CMC-Fe₃O₄ nano-composite particles were prepared in the carboxymethyl cellulose CMC solution by a modified oxidation deposition method, and characterized by TEM, XRD, IR, ZP (zeta potential) and VSM (vibrating sample magnetometer). The adsorption of Cu^2＋ on CMC-Fe₃O₄ was further researched. Different pH, reaction time and Cu^2＋ initial concentration affecting adsorption of CMC-Fe₃O₄ was studied. The results show that CMC-Fe₃O₄ is inverse spinel structure; the particle size is 40 nm on an average and dispersed homogeneously in water. Carboxymethyl cellulose molecules are chemically adsorbed on the surface of Fe₃O₄ nano-particles. Its saturation magnetization is 36.74 emu/g. The maximum adsorption for Cu^2＋ occurred at pH＝7 in water. The adsorption equilibrium time was reached in 1.5 h. The adsorption kinetics and isotherm data were well described by pseudo-second-order equation and Langmuir isotherm models, respectively. The adsorption mechanism of Cu^2＋ was main complexation reaction.

Key words: oxidation deposition method, carboxymethyl cellulose, Fe₃O₄ nano-particle, magnetic particle