Bleaching effectiveness and cytotoxicity of new experimental formulation of niobium-based bleaching gel.

Objectives: The development of new bleaching agents with minimum concentration of hydrogen peroxide (HP), without adverse effects, and with bleaching effectiveness, has great clinical relevance. The aim of this study was to evaluate the bleaching efficacy and cytotoxicity of a new niobium-based bleaching gel, compared to already available HP-based gels.

Materials And Methods: For the bleaching efficacy analysis, 40 bovine incisors were randomly divided into 4 groups according to the established bleaching protocol: control, untreated; 35HP, 35% HP bleaching gel; 6HP, 6% HP bleaching gel; NbHP, niobium gel associated with 3% HP gel.

Effect of pH, ionic strength, and temperature on the adsorption behavior of Acid Blue 113 onto mesoporous carbon.

Mesoporous carbon (MC) derived from cassava starch was used to remove Acid Blue 113 azo dye from aqueous solutions. The influence of temperature, pH, ionic strength, and the adsorbent dose was investigated in a set of batch experiments. Experimental data showed that Acid Blue 113 adsorption was higher in the acid pH range than in the alkaline one, that dye adsorption increases when the ionic strength and temperature increase, and that adsorption results presented a good correlation with the Langmuir isotherm model.

Use of iron ore tailing from tailing dam as catalyst in a fenton-like process for methylene blue oxidation in continuous flow mode.

The global demand for iron ore with high iron contents to supply the steel industry is associated, in most countries, with the generation of tailings from mineral processing. The chemical compositions of iron ore tailings (basically FeO and SiO) make them an excellent candidate as a catalyst for advanced oxidation processes (AOPs), especially the Fenton process and its derivatives. Therefore, this paper aimed to transform iron ore tailings from tailing dams into catalysts able to activate HO for the purpose of treating, in a continuous flow, effluents contaminated with organic dyes, employing methylene blue as a model molecule.

Removal of mercury(II) from contaminated water by gold-functionalised FeO magnetic nanoparticles.

FeO nanoparticles were prepared by co-precipitation of Fe and Fe and then modified with Au to produce an effective adsorbent (FeO/Au) for aqueous Hg(II) in contaminated water. Rietveld refinement on the XRD pattern confirmed that the FeO/Au was synthesised. Mössbauer spectra exhibited broad and asymmetric resonance lines with two sextets which can be assigned to tetrahedral Fe; and octahedral Fe/Fe.

Activated carbon prepared from coffee pulp: potential adsorbent of organic contaminants in aqueous solution.

The processing of coffee beans generates large amounts of solid and liquid residues. The solid residues (pulp, husk and parchment) represent a serious environmental problem and do not have an adequate disposal mechanism. In this work, activated carbons (ACs) for adsorption of organic compounds were prepared from coffee pulp by controlled temperature at different pulp/Na2HPO4 ratios (4:1, 2:1, 5:4 and 1:1).

Controlling the morphology and pore size of mesostructured silica nanoparticles: the role of the iron oxidation state.

We demonstrate morphology and pore size dependence of silica nanoparticles (SNPs) synthesized via control of the iron oxidation state. In the absence of any Fe species, only spherical SNPs are produced, whereas in the presence of Fe³⁺ and Fe²⁺ ions, SNPs with rod-like and nanosheet morphologies, respectively, are formed. The average pore size increases from 1.

A friendly environmental material: iron oxide dispersed over activated carbon from coffee husk for organic pollutants removal.

A friendly environmental material for organic contaminants removal was prepared in this work: small particles of iron oxide dispersed over activated carbon from coffee waste for Fenton-like application. The materials were characterized by means of XRD, N2 physisorption, Mössbauer spectroscopy and H2 pulse titration. The composites showed very good catalytic performances for methylene blue organic dye oxidation.