Wetting and Imbibition Characteristics of Biofilms Grown on Stainless Steel.

This study aims to provide insights into biofilm resistance associated with their structural properties acquired during formation and development. On this account, the wetting and imbibition behavior of dehydrated biofilms grown on stainless steel electropolished substrates is thoroughly examined at different biofilm ages. A polar liquid (water) and a non-polar liquid (diiodomethane) are employed as wetting agents in the form of sessile droplets.

Magnetic solid-phase extraction of caffeine from surface water samples with a micro-meso porous activated carbon/FeO nanocomposite prior to its determination by GC-MS.

A novel micro-meso porous activated carbon/FeO (Bm) composite was synthesized from the active charcoal precursor BAX-1500 and used in the magnetic solid-phase extraction (MSPE) of caffeine prior to its determination by gas chromatography-mass spectrometry (GC-MS). The main factors affecting the extraction and desorption steps of the MSPE procedure were investigated and optimized. These factors include extraction time, sorbent mass and salt addition for the adsorption step and type of eluent, desorption time and volume of desorption solution for the desorption step.

Chromium(VI) Removal from Water by Lanthanum Hybrid Modified Activated Carbon Produced from Coconut Shells.

Cr(VI) is considered to be the most hazardous and toxic oxidation state of chromium and hence the development of effective removal technologies, able to provide water with Cr(VI) below the drinking water limits (US EPA 100 μg/L, European Commission 50 μg/L, which will be reduced to 25 by 2036) is a very important issue in water treatment. This study aimed at examining the performance of activated carbon produced from coconut shells, modified by lanthanum chloride, for Cr(VI) removal from waters. The structure of the formed material (COC-AC-La) was characterized by the application of BET, FTIR and SEM techniques.

Green Bioanalytical Applications of Graphene Oxide for the Extraction of Small Organic Molecules.

Bioanalysis is the scientific field of the quantitative determination of xenobiotics (e.g., drugs and their metabolites) and biotics (e.

Sample Preparation Using Graphene-Oxide-Derived Nanomaterials for the Extraction of Metals.

Graphene oxide is a compound with a form similar to graphene, composed of carbon atoms in a sp single-atom layer of a hybrid connection. Due to its significant surface area and its good mechanical and thermal stability, graphene oxide has a plethora of applications in various scientific fields including heterogenous catalysis, gas storage, environmental remediation, etc. In analytical chemistry, graphene oxide has been successfully employed for the extraction and preconcentration of organic compounds, metal ions, and proteins.

Adsorption of DBT and 4,6-DMDBTon nanoporous activated carbons: the role of surface chemistry and the solvent.

Adsorption of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) from solutions in hexane and hexadecane respectively as well as in acetonitrile for both thiophenic compounds was investigated with sorbents of three activated carbons and their oxidized counterparts. The raw sorbents were of different surface acidity. Oxygen surface groups created after oxidation increased the adsorption of thiophenic compounds via polar interactions.

Magnetic Solid-Phase Extraction of Organic Compounds Based on Graphene Oxide Nanocomposites.

Graphene oxide (GO) is a chemical compound with a form similar to graphene that consists of one-atom-thick two-dimensional layers of sp-bonded carbon. Graphene oxide exhibits high hydrophilicity and dispersibility. Thus, it is difficult to be separated from aqueous solutions.

Metal Organic Frameworks: Synthesis and Application.

The concept of metal-organic frameworks (MOFs) was first introduced in 1990; nowadays they are among the most promising novel materials. MOFs belong to a new class of crystalline materials that consist of coordination bonds between metal clusters (e.g.

On the use of metal-organic frameworks for the extraction of organic compounds from environmental samples.

The determination of trace metals and organic contaminants in environmental samples, such as water, air, soil, and sediment, is until today a challenging process for the analytical chemistry. Metal-organic frameworks (MOFs) are novel porous nanomaterials that are composed of metal ions and an organic connector. These materials are gaining more and more attention due to their superior characteristics, such as high surface area, tunable pore size, mechanical and thermal stability, luminosity, and charge transfer ability between metals and ligands.

