Abstract: The embodiments of this disclosure are related to a water treatment system comprising a flotation tank, a shell-tube inlet conduit connected to the flotation tank and comprising a shell configured to supply a gas and at least one tube configured to supply untreated water, wherein each of the shell and the tube has a first part exposed to an outside of the flotation tank and a second part extending into the flotation tank, a microbubble forming means positioned on or adjacent to the second part of the shell, and a treated water outlet connected to the flotation tank and configured to allow treated water separated from solids in the flotation tank to be discharged therethrough.

Abstract: Proposed is a method of analyzing microplastic particles in a water system. The method includes providing raw water containing microplastic particles, freezing and thawing the raw water at least once to generate microplastic aggregates in the raw water, recovering the microplastic aggregates, and analyzing the recovered microplastic aggregates. According to the method, the microplastic particles are precipitated in the water system without the use of an additional coagulant, whereby the effect of coagulants on the subsequently recovered microplastic aggregates may be ruled out. In addition, the process configuration is simple because the aggregates can be separated from the supernatant without using any additional treatment process.

Abstract: Proposed is a method of extracting a metal from a salt solution derived from a spent battery, the method including preparing a salt solution derived from a spent battery containing metal ions, preparing a metal extractant mixture including a metal extractant and a metal extractant activator, bringing the metal extractant mixture into contact with the salt solution to produce a complex compound of the metal extractant mixture and the metal, and a first filtrate. The method further comprises recovering the complex compound and the first filtrate and bringing an acid into contact with the complex compound to produce a metal salt, and a second filtrate, recovering the metal salt and the second filtrate, and recovering each of the activator and acid from the first filtrate through electrodialysis.

Abstract: Proposed is a method of recovering acids and alkalis from raffinate generated from a metal extraction process. The method includes pretreating raffinate generated from a metal extraction process and performing electrodialysis of the pretreated raffinate. The method recovers some components present in raffinate generated from a battery manufacturing process and a battery treatment process to reuse the recovered components. Therefore, the method provides economic and environmental benefits.

Abstract: According to one embodiment of the present disclosure, an electrochemical water treatment reactor includes a first cavity with a wastewater inlet, a second cavity with a wastewater outlet, a spacer disposed between the first and second cavities, the spacer separating the first and second cavities from each other, an anode disposed in the first cavity, a cathode disposed in the second cavity, and a metal powder disposed in the first cavity and being in direct or indirect contact with the anode. The reactor can be used to efficiently remove contaminants from wastewater without consuming the anode.

Abstract: Proposed is an electro-coagulation apparatus. The electro-coagulation apparatus includes a reactor having an internal space defined by a top surface, a bottom surface, and a side surface of the reactor; a plurality of electrode plates disposed spaced apart from each other inside the internal space of the reactor, and a pair of first conduits respectively connected to a front end and a rear end of the reactor. Furthermore, a cross-sectional area of the reactor is smaller than a cross-sectional area of each of the first conduits.

Abstract: Proposed is a process for collecting and removing microplastics in wastewater. The process includes coagulating microplastics in wastewater and adding an enzyme to the coagulated microplastics. Also, a method for collecting and removing microplastics is provided, the process comprising: pulverizing polyethylene terephthalate (PET) bottles into microplastics; dispersing the microplastics into a water system; coagulating the microplastics to produce coagulated microplastics; and adding an enzyme to the coagulated microplastics whereby the coagulated microplastics are decomposed by the enzyme into their monomer constituents. According to this process and method, the microplastics in wastewater can be removed with high efficiency.

Abstract: The present invention relates to a process of converting carbon dioxide using a combination of a carbon dioxide mineralization and the metabolism of sulfur-oxidizing microorganisms. According to the process, a carbonate produced in the carbon dioxide mineralization reaction can be converted to a useful substance without supplying an external additional energy source (light, electrical energy, etc.) and mineral resources (metal ions). In addition, the process can be continuously performed by recycling metal ions necessary for the carbon dioxide mineralization reaction.

Abstract: In a method for regenerating a lithium precursor, a lithium-containing waste mixture is put into a reactor. An inside of the reactor is replaced with carbon dioxide. Temperature raising treatment is performed on the lithium-containing waste mixture and the carbon dioxide to produce lithium carbonate and a transition metal-containing mixture. The lithium precursor may be recovered with high yield and high efficiency through dry treatment using carbon dioxide.

