Food- and cosmetic-grade C-Phycocyanin leads to Spirulina (Arthrospira)-derived products with the highest potential commercial value, but its production is still a significant challenge due to economic issues and green metrics, with scalability at required purities. In this study, an efficient purification method for C-Phycocyanin of analytical grade in foods was developed. C-Phycocyanin was efficiently extracted and purified using ultrasonic extraction combined with pH shifting and purification with activated charcoal, achieving significantly increased purities from 0.45 to 3.31. Activated charcoal was used with the following optimal parameters: 4% (w/v), pH 5.0, and a mixing speed of 200 rpm for 2 min at room temperature (25 ℃). Further research was conducted to investigate the kinetic adsorption of C-Phycocyanin and total proteins on activated charcoal using the Langmuir, Freundlich, and Temkin isotherm models. The results indicated that the Langmuir isotherm model was suitable for the adsorption of C-Phycocyanin onto activated charcoal, while the Freundlich isotherm model was more appropriate for the adsorption of total proteins. These findings suggest that activated charcoal is more effective in removing heteroproteins other than C-Phycocyanins under the purification conditions studied. After purification with activated charcoal, the proportion of C-Phycocyanin in the total proteins increased from 31.2% to 51.5%. This study provides additional evidence that activated charcoal treatment is a viable purification step for C-Phycocyanin after the pH-induced precipitation of contaminants. This study presents a cost-effective and scalable preparation process for the efficient purification of high-purity grade C-Phycocyanin from Arthrospira maxima, which can be utilized extensively in the food and cosmetic industries.