Impact of Pyrolysis Temperature on the Physical and Chemical Properties of Non-Modified Biochar Produced from Banana Leaves: A Case Study on Ammonium Ion Adsorption.

Given the current importance of using biochar for water treatment, it is important to study the physical-chemical properties to predict the behavior of the biochar adsorbent in contact with adsorbates. In the present research, the physical and chemical characteristics of three types of biochar derived from banana leaves were investigated, which is a poorly studied raw material and is considered an agricultural waste in some Latin American, Asian, and African countries. The characterization of non-modified biochar samples pyrolyzed at 300, 400, and 500 °C was carried out through pH, scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and specific surface area measurements.

Ammonium ion removal from aqueous solutions in the presence of organic compounds, using biochar from banana leaves. Competitive isotherm models.

Industrial, e.g. food industrial and domestic wastewaters contain huge amount of compounds causing eutrophication, and should be removed with high cost during wastewater treatment.

Effects of Different TiO/CNT Coatings of PVDF Membranes on the Filtration of Oil-Contaminated Wastewaters.

Six different TiO/CNT nanocomposite-coated polyvinylidene-fluoride (PVDF) microfilter membranes (including -OH or/and -COOH functionalized CNTs) were evaluated in terms of their performance in filtering oil-in-water emulsions. In the early stages of filtration, until reaching a volume reduction ratio (VRR) of ~1.5, the membranes coated with functionalized CNT-containing composites provided significantly higher fluxes than the non-functionalized ones, proving the beneficial effect of the surface modifications of the CNTs.

Hungarian and Indonesian rice husk as bioadsorbents for binary biosorption of cationic dyes from aqueous solutions: A factorial design analysis.

The wastewater of the dye industry can be characterized by a complex chemical composition and consists of numerous dyes. Bioadsorbents are increasingly applied for the biosorption of dyes because they are inexpensive and environmentally friendly. Rice husk (RH) is a potential agricultural waste that can be converted into a bioadsorbents for the biosorption of cationic dyes.

Novel Magnetic Composite Materials for Dental Structure Restoration Application.

In general, magnetic nanoparticles are not often used in dental applications due to some limitations of these materials, such as aggregation problems and low mechanical and chemical resistance but also esthetic problems due to their black color. Our research presents the synthesis of novel magnetic dental composite materials based on magnetic nanoparticles, functionalized and properly coated to overcome the limitations of using magnetic nanoparticles in dental applications. The composites were prepared using a preparation flow containing several integrated reaction steps used previously sequentially.

Amino Acid Complexes of Zirconium in a Carbon Composite for the Efficient Removal of Fluoride Ions from Water.

Amino acid complexes of zirconia represent an entirely new class of materials that were synthesized and studied for the first time for the decontamination of fluoride ion containing aqueous solutions. Glutamic and aspartic acid complexes of zirconia assembled with thin carbon (stacked graphene oxide) platelets deriving from graphite oxide (GO) were synthesized by a two-step method to prepare adsorbents. The characterization of the complexes was carried out using infrared spectroscopy to determine the functional groups and the types of interaction between the composites and fluoride ions.

Colloidal Stability of Silica-Modified Magnetite Nanoparticles: Comparison of Various Dispersion Techniques.

The production of stable and homogeneous batches during nanoparticle fabrication is challenging. Surface charging, as a stability determinant, was estimated for 3-aminopropyltriethoxysilane (APTES) coated pre-formed magnetite nanoparticles (MNPs). An important consideration for preparing stable and homogenous MNPs colloidal systems is the dispersion stage of pre-formed samples, which makes it feasible to increase the MNP reactive binding sites, to enhance functionality.

Fabrication, Microstructure and Colloidal Stability of Humic Acids Loaded FeO/APTES Nanosorbents for Environmental Applications.

