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

• Published in: Chemosphere (Oxford) Vol. 287; p. 132287
• Main Authors: Aggarwal, Ruchi, Saini, Deepika, Sonkar, Sumit Kumar, Sonker, Amit Kumar, Westman, Gunnar
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2022
• Subjects: Acid assisted carbonization; Biomass; Heavy metal removal; Photocatalysis; Acid assisted carbonization; Biomass; Heavy metal removal; Photocatalysis
• ISSN: 0045-6535; 1879-1298; 1879-1298
• DOI: 10.1016/j.chemosphere.2021.132287

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 °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 pseudo-first-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. [Display omitted] •Photoactive nano carbon dots (CD) are synthesized from cellulose by carbonization.•Carbonization is performed at ∼90 °C for 30 min.•CD shows significant photocatalytic activity by sunlight illumination for Cr(VI) removal.