腐植酸对砷的吸附作用研究

Adsorption of arsenic by humic acid

腐植酸中含有大量的极性基团,对金属离子有较强的吸附性能。运用氢化物-原子荧光光谱法,以泥炭腐植酸为原料,研究了腐植酸对砷(V)离子的吸附作用和腐植酸吸附剂中砷的回收,并得出了最佳的吸附和脱附条件。实验考察了酸度、时间分别对吸附和脱附的影响。结果表明,泥炭腐植酸对砷吸附的最佳模型为Freundlich吸附方程,当溶液成中性时腐植酸对砷的吸附量较大且趋于平稳。砷的浓度为1μg/mL,溶液的pH值为7,吸附时间控制在55min时,吸附效果最佳,最大吸附率为85.49%。脱附的最佳条件为:pH值14,脱附时间20min。

The adsorption and desorption of arsenic As（V） ions with peat humic acid as an adsorbent were investigated by using hydride generation atomic fluorescence spectrometry;the optimal conditions for the adsorption of As（V） in humic acid and the recovery of As（V） through desorption from the adsorbent were obtained.The results indicated that humic acid is provided with plentiful polar groups and exhibits strong adsorption ability for metal ions.The adsorption of As（V） ion in peat humic acid follows the Freundlich adsorption equation.The acidity of aqueous solution influences the adsorption significantly;the adsorption quantity is high and stable when the solution is neutral.The adsorption rate reaches 85.49% under the optimal conditions where As（V） concentration is 1μg/mL,pH value of the solution is 7 and adsorption time is 50min～60min.The most suitable conditions for the desorption are that pH value of the solution is 14 and desorption time is 20min.