Controllable synthesis of bifunctional corn stalk cellulose as a novel adsorbent for efficient removal of Cu2+ and Pb2+ from wastewater

A corn stalk cellulose-based adsorbent with bifunctional groups of -NH-/-NH₂ and C-S/C=S for efficient removal of Cu²⁺ and Pb²⁺ was successfully synthesized. Under specific alkali and reaction conditions, 4.58 mmol/g of C-S/C=S groups were further introduced on surface of aminated cellulose with 6.99 mmol/g of amino groups. The introduced CS₂ would only participate in the esterification with -NH₂ groups to form special dithiocarbamate (DTC) structures containing -NH- groups (-NHCS₂^-). The synthesized DTC structures would not reduce total amount of -NH-/-NH₂ groups on aminated cellulose to keep its excellent adsorption performance for Cu²⁺, and the introduced appropriate number of C-S/C=S groups could ensure the efficient removal of Pb²⁺. It was suitable for removal of coexisting Cu²⁺ and Pb²⁺ with low initial concentration in real wastewater, and the removal rates were both close to 100%. The application of the bifunctional cellulose offered a novel way for purpose of 'waste treatment by waste'.

Dithiocarbamate-modified cellulose-based sorbents with high storage stability for selective removal of arsenite and hazardous heavy metals

A series of cellulose derivatives bearing dialkyl dithiocarbamate (DTC) groups were synthesized. Their ability of sorption of arsenite (As(iii)) and heavy metals and their storage stability in the solid state were investigated. Among them, DTC-modified cellulose derived from l-proline showed the highest sorption capacity for As(iii) and heavy metals to selectively remove them from aqueous media. It also showed exellent storage stability in air at 40 °C.

Dithiocarbamate-modified cellulose derived from l-proline works as a storable sorbent for selective removal of toxic As(iii) and heavy metals from aqueous media.