黄芪废渣活性炭的制备及其对Cu^(2+)和Cd^(2+)的吸附特性

Preparation of activated carbon from astragalus residue and its adsorption characteristics for Cu^(2+) and Cd^(2+) removal

以黄芪废渣(AS)为原料,用KOH为活化剂制备黄芪废渣活性炭(ASC)并用于对水溶液中Cu^(2+)和Cd^(2+)的吸附.考察了KOH质量浓度、活化时间、活化温度和浸渍比(活化剂体积(mL):黄芪废渣质量(g))等因素对黄芪废渣活性炭碘吸附值和得率的影响;通过扫描电子显微镜、比表面积测定和X射线衍射等方法对黄芪废渣活性炭进行表征.结果表明,在KOH质量浓度为20%,浸渍比3∶1,温度为600℃,活化炭化时间为80 min时,制备的黄芪废渣活性炭的比表面积为1 519.53 m^2·g^(-1),对重金属离子Cu^(2+)和Cd^(2+)在20℃,pH分别为5.0和6.0时饱和吸附量分别为1.98和1.04 mmol·g^(-1).

Taking astragalus residue(AS)as raw materials and KOH as activator,the activated carbon(ASC)was prepared from astragalus residue and it was used as adsorbent for removal of Cu^2+ and Cd^2+ in aqueous solution.The influence of mass concentration of KOH,impregnation ratio(ratio of activator volume(mL)to AS mass(g)),activation time,and activation temperature on the iodine adsorption value and the yield of ASC was investigated.Analysis methods such as scanning electron microscopy(SEM),specific surface area analyser and X-ray diffraction(XRD)were used to characterize the ASC.The result showed that when the mass concentration of KOH was 20%,the activation and carbonization time was 80 min,the impregnation ratio was 3∶1,and the activation temperature was 600 ℃,the specific surface area of ASC would be 1519.53 m^2 ·g^-1.When the pH value were 5.0 and 6.0 separately at 20 ℃,the maximum adsorption capacity of ASC for removal of heavy metal ions Cu^2+ and Cd^2+ would be 1.98 mmol·g^-1 and 1.04 mmol·g^-1,respectively.