BACKGROUND OF THE INVENTION

Technical Field

The present invention relates to a method of using ZnO particles to treat colon cancer and a method of using ZnO nanoflowers to reduce a concentration of an organic contaminant in an aqueous solution.

Description of the Related Art

The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.

Zinc oxide (ZnO) is used for various purposes including as a white pigment, as a catalyst, as a constituent of anti-bacterial skin protection ointment, sunscreens, and wood varnishes. Zinc oxide is also known as wide band gap semiconductor and is well suited for emissive devices. Materials used for blocking UV radiation are required to be transparent to the visible part of the solar radiation while blocking the harmful UV radiation and zinc oxide is considered favorable in this regard.

However, many of the above applications use nano-scale zinc oxide, and little progress has been made in using zinc oxide particles on larger scales having different morphologies and increased surface areas. Though numerous processes are known for the synthesis of zinc oxide particles, such processes are not efficient and do not reliably produce zinc oxide particles with high surface areas or with attached nanostructures. This limitation is often a significant deterrent in exploring new uses of zinc oxide particles. In view of the foregoing, one objective of the present invention is to provide a method of using ZnO particles to treat colon cancer in a mammal and a method of using the particles to reduce a concentration of an organic contaminant in an aqueous solution by photocatalytic degradation and/or adsorption. The ZnO particles may be made by a specific synthesis route.

BRIEF SUMMARY OF THE INVENTION

According to a first aspect, the present disclosure relates to a method for treating a colon cancer in a mammal. This method involves administering, to the mammal, a therapeutically effective dose of ZnO particles having substantially spherical shapes with diameters of 220 nm-3.5 μm and BET surface areas of 8-25 m2/g.

In one embodiment, the therapeutically effective dose is 0.1 to 5 g of ZnO particles per kg of the mammal per day.

In one embodiment, the diameters are 1.5-3.5 μm, and the BET surface areas are 15-25 m2/g.

In one embodiment, the ZnO particles are porous with pore sizes of 20-35 nm.

In one embodiment, a surface of the ZnO particles has nanopetals of 50-200 nm thickness extending 100-500 nm from the surface, the nanopetals traversing the surface with lengths of 500 nm-2 μm.

In one embodiment, the ZnO particles are administered as a part of a composition, wherein the composition further comprises a food product, a pharmaceutically acceptable excipient, a pharmaceutically acceptable carrier, or an antioxidant.

In one embodiment, the mammal is a human, a non-human primate, a dog, a cat, a horse, a cow, a goat, a rat, a pig, a rabbit, or a mouse.

In one embodiment, the ZnO particles consist essentially of ZnO.

In one embodiment, the ZnO particles contact a first population of colon cancer cells in the colon cancer. At a time 24 hours after the contacting, the first population has a growth inhibition of 60-80% in relation to a second population of colon cancer cells in the colon cancer that were not contacted.

According to a second aspect, the present disclosure relates to a method of reducing an organic contaminant concentration in an aqueous solution. This method involves contacting ZnO nanoflowers with the aqueous solution comprising the organic contaminant at a contaminant concentration of 1 mg/L-1 g/L and irradiating the ZnO nanoflowers while in contact with the solution. Here, the ZnO nanoflowers have a generally spherical shape with a diameter of 1.5-3.5 μm. A surface of the ZnO nanoflowers has nanopetals of 50-200 nm thickness extending 100-500 nm from the surface, and these nanopetals traverse the surface with lengths of 500 nm-2 μm. The ZnO nanoflowers reduce the contaminant concentration in the solution by adsorption and/or photocatalytic degradation.

In one embodiment, the ZnO nanoflowers are dispersed within the solution at a concentration of 0.5-100 mg/L.

In one embodiment, the irradiating is 15-30 minutes of UV light irradiation, and the concentration of the organic contaminant after the irradiating is 40-50% of the concentration of the organic contaminant before the irradiating.

In one embodiment, the organic contaminant is at least one selected from the group consisting of pharmaceutical compound, a dye, a metabolite, a microbial toxin, an herbicide, a pesticide, and a steroid.

In one embodiment, the ZnO nanoflowers are made by heating an aqueous Zn2+solution with sodium hydroxide.

In one embodiment, the aqueous Zn2+solution comprises Zn(NO3)2.

In one embodiment, the ZnO nanoflowers consist essentially of ZnO.

In one embodiment, the ZnO nanoflowers have a band gap energy of 2.90-3.31 eV.

In one embodiment, the irradiating uses sunlight as an irradiation source.

In one embodiment, the method further comprises contacting the solution with a second absorbent or a second photocatalyst to reduce the concentration of the contaminant and/or reduce a concentration of a second contaminant in the solution.

In one embodiment, the method also involves rinsing the ZnO nanoflowers to produce cleaned ZnO nanoflowers and reusing the cleaned ZnO nanoflowers, which maintain a contaminant reduction capacity for at least 5 purification cycles.

The foregoing paragraphs have been provided by way of general introduction, and are not intended to limit the scope of the following claims. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