Nowadays, numerous researches are being performed to formulate nontoxic multifunctional magnetic materials possessing both high colloidal stability and magnetization, but there is a demand in the prediction of chemical and colloidal stability in water solutions. Herein, a series of silica-coated magnetite nanoparticles (MNPs) has been synthesized via the sol-gel method with and without establishing an inert atmosphere, and then it was tested in terms of humic acids (HA) loading applied as a multifunctional coating agent. The influence of ambient conditions on the microstructure, colloidal stability and HA loading of different silica-coated MNPs has been established.

Tunable Magnetic Hyperthermia Properties of Pristine and Mildly Reduced Graphene Oxide/Magnetite Nanocomposite Dispersions.

We present a study on the magnetic hyperthermia properties of graphene oxide/magnetite (GO/MNP) nanocomposites to investigate their heat production behavior upon the modification of the oxidation degree of the carbonaceous host. Avoiding the harsh chemical conditions of the regular in situ co-precipitation-based routes, the oppositely charged MNPs and GO nanosheets were combined by the heterocoagulation process at pH ~ 5.5, which is a mild way to synthesize composite nanostructures at room temperature.

Effects of Modified Magnetite Nanoparticles on Bacterial Cells and Enzyme Reactions.

Current paper presents biological effects of magnetite nanoparticles (MNPs). "Relations of MNP' characteristics (zeta-potential and hydrodynamic diameters) with effects on bacteria and their enzymatic reactions were the main focus.".

The Fe(citrate) Fenton reaction under physiological conditions.

The Fenton reaction of Fe(citrate) in the presence and absence of bicarbonate (HCO) is studied. It is found that the rate constant of the Fenton reaction (k) increases with increasing [citrate]. k also increase with increasing [HCO]; this effect is most significant at biological citrate concentrations.

Cobalt Carbonate as an Electrocatalyst for Water Oxidation.

Co salts in the presence of HCO /CO in aqueous solutions act as electrocatalysts for water oxidation. It comprises of several key steps: (i) A relatively small wave at E ≈0.71 V (vs.

Chondroitin-Sulfate-A-Coated Magnetite Nanoparticles: Synthesis, Characterization and Testing to Predict Their Colloidal Behavior in Biological Milieu.

Biopolymer coated magnetite nanoparticles (MNPs) are suitable to fabricate biocompatible magnetic fluid (MF). Their comprehensive characterization, however, is a necessary step to assess whether bioapplications are feasible before expensive in vitro and in vivo tests. The MNPs were prepared by co-precipitation, and after careful purification, they were coated by chondroitin-sulfate-A (CSA).

Carbonate-radical-anions, and not hydroxyl radicals, are the products of the Fenton reaction in neutral solutions containing bicarbonate.

The Fenton reaction, Fe(HO) + HO → Oxidizing product, is of major importance in biology as the major cause of oxidative stress, and in advanced oxidation processes. It is commonly assumed that ·OH is the product of the Fenton reaction. The results presented herein point out that ·OH is indeed the oxidizing product in acidic solutions for [Fe(HO)] > [HO]; Fe is the active oxidizing product in neutral solutions; in slightly acidic solutions for [HO] > [Fe(HO)] a mixture of ·OH and Fe is formed.

PEGylation of Superparamagnetic Iron Oxide Nanoparticles with Self-Organizing Polyacrylate-PEG Brushes for Contrast Enhancement in MRI Diagnosis.

For biomedical applications, superparamagnetic nanoparticles (MNPs) have to be coated with a stealth layer that provides colloidal stability in biological media, long enough persistence and circulation times for reaching the expected medical aims, and anchor sites for further attachment of bioactive agents. One of such stealth molecules designed and synthesized by us, poly(polyethylene glycol methacrylate--acrylic acid) referred to as P(PEGMA-AA), was demonstrated to make MNPs reasonably resistant to cell internalization, and be an excellent candidate for magnetic hyperthermia treatments in addition to possessing the necessary colloidal stability under physiological conditions (Illés et al. J.

Polyelectrolyte coating on superparamagnetic iron oxide nanoparticles as interface between magnetic core and biorelevant media.

