In order to investigate chelating ability of sodium carboxymethyl cellulose (CMC) on copper ions

the absorption spectra of the copper ion complex with CMC were measured via ultraviolet spectrophotometry. The composition of the complex was discussed and its stability constants were calculated. The experimental results show that CMC exhibits adsorption peak at 196 nm. When c(Cu2+)/c(—COO-) is less than 0.6

the absorption peak of the complex appears at 237 nm

—COO- group of CMC is the main ligand and reacts with Cu2+ in a molar ratio of 2:1 to form complex CMC-Cu2+

and the complex stability constant is 1.88×1010. When c(Cu2+)/c(—COO-) is from 0.6 to 1.0

the maximum absorption peak of the complex appears at 214

237 nm. —COO- and —OH are involved in the complexation reaction to form a new complex. When c(Cu2+)/c(—COO-) is greater than 1.0

the maximum absorption is in 214 nm and —OH is the primary ligand. The paper also investigates the removal effect of Cu2+ by CMC chelating. Experiments show that CMC-Cu directly precipitates to complexes in the solution

with precipitates as floc. c(Cu2+)/c(—COO-) of 0.5 is the optimal usage of CMC in the supernatant

and the removal rate of Cu2+ can reach above 96%.