Even the average aquarist should consider this water parameter when all other parameters check out, yet fish continue to be susceptible to disease. This may be an important parameter to consider as growing research in human disease resistance, and even plant growth also continues to show as research progresses.
As research grows, knowing what can affect oxidation and reduction which are both important in their own way can help an aquarium keeper deal better with sick fish or an aquarium that has a sudden build up of organics. Even lighting and quality of light is showing to have an affect on Redox based on tests!
However some in the aquarium keeping community still seem to be in the dark as per this growing documented research.
Redox, also known as Redox Potential, oxidation potential, & ORP (oxidation reduction potential) describes the ability for the loss of an electron by a molecule, atom or ion to the gain of an electron by another molecule, atom or ion.
Without this ability to gain electrons, many minerals cannot be absorbed and properly assimilated, especially in times of stress.
Solar energy utilization is accomplished in green plants through a cascade of photo-induced electron transfer, which remains a target model for realizing artificial photosynthesis. In this article, we introduce the concept of about how to design biocatalyzed artificial photosynthesis through coupling redox biocatalysis and photocatalysis to mimic natural photosynthesis. Key design principles for reaction components, such as electron donors, photosensitizers, and electron mediators, are described for artificial photosynthesis involving biocatalytic assemblies. Recent research outcomes that serve as a proof of the concept are summarized and current issues are discussed to provide a future perspective.
Cellular metabolism comprises energy transduction machineries that operate by a series of redox-active components to store energies from nutrients, which are transduced into high-energy intermediates for cellular works such as chemical synthesis, transport, and movement. Biological energy transduction mechanism hints at the construction of a man-made energy storage system. Herein, we present a bio-inspired strategy to design high-performance energy devices based on the analogy between energy storage phenomena of mitochondria and lithium rechargeable batteries. Flavins, a key redox element in respiration and photosynthesis, facilitate either one- or two-electron-transfer redox processes accompanying proton transfer at nitrogen atoms of diazabutadiene motif during cellular metabolism. We have successfully demonstrated flavins as a molecularly tunable cathode material that exhibits reversible reactivity with two lithium ions and electrons per formula unit. Analysis of both the ex situ characterizations and density-functional theory (DFT)-based calculations revealed that the redox reaction occurs via two successive single-electron transfer steps, which is analogous to the proton-coupled electron transfer mechanism of flavoenzymes. Tailored flavin analogues obtained via chemical substitution on the isoalloxazine ring showed fine tunability of electrochemical properties, exhibiting a gravimetric capacity of 174 mAh/g and an average redox potential of 2.65 V, and its expected energy density is comparable to that of LiFePO4.
Artificial photosynthesis is an attractive way to utilize solar energy through inspiration from natural photosynthesis in green plants. Water-splitting is critically required to establish an artificial photosynthetic system that consists of sequential charge-obtaining and transferring reactions. The oxidation of water is a limiting step to achieving water-splitting because of its multi-hole-related characteristics. A key to the development of effective water oxidation catalysts is the optimized control of material structure and composition through a facile synthetic method. This work synthesized polycrystalline RuO2/Co3O4 core/shell nanofibers by electrospinning and evaluated their photocatalytic water oxidation performance using a Ru(bpy)32+/persulfate system under visible light illumination. Our results show that RuO2/Co3O4 nanofibers exhibit significantly enhanced efficiency of photocatalytic water oxidation with a higher number of turnover frequency than those of pristine Co3O4 nanoparticles, Co3O4 nanofibers, and RuO2 nanofibers, respectively. The unique core-shell structure of RuO2/Co3O4 nanofibers comprising the inner region of highly conductive RuO2 and the outer region of catalytic Co3O4 provided a fast and effective transport highway for holes to O2-evolving sites. This work highlights the potential of tailored 1D binary composite nanofibers for the development of efficient oxygen-evolving catalysts and offers a new viewpoint for exploring multi-component catalysts through electrospinning.
