The possibility of wastewater treatment and electricity production using a microbial fuel cell with Cu–B alloy as the cathode catalyst is presented in this paper. Our research covered the catalyst preparation; measurements of the electroless potential of electrodes with the Cu–B catalyst, measurements of the influence of anodic charge on the catalytic activity of the Cu–B alloy, electricity production in a microbial fuel cell (with a Cu–B cathode), and a comparison of changes in the concentration of chemical oxygen demand (COD), NH4+, and NO3– in three reactors: one excluding aeration, one with aeration, and during microbial fuel cell operation (with a Cu–B cathode). During the experiments, electricity production equal to 0.21–0.35 mA·cm−2 was obtained. The use of a microbial fuel cell (MFC) with Cu–B offers a similar reduction time for COD to that resulting from the application of aeration. The measured reduction of NH4+ was unchanged when compared with cases employing MFCs, and it was found that effectiveness of about 90% can be achieved for NO3– reduction. From the results of this study, we conclude that Cu–B can be employed to play the role of a cathode catalyst in applications of microbial fuel cells employed for wastewater treatment and the production of electricity.

Wastewater originating from the yeast industry is characterized by high concentration of pollutants that need to be reduced before the sludge can be applied, for instance, for fertilization of croplands. As a result of the special requirements associated with the characteristics of this production, huge amounts of wastewater are generated. A microbial fuel cell (MFC) forms a device that can apply wastewater as a fuel. MFC is capable of performing two functions at the same time: wastewater treatment and electricity production. The function of MFC is the production of electricity during bacterial digestion (wastewater treatment). This paper analyzes the possibility of applying yeast wastewater to play the function of a MFC (with Ni–Co cathode). The study was conducted on industrial wastewater from a sewage treatment plant in a factory that processes yeast sewage. The Ni–Co alloy was prepared by application of electrochemical method on a mesh electrode. The results demonstrated that the use of MFC coupled with a Ni–Co cathode led to a reduction in chemical oxygen demand (COD) by 90% during a period that was similar to the time taken for reduction in COD in a reactor with aeration. The power obtained in the MFC was 6.1 mW, whereas the volume of energy obtained during the operation of the cell (20 days) was 1.27 Wh. Although these values are small, the study found that this process can offer an additional level of wastewater treatment as a huge amount of sewage is generated in the process. This would provide an initial reduction in COD (and save the energy needed to aerate wastewater) as well as offer the means to generate electricity.

With the increasing standard of living, energy consumption increases as well. So, waste production, including wastewater, increases as well. One of the types of wastewater is wastewater from yeast industry. Wastewater from this industry has not only a high pollutants load but it is produced in great amounts as well. Technical devices that can accomplish the wastewater treatment and electricity production from wastewater is a microbial fuel cell. In microbial fuel cells activated sludge bacteria can be used for electricity production during wastewater treatment. The possibility of using the Cu-B alloy as cathode catalyst for microbial fuel cells to wastewater treatment of wastewater from yeast industry is presented in this paper. The reduction time for COD with the use of microbial fuel cell with the Cu-B catalyst (with 5, 10 and 15% amount of B) is similar to the reduction time with aeration. The obtained power (4.1 mW) and the amount of energy (0.93 Wh) are low. But, if one can accept a longer COD reduction time, the obtained amount of energy will allow elimination of the energy needed for reactor aeration.

This paper reports the results of research on the effect of hydrogen permeation and the absence of passive layers on the variations in the corrosive properties of aluminum alloys. The study demonstrated that such variations contribute to the deterioration of corrosive properties, which in turn contributes to shortening the reliability time associated with the operation of aluminum alloy structures. The analysis involved structural aluminum alloys: EN AW-1050A, EN AW-5754, and EN AW-6060. It was demonstrated that the absorption of hydrogen by the analyzed alloys led to the shift of the electrode potential to the negative side. The built hydrogen corrosion cells demonstrate in each case the formation of electromotive force (EMF) cells. The initial EMF value of the cell and its duration depends on the duration of hydrogenation. As a result of removing the passive layers, the electrode potential also changes to the negative side. Following the removal of the passive layer from one of the electrodes, the cells also generated a galvanic (metal) cell. The duration of such a cell is equivalent to the time of restoration of the passive layer. The formation of such hydrogen and metal galvanic cells changes the electrochemical properties of aluminum alloys, therefore deteriorates the corrosive properties of aluminum alloys.

