Water pollution is more dangerous than air pollution, as the sources of water contamination are more diverse and water’s self-purification rate is slower than that of air [1]. One of the most dangerous water pollutants are the synthetic organic dyes. There are many methods of cleaning water from synthetic organic dyes, but adsorption is the most favourable one, as it is efficient, expedient and costs less. In recent years, heteroatom-functionalized carbon materials are widely used as adsorbents to remove the hazardous substances from the wastewater. The heteroatom-containing functional groups act as adsorption sites increasing the electrostatic interaction between adsorbents and adsorbates [2]. This study investigates the adsorption of Crystal Violet (CV) from aqueous solutions using the phosphorus-functionalized carbon material (PFCM) as an adsorbent. The CV is a cationic type dye, widely used to dye paper, leather and plastics. It is very toxic, carcinogenic, genotoxic and mutagenic [1]. The PFCM used in this study was synthesized via oxidative chlorophosphorylation of graphite and its subsequent hydrolysis. The chemical structure of PFCM was characterized using FTIR and UV-Vis spectroscopy. The morphology of PFCM was studied by SEM analysis. The results of these studies showed that the chlorophosphorylation affect the morphology of the graphite. To study the adsorption of the CV onto the PFCM, CV solutions in different concentrations were prepared. Each concentration of the dye was added the PFCM and kept for 48 hours in static condition. After 48 hours in static condition, each concentration’s solid and liquid phases were separated from each other and the concentrations in the filtrate were analyzed using ultraviolet-visible spectrometer (λ=590 nm). Results showed that the adsorption capacity of the PFCM rises with an increase in the dye solution’s initial concentration and removal percentage of the CV using the PFCM is 95.65%.