Nanoparticles do not exist in thermodynamical equilibrium because of high surface free energy, thus they have only kinetic stability. Spontaneous changes can be delayed by designed surface coating. In biomedical applications, superparamagnetic iron oxide nanoparticles (SPIONs) require an optimized coating in order to fulfil the expectation of medicine regulatory agencies and ultimately that of biocompatibility.

The effect of hydroxyl moieties and their oxosubstitution on bile acid association studied in floating monolayers.

Bile salt aggregates are promising candidates for drug delivery vehicles due to their unique fat-solubilizing ability. However, the toxicity of bile salts increases with improving fat-solubilizing capability and so an optimal combination of efficient solubilization and low toxicity is necessary. To improve hydrophilicity (and decrease toxicity), we substituted hydroxyl groups of several natural bile acid (BA) molecules for oxogroups and studied their intrinsic molecular association behavior.

Mechanism of in situ surface polymerization of gallic acid in an environmental-inspired preparation of carboxylated core-shell magnetite nanoparticles.

Magnetite nanoparticles (MNPs) with biocompatible coatings are good candidates for MRI (magnetic resonance imaging) contrasting, magnetic hyperthermia treatments, and drug delivery systems. The spontaneous surface induced polymerization of dissolved organic matter on environmental mineral particles inspired us to prepare carboxylated core-shell MNPs by using a ubiquitous polyphenolic precursor. Through the adsorption and in situ surface polymerization of gallic acid (GA), a polygallate (PGA) coating is formed on the nanoparticles (PGA@MNP) with possible antioxidant capacity.

Ketoprofen removal by O₃ and O₃/UV processes: kinetics, transformation products and ecotoxicity.

Ozonation (O3) and its combination with ultraviolet radiation (O3/UV) were used to decompose ketoprofen (KET). Depending on the initial KET concentration, fourteen to fifty time's faster KET degradation was achieved using combined O3/UV method compared to simple ozonation. Using both methods, formation of four major aromatic transformation products were observed: 3-(1-hydroxyethyl)benzophenone, 3-(1-hydroperoxyethyl) benzophenone, 1-(3-benzoylphenyl) ethanone and 3-ethylbenzophenone.

Chemical and colloidal stability of carboxylated core-shell magnetite nanoparticles designed for biomedical applications.

Despite the large efforts to prepare super paramagnetic iron oxide nanoparticles (MNPs) for biomedical applications, the number of FDA or EMA approved formulations is few. It is not known commonly that the approved formulations in many instances have already been withdrawn or discontinued by the producers; at present, hardly any approved formulations are produced and marketed. Literature survey reveals that there is a lack for a commonly accepted physicochemical practice in designing and qualifying formulations before they enter in vitro and in vivo biological testing.

Hydroxyl radical induced degradation of ibuprofen.

Pulse radiolysis experiments were used to characterize the intermediates formed from ibuprofen during electron beam irradiation in a solution of 0.1mmoldm(-3). For end product characterization (60)Co γ-irradiation was used and the samples were evaluated either by taking their UV-vis spectra or by HPLC with UV or MS detection.

Designed polyelectrolyte shell on magnetite nanocore for dilution-resistant biocompatible magnetic fluids.

Magnetite nanoparticles (MNPs) coated with poly(acrylic acid-co-maleic acid) polyelectrolyte (PAM) have been prepared with the aim of improving colloidal stability of core-shell nanoparticles for biomedical applications and enhancing the durability of the coating shells. FTIR-ATR measurements reveal two types of interaction of PAM with MNPs: hydrogen bonding and inner-sphere metal-carboxylate complex formation. The mechanism of the latter is ligand exchange between uncharged -OH groups of the surface and -COO(-) anionic moieties of the polyelectrolyte as revealed by adsorption and electrokinetic experiments.

Water in contact with magnetite nanoparticles, as seen from experiments and computer simulations.

The adsorption of water vapor at the surface of magnetite nanoparticles has been investigated both by experimental and by computer simulation methods. The water vapor adsorption/desorption isotherm has been measured on freshly prepared magnetite nanocrystals of the size below 10 nm. The change of the isosteric heat of adsorption with the surface coverage has been determined from the temperature dependence of this isotherm using the isosteric method.