Microbial fuel cells (MFCs) are devices than can contribute to the development of new technologies using renewable energy sources or waste products for energy production. Moreover, MFCs can realize wastewater pre-treatment, e.g., reduction of the chemical oxygen demand (COD). This research covered preparation and analysis of a catalyst and measurements of changes in the concentration of COD in the MFC with a Ni–Co cathode. Analysis of the catalyst included measurements of the electroless potential of Ni–Co electrodes oxidized for 1–10 h, and the influence of anodic charge on the catalytic activity of the Ni–Co alloy (for four alloys: 15, 25, 50, and 75% concentration of Co). For the Ni–Co alloy containing 15% of Co oxidized for 8 h, after the third anodic charge the best catalytic parameters was obtained. During the MFC operation, it was noted that the COD reduction time (to 90% efficiency) was similar to the reduction time during wastewater aeration. However, the characteristic of the aeration curve was preferred to the curve obtained during the MFC operation. The electricity measurements during the MFC operation showed that power equal to 7.19 mW was obtained (at a current density of 0.47 mA·cm−2).

Recent times have shown significant development of non-conventional and renewable sources of energy. Much attention has been paid to increase the use of fuel cells (FCs). However, the use of FCs on a large scale is mainly limited by the high cost of catalysts. Due to its excellent catalytic properties, platinum is most commonly used as the catalyst. However, due to the high price of platinum, other high efficiency catalysts should be researched. Elimination of platinum as catalyst would allow for wider commercial application of FCs. This will contribute to the development of high efficiency green energy sources. The paper presents a study of hydrazine electro-oxidation on electrode with Ni-Co alloy catalyst. The work shows a possibility of use of Ni-Co alloys as catalysts for electro-oxidation of hydrazine. Researches were done by the method of polarizing curves of electro-oxidation of hydrazine in glass vessel, on a copper electrode with Ni-Co alloy as a catalyst. An aqueous solution of KOH was used as the electrolyte. Measurements were done with the use of potentiostat. Conducted measurements show that there is a possibility of electro-oxidation of hydrazine on Ni-Co electrode. In any case, the process of electro-oxidation of hydrazine occurs. A current density of about 40-60 mA/cm 2 has been obtained for all concentrations of hydrazine and electrolyte. The current density is low, but the price of the catalyst is much lower than platinum. At 75% of Co, there is a sudden fall of current density. So, the work shows possibility to use Ni-Co alloys as catalysts for fuel electrode of hydrazine FCs.

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Providing more and more energy is an essential task of the today's energetic industry. In the last few years, in addition to the traditional methods of energy production, alternative energy sources have been developing fast. One of the devices that can make use of these sources is a fuel cell. The fuel cells can be a power source of future mainly due to their high efficiency, low influence on environment and the possibility of powering with different fuels. Most often, fuel cells are powered by hydrogen. However, the problems with its cheap production and storage are the reason for the search for alternative fuels for fuel cells. It is important that the new fuel will be characterized by zero or low emission level. One of these fuels can be vegetable oil. The paper presents the measurements pertaining to electrooxidation of coconut oil emulsion on a smooth platinum electrode in an aqueous solution of KOH. The electrochemical measurements were performed in a glass cell with AMEL System 5000 potentiostat. The obtained maximum current density is equal to 25 mA/cm 2. Therefore the coconut oil can be used as fuel for fuel cell provided that the temperature of process is kept above 303K.