Eric M. Garcia

Nanostructured δ-FeOOH: a novel photocatalyst for water splitting

We report on the first use of nanostructured δ-FeOOH as a promising photocatalyst for hydrogen production. The high surface area, interparticle mesoporosity, small particle size and band gap energy in the visible region make nanostructured δ-FeOOH a suitable candidate for use as a photocatalyst.

Chemical recycling of cell phone Li-ion batteries: Application in environmental remediation.

This paper presents, for the first time, the recycling and use of spent Li-ion battery cathode tape as a catalyst in the degradation of an organic dye. In our proposal, two major environmental problems can be solved: the secure disposal of cell phone batteries and the treatment of effluents with potentially toxic organic dyes. The spent Li-ion battery cathode investigated in this paper corresponds to 29% of the mass of Li-ion batteries and is made up of 83% LiCoO2, 14.5% C and less than 2.5% Al, Al2O3 and Co3O4. The use of spent Li-ion battery cathode tape increased the degradation velocity constant of methylene blue in the absence of light by about 200 times in relation to pure H2O2. This increase can be explained by a reduction in the activation energy from 83 kJ mol(-1) to 26 kJ mol(-1). The mechanism of degradation promoted by LiCoO2 is probably related to the generation of superoxide radical (O2(-)). The rupture of the aromatic rings of methylene blue was analyzed by ESI-MS.

Development of non-enzymatic glucose sensor using recycled cobalt from cell phone Li-ion batteries.

This article aims to present an alternative to recycling of spent Li-ion batteries applied to electrochemical sensor manufacturing. The cobalt, from cathode of Li-ion batteries, was recovered by electrodeposition onto AISI 430 stainless steel substrate and applied as glucose sensor. The composition of cathode utilized was obtained by AAS measures and corresponds to LiNi0,40Co0,60O2. Despite this composition, in the cobalt electrodeposition onto AISI 430 stainless steel the Ni is less of 1.7% (w/w) due the anomalous electrodeposition. The sensitivity of cobalt electrode for glucose detection is 70.2 μA/mmol cm(2) and the linear range is 1-10 mmol/L. This result shows that the Co electrodeposited onto AISI 430 stainless steel is a promissory and low-cost non-enzymatic glucose sensor.

Application of Spent Li-Ion Batteries Cathode in Methylene Blue Dye Discoloration

This paper aims to present the mechanism study of methylene blue (MB) discoloration using spent Li-ion battery cathode tape and hydrogen peroxide. The recycled cathode used in this work is composed of 72% of LiCoO2, 18% of carbon, and 10% of Al. The value found for surface area is 8.9 m2/g and the ZCP value occurs in pH = 2.95. Different from what is proposed in the literature, the most likely mechanism of methylene blue discoloration is the oxidation/delitiation of LiCoO2 and the reduction of H2O2 forming . Thus, in this paper, an important and promising alternative for discoloration of textile industry dyes using spent Li-ion battery cathode is presented.

Electrochemical study of corrosion in aluminium cans in contact with soft drinks

Abstract This work evaluates the corrosion resistance of the inner surface of the aluminium cans in guarana, cola flavoured and tonic water soft drinks using electrochemical impedance spectroscopy (EIS) measurements. The less aggressive electrolyte was tonic water. One time constant was identified for the aluminium can in contact with guarana and tonic water. In the most aggressive medium of cola flavoured soft drinks, two time constants were identified and a charge transfer resistance was obtained associated to a corrosion of aluminium in contact with the electrolyte.

Seasonal Water Evaluation of Main Lagoons in the City of Sete Lagoas-MG

The city of Sete Lagoas is set in a karst system and has the presence of lagoons, which, in some cases, are interconnected to the regime of free aquifers. The objective of this work was to evaluate the water quality of the lagoons of Boa Vista, Brejao, Catarina, Cercadinho, Jose Felix, Mucuri and Paulino, situated in the city, over a period of 12 months, through physical and chemical analyzes. Conductivity, pH, turbidity, chloride, calcium, magnesium, sodium and potassium parameters were determined. The results showed that the Paulino and Mucuri lagoons presented higher sodium and conductivity index and, since they are located in the central area of Sete Lagoas, may have been influenced by anthropic actions. In addition to these, the Brejao lagoon presented high values of potassium, which may be related to the agricultural activity developed in its environment. In this sense, the study of the water quality is of fundamental importance so that the county can develop specific measures to improve the quality of the waters of each pond and improve evaluating the basic sanitation of the city.

The New Anode Environmentally Friendly for Water Electrolysis Based on 430 Stainless Steel Coated with Recycled Cobalt from Spent Lithium–Ion Batteries

In this paper, a new anode environmentally friendly for hydrogen production was developed based on 430 stainless steel with an electrodeposited cobalt layer. The novelty of this work is the cobalt source once the electrodeposition bath was obtained from recycling of spent Li-ion batteries cathode with composition LiCoO2. The electrodeposited cobalt behaves as supercapacitor in KOH 1M. In the linear voltammetry in KOH 1M, when the overpotential reaches 370mV, the anodic density current for 430 SS/Co is 19mAcm. Thus, the anode developed in this paper achieves the double of density current with half of production cost if compared with 316SS. Moreover the anode construction described in this paper is an excellent option for Liion battery recycling.