Application of TiO2-nanotubes/PbO2 as an anode for the electrochemical elimination of Acid Red 1 dye

Journal of Solid State Electrochemistry - In this study, galvanostatic electrolysis, through the use of the platinum supported on Ti (Ti/Pt) and Ti/TiO2-nanotubes/PbO2 anodes, was conducted in an...     

Metal Organic Framework-235 (MOF-235) Modified Carbon Paste Electrode for Catechol Determination in Water

MOF-235 is presented as an orange powder, with crystals of the octahedral formation. It was already used as adsorbent to remove different compounds from water; however, no attempts have been published about the exploration of the MOF-235 application as electrochemical sensor for organic compounds yet. MOF-235 was synthetized and after that, it was characterized by SEM, XRD and FTIR. Graphite electrodes (GEs) were modified with different MOF-235 ratio (5 %, 7 %, 10 %, 12 % and 14 %) and these modified GEs were characterized by cyclic voltammetry (CV) measurements in order to determine the effect of MOF-235 concentration on the current response. Results indicated that, a significant improvement on the current response was attained at MOF-235(10 %)/GE respect to unmodified GE. This behavior is related to the pore structure and multiple active sites on the MOF surface. The performance of the MOF-235(10 %)/GE as electrochemical sensor for detecting catechol was assessed by differential pulse voltammetry (DPV). Catechol detection response of MOF-based sensor provided a detection limit of about 12.79 μmol L⁻¹ with a correlation coefficient (R²) of about 0.9928 ranging from 12 to 514 μmol L⁻¹. Finally, MOF-235(10 %)/GE was used to determine catechol in real water matrixes.     

Exposure risk assessment of uranium intake of the milk products from the region of Pernambuco,Brazil

Journal of Radioanalytical and Nuclear Chemistry - Haloperidol (HP) is a dopamine blocking agent. HP was radiolabeled with 125I using direct electrophilic substitution. Different HP formulations...     

Influence of thermoplastic starch plasticized with biodiesel glycerol on thermal properties of pp blends

Plastics have been used in short-life products, which have presented harmful consequences for the nature, because of the low degradation rate reached by the most common polyolefins. This work evaluates the mechanical and thermal properties of pure iPP, plasticized starch (TPS) with biodiesel (TPS_Bio) or commercial (TPS_Com) glycerols, and their blends (iPP/TPS_Plas). The addition of TPS_Plas caused an increasing on the cristallinity of iPP, mainly for the compositions 90/10 and 80/20, probably due to morphological alterations such as crosslinking, that may have modified the molecular arrangement of the iPP in the presence of glycerol.     

Photoelectrochemical Properties of Sol-Gel Nb2O5 Films

Structural, optical, electro and photoelectrochemical properties of amorphous and crystalline sol-gel Nb₂O₅ coatings have been determined. The coatings are n-type semiconductor with indirect allowed transition and present an overall low quantum efficiency ( < 4%) for UV light to electric conversion. The photoconducting behavior of the coatings is discussed within the framework of the Gärtner and Södergren models. Improvement can be foreseen if Nb₂O₅ coatings can be made of 10–20 nm size nanoparticles.     

Effect of Er:YAG laser energy on the morphology of enamel/adhesive system interface

The aim of this study was to evaluate in vitro the influence of Er:YAG laser energy variation to cavity preparation on the morphology of enamel/adhesive system interface, using SEM. Eighteen molars were used and the buccal surfaces were flattened without dentine exposure. The specimens were randomly assigned to two groups, according to the adhesive system (conventional total-etching or self-etching), and each group was divided into three subgroups (bur carbide in turbine of high rotation, Er:YAG laser 250 mJ/4 Hz and Er:YAG laser 300 mJ/4 Hz) containing six teeth each. The enamel/adhesive system interface was serially sectioned and prepared for SEM. The Er:YAG laser, in general, produced a more irregular adhesive interface than the control group. For Er:YAG laser 250 mJ there was formation of a more regular hybrid layer with good tag formation, mainly in the total-etching system. However, Er:YAG laser 300 mJ showed a more irregular interface with amorphous enamel and fused areas, for both adhesive systems. It was concluded that cavity preparation with Er:YAG laser influenced on the morphology of enamel/adhesive system interface and the tissual alterations were more evident when the energy was increased.     

Polyethylene foams cross-linked by electron beam

Cross-linking of low-density polyethylene by electron beam irradiation was studied in this work with the aim of foam production by thermal expansion. Mechanical and thermal properties of the obtained foams were studied and it was found that relatively low doses up to 40 kGy could be used leading to a product with excellent surface appearance.     

Conformational study of 3β,16β-dihydroxyfriedelane by NMR and ab initio calculations

The complete chemical shift assignments of 3β,16β-dihydroxyfriedelane, a natural compound isolated from the hexane extract of Maytenus acanthophylla leaves was achieved through 1D/2D NMR spectral data. Combining ab initio Hartree-Fock [HF/6-31G(d)] and Density Functional Theory [DFT/B3LYP/6-31G(d,p)] calculations with NMR spectral data, it was possible to establish the predominance of the chair-chair-chair-boat-boat conformation for the five six-membered ring systems in this pentacyclic triterpene.     

Application of advanced oxidation processes for removing salicylic acid from synthetic wastewaters

<正>In this study,advanced oxidation processes(AOPs) such as anodic oxidation(AO),UV/H_2O_2 and Fenton processes(FP) were investigated for the degradation of salicylic acid(SA) in lab-scale experiments.Boron-doped diamond(BDD) film electrodes using Ta as substrates were employed for AO of SA.In the case of FP and UV/H_2O_2,most favorable experimental conditions were determined for each process and these were used for comparing with AO process.The study showed that the FP was the most effective process under acidic conditions,leading to the highest rate of SA degradation in a very short time interval.However,the results showed that Ta/BDD films had high electrocatalytic activity for complete degradation of SA;even if it employs more time for complete elimination of the SA respect to FP.Additionally,AO led to a sixfold acceleration of the oxidation rate compared with the UV/H_2O_2 process.Finally a rough comparison of the specific energy consumption shows that AO process reduced the energy consumption by at least 90%compared with the UV/H_2O_2 process.