Graphene Oxide Based Magnetic Nanocomposites with Polymers as Effective Bisphenol-A Nanoadsorbents.

Magnetic graphene oxide was impregnated with polymers for the preparation of nanocomposite adsorbents to be examined for the adsorptive removal of a typical endocrine disruptor, bisphenol-A (BPA) from aqueous solutions. The polymers used were polystyrene, chitosan and polyaniline. The nanocomposites prepared were characterized for their structure, morphology and surface chemistry.

Synthesis of Graphene Oxide Based Sponges and Their Study as Sorbents for Sample Preparation of Cow Milk Prior to HPLC Determination of Sulfonamides.

In the present study, a novel, simple, and fast sample preparation technique is described for the determination of four sulfonamides (SAs), namely Sulfathiazole (STZ), sulfamethizole (SMT), sulfadiazine (SDZ), and sulfanilamide (SN) in cow milk prior to HPLC. This method takes advantage of a novel material that combines the extractive properties of graphene oxide (GO) and the known properties of common polyurethane sponge (PU) and that makes sample preparation easy, fast, cheap and efficient. The PU-GO sponge was prepared by an easy and fast procedure and was characterized with FTIR spectroscopy.

Modified graphene oxide as manganese oxide support for bisphenol A degradation.

Sodium hydroxide modified graphene oxide was used as manganese oxide support for the preparation of three nanocomposite catalysts via an one-pot preparation route, for the degradation of an endocrine disruptor, bisphenol-A. The nanocomposites were characterized for their structure by X-ray diffraction, for their morphology with scanning electron microscopy and for their surface chemistry with Fourier transform infrared spectroscopy, potentiometric titration and thermal analysis measurements. The nanocomposites prepared showed to possess high catalytic activity for the degradation/oxidation of bisphenol-A at ambient conditions, without light irradiation and/or the addition of oxidants, which was higher than that of the pure manganese oxides and can be attributed to the synergistic effect of the manganese oxide and the modified graphene oxide.

Degradation of endocrine disruptor, bisphenol-A, on an mixed oxidation state manganese oxide/modified graphite oxide composite: A role of carbonaceous phase.

Modified graphite oxide (ΝGO) was used as a support of a manganese oxide of hausmannite type (MnO) nanocatalyst and applied for the degradation of an endocrine disruptor, bisphenol-A (BPA). The prepared nanocomposite/catalyst (NGO-MnO), as well as pure modified graphite oxide and manganese oxide, were characterized by X-ray diffraction, Scanning Electron Microscopy, nitrogen adsorption, X-ray photoelectron spectroscopy, Fourier Transform Infrared Spectroscopy, and potentiometric titration. The maximum removal activity for all the materials was measured at pH = 3.

Applications of Metal-Organic Frameworks in Food Sample Preparation.

Food samples such as milk, beverages, meat and chicken products, fish, etc. are complex and demanding matrices. Various novel materials such as molecular imprinted polymers (MIPs), carbon-based nanomaterials carbon nanotubes, graphene oxide and metal-organic frameworks (MOFs) have been recently introduced in sample preparation to improve clean up as well as to achieve better recoveries, all complying with green analytical chemistry demands.

Removal of bisphenol A by Fe-impregnated activated carbons.

A commercial wood-based activated carbon and the oxidized counterpart were impregnated with iron. The two Fe-impregnated carbons were prepared and characterized for their iron content, textural characteristics, surface chemistry, and their performance for bisphenol A adsorption. Batch adsorption experiments were conducted to study the effect of pH, ionic strength, kinetics, and thermodynamic equilibrium.

Fabrication and evaluation of magnetic activated carbon as adsorbent for ultrasonic assisted magnetic solid phase dispersive extraction of bisphenol A from milk prior to high performance liquid chromatographic analysis with ultraviolet detection.

In the present study, the impregnation of a micro - meso porous activated carbon with magnetite (FeO) was successfully achieved by sonication and the magnetic activated carbon prepared (Bmi) was evaluated as a new adsorbent for ultrasonic assisted magnetic solid phase dispersive extraction of Bisphenol A (BPA) from cow milk and human breast milk samples, prior to the determination by HPLC with UV detection. The prepared Bmi was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The effect of pH on adsorption, initial concentration, contact time and desorption were studied.

