How to effectively deal with the polluted water by the pollutant of organic dyes is the world problem. It is of great significance if the organic dyes in the polluted water can be directly turned into the useful materials through a facile approach. Herein, the water which contains the common organic dye, Reactive red 2 (RR2), has been chosen to be the model to synthesize graphene quantum dots (GQDs) by a facile route. The comprehensive characterizations, including TEM (HRTEM), XPS, Raman, PL and UV–Vis. spectra, have been performed to confirm the structures and explore the properties of the synthesized GQDs. Meanwhile, the excellent PL properties and low biotoxicity of the GQDs confer them with the potential applications in the biological fields. When the GQDs are excited by the wavelength of 360 nm, the maximum emission is achieved at 428 nm. It is well demonstrated that the synthesized GQDs are able to detect the Al3+ which causes multiple diseases, such as Parkinson, Alzheimer, kidney disease, and even cancer. The detection range is from 90 to 800 μM, which is different from the reported kinds of the literature. Therefore, this work not only provides an economical and environmental route on solving the universal problem from organic dyes, but also facilitates to advancing the synthesis and application of GQDs.