A two-dimensional particle including: one or plural layers, the one or plural layers having a layer body represented by: M.sub.mX.sub.n, wherein M is at least one metal of Group 3, 4, 5, 6, or 7, X is a carbon atom, a nitrogen atom, or a combination thereof, n is 1 to 4, m is more than n but not more than 5, and a modifier or terminal T existing on a surface of the layer body, wherein T is at least one selected from a hydroxyl group, an amine group, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an oxygen atom, a sulfur atom, a selenium atom, a tellurium atom and a hydrogen atom; a metal cation is at least one cation selected from Na and K, and a content of Li in the two-dimensional particle is less than 0.002% by mass.

A method of removing barium from a liquid includes adding a two-dimensional metal carbide water contaminant adsorbent to water to adsorb contaminants, such as barium (II), from the liquid. The two-dimensional metal carbide water contaminant adsorbent is in the form of at least one MXene, having the formula M.sub.n+1X.sub.n, where n=1, 2 or 3, M is an early transition metal, such as scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo) or the like, and X is either carbon or nitrogen. The MXene may be Ti.sub.3C.sub.2. The liquid may be, for example, at least one water by-product from at least one oilfield reservoir, such as produced water, co-produced water or a combination thereof.

There is provided an aggregate of radioactive material removing particles in which two or more radioactive material removing particles having magnetic particles and a radioactive material adsorption component are assembled, wherein a pore volume in the aggregate is 0.5 mL/g or more and 5.0 mL/g or less, and the pore volume means a cumulative value obtained by a mercury press-in method.

A multilayer composite for reversible sorption of mercury, with a carrier core made of a metal or an alloy based on transition metals, has isolating layers of a transition metal nitride and externally located sorptive layers, made of a mixture of sulfides and nitrides of transition metals, the layers being deposited on both sides of the core. A method for sorption of mercury from a gaseous phase during an exposition of the multilayer composite to the influence of multicomponent gaseous mixtures that contain mercury vapors or compounds for a time period of 0.5 to 24 hours, while the temperature of the multilayer composite is maintained in the range from 20 to 150 C.

The sodium ferrite particle powder according to the present invention is characterized in that at least one metal or more selected from the metal group consisting of silicon, aluminum, titanium, manganese, cobalt, nickel, magnesium, copper and zinc is contained in an amount of 0.05 to 20% by weight in terms of the oxide, and the molar ratio of Na/Fe is 0.75 to 1.25.

A ZnFe(BO.sub.3)O/Fe.sub.2CaO.sub.4/C nanocomposite material includes an orthorhombic zinc iron borate oxide (ZnFe(BO.sub.3)O) phase and an orthorhombic iron calcium oxide (Fe.sub.2CaO.sub.4) phase. The ZnFe(BO.sub.3)O/Fe.sub.2CaO.sub.4/C nanocomposite material includes irregularly shaped granular and flake-like particles. Further, a method of producing the ZnFe(BO.sub.3)O/Fe.sub.2CaO.sub.4/C nanocomposite material includes calcining metal precursors.

The present invention relates to a MXene nanosheet ink for palladium recovery, a method of manufacturing the same, a method of recovering palladium using a MXene nanosheet ink, an electrochemical catalyst using recovered palladium, and a method of manufacturing the same that are capable of significantly improving the recovery efficiency of palladium ions in water.