Abstract: In this study a ultrasonic wave-assisted chemical modification of bamboo powder was carried out to prepare an effective amidoximated bamboo powder-based absorbents for Pb²⁺ removal from water. The bamboo powders were first pretreated by ultrasonic wave, then subsequently modified by acrylonitrile in alkaline medium and aqueous hydroxylamine. The resulting absorbents were characterized using Fourier transform infrared (FT-IR) and the characteristic absorption peaks corresponding to —C≡N,—CN and N—OH groups were observed. XRD showed that the degree of crystalline of resulting product decreased from 64% to 42%. The nitrogen content determined by elemental analysis is 9.8%. This indicated that the amidoxime group was successfully attached onto the bamboo powders. Adsorption of Pb (Ⅱ) ions by the modified bamboo powder adsorbents were also performed by batch experiments in order to investigate the effects of the adsorbent dosage, initial pH of the solution, and initial Pb²⁺ concentration on the adsorption of Pb²⁺, respectively. Langmuir-Freundlich plots and their isotherm coefficients for the adsorption of Pb(Ⅱ) using the adsorbent were probed. It was found that modified bamboo powders with the aid of ultrasound have a maximum absorption of Pb²⁺ 243.09 mg/g under the condition of pH at 6.0, amount of 2.5g/L for absorption and initial ionic concentration of 1 300 mg/L. It agreed with Langmuir-Freundlich isotherm model.

Key words: ultrasonic wave, bamboo powder, adsorption, modification, heavy metal ion