Facile functionalization of cellulose from discarded cigarette butts for the removal of diclofenac from water

In this study, cellulose nanocrystals (CNCs), and cellulose nanofibers (CNFs) were extracted from discarded cigarette butts (DCBs), and investigated for their efficiency for diclofenac (Dfc) removal from water. CNFs extraction process involved cleaving of acetyl group by alkali treatment and etched with phosphate ions (HPO) from phosphoric acid to obtain the variably charged HPO-CNFs. To obtain CNCs, sulfuric acid was used to cleave phenol moieties from CNFs under high temperature and agitation. SEM, FT-IR, SEM-EDS, Raman spectroscopy were used to analyze the physico-chemical properties of synthesized cellulose materials. The SEM images revealed the exfoliated fiber strands of CNFs after extraction procedure, and the difference in the crystal structure of CNCs30 and CNCs60. The EDS analyses revealed the presence of higher amount of carbon in DCBs compared to other forms of synthesized celluloses. The FT-IR analyses revealed functional group shifts and bond reductions after various treatment steps, while the HPO attachment on the CNFs surfaces was confirmed by the presence of P-O bonds. Raman analyses revealed clear crystals in the CNCs60 compared to the other celluloses. The adsorption capacity of HPO-CNFs for diclofenac removal was found to be 107.90 mg g(-1) and Langmuir model fitted well to the adsorption data.