Sunlight promoted removal of toxic hexavalent chromium by cellulose derived photoactive carbon dots

A scalable synthetic procedure for fabricating photoactive carbon dots (CD) from microcrystalline cellulose (MCC) is presented. The MCC was transformed into a photoactive nanosized CD by a one-step acid-assisted thermal-carbonization (-90 degrees C for 30 min). The efficiency of the obtained CD was determined by photo-removal of toxic hexavalent chromium (Cr(VI)) ions from wastewater. CD obtained from cellulose completely removed 20 ppm of Cr(VI) wastewater within -120 min under sunlight illumination. No Cr(VI) removal was observed in dark conditions and with control cellulose material as reference samples. The Cr(VI) removal follows pseudofirst-order kinetics along with a half-life of -26 min. Furthermore, the Cr(VI) removal from wastewater was supported via cyclic voltammetry analysis. Using a low-cost, naturally available cellulose material and sulfuric acid, the world's most-used chemical, creates techno-economic prerequisites for a scalable process of photoactive carbon dots.

Automated summary

A scalable synthetic procedure was developed to fabricate photoactive carbon dots from microcrystalline cellulose, which can efficiently remove toxic hexavalent chromium ions from wastewater through photocatalysis. The study demonstrated the feasibility of large-scale production of carbon dots using low-cost materials such as cellulose and sulfuric acid, showing promising industrial applications.