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Corrosion evaluation of SS-316L exposed to LiBr-H 2 O solution of 50 wt-% was investigated applying the electrochemical noise technique (ENT), potentiodynamic polarisation curves, and the weight loss method (WLM) at 25, 50, 60, 70 and 80uC. The current and potential noise signals were obtained each four hours during 15 days. These data were analysed in the time and frequency domains. A statistical analysis was made to obtain the localisation index and the resistance noise. Also, the Stern-Geary equation and the Faraday's law were used to determine the corrosion rates. A comparison of the corrosion rates obtained from ENT and WLM showed the same tendency with temperature, but a difference of one order of magnitude was seen. The results of the corrosion rates from ENT and WLM presented a good agreement with the inverse noise resistance results. SEM analyses of the corroded samples together with atomic absorption analysis of corrosion products are also presented.

In the present study, a novel laccase from ascomycete Gliomastix murorum was produced in agro-industrial wastes and entrapped in galactomannan beads for Reactive Blue 2 (Rb-2) decolorization. The maximum laccase production in agave bagasse-based medium occurred at 72 h (1798.6 UL−1). Entrapped laccase decolorized ˃80% of 0.5 mM Rb-2 in 2 h without the addition of redox mediator. Km for Rb-2 substrate was 1.42 mM, with a Vmax of 1.19 µmol min−1 for entrapped laccase. Galactomannan matrices produce stability to acid pH (2–5) and temperatures from 20–70 °C. Reusability assays showed that entrapped laccase could retain efficient Rb-2 decolorization of ˃80% six times. In general, galactomannan used for entrapment of laccase provides economic advantages in large-scale wastewater treatment due to its natural origin and efficient results.

Synthesis and characterization of nanostructured TiO2 arrays obtained by electrochemical anodization of Ti foils at low (<3V) and high (50V) potential, using different electrolyte solutions, are presented. Scanning electron microscopy studies indicated that at low potential film formation is characterized by a porous array with pore length < 1 micrometer, whereas at high potential it corresponds to a nanotube array with nanotube length of 8 micrometers. The difference in surface roughness between the porous and nanotube arrays did not agree with the photocurrent difference observed in a photoelectrochemical cell, suggesting the presence of limiting phenomena in the longer tubes for this application. Electrochemical impedance studies revealed low capacitance and large pore resistance in TiO2 nanotubes, which point out to restricted ion diffusion in photoelectrochemical devices working at low bias, as well as different surface reactivity.

In this paper, the synthesis of TiO2 porous arrays on titanium substrates in non-aqueous solution of ethylene glycol (1 vol.% H2O) + 0.5 wt.% NH4F was investigated. Electrochemical anodization of titanium was carried out at 3V during 39 to 72 hours. The microstructural analysis of samples by scanning electron microscopy and atomic force microscopy suggests that the thickness of porous layers decrease with the anodization time, whereas the polydispersity in the pore size increases by the integration of small pores formed early during the anodization process. At 72 hours the presence of a double wall of the porous is indicative of the incipient formation of nanotubes. By the other hand, the pore depth suggests that the oxide film was formed by the coalescence of 20-50 nm diameter hemispherical titania particles.