钝顶螺旋藻和小球衣藻富集Cd2+

为了探究我国北方水体中藻类对Cd2+的富集行为,选取常见的蓝藻(钝顶螺旋藻)和绿藻(小球衣藻),模拟天然藻类对Cd2+的吸附和吸收,研究藻液浓度、时间、pH值、温度、共存阳离子类型对富集过程的影响。结果发现:2种藻对Cd2+的富集性能优于活性炭,富集量高出2~17倍左右。藻对Cd2+的富集率随着藻液浓度的增加而升高,而单位富集量则呈现下降趋势;8 h后富集达到饱和;当pH值在3.0~9.0范围内,富集量随着pH值的升高而增加;在室温25℃时富集量最高,低温或高温时富集量都有明显下降;Fe3+对钝顶螺旋藻富集Cd2+几乎没有影响,但对小球衣藻有拮抗作用,Na+、Ca2+对2种藻类富集Cd2+均表现为拮抗作用,且价态越高,拮抗作用越明显。因此,在适宜的环境中,钝顶螺旋藻和小球衣藻对Cd2+具有良好的富集效果。

Cd2+ accumulation by Spirulina platensis and Chlamydomonas microsphaera

Two kinds of common algal species (Spirulina platensis and Chlamydomonas microsphaera) in northern surface waters were selected to absorb Cd2+ in order to investigate the accumulation behavior of cadmium ion (Cd2+) on aquatic algae. Accordingly, various factors that known to influence Cd2+ accumulation on algae, such as algal concentration, exposure time, pH value, temperature, and the type of coexisting cations, were studied. Our results showed that the Cd2+ accumulation capacities of the two kinds of algal species to Cd2+ were higher than that of active carbon by about 2 to 17 times. With the increase of algal concentrations, we found that bio-enrichment ratios of Cd2+ increased, whereas bio-enrichment capacity per unit mass decreased. And we also found that accumulation tended to saturate 8 h later. Bio-enrichment capacity rose when pH increased from 3.0 to 9.0. The accumulation capacity to Cd2+ was the greatest at 25℃, and it declined when increasing or decreasing the temperature. Ferric iron (Fe3+) had no effect on accumulation of Cd2+ by S. platensis, but it showed antagonistic to accumulation by C. microsphaera. In addition, ionic sodium (Na+) and calcium (Ca2+) were antagonistic for Cd2+ accumulation on both algal species, and the antagonism was reinforced with cationic valence increasing. Therefore, both S. platensis and C. microsphaera can present excellent Cd2+ accumulation abilities in suitable aquatic environment.