Polysaccharide was extracted from Cyanobacteria collected from Taihu Lake, and further used to adsorb Pb2+ and Cd2+.Polysaccharide from Cyanobacteria was extracted with ultrasonic assisted hot water extraction, and extraction conditions, including extraction time, temperature and solid-liquid ratio, were optimized.Meanwhile, effects of adsorption conditions (polysaccharide dosage, adsorption time, pH and treating temperature) on Pb2+ and Cd2+ adsorption by crude polysaccharide were also investigated.The highest yield of polysaccharide was 25.1％ under the following condition:solid-liquid ratio of 40∶ 1 mL/g, temperature of 80 ℃ and extraction time of 5 h.Moreover, with the dosage of 100 mg, biosorption time of 3 h, pH 7.0, treating at 25 ℃, the equilibrium adsorption of Pb2+ and Cd2+ was up to 73.81 and 49.69 mg/g, respectively.Compared with Freundlich isotherm model, Langmuir isotherm model was more suitable to describe the adsorption of Pb2+ and Cd2+ by extracted polysaccharide.Depending on this study, Cyanobacteria collected from Taihu Lake could be the extraction source of polysaccharide, with the potential for absorption of heavy metals in polluted water.%对太湖蓝藻多糖进行提取, 并利用这种多糖对重金属离子进行吸附试验.在蓝藻多糖提取中, 采用超声波辅助热水浸提的方法并对浸提时间、浸提温度和料液比条件进行优化, 同时考察多糖投加量、吸附时间、pH和温度条件对多糖吸附Pb2+和Cd2+离子的影响.结果表明:在液料比40∶1 mL/g、浸提温度80℃条件下提取5 h多糖得率达到25.1％.在重金属离子吸附研究中发现, 当1 000 mL溶液中多糖投加量为100 mg, 吸附时间为3 h, pH为7.0, 处理温度为25℃时, 吸附效果最好, 铅、镉的平衡吸附量分别可达到73.81 mg/g和49.69 mg/g, 并且Langmuir模型比Freundlich模型更适用于描述蓝藻多糖对Pb2+和Cd2+的吸附平衡.研究表明, 太湖蓝藻可作为提取具有污水重金属吸附作用的多糖的来源, 从而提高太湖蓝藻的应用潜力和价值.
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