Chlorine-containing phenolic resin nanometer material and preparation and application thereof

The invention provides preparation and application of modified chlorine-containing phenolic resin nanoparticles with strong yellow-green fluorescence emission. The preparation method of the modified chlorine-containing phenolic resin nanoparticles with the strong yellow-green fluorescence emission comprises the following steps of: carrying hydrothermal reaction on p-chlorophenol, hexamethylene tetramine and water for 6 hours in proportion at the temperature of 160 DEG C, taking liquid supernatant, and dialyzing for 2 to 3 days for later use. A method of detecting Fe3+ by using the chlorine-containing phenolic resin nanoparticles comprises the following steps of: mixing a certain amount of chlorine-containing phenolic resin nanoparticles with a certain volume and concentration of Fe3+, wherein the concentration of the chlorine-containing phenolic resin nanoparticles is fixed, the concentration of the Fe3+ is controlled to be 0-1 mM, putting the mixed solution in a fluorescence spectrophotometer to detect the c