The frequent occurrence of cyanobacteria blooms has gained worldwide concern. The conventional pre-oxidation methods are not only less effective in removing Microcystis aeruginosa cells, but also tend to trigger secondary pollution with an inevitable release of intracellular organic matter. In this study, Fe²⁺/persulfate process was applied to generate sulfate radicals and simultaneously form in situ Fe (III) for integrated oxidation–coagulation, leading to a notable enhancement in M. aeruginosa removal without cell breakage and better control of microcystins. Results showed that the Fe²⁺/persulfate mass ratio of 1:1 and the FeSO₄ dosage of 0.1 mmol/L were efficient in M. aeruginosa removal. With the optimal FeSO₄ dosage, up to 90.1% of M. aeruginosa were removed intact with the cell zeta potential of − 0.814. After settling down of M. aeruginosa within 30 min, the chlorophyll-a removal efficiency reached 98.9% and microcystins decreased remarkably. Furthermore, the degradation of algal organic matters was significantly enhanced with a relatively lower residual Fe. Protein-like substances and dissolved microbial metabolites were preferentially oxidized. The cell lysis only occurred to a small number of M. aeruginosa during the Fe²⁺/persulfate process, preventing from the environmental risk posed. This work demonstrates that an appropriate Fe²⁺/persulfate ratio and FeSO₄ addition is a feasible and promising method for removing M. aeruginosa in an environmental-friendly and cost-effective way.

中文翻译：

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通过整合的预氧化和混凝有效去除铜绿微囊藻和微囊藻毒素：一种环境经济的方法

蓝藻水华的频繁发生已引起全世界的关注。常规的预氧化方法不仅在去除铜绿微囊藻细胞方面不那么有效，而且还趋向于引发不可避免的细胞内有机物释放的二次污染。在这项研究中，Fe ²⁺ /过硫酸盐工艺被用于生成硫酸根，并同时形成原位的Fe（III）以进行整合的氧化-凝结，从而导致铜绿假单胞菌的去除显着增强，而不会破坏细胞并更好地控制微囊藻毒素。结果表明，铜绿假单胞菌有效的Fe ²⁺ /过硫酸盐质量比为1：1，FeSO ₄剂量为0.1 mmol / L。去除。使用最佳的FeSO ₄剂量，可以完整清除高达90.1％的铜绿分支杆菌，细胞zeta电位为− 0.814。在30分钟内稳定铜绿假单胞菌后，叶绿素a去除效率达到98.9％，微囊藻毒素显着下降。此外，藻类有机物的降解显着增强，残留铁含量相对较低。蛋白质样物质和溶解的微生物代谢产物被优先氧化。在Fe ²⁺ /过硫酸盐过程中，细胞裂解仅在少数铜绿假单胞菌中发生，从而避免了所造成的环境风险。这项工作表明适当的Fe ²⁺/过硫酸盐比和FeSO _4的添加是一种以环保，经济的方式去除铜绿假单胞菌的可行且有前途的方法。