环保型微藻絮凝剂的制备及应用

Preparation and application of green microalgae flocculant

微藻因其具有各种高价值的营养物质在各行业具有广泛的应用前景,但因其个体小,培养液浓度低等因素,高效低廉的采收方式技术一直是个巨大的挑战。为制备出低廉、无毒的环保型微藻絮凝剂—阳离子淀粉,以阳离子淀粉取代度为指标,采用二次旋转正交试验优化阳离子淀粉的制备工艺。结果表明:当反应温度为84℃,醚化剂用量为53.8%(m),NaOH含量为14%(m),体系含水量为23%(m)时,可得到阳离子淀粉的最优取代度为0.35。通过对阳离子淀粉进行红外光谱、环境扫描电子显微镜分析,证实醚化反应过程中淀粉结构发生了一定程度的变化。絮凝试验还表明:阳离子淀粉可以高效絮凝二形栅藻,30mg阳离子淀粉(DS=0.33)在30min内完全絮凝1.0g干重的二形栅藻,絮凝效率高达97%以上。

Microalgae have remarkable potential for food and feed pro- cessing, environmental protection and producing biofuels owning to its all kinds of high value of nutrition. Due to their small size and low concentration in the culture medium, cost-efficient harvesting of mi- croalgae is a major challenge. Therefore this paper aims at preparing a cheap, non-toxic and environmentally friendly microalgae flocculant -cationic starch. Taking cationic starch degree of substitution （DS） as the target, the quadratics rotary orthogonal combination design was used to optimize the preparation condition of cationic starch. The experiment result showed that when reaction temperature was 84 ℃, Etherifying agent content was 53%, moisture content was 23%,NaOH content was 14%, the optimum cationic starch DS was 0.35. Infrared and electron-microscopic scanning demonstrated some chan- ges in the structure of starch due to substitution. Eventually floecu- lation experiment result comfirmed Scenedesmus Dirnorphus could be collected efficiently by cationic starch, and the flocculation efficiency could reach above 97% in 30 minutes with the optimal cationic starch dosage （30 mg per gram microalgal dry weight）.