Synthesis, characterization and evaluation of cellulose-graft-poly(4-vinylpirydine), using cellulose from a new pretreatment process, for heavy metal removal from wastewater

The synthesis, characterization and evaluation of cellulose-graft-poly(4-vinylpirydine) for heavy metal removal from wastewater, is reported. Cellulose was obtained from a corn cob biomass using a recently developed gas-phase acid pretreatment process (GPAPP). The obtained corn cob cellulose (CCC) was functionalized by partial esterification of the superficial -OH groups with α-bromoisobutyryl bromide (BIBB) under mild conditions (room temperature and dimethyl formamide, DMF as solvent). The functionalized cellulose was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). The BIBB-functionalized CCC was used as initiator for surface-initiated (SI) atom transfer radical polymerization (ATRP) of 4-vinylpyridine (4VP). Grafting of the polymer (p4VP) onto cellulose was confirmed by FTIR, TGA and XPS. The same procedure was carried out with microcrystalline cellulose (MCC) as a reference. The performance of the cellulose copolymers for the removal of lead and iron from water was evaluated. Removal percentages of 83 % in 30 min for lead and 79 % in 180 min for iron were obtained with MCC-g-p4VP. In contrast, removal percentages of 50 % were obtained in 30 min for lead and 30 % for iron in 180 min, respectively, when CCC-g-p4VP was used.