摘要
运用沉水植物修复低浓度重金属污染是一种廉价和清洁的技术。采用摇床振荡试验方法,研究了不同pH条件下,沉水植物——轮叶黑藻鲜样对重金属镉和铜的吸附特征。结果表明,pH值对吸附结果影响较大,黑藻对镉和铜的吸附,最适宜的pH值分别为7.0和5.0。在选用的3个拓展Langmuir模型中,模型A拟合效果最好,模型B大大低估了黑藻对重金属镉和铜的吸附能力,模型C则略偏高,表明沉水植物黑藻对重金属镉和铜的吸附与离子所带电荷关系不大,且没有产生吸附剂-重金属-H+的复合式吸附产物(BMH)。运用模型A的回归参数,绘制的三维吸附网格图清晰阐明了不同H+浓度下,黑藻对重金属镉和铜的吸附曲面特征。拓展Langmuir模型A的计算值与实测值的对比表明:24mg·L-1≤C0≤72mg·L-1时,78%的镉吸附量计算值与实测值偏差控制在22%以内,90%的铜吸附量计算值与实测值偏差控制在10%以内。研究不同pH条件下黑藻对镉和铜的生物吸附特征,将有助于对沉水植物修复低浓度重金属污染技术的理解和规范。
Using submerged aquatic plant is a cheap and clean technique to remediate contaminated water with low concentrations of heavy metals. Biosorption of both cadmium and copper by fresh tissues of H. verticillata, a submerged aquatic plant, was investigated in aqueous solu- tion at various initial pH values. We found the biosorption process was strongly pH-dependent and the optimum pH value of adsorption was de- termined as 7.0 for cadmium ions, and 5.0 for copper ions, respectively. Of three selected extended Langmuir models, the fitting results of mod- el A were the best. In contrast to model A, the adsorption capacity ofH. verticallata was largely undervalued by the model B, and slightly over- rated by the model C. This result indicated that the sorption ofH. verticillata for cadmium and copper was independent on the valency charge of heavy metals, and no further interactions occurred to form the complex of biosorbent-metal-H＋（BMH）. Three-dimensional biosorption sur- faces were plotted by using the regression parameters of extended Langmuir model A, which clearly illustrating the characteristics of H. verti- callata biosorption for cadmium and copper ions at different pH values. The comparison of theoretical q values and experimental q values showed that ： when Co was between 24 mg. L-1 and 72 mg. L-1, a relative error between 78% of theoretical q values and experimental q values was within 22% for cadmium, and a relative error between 90% of theoretical q values and experimental q values was within 10% for copper. This research provides a case study on cadmium and copper biosorption by H. verticillata at different pH values, which might improve our knowl- edge of understanding and regulating submerged aquatic plant for remediation of water pollution with low concentrations of heavy metals.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2010年第1期145-151,共7页
Journal of Agro-Environment Science
基金
国家自然科学基金面上项目(20777059)
