生物膜吸附重金属离子的模型及影响因素的研究

重金属是对生态环境危害极大的一类污染物。去除废水中的重金属元素,生物膜法是一种有效的净化工艺。为了寻找生物膜去除重金属离子的最优操作条件,考察了各种影响因素pH值、温度、吸附时间、生物膜量、共存离子对吸附的影响。从实验结果可知,Cu2+的最优操作条件是pH值为6,温度在30℃左右,吸附时间为15min,生物膜量为12g,吸附率可达到65%;Cr3+的最优操作条件是pH值为3～7,温度在25℃左右,吸附时间为5min,生物膜量为10g,吸附率可达到87%。共存离子的竞争吸附会对吸附能力弱的Cu2+产生很大的影响,Cr3+没有表现出受到抑制或促进作用的影响,对单一Cu2+或Cr3+吸附体系,可以用经典的吸附模型进行拟合。

Research on model for heavy metal ions adsorption by bio-film and its affecting factors

Heavy metals are contaminations which damage to the entironment greatly. Bio-film method is an effective purify process for the removal of heavy metals from wastewater. In order to find the optimal operation condition for heavy metal ions removal by bio-film, the effects of some affecting factors included: pH value, temperature, adsorption time, quantity of bio-film, co-existed ions on the adsorption were investigated. It can be known from the results of the test that: the optimal operation condition for the adsorption of Cu2+ is: pH value is 6, temperature is about 30 ℃, adsorption time is 15 min, quantity of bio-film is 12 g, the adsorption rate can reach 65%;while, the optimal operation condition for the adsorption of Cr3+ is: pH value is 3 - 7, temperature is about 25 ℃, adsorption time is 5 min, quantity of bio-film is 10 g, the adsorption rate reachs 87%. The competitive adsorption between co-existed ions may give a great influence to Cu2+ of which the adsorption capacity is weak. There is no evidence shows that Cr3+ be affected by inhibitive action or accelerative action, thus, adsorption systems which adsorb Cu2+ only or adsorb Cr3+ only can be fitted by the classical adsorption model.