Abstract: The present invention relates to a method of reducing carbon dioxide and air pollutants, and more particularly to a method of simultaneously reducing emissions of carbon dioxide and air pollutants, in which an off-gas containing carbon dioxide, SOx, and NOx is passed through a sulfur-oxidizing microorganism reactor, thereby converting carbon dioxide present in the off-gas into biomass, SOx into sulfate ions, and NOx into amino-N.

Abstract: A method of preparing ammonium sulfate includes feeding biosulfur and ammonia produced during anaerobic fermentation into a sulfur-oxidizing microbial reactor to cause sulfur-oxidizing microorganisms to produce sulfuric acid through oxidation of the biosulfur and reacting the produced sulfuric acid with ammonia to produce the ammonium sulfate. A culture medium containing the produced ammonium sulfate and microorganisms can be used as fertilizers.

Abstract: The invention relates to a method of reducing carbon dioxide and metal-containing dust and, more particularly, to a method of simultaneously reducing carbon dioxide and metal-containing dust by passing an off-gas, which contains carbon dioxide or carbon dioxide and metal-containing dust, through a reactor in which a sulfur-oxidizing microorganism is grown using carbon dioxide as a carbon source to produce sulfuric acid, and producing metal sulfates (MeSO4) by reaction of the produced sulfur acid with metal components present in the off-gas.

Abstract: The present invention relates to a method of reducing carbon dioxide and air pollutants, and more particularly to a method of simultaneously reducing emissions of carbon dioxide and air pollutants, in which an off-gas containing carbon dioxide, SOx, and NOx is passed through a sulfur-oxidizing microorganism reactor, thereby converting carbon dioxide present in the off-gas into biomass, SOx into sulfate ions, and NOx into amino-N.

Abstract: A method for recovering an active metal of a lithium secondary battery according to an embodiment of the present application whereby a cathode active material mixture obtained from a used cathode of a lithium secondary battery is prepared, and the cathode active material mixture is reacted in a fluidized bed reactor to form a preliminary precursor mixture. A lithium precursor is recovered from the preliminary precursor mixture. Yield and selectivity of a lithium precursor can be improved using the fluidized bed reactor.

Abstract: Disclosed are a carbonic anhydrase mutant having heat resistance at a high temperature of 80° C. as well as excellent activity to capture carbon dioxide and a composition for capturing carbon dioxide containing the same. The heat-resistant carbonic anhydrase mutant can be applied to a high-temperature carbon dioxide capture process due to high stability at high temperatures and a high carbon dioxide hydration rate.

Abstract: A method for recovering an active metal of a lithium secondary battery according to an embodiment of the present application whereby a used lithium-containing mixture is prepared, and the used lithium-containing mixture is treated with a hydrogen reduction to prepare a preliminary precursor mixture. The preliminary precursor mixture is washed with water to generate a lithium precursor including lithium hydroxide. Lithium hydroxide can be obtained by the washing treatment with high purity.

Abstract: In a method for regenerating a lithium precursor, a lithium-containing waste mixture is put into a reactor. An inside of the reactor is replaced with carbon dioxide. Temperature raising treatment is performed on the lithium-containing waste mixture and the carbon dioxide to produce lithium carbonate and a transition metal-containing mixture. The lithium precursor may be recovered with high yield and high efficiency through dry treatment using carbon dioxide.

Abstract: Disclosed is a method of purifying carbon nanotubes, including treating carbon nanotubes with an inert gas at a high temperature in a low vacuum in a reactor and obtaining ultrapure carbon nanotubes, wherein the ultrapure carbon nanotubes contain 50 ppm or less of each metal remaining therein.

Abstract: The invention relates to a method of reducing carbon dioxide and metal-containing dust and, more particularly, to a method of simultaneously reducing carbon dioxide and metal-containing dust by passing an off-gas, which contains carbon dioxide or carbon dioxide and metal-containing dust, through a reactor in which a sulfur-oxidizing microorganism is grown using carbon dioxide as a carbon source to produce sulfuric acid, and producing metal sulfates (MeSO4) by reaction of the produced sulfur acid with metal components present in the off-gas.

Abstract: Disclosed are a carbonic anhydrase mutant having heat resistance at a high temperature of 80° C. as well as excellent activity to capture carbon dioxide and a composition for capturing carbon dioxide containing the same. The heat-resistant carbonic anhydrase mutant can be applied to a high-temperature carbon dioxide capture process due to high stability at high temperatures and a high carbon dioxide hydration rate.