Versatile Bioelectrochemical system for heavy metals removal

Industrial activity has resulted in heavy metals anthropogenic contamination of groundwater, especially in industrial or mining areas. Bioelectrochemical systems (BES) can be used for metals removal and recovery from aqueous solutions. In the framework of GREENER project, double-chamber BES have been adopted to treat groundwater from industrial sites containing copper, nickel and zinc (Cu, Ni and Zn), among other contaminants. Two operation modes, (i) short-circuited microbial fuel cell (MFC), and (ii) power supply driven microbial electrolysis cell (MEC, poisoning the cathode at -0.4 V vs. Ag/AgCl), were studied for metals removal at lab-scale. Two control reactors were run to evaluate metals adsorption on cathodes and membranes, and the effect of anolyte composition. Synthetic water containing different concentrations of Cu, Ni and Zn were treated, and metals removal pathways were studied. MEC and MFC performed similarly and the highest removal efficiencies were 97.1±3.6%, 50.7±6% and 74,5% for Cu, Ni and Zn respectively, from initial concentrations in the range of 1.1-1.5 mM.

Testing novel multicomposite materials for electromethanogenesis

Electromethanogenesis is an innovative technology that uses a microbial electrochemical system to produce methane from CO2, in a power-to-gas (BEP2G) concept. The results of experimental tests of new and cost-effective carbonaceous materials for electrode are presented here. The study aims at optimizing electromethanogenesis processes at laboratory level in mesothermic condition. As part of the experiments, hydrogenotrophic microorganisms (Family Metanobacteriaceae of Archaea domains) were selected from a mixed consortium taken from a biogas digestate and inoculated in double-chamber bioelectrochemical systems. The maximum amount of methane produced was 0.3 - 0.8 mol/m2g (normalized to the cathode area) with carbon cloth electrodes. Aiming at improving the methane productivity, innovative materials for the electrodes were now studied, creating porous high-surface composites, and studying nitrogen carbons doped with Cu and hydroxyapatite (Multicomposite Cu@/HAP/C), as chemical catalysts for CO2 reduction (CO2RR). The description of the procedure for the Multicomposite Cu@/HAP/C production is reported in detail.

The different behaviour of Thermotoga neapolitana in the anodic and cathodic compartment of a bioelectrochemical system

Thermotoga neapolitana is a hyperthermophilic bacterium that can metabolize glucose and several organic wastes in hydrogen and lactate at a temperature of 80°C. Their high performance in producing hydrogen at so high a temperature as 80°C suggests a potential energy application of them where hydrogen is an important element of the process. In this view, experimentation of a T.neapolitana strain is carried out in double-chamber electrochemical systems. The aim is to explore the interaction of these bacteria with the anode and the cathode, stressing their capability to survive in presence of a polarized electrode which can drastically change the pH of the media. A culture enriched of 5 g/L of glucose, under CO2 pressure (80 °C) was used to fill both the anodic and cathodic compartments of the electrochemical system, applying a voltage of 1.5 V between the anode and the cathode. The test lasted ten days. Results clearly indicate that bacteria colonize both electrodes, but the glucose metabolism is completely inhibited in the anodic compartments. On the contrary, metabolism is stimulated in the cathodic compartment. Bacteria are alive on the electrodes in the pH interval of 3 - 9.

Numerical study of a double inlet chamber counter flow vortex tube with insulation

The present study intends to improve the performance of the Ranque-Hilsch counter flow vortex tube, analysed using computational fluid dynamics. In the axisymmetric 3-D, steady-state, compressible, and turbulent flow vortex tube, the air has been used as the working fluid. The ANSYS17.1 FLUENT software has been used with the standard º-ε turbulent model for different mass fraction of cold fluid and inlet pressure in the numerical simulation and validated with the experimental results. It is observed from the study that as the inlet chambers number increases from 1 to 2, there is a decrease of 7.8 % in the cold exit temperature of the vortex tube. However, insulating the double chamber vortex tube leads to a further reduction of 4.2% in the cold exit temperature. Therefore, it indicates that the overall decline in the cold exit temperature from one chamber non-insulated vortex tube to double chamber insulated vortex tube is 9.6%. In terms of cold exit temperature, it can be concluded that using a double inlet chamber vortex tube with insulation yields the optimum results.

Microbial fuel cells constructed from the integration of anaerobic and aerobic sanitary landfill site systems

The world’s main source of energy now is fossil fuels but the demand for power is increasing. In addition, the burning of fossil fuels produces harmful greenhouse gases and has a significant impact on the environment. The fuel cell system in this study is based on the aerobic and anaerobic integration system are used in most waste disposal methods in Malaysia. It is a system of electrochemistry results from the oxidation of organic matter that transfers electrons to carbon graphite This research is to study the effectiveness of the method generating electricity from micro-fuel cells produced from leachate wastewater and it is also conducted to identify microbial activity using a double chamber system. The food waste obtain is divided into double chambers which is aerobic and anaerobic. Digital readings using a multimeter are performed for ten to thirteen days continuously to obtain the highest reading results for voltage and electric current. The measurement of the highest reading result on the 11th day recorded a reading as high as 146.8 mV at 2000 mV while the current reached 28 μA at 2000 μA. This study has proven that there is the production of electrical sources from the activity of organisms present in food waste using microbial fuel cell systems. The result show that food waste and cattle manure produce the highest voltage and current. This has provided an opportunity to explore alternative ways of generating electricity according to the environment and conditions of each region.

TEMPERATURE CONTROL SYSTEM FOR MINT DEHYDRATION IN DOUBLE-CHAMBER MARQUEE USING LINEAR ACTUATORS

The objective of this research was to determine the thermal performance of a solar dehydration system that allows controlling the temperature for the dehydration of aromatic herbs such as mint. The use of a double chamber marquee allowed obtaining high thermal values, even with low radiation levels. For temperature control, a system of vertical mobile beds was used in order to reach the programmed temperature. This temperature was monitored using an embedded Arduino-type system that allows both monitoring and controlling motors, as well as recording temperature information. It was possible to keep the temperature approximately constant at 40°C, the ideal value for drying aromatic and medicinal herbs.