Studies On Preparation And Properties Of Novel Composite Adsorbent

Black carbon(HT) was prepared from lignocellulose by pyrolysis methods, preparation conditions and its effect in dye waste water treatment were explored. Composite adsorbent HTF and GZTF were prepared respectively by dip-pyrolysis methed with the HT and commercial diatomite as the carriers, they are used to removal Cr (Ⅵ) from aqueous solution and the effects of experimental conditions were investigated. The simples were characterized by XRD, SEM-EDS, TG-SDC, BET, XPS and others. The experimental results show that when the calcination temperature 350 ℃, calcination time 2 h, the HT material show best decoloring effect of MB solution, when the initial concentration of MB is less than 50 mg/L, the decolorization rate can reach above 90%, the adsorption process conforms to the Langmuir isotherm adsorption model and quasi-secone-order kinatics. For 20 mg/L Cr (Ⅵ) wastewater, when the optimum reaction conditions are as follows:the pH value is 5, adsorption time for 60min, adsorbent dosage 4 g/L, Cr (Ⅵ) removal rate can reach 99.15% by HTF adsorbent, the adsorption process conforms to the Freundlich isothermal adsorption model and the maximum adsorption capacity can reach 14.66 mg/g; When the optimum reaction conditions are as follows:the pH value is 5, adsorption time for 30 min, adsorbent dosage 4 g/L, Cr (Ⅵ) removal rate can reach 98.85% by GZTF adsorbent, the adsorption process conforms to the Freundlich and Langmuir isothermal adsorption model and the maximum adsorption capacity can reach 14.05 mg/g; The Cr (Ⅵ) concentration of influence is lower than 0.5 mg/L after both kinds of adsorbent treated, meet the requirements of the wastewater discharge standard in China. XPS analysis shows that Cr (Ⅵ) in aqueous solution was restored to Cr (Ⅲ) after adsorped by HTF adsorbent, while the Cr (Ⅵ) adsorped by GZTF is given priority to with Cr (Ⅵ), there is only a small amount of Cr (Ⅲ), adsorption on GZTF was thought to be mainly electrostatic adsorption.