FROM WASTE TO VALUABLES: Human urine is studied as a potential source of energy for light-driven redox biocatalytic reactions. The urea-rich human urine functions as an efficient chemical fuel in a photoelectrochemical cell regenerating nicotinamide cofactor (NADH), an essential hydride mediator that is required for numerous redox biocatalytic reactions. We demonstrate the utility of human urine as a chemical fuel for driving redox biocatalysis in a photoelectrochemical cell. Ni(OH)2-modified alpha-Fe2O3 is selected as a photoanode for the oxidation of urea in human urine and black silicon (bSi) is used as a photocathode material for NADH regeneration. The electrons extracted from human urine are used for the regeneration of NADH. The catalytic reactions at both the photoanode and the photocathode were significantly enhanced by light energy that lowered the overpotential and generated high currents in the full cell system.
We report on a silicon-based photoelectrochemical cell that integrates a formate dehydrogenase from Thiobacillus sp. (TsFDH) to convert CO2 to formate using water as an electron donor under visible light irradiation and an applied bias. Our results revealed that sequential transfer of electrons, extracted via a water oxidation reaction at a npp+ triple-junction silicon on ITO (3-jn-Si/ITO/CoPi) photoanode, to a a hydrogen-terminated silicon nanowire (H-SiNW) photocathode, and further to TsFDH, leads to effective formate production with a faradaic efficiency of 16.18% under the applied bias of 1.8 V, while no formate was synthesized directly at the H-SiNW photocathode alone. The formate yield increased significantly through the integrated PEC system, which continuously regenerated NADH for TsFDH-catalyzed CO2 reduction. Moreover, we demonstrated that our silicon-based biocatalytic system could be operated under natural sunlight using a solar tracking module, which is a highly desirable result for the practical utility of the PEC as a sustainable solar energy harvesting system. The current study suggests that the deliberate integration of biocatalysis to a PEC platform can provide an opportunity to synthesize valuable chemicals with the use of earth-abundant materials and sustainable resources. With our biocatalysis-integrated PEC platform, further engineering of enzymes and photoelectrode materials would provide more opportunity to improve efficiency of the system.
In nature, quinone plays a vital role in numerous electrochemical reactions for energy transduction and storage; such processes include respiration and photosynthesis. For example, fast proton-coupled electron transfer between primary and secondary quinones in green plants triggers the rapid charge separation of chlorophyll molecules, achieving unparalleled photosynthesis with near-unity quantum yield. In addition, quinone-rich polymers such as eumelanin and polydopamine show unique optical and electrical properties (e.g., strong broadband absorbance or a switching response to external stimuli), mostly arising from their chemically disordered structures. Understanding the unique features of quinone and its derivatives can provide solutions to the construction of bio-inspired systems for energy harvesting and conversion. This paper reviews recent advances in the design of quinone-functionalized hybrid materials based on quinones redox, electrical, optical, and metal chelating/reducing properties to determine these materials applications in energy-harvesting and -storage systems, such as artificial photosynthetic platforms, rechargeable batteries, pseudocapacitors, phototransistors, plasmonic light harvesting platforms, and dye-sensitized solar cells.
Redox enzymes are industrially important for catalyzing highly complex reactions because of their excellent regio- and stereo-selectivity; however, broad application of redox enzymes has been often limited by the requirement of stoichiometric supply of cofactors such as β-nicotinamide adenine dinucleotide (NADH). Here, we report light-driven cofactor regeneration coupled with water oxidation by employing a photoelectrochemical cell platform consisted of a FeOOH/Fe2O3 photoanode and a black silicon photocathode. The FeOOH layer deposited on Fe2O3 surface decreased reaction barriers for water oxidation. The black silicon photocathode exhibited high photocurrent response and superior capacity to drive cofactor reduction. The cofactor regeneration yield in the photoelectrochemical cell was almost two-fold higher than that obtained in homogenous system, which demonstrates that photoelectrochemical cell is a promising platform for redox biocatalytic reactions using water as an electron donor.
I read a recent article that is easily found in search that is admittedly well written dealing with Aquarium Redox, with a good explanation as to what Redox is and more, however this article still chooses to repeat much of the same tired old information about only the positives of the oxidative side of the Redox equation, missing the evidence that the reduction side is also VERY important to a healthy Aquarium Redox Balance (I noted that the sources this particular article sited were all more than 15 years old which may explain much of the out of date information).