Rainwater-driven microbial fuel cells for power generation in remote areas

The possibility of using rainwater as a sustainable anolyte in an air-cathode microbial fuel cell (MFC) is investigated in this study. The results indicate that the proposed MFC can work within a wide temperature range (from 0 to 30°C) and under aerobic or anaerobic conditions. However, the rainwater season has a distinct impact. Under anaerobic conditions, the summer rainwater achieves a promised open circuit potential (OCP) of 553 ± 2 mV without addition of nutrients at the ambient temperature, while addition of nutrients leads to an increase in the cell voltage to 763 ± 3 and 588 ± 2 mV at 30°C and ambient temperature, respectively. The maximum OCP for the winter rainwater (492 ± 1.5 mV) is obtained when the reactor is exposed to the air (aerobic conditions) at ambient temperature. Furthermore, the winter rainwater MFC generates a maximum power output of 7 ± 0.1 mWm −2 at a corresponding current density value of 44 ± 0.7 mAm −2 at 30°C. While, at the ambient temperature, the maximum output power is obtained with the summer rainwater (7.2 ± 0.1 mWm −2 at 26 ± 0.5 mAm −2 ). Moreover, investigation of the bacterial diversity indicates that Lactobacillus spp. is the dominant electroactive genus in the summer rainwater, while in the winter rainwater, Staphylococcus spp. is the main electroactive bacteria. The cyclic voltammetry analysis confirms that the electrons are delivered directly from the bacterial biofilm to the anode surface and without mediators. Overall, this study opens a new avenue for using a novel sustainable type of MFC derived from rainwater.

Role of the Anilinium Ion on the Selective Polymerization of Anilinium 2-Acrylamide-2-methyl-1-propanesulfonate

The development of anilinium 2-acrylamide-2-methyl-1-propanesulfonate (Ani-AMPS) monomer, confirmed by 1H NMR, 13C NMR, and FTIR, is systematically studied. Ani-AMPS contains two polymerizable functional groups, so it was submitted to selective polymerization either by free-radical or oxidative polymerization. Therefore, poly(anilinium 2-acrylamide-2-methyl-1-propanesulfonic) [Poly(Ani-AMPS)] and polyaniline doped with 2-acrylamide-2-methyl-1-propanesulfonic acid [PAni-AMPS] can be obtained. First, the acrylamide polymer, poly(Ani-AMPS), favored the π-stacking of the anilinium group produced by the inter- and intra-molecular interactions and was studied utilizing 1H NMR, 13C NMR, FTIR, and UV-Vis-NIR. Furthermore, poly(Ani-AMPS) fluorescence shows quenching in the presence of Fe2+ and Fe3+ in the emission spectrum at 347 nm. In contrast, the typical behavior of polyaniline is observed in the cyclic voltammetry analysis for PAni-AMPS. The optical properties also show a significant change at pH 4.4. The PAni-AMPS structure was corroborated through FTIR, while the thermal properties and morphology were analyzed utilizing TGA, DSC (except PAni-AMPS), and FESEM.

Role of Bi3+ ions on structural, optical, photoluminescence and electrical performance of Cd0.9-xZn0.1BixS QDs

In this work, the Cd0.9-xZn0.1BixS QDs with different compositions of Bi3+ ions (0 ≤ x ≤ 0.05) were synthesized using a facile chemical route. The prepared QDs were characterized for analyzing the structural, morphological, elemental, optical, band gap, photoluminescence and electrochemical properties. XRD results confirmed that the Cd0.9-xZn0.1BixS QDs have a cubic structure. The mean crystallite size was increased from ~ 2 to ~ 5 nm for the increase of Bi3+ ions concentration. The optical transmittance behavior was decreased with increasing Bi3+ ions. The scanning electron microscope images showed that the prepared QDs possessed agglomerated morphology and the EDAX confirmed the presence of doped elements as per stoichiometry ratio. The optical band gap was slightly blue-shifted for initial substitution (Bi3+ = 1%) of Bi3+ ions and red-shifted for further increase of Bi3+ compositions. The optical band gap was ranged between 3.76 and 4.0 eV. High intense red emission was received for Bi3+ (1%) doped Zn:CdS QDs. The red emission peaks were shifted to a higher wavelength side due to the addition of Bi3+ ions. The PL emission on UV-region was raised for Bi3+ (1%) and it was diminished. Further, a violet (422 nm) and blue (460 nm) emission were received for Bi3+ ions doping. The cyclic voltammetry analysis showed that Bi3+ (0%) possessed better electrical properties than other compositions of Bi3+ ions.

