds...

Interface induced phenomena in layered magnetic/non-magnetic structures have led to big discoveries, such as giant magnetoresistance, which has defined the field of spintronics. Interfaces are capable of inducing magnetism even in non-magnetic layers, like platinum. Here, we investigated the static magnetic properties of modified interfaces in Fe/P...

Despite significant risks to human health due to elevated Cr(VI) concentrations in drinking water, a selective adsorbent capable of purifying water before consumption is still not commercially available. This work introduces an integrated household water filtration setup, for point-of-use applications, loaded with a tin-based Cr(VI)-oriented adsorb...

Magnetic particle hyperthermia, in which colloidal nanostructures are exposed to an alternating magnetic field, is a promising approach to cancer therapy. Unfortunately, the clinical efficacy of hyperthermia has not yet been optimized. Consequently, routes to improve magnetic particle hyperthermia such as designing hybrid structures comprised from...

In magnesite-producing mines, the initial extraction of the ore is followed by a series of processes for the separation of magnesite from the host ultramafic rock, with the latter considered the by-product of the separation processes. Due to the serpentinization of the ultramafic rocks and the consequent alteration of the primary minerals olivine a...

Qualitative and quantitative characterization of seven samples (W 1-W 7), which were collected from various grades from "Rachoni" magnesite mine of "Grecian Magnesite SA" company in Gerakini, Chalkidiki, Greece, was performed in this study. The characterization was aiming to their evaluation regarding the possibility of upgrading their properties u...

The presence of antimony in water remains a major problem for drinking water technology, defined by the difficulty of available adsorbents to comply with the very low regulation limit of 5 μg/L for the dominant Sb(V) form. This study attempts to develop a new class of water adsorbents based on the combination of amorphous iron oxy-hydroxide with Fe...

The implementation of nanotechnology in drinking water treatment is a very promising field for applied research. A major part of this effort focuses on the reduction of the dimensionality of the conventional cost-effective adsorbents that have been successfully used for decades. The development of engineered nanoparticles has the potential to provi...

Η παρούσα εφεύρεση αναφέρεται στη μέθοδο σύνθεσης νανοσωματιδίων γεωμετρίας πυρήνα-φλοιού που αποτελούνται από μια εσωτερική μαγνητική φάση και επικάλυψη από μια ενδιάμεση στρώση υδροξυ-οξειδίου του σιδήρου και ενός πολυστρωματικού διπλού υδροξειδίου δισθενούς-τρισθενούς μετάλλου με υποκατάσταση ανθρακικών ιόντων από θειικά και μοριακό τύπο Μ2+1-xM...

Magnetic particle hyperthermia is a promising cancer therapy, but a typical applicability problem is to localize heat solely to malignant regions sparing healthy surrounding tissues. By simultaneous application of a static magnetic field together with the hyperthermia alternating magnetic field, heating focus may be achieved in small tunable region...

The implementation of nanotechnology in drinking water treatment is a very promising field for applied research. A major part of this effort focuses on reducing the building units dimensions in the existing inorganic adsorbents used for the purification of water versus heavy metal species. The development of engineered nanoparticles has the potenti...

Chromium (Cr(VI)) is a very toxic and carcinogenic element, which is widely present in groundwaters, mainly due to geogenic conditions. The limit of Cr(VI) in drinking water is expected to be reduced to 10 μg/L in both the USA and the European Union. Recent literature findings indicated that the most efficient process in reducing Cr(VI) levels to b...

The present invention relates to a method of producing an adsorbant consisting of a single phase of tetravalent manganese feroxyhite (6-Fe(i.X)MnxOOH) with a negatively charged particle surface, in which a portion of the iron has been isomorphically substituted by manganese atoms at a proportion of 0.05-25%. Its production is performed in a two con...

The present invention refers to the method for synthesis an absorbent material consisting of a phase of tetravalent manganese feroxyhyte (δ-Fe(1-x)MnxOOH) with a negatively charged grain surface in which a percentage of iron-has been isomorphically substituted by manganese atoms at 0,05-25%. Its' production is carried out in two continuous flow sti...

Novel adsorbents consisting of ZnFe2O4/Zn5(OH)6(CO3)2 (hydrozincite) nanocomposite materials were studied for efficient As(V) removal from water. Nanocomposites were synthesized by the co-precipitation of Zn and Fe salts in alkaline conditions. Depending on the Zn/Fe molar ratio, a variety of materials was produced with different ZnFe2O4/Zn5(OH)6(C...

The development of a novel adsorbent based on Sn(II) oxy-hydroxide nanoparticles and the optimization of main synthesis parameters was examined for the efficient removal of hexavalent chromium at low residual concentration levels. The aqueous hydrolysis of Sn(II) salts in a continuous-flow process was evaluated as an effective method to synthesize...

La invención se refiere a una composición núcleo-envuelta que comprende un núcleo de nanopartículas magnéticas y una envoltura de un compuesto doble hidróxido estratificado, y su procedimiento de obtención. Además, la invención se refiere al uso de dicha composición para purificar agua contaminada, especialmente útil para la eliminación de contamin...

The present invention refers to a method for the synthesis of an adsorbent which is realized by the production of a bivalent tin oxy-hydroxide [SnxOy(OH)z], with 1<x<6, 0<y<4 and 0<z<4, into a two-stage continuous flow reactor and a pH range 2-12. The material can be applied for the removal of hexavalent chromium, bromate, chlorate and perchlorate...

