Photochemical energy conversion is more efficient when a single light-absorbing unit is split into multiple light-absorbing units (N) that are each 1/N as thick as the single light-absorbing unit and thus use the same amount of material as the single light-absorbing unit. For electrocatalytic parameters relevant to water electrolysis, the maximum efficiency for solar-to-fuel conversion from a 1.75 eV bandgap material increases from approximately 1% for a single light-absorbing unit to greater than 20% for 128 identical stacked light-absorbing units. Alterations in utilization of photons results in a better match of the light-absorber power output to the load of the chemical transformation and in the case of high-quality light-absorbers there is an added benefit from radiative coupling between the light-absorbing units via photon recycling.

A water treatment apparatus includes: a first granular electrode member and a second granular electrode member stored in a water treatment unit and provided so as to be separated from each other; a power supply unit which applies voltage between the first granular electrode member and the second granular electrode member so that ions contained in treatment target water supplied from one side of the water treatment unit are adsorbed to the first granular electrode member and the second granular electrode member; and a washing water supply pump which causes washing water to flow from the other side of the water treatment unit to the one side of the water treatment unit, thereby washing the first granular electrode member and the second granular electrode member, wherein the first granular electrode member and the second granular electrode member each include a plurality of flowable granular electrode members.

The invention relates to a device and a process for the desalination of NaCl solutions employing a three-chamber electrochemical cell separated by relative ion exchange membranes, namely a succession of a cathode chamber, a cation exchange membrane, a central chamber for the saline solution, an anion exchange membrane and an anode chamber. The oxidation of OH.sup.? and the reduction of H.sub.3O.sup.+ under the formation of OH.sup.? and H.sub.2 causes the passage of Na and Cl.sup.? ions from the central chamber to the other chambers, thereby reducing the salt concentration. The feeding of the cathode chamber can be managed in a circuit with the insertion of a carbonation reactor to reduce the concentration of NaOH and eliminate CO.sub.2 from the air. Under certain conditions, the chlorides entering the anode chamber undergo oxidation and the chlorine formed therein reacts with water to produce HCl and HClO.

A water treatment apparatus includes: a first granular electrode member and a second granular electrode member stored in a water treatment unit and provided so as to be separated from each other; a power supply unit which applies voltage between the first granular electrode member and the second granular electrode member so that ions contained in treatment target water supplied from one side of the water treatment unit are adsorbed to the first granular electrode member and the second granular electrode member; and a washing water supply pump which causes washing water to flow from the other side of the water treatment unit to the one side of the water treatment unit, thereby washing the first granular electrode member and the second granular electrode member, wherein the first granular electrode member and the second granular electrode member each include a plurality of flowable granular electrode members.

Bismuth-based, chloride-storage electrodes and rechargeable electrochemical cells incorporating the chloride-storage electrodes are provided. Also provided are methods for making the electrodes and methods for using the electrochemical cells to remove chloride ions from a sample. The chloride-storage electrodes, which are composed of bismuth metal, can store chloride ions in their bulk by forming BiOCl via an oxidation reaction with bismuth in the presence of an oxygen source.

A method for regulating ion transport between first and second regions of a liquid solution containing ionic species in at least one of said first and second regions, the method comprising applying a voltage on an electrically conductive mesoporous carbon membrane situated between said first and second regions of the liquid solution, wherein liquid flow between first and second regions is permitted only through said mesoporous carbon membrane, and the applied voltage is selected to modulate the degree of ion transport between said first and second regions, wherein an increase in applied voltage results in a reduction in the degree of ion transport between said first and second regions, optionally up to a critical voltage at which ion transport ceases.

The United States faces significant environmental burden to treat and transport 0.61 billion kg of defective tomatoes (culled tomatoes) every year. The present disclosure provides for the treatment and processing of culled tomatoes in microbial-electrochemical systems, using the microbial fuel cell as a model reactor. The fundamental differences between the long-term oxidative behavior of unprocessed culled tomatoes compared to the three readily soluble substrates (dextrose, acetate, and wastewater) are disclosed. AC electrochemical impedance spectroscopy (EIS) analyses indicate the influential impedance contributions of the peel & seed to the cull oxidation. Cyclic voltammetry tests indicate that the indigenous redox-active pigments in the cull influence the faradaic processes involved in the cull oxidation.

A photovoltaic desalination system can comprise a solar cell, configured to receive solar radiation, including an n-doped semiconductor layer, a p-doped semiconductor layer, the two semiconductor layers forming a p-n junction, and an channel array, formed in the p-n junction; an input reservoir, coupled to the solar cell, the input reservoir configured to contain a salty fluid, and to release the salty fluid to the solar cell; an output fluid management system, coupled to the solar cell, the output fluid management system configured to receive an output fluid from the solar cell; wherein the channel array is configured to receive the salty fluid from the input reservoir, and to output the output fluid to the output fluid management system.

A piezoelectric deionization system uses a piezoid bed made up of multiple piezoids for deionization of a working fluid containing charged particles, ions, and/or ionic complexes. The working fluid may be salt water in various embodiments. A uniaxial compressive force is applied to the piezoid bed causing a piezoelectric effect in the piezoids, resulting in a piezoelectric field generated by each particle, which attracts charged particles, ions, and/or ionic complexes contained in the working fluid. The piezoid bed is contained in a closed chamber to which the uniaxial compressive force is applied. Monocrystalline quartz particles or another suitable piezoid, natural or synthetic, may be used. A fluid is used to purge the piezoid bed of charged particles, ions, and/or ionic complexes after the piezoid bed becomes saturated through use. The working fluid may be used to purge the piezoid.

The systems and methods described herein relate to use of a reverse diffusion system for removal of dissolved ions from a fluid, for example, salt ions. Specific embodiments include a system for desalinating salt water to produce potable water. The systems and methods can include pulsing low levels of electricity via electrodes in a scrolling pattern, so as to sweep the ions across a unit.