CuO-Doped Alginate for Simple Electrochemical Vitamin C Sensing in Sweat

Heat-exposed work activities or prolonged sport sessions suppose a continuous nutrient loss through sweating, leading to long-term health issues. Among prevention steps, the use of miniaturized sensors for real-time monitoring of micronutrient presence directly in sweat can be of great interest. Here, we propose a flexible sensor for the detection of vitamin C (ascorbic acid) based on a very simple process of electrode modification via electrodeposition of a membrane containing CuO nanoparticles. The reductive effect of ascorbic acid on the nanoparticles produces a shift of the redox peaks in cyclic voltammetry analysis, which can be measured at nearly zero volts as a current increase by amperometry. The detection is performed efficiently at the micromolar ascorbic acid levels found naturally in sweat and works at ultra-low potential (−5 mV), showing no interferences with other typical molecules found in the samples. In combination with sensors for other nutrients, this can be a promising approach for preventive healthcare applications.

Graphene Oxide-Paraffin-Nanobentonite as Working Electrode for Cyclic Voltammetry Analysis for Nicotinic Acid

The composition of graphene oxide (GO):paraffin:nanobentonite electrode was optimized to acquire the optimal working electrode to analyze nicotinic acid under the optimum conditions through cyclic voltammetry. Graphene oxide was synthesized from graphite by employing the improved Hummer method. Bentonite was synthesized using the sonothermal method. The ratio of GO:paraffin:nanobentonite electrodes of 3:3:4 provided the optimal voltammogram. The results indicated that the composition of the comparative working electrodes of GO-modified nanobentonite was best 3:3:4 with a good peak recovery averaged value of 96.16%.

Solvothermal Synthesis of Bi2s3 Nanoparticles for Active Photocatalytic and Energy Storage Device Applications

High edge energy storage with large life-span stable materials have become the most significant and major requirement in near future. Bismuth sulfide (Bi2S3) Nanoparticles (NPs) was effectively synthesized by utilizing Bismuth diethyldithiocarbamate (Bi[DTC]) complex as single-source antecedent. The synthesized Bi2S3 NPs were affirmed by structural, morphological and thermal analysis with various analytical studies. The electrochemical performance of Bi2S3 NPs reveals that, exhibit redox behavior from cyclic voltammetry analysis, the charge-discharge analysis was examined by the galvanostatic chronopotentiometry. Bi2S3 NPs exhibit excellent supercapacitor behavior with value of the specific capacitance 470 Fg-1 at current density 0.5 Ag-1 and the retentivity of 79 % after 1000 cycles. The Bi2S3 NPs were further utilized as photocatalytic discoloration of Congo Red (CR) dye in aqueous medium under UV-light irradiation. Which shows, excellent catalytic behaviour, up to 98% of CR dye degrade within 150 min. and it is exhibit good catalytic stability and reusability.

Carbon Nanofibers Form by Electrospinning with Flowrate Variations as Electrodes for Capacitive Deionization

Carbon nanofibers (CNFs) have been successfully prepared by using electrospinning at various flowrates, and were formed from polyvinyl alcohol (PVA) and activated carbon (700-1400 m2/g) as electrodes on capacitive deionization. Before being furthermore deposited into electrodes, characterization was carried out on CNFs by using SEM. Cyclic voltammetry analysis was also performed to determine the electrolysis mechanism of the electrodes. The best results in removing salt reaching 70% were achieved by capacitive deionization systems with the smallest diameter size of CNFs, at a voltage of 1.5 V. The CNFs formed by electrospinning have potential to be used as excellent capacitive deionization electrodes for the desalination process.

Cyclic Voltammetry and Oxidation Rate Studies of Ferrous Gluconate Complex Solutions for Preparation of Chitosan-Tripolyphosphate Microparticles

A proper understanding of the properties of iron could increase the effectiveness of programmes for alleviating iron deficiency. Recently, encapsulation has been considered an appropriate method for protecting iron from injurious reactions. However, several events may occur during encapsulation processes, including changes in the iron’s oxidation state. Oxidation of ferrous iron is not desirable since the intestines can only absorb iron in the ferrous form. In this study, a cyclic voltammetry method was applied to investigate the likelihood of ferrous gluconate oxidation for the preparation of chitosan-tripolyphosphate microparticles. Then, the electrochemical properties of ferrous gluconate were confirmed experimentally. The oxidation rate of ferrous gluconate is also discussed in this paper. All the experimental solutions were formulated in detail to produce conditions similar to those of microparticle production. Cyclic voltammetry analysis was conducted using a configuration of three electrodes connected to an electrochemical analyser. Graphite, platinum wire, and Ag/AgCl were employed as the auxiliary, working, and reference electrodes, respectively. The cyclic voltammetry results show that the observed potential for each anodic peak shifted negatively in the presence of chitosan and sodium tripolyphosphate. Moreover, the rate of ferrous oxidation tended to increase during 75 min of experiments due to the presence of chitosan and sodium tripolyphosphate. These behaviours indicate the transformation of ferrous iron to ferric iron during iron microparticle preparation. Furthermore, these findings suggest that spray drying is a preferable method to minimise the oxidation reaction.