Method of detecting antimony ions and method of removing antimony ions using a fluorescent nanocomposite

A method of removing antimony ions from a fluid sample, comprising:

• contacting the fluid sample with a fluorescent nanocomposite to form a mixture, whereby antimony ions adsorb onto the fluorescent nanocomposite to form a loaded nanocomposite;
• and
• separating the loaded nanocomposite from the mixture by centrifugation and/or filtration,
• wherein a concentration of antimony ions in the fluid sample after the contacting and separating is lower than an initial concentration of antimony ions in the fluid sample,
• wherein the fluorescent nanocomposite comprises:
• a thallium doped gadolinium chalcogenide having formula TlxGd1-xY, wherein x is 0.01 to 0.1, and Y is selected from the group consisting of S, Se, or Te;
• and
• a benzothiazolium salt of formula I bound to a surface of the thallium doped gadolinium chalcogenide,
• wherein:
• R1 is a C1-C4 alkyl or an arylalkyl,
• R2 and R3 are independently an optionally substituted alkyl group, or wherein R2 and R3 together form a five or six membered ring with the nitrogen to which they are attached,
• R4 and R5 are independently a hydrogen or an alkyl group, and
• A is Br, I, or ClO4.