Polyacrylic acid/Bentonite multifunctional composite with three- dimentional network was prepared through aqueous solution polymerization. The properties of the composites were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The resulted composite material was applied to remove Cd²⁺ ions in wastewater as adsorbent. The effect of time, the initial pH value and initial concentration of Cd²⁺ solution was examined. The adsorption isotherm as well as the reusability of the composite is evaluated. The results indicated that the saturated adsorption capacities of the composite for Cd²⁺ was found to be 843 mg· g^-1 under the following condition: contact time 24 h, pH=6, initial Cd²⁺ concentration 450 mg. L^-1 and amount of adsorbent 100 mg. The adsorption process for Cd²⁺ is in line with Langmuir isotherm model. Compared with other adsorption materials, the composites exhibited good adsorption of Cd²⁺ ions in water and retained 74% of their initial adsorption capacity after six adsorption-desorption cycles. Compared to some reported adsorbents such as activated carbon, the synthesised polyacrylic acid/bentonite adsorbent has a high adsorption capacity for Cd²⁺ and is expected to be a new type of adsorbent material for heavy metal ions in wastewater.
 

Acrylic acid, bentonite, characterization, adsorption, cadmium ion