用响应面法优化小球藻絮凝沉降工艺的研究

Flocculation of Chlorella vulgaris by calcium hydroxide via response surface analysis( RSA)

以氢氧化钙为絮凝剂,对海水小球藻Chlorella vulgaris絮凝工艺效果进行了试验研究.单因素试验结果表明,当絮凝时间为60～ 80 min、氢氧化钙添加量为0.6～0.8 g/L和藻液pH为8～10时,最有利于小球藻的采收.在单因素试验的基础上,利用响应面法对小球藻的絮凝条件进行了优化,建立了二次回归模型.通过分析得出：各因素对小球藻采收率均有极显著性影响（P＜0.01）,影响次序为氢氧化钙添加量＞絮凝时间＞藻液pH;絮凝时间与藻液pH以及氢氧化钙添加量与藻液pH的交互作用对小球藻采收率均有极显著性影响（P＜0.01）.利用回归方程预测小球藻的最佳絮凝条件,当絮凝时间为77 min、氢氧化钙添加量为0.7 g/L、小球藻液pH为9.3时,小球藻的采收率可达93.9％.

Flocculation experiments of green alga Chlorella vulgaris by calcium hydroxide were carried out.Results of single-parameter experiments showed that higher recovery of Chlorella vulgaris was achieved when the flocculation time,the dosage of calcium hydroxide,and the pH of culture fluid were kept at 60-80 min,0.6-0.8 g/L,and 8-10,respectively.Additionally,a regression model regarding to Chlorella vulgaris recovery ratio was established by the response surface analysis（RSA） and based on the results of multi-parameter experiments.The optimum conditions for Chlorella vulgaris flocculation were determined correspondingly.It was demonstrated that the influence of calcium hydroxide dosage on Chlorella vulgaris recovery was the most significant and followed were the flocculation time and the pH of algae fluid.It was also known that the interaction of flocculation time with pH,and calcium hydroxide dosage with pH were relatively significant to the recovery of Chlorella vulgaris.The recovery ratio of Chlorella vulgaris reached to 93.9% when the flocculation time,the dosages of calcium hydroxide,and the pH of culture fluid were maintained at 77 min,0.7 g/L,and 9.3,respectively.