An emitter apparatus is mounted on a marine structure powered by wind or marine hydrokinetic energy to disperse a carbon dioxide sorbent such as sodium hydroxide. The sorbent can be generated by reverse osmosis of seawater with electrolysis of the brine, or delivered from an external supply. Suitable marine structures include offshore wind turbines, marine hydrokinetic generators, offshore oil platforms, merchant vessels, and other fixed and mobile structures. Effective capture is made by dispersing a fine mist or fog of aqueous sorbent from nozzles with a particle size from a nozzle of less than 100 microns. The sorbent reacts with atmospheric carbon dioxide forming carbonates and bicarbonates, which drift and fall to the ocean surface, reducing surface acidity and capturing additional atmospheric carbon dioxide via absorption at the local ocean surface. The resulting carbonates sink to the ocean floor and are there sequestered.

In this disclosure, a process of recycling acid, base and the salt reagents required in the Li recovery process is introduced. A membrane electrolysis cell which incorporates an oxygen depolarized cathode is implemented to generate the required chemicals onsite. The system can utilize a portion of the salar brine or other lithium-containing brine or solid waste to generate hydrochloric or sulfuric acid, sodium hydroxide and carbonate salts. Simultaneous generation of acid and base allows for taking advantage of both chemicals during the conventional Li recovery from brines and mineral rocks. The desalinated water can also be used for the washing steps on the recovery process or returned into the evaporation ponds. The method also can be used for the direct conversion of lithium salts to the high value LiOH product. The method does not produce any solid effluent which makes it easy-to-adopt for use in existing industrial Li recovery plants.

A novel solar-powered desalination and water purification system is disclosed herein. The system includes a nanofiber-impregnated graphene aerogel, an untreated water source, a water collection surface, and a purified water storage container. A novel photocatalytic nanofiber-impregnated graphene aerogel for desalination and photodegradation of contaminants for use in the disclosed system is also disclosed herein. The nanofiber-impregnated graphene aerogel exhibits excellent hydrophilicity, thermal insulation, and photodegradation capability, and allows for efficient solar-powered evaporation of water. The introduction of photocatalytic nanofibers into the graphene aerogel allows effective interfacial evaporation and in situ photodegradation of contaminants. The rate of water evaporation is preferably greater than 1.3 gal/ft.sup.2 per day, and the contaminant removal is preferably greater than 90%. A method of desalinating and purifying water using the disclosed system is also disclosed herein.

An apparatus and method for determining an amount of chemical input, and more particularly to an apparatus and method for determining the amount of a chemical to be added, which is necessary to achieve target water quality, wherein a required chemical concentration can be accurately calculated based on the temperature of the water and the target turbidity of the water includes an information-receiving unit configured to receive at least one of environmental information, chemical information, and water-quality information of the water present in a specific area and a chemical input determination unit configured to derive a multiple regression equation based on the received environmental information, chemical information, and water-quality information and to determine the future input of a chemical that is added to satisfy a target turbidity of the water present in the specific area based on the multiple regression equation.

A porous membrane comprising stacked layers of nanosheets, each nanosheet comprising one to three atomic layers of a 2D material comprising or consisting of one or more transition metal dichalcogenides is provided. The nanosheets have pores and the membrane comprises a network of water permeation pathways including through-pathways formed by the pores, horizontal pathways formed by gaps between the layers, and vertical pathways formed by gaps between adjacent nanosheets and stacking defects between the layers. Also provided is a method for making the membrane.

A chemical dosing optimization apparatus includes a chemical dosing optimization part and a chemical dosing output control part, wherein the chemical dosing optimization part receives real-time data at least from a water treatment plant treating feed water by dosing a chemical and providing a treated water, analyzes the real-time data through a water treatment model in response to receiving the real-time data, derives a prediction value for predicting a state of the treated water of the water treatment plant, and derives a control value based on the prediction value through a controller, such that the control value is to set a minimum of a chemical dosage to be dosed in the feed water while the state of the treated water of the water treatment plant is maintained in a normal range, and wherein the chemical dosing output control part provides the control value to a water treatment control device.

An apparatus for controlling chemical dosing optimization in a water treatment plant treating feed water includes: a control value derivation part configured to receive real-time data, analyze the real-time data through a water treatment model and a controller in response to receiving the real-time data, and calculate a control value, such that the control value is to set a minimum of a chemical dosage while maintaining a state of treated water of the water treatment plant in a normal range, the water treatment model simulating the water treatment plant and the controller being an optimization algorithm; and a chemical dosing output control part configured to provide the control value to a water treatment control device.

An ocean alkalinity enhancement (OAE) system that reduces atmospheric CO.sub.2 and mitigates ocean acidification by electrochemically processing feedstock solution (e.g., seawater or brine) to generate an alkalinity product that is then supplied to the ocean. The OAE system includes a base-generating device and a control circuit disposed within a modular system housing deployed near a salt feedstock. The base-generating device (e.g., a bipolar electrodialysis (BPED) system) generates a base substance that is then used to generate the ocean alkalinity product. The control circuit controls the base-generating device such that the alkalinity product is supplied to the ocean only when (1) sufficient low/zero-carbon electricity is available, (2) it is safe to operate the base-generating device, and (3) supplying the alkalinity product will not endanger sea life. Modified BPED systems include features that facilitate autonomous system operations including enhanced maintenance cycle operations and a reduced reliance on external fresh water sources.

A foam electrode comprising surface treatment by the steps of: 1) impregnating soft compressible polymeric foams with a conductive coating via sequential infiltration synthesis and 2) functionalizing the chemically altered voids with an ultrathin redox coating to enhance capacitive deionization (CDI). The redox coating will allow treated foam to absorb ions under the application of a bias, and mechanical compression/decompression. The CDI apparatus uses the void volume of the foam in the uncompressed state to flow liquids through it while the compressed state is used to enhance desalination by limiting the diffusion pathways for the ions to find an adsorption surface.

A water treatment system includes a water inlet that intakes water to be treated, a high voltage (HV) electrode having a porous metal surface area in a range of between 0.1 cm.sup.2 and 5 cm.sup.2 in fluid communication with the water, such that the water flows through the porous metal surface area of the HV electrode, a ground electrode disposed across a gap from the HV electrode, in fluid communication with the water, a high voltage power supply electrically connected to the HV electrode for generating spark plasma or pulsed electric fields having a rise time equal to or less than 60 nanoseconds (ns) and an amplitude greater than or equal to 30 kV/cm across the gap, thereby producing treated water, and a water outlet that discharges the treated water.