A method of reducing a biofilm, including mixing a cobalt salt and an iron salt in water to form a solution. The method further includes adding an aloe vera extract to the solution and stirring for 1 hour to 10 hours at a temperature of 30 degrees Celsius ( C.) to 80 C. to form a gel. Heating the gel to form a foam, calcining the foam at a temperature of 600 C. to 1000 C. for 1 hour to 3 hours to form CoFe.sub.2O.sub.4 NPs, and contacting the CoFe.sub.2O.sub.4 NPs with a biofilm on a surface. The CoFe.sub.2O.sub.4 NPs reduce an amount of the biofilm after the contacting. The CoFe.sub.2O.sub.4 NPs have an average size of 5 nanometers (nm) to 35 nm. The CoFe.sub.2O.sub.4 NPs form aggregates having an average size of 500 micrometers (m) to 1 m.

The present invention provides a photocatalyst composite, a method of preparing the same, and a method of producing hydrogen. The method of preparing the photocatalyst composite includes a step of preparing g-C.sub.3N.sub.4, a step of preparing CuFeO.sub.2 and a step of synthesizing g-C.sub.3N.sub.4/CuFeO.sub.2. Preparing g-C.sub.3N.sub.4 includes heating a predetermined weight of melamine at a predetermined heating rate for a predetermined time to obtain g-C.sub.3N.sub.4 powder. Preparing CuFeO.sub.2 includes hydrothermal synthesis followed by drying to obtain CuFeO.sub.2 powder. Synthesizing g-C.sub.3N.sub.4/CuFeO.sub.2 includes mixing the g-C.sub.3N.sub.4 powder and the CuFeO.sub.2 powder obtained in the previous steps with a predetermined ratio to obtain a photocatalyst composite of g-C.sub.3N.sub.4/CuFeO.sub.2 in which the photocatalyst composite has a heterogeneous structure. The method of producing hydrogen includes adding plastic to an alkaline solution to form a pretreatment solution and performing hydrogen production through a photoreforming reaction in the plastic pretreatment solution using the aforementioned photocatalyst composite.

The present invention relates to a method of preparing an iron-chromium oxide using an ion-exchange resin. Moreover, the present invention relates to a method of preparing an iron-chromium oxide that can be used as a cathode material for lithium-ion batteries. According to one aspect of the present invention, it has the effect of providing a cathode material for lithium-ion batteries with a high capacitance, while exhibiting a voltage similar to that of a transition-metal oxide (2-4.5 V vs Li.sup.+/Li).

Doped titanium niobate is provided, which has a chemical structure of Ti.sub.(1-x)M1.sub.xNb.sub.(2-y)M2.sub.yO.sub.(7-z)Q.sub.z or Ti.sub.(2-x)M1.sub.xNb.sub.(10-y)M2.sub.yO.sub.(29-z)Q.sub.z, wherein M1 is Li, Mg, or a combination thereof; M2 is Fe, Mn, V, Ni, Cr, or a combination thereof; Q is F, Cl, Br, I, S, or a combination thereof; 0x0.15; 0y0.15; 0.01z2; 0x0.3; 0y0.9; and 0.01z8.

A treatment method for full resource recovery from sludge in municipal wastewater treatment plants is provided. Ozone is used to oxidize the cell contents of sludge, and the hermetia illucens pupa shell powder slurry, polydimethyl diallyl ammonium chloride and the like are used as conditioning materials and materials for improving the water retention performance of residues. The dehydrated products are prepared into soil water retention materials, the heavy metals separated from the sludge are recovered in a ferrite way, and the organic carbon in the liquid phase is utilized as a carbon source of a wastewater treatment plant.

A MnZn-based ferrite that can reduce the loss even when a high-frequency voltage fluctuation occurs is provided. The above MnZn-based ferrite is a MnZn-based ferrite including Fe2O3, ZnO, and MnO as main components, in which of Fe2O3 is 53.2 to 56.3 mol % and ZnO is 1.0 to 9.0 mol %, with a balance of MnO, in 100 mol % of the main components, and the MnZn-based ferrite includes 0.9 to 2.0% by mass of Co.sub.2O.sub.3, 0.005 to 0.06% by mass of SiO.sub.2, and 0.01 to 0.06% by mass of CaO, as auxiliary components, per 100% by mass of the main components.