米根霉菌对模拟环境废水中镍的吸附特性研究

Adsorption Properties of Rhizopus Oryzae to Nickel in Model Environmental Wastewater

从铀钨废水中分离出的一种米根霉菌(OR菌)对以电镀废水配制的模拟环境废水中镍的静态吸附特性,以及试液浓度、pH、菌用量和吸附时间等因素对其吸附效果的影响,同时对吸附前后菌株细胞形态改变和吸附机理进行了初步探索。结果显示,OR菌对镍的吸附在30min内即可达到平衡;在室温20℃和pH3.1～8.6范围内菌用量和溶液浓度对吸附效率的影响显著:25ml浓度为33.6mg/L的废水中加入OR菌0.3g,150r/min反应30min镍的去除率即可达到97.1%;在镍离子浓度不高于66mg/L的情况下,OR菌的吸附量随浓度增加而呈线性增加;吸附过程服从于Langmuir单分子层机理。透射电镜照片显示吸附镍以后菌株细胞壁的厚度显著增加,细胞内被更多物质充盈而显得饱满;镀银微区X衍射分析结果证实了镍、铁、铜、锌等在细胞内的存在。

Rhizopus oryzae (OR) separated from the wastewater containing uranide and tungsten was used to adsorb nickel in model wastewater, prepared with electroplating wastewater. The static adsorption performance and the related affecting factors such as nickel concentration, pH value of solution, the dosage of adsorbent and reaction time were studied. The variations of bacteria state and the adsorption mechanism in the process were also discussed. The results show that the biosorption by OR reaches equilibrium with 30 minutes. And at 20 ℃ and pH value ranging from 3.1 to 8.6, adsorbent dosages and nickel concentration have significant influence to the adsorbing efficiency. By adding 0.3 g OR to the wastewater of 25 ml with concentration 33.6 mg/L, the removal rate of nickel reaches up to 97.1% after 30 min. The adsorption capacity of OR to Ni increases linearly when nickel concentrations change from 0 to 66 mg/L, consistent with Langmuir monomolecular adsorbed layer formation. Transmission electron-microscope shows that the cell walls obviously increase because of more materials filled in the cell. Also, the silvering X-ray microanalysis indicates that there exist Ni, Fe, Cu and Zn in the cell.