Comparison of activation media and pyrolysis temperature for activated carbons development by pyrolysis of potato peels for effective adsorption of endocrine disruptor bisphenol-A.

Activated carbon prepared from potato peels, a solid waste by product has been studied for the adsorption of an endocrine disruptor, Bisphenol-A, from aqueous solutions. The potato peels biomass was activated with H3PO4, KOH and ZnCl2 in order the effect of the activation agent to be evaluated. The activated biomass was carbonized at 400, 600 and/or 800 °C in order the effect of carbonization temperature on the texture, surface chemistry and adsorption properties to be found.

Magnetic modification of microporous carbon for dye adsorption.

In this study, impregnation of microporous activated carbon with magnetite was achieved by co-precipitation of iron salts onto activated carbon. The evaluation of the adsorption ability of this material was examined using the anionic dye Reactive Black 5 as model dye pollutant (adsorbate). The effect of pH, ionic strength, contact time and initial dye concentration were also studied.

Removal of dorzolamide from biomedical wastewaters with adsorption onto graphite oxide/poly(acrylic acid) grafted chitosan nanocomposite.

A novel graphite oxide/poly(acrylic acid) grafted chitosan nanocomposite (GO/CSA) was prepared and used as biosorbent for the removal of pharmaceutical compound (dorzolamide) from biomedical synthetic wastewaters. The performance was evaluated taking into account pH, kinetics and thermodynamics of adsorption. GO/CSA presented higher adsorption capacity in comparison with the parent materials (graphite oxide and poly(acrylic acid) grafted chitosan).

The role of chitosan as nanofiller of graphite oxide for the removal of toxic mercury ions.

The present study focuses on the role of chitosan (CS) as nanofiller of graphite oxide (GO) in order to prepare composite materials with improved Hg(II) adsorption properties. The removal of Hg(II) from aqueous solutions was studied using adsorbents as graphite oxide (GO), graphite oxide nanofilled with chitosan (GO/CS) and magnetic chitosan (GO/mCS). Many possible interactions between materials and Hg(II) were observed after adsorption and explained via characterization with various techniques (SEM/EDAX, FTIR, XRD, DTG).

Mercury(II) removal with modified magnetic chitosan adsorbents.

Two modified chitosan derivatives were prepared in order to compare their adsorption properties for Hg(II) removal from aqueous solutions. The one chitosan adsorbent (CS) is only cross-linked with glutaraldehyde, while the other (CSm), which is magnetic, is cross-linked with glutaraldehyde and functionalized with magnetic nanoparticles (Fe₃O₄). Many possible interactions between materials and Hg(II) were observed after adsorption and explained via characterization with various techniques (SEM/EDAX, FTIR, XRD, DTG, DTA, VSM, swelling tests).

Magnetic Graphene Oxide: Effect of Preparation Route on Reactive Black 5 Adsorption.

In this study, the effect of preparation route of magnetic graphene oxide (mGO) on Reactive Black 5 (RB5) adsorption was investigated. The synthesis of mGO was achieved both with (i) impregnation method (mGOi nanoparticles), and (ii) co-precipitation (mGOp nanoparticles). After synthesis, the full characterization with various techniques (SEM, FTIR, XRD, DTA, DTG, VSM) was achieved revealing many possible interactions/forces of dye-composite system.

Functionalization of graphite oxide with magnetic chitosan for the preparation of a nanocomposite dye adsorbent.

In the current study, the functionalization of graphite oxide (GO) with magnetic chitosan (Chm) was investigated to prepare a nanocomposite material (GO-Chm) for the adsorption of a reactive dye (Reactive Black 5). The synthesis mechanism was investigated by various techniques (SEM/EDAX, FTIR spectroscopy, XRD, XPS, DTA, DTG, VSM). Characterization results indicated that a significant fraction of the amines of the chitosan (i) were inserted between the GO layers and (ii) reacted with carboxyl and epoxy groups of GO, leading to its reduction and hence the destruction of the layered structure.