The objective of this study was the detailed characterization of “technogenic” magnetic particles (TMPs) separated from contaminated industrial soils. Moreover, non-carcinogenic health risk posed by “technogenic” metals Pb and Zn via the ingestion exposure pathway was carried out. Volume magnetic susceptibility (κ) was measured directly in the fiel...

The invention relates to core-shell composition comprising a core of magnetic nanoparticles and a shell of a layered double hydroxide compound, and its procedure of obtainment. Furthermore, the invention refers to the use of said composition for purifying contaminated water, especially useful for the removal of harmful contaminants like arsenic, to...

The spin-pumping mechanism is probed through a tunnelling MgO interlayer in Fe/Pt bilayers. We show by ferromagnetic resonance technique and spin-pumping experiments that spin currents can tunnel through the MgO interlayer for thickness up to 2~{nm} and can produce significant voltages in the Pt layer. The electrical detection of spin-pumping furth...

This study evaluates the efficiency of iron-based oxy-hydroxides to remove antimony from groundwater to meet the requirements of drinking water regulations. Results obtained by batch adsorption experiments indicated that the qualified iron oxy-hydroxide (FeOOH), synthesized at pH 4 for maintaining a high positive charge density (2.5 mmol OH−/g) ach...

The mineralogy, morphology, and chemical composition of magnetic fractions separated from fly ashes (FAs) originating from Greek lignite-burning power plants was investigated. The oral bioaccessibility of potentially harmful elements (PHEs) from the fly ash magnetic fractions (FAMFs) was also assessed using in vitro gastrointestinal extraction (BAR...

Promising advances in nanomedicine such as magnetic hyperthermia rely on a precise control of the nanoparticle performance in the cellular environment. This constitutes a huge research challenge due to difficulties for achieving a remote control within the human body. Here we report on the significant double role of the shape of ellipsoidal magneti...

BACKGROUND: Over recent decades, there has been increasing global concern over public health impacts related to water pollution with arsenic. With the development of nanotechnology, nanomaterials are being proposed as alternative agents for water treatment. This study focuses on the use of core-shell nanoparticles as secondary receptors able to ope...

In this work, we present the arrangement of Fe3O4 magnetic nanoparticles into 3D linear chains and its effect on magnetic particle hyperthermia efficiency. The alignment has been performed under a 40 mT magnetic field in an agarose gel matrix. Two different sizes of magnetite nanoparticles, 10 and 40 nm, have been examined, exhibiting room temperat...

In this work, we present the arrangement of Fe3O4 magnetic nanoparticles into 3D linear chains and its effect on magnetic particle hyperthermia efficiency. The alignment has been performed under a 40 mT magnetic field in an agarose gel matrix. Two different sizes of magnetite nanoparticles, 10 and 40 nm, have been examined, exhibiting room temperat...

The design and engineering of earth-abundant catalysts that are both cost-effective and highly active for water splitting is a crucial challenge in a number of energy conversion and storage technologies. In this direction, herein we report the synthesis of Fe3O4@NiFexOy core-shell nano-heterostructures and the characterization of their electrocatal...

The fabrication procedure of hollow iron oxide nanoparticles with a large surface to volume ratio by a single-step gas condensation process at ambient temperature is presented. Fe clusters formed during the sputtering process are progressively transformed into hollow cuboids with oxide shells by the Kirkendall mechanism at the expense of oxygen cap...

This study demonstrates an optimization procedure for the development of an Hg-specified adsorbent able to comply with the regulation limit for drinking water of 1μg/L. On this purpose, the synthesis of Mn(IV)-feroxyhyte was modified to achieve high negative charge density by combining alkaline and extreme oxidizing conditions. In particular, preci...

The feasibility of implementing a Sn(II) oxy-hydroxide (Sn6O4(OH)4) for the reduction and adsorption of Cr(VI) in drinking water treatment was investigated using XAFS spectroscopies at the Cr-K-edge. The analysis of the Cr-K-edge XANES and EXAFS spectra verified the effective use of Sn6O4(OH)4 for successful Cr(VI) removal. Adsorption isotherms, as...

Abstract The implementation of amorphous tetravalent manganese feroxyhyte (TMFx) nanoparticles, prepared via co-precipitation synthesis, as an efficient As(V)-removal material is investigated using X-ray absorption fine structure (XAFS) spectroscopy at the Fe-, Mn- and As-K-edges. The optimum synthesis conditions and chemical composition of the TMF...

The reduction mechanism and adsorption behaviour of Cr(VI) onto Tin(II) oxy- hydroxides are investigated using Cr-K edge X-ray absorption fine structure (XAFS) spectroscopies. The synthesis of the Sn oxy-hydroxide proceeds via hydrolysis of SnSO4. The successful reduction of Cr(VI) was identified by the analysis of the Cr-K edge XANES spectra where...

The importance of magnetic interactions within an individual nanoparticle or between adjacent ones is crucial not only for the macroscopic collective magnetic behavior but for the AC magnetic heating efficiency as well. On this concept, single- (MFe2O4 where M=Fe, Co, Mn) and core-shell ferrite nanoparticles consisting of a magnetically softer (MnF...