Calcium peroxide (CP) has been widely applied in environmental remediation, but few studies have reported its application in controlling Microcystis blooms. To recognize its feasibility for mitigating Microcystis blooms, the properties of CP in terms of hydrogen peroxide (HP) release and phosphate removal were investigated at different CP doses, temperatures, and initial pH values. HP release kinetics followed the Higuchi model. Batch experiments conducted in this study suggested that the HP yield and release rate were positively correlated with the CP dose. Increasing temperature decreased the HP yield but accelerated the HP release rate. The phosphate removal kinetics were well simulated by the pseudo-second-order model. The batch experiments suggested that an increased CP dose enhanced the phosphate removal capacity, but it did not affect the phosphate removal rate. Moreover, increased temperature accelerated both phosphate removal capacity and rate. However, the initial pH of low-buffer-capacity solutions did not notably affect HP release and phosphate removal. According to laboratory experiments, HP released from CP could impair photosynthetic activity, resulting in Microcystis mortality. Furthermore, the reduced phosphate concentration in the solutions suggested that CP could facilitate the control of eutrophication, which directly reduced bloom formation. Hence, our results confirmed CP as a promising algicide for Microcystis bloom control, and it is worthwhile to develop novel methods for bloom mitigation based on CP.

Graphic abstract

过氧化钙（CP）已广泛应用于环境修复，但很少有研究报道其在控制微囊藻水华中的应用。认识到其减轻微囊藻的可行性对于水华，在不同的 CP 剂量、温度和初始 pH 值下，研究了 CP 在过氧化氢 (HP) 释放和磷酸盐去除方面的特性。HP 释放动力学遵循 Higuchi 模型。本研究中进行的批量实验表明，HP 产量和释放率与 CP 剂量呈正相关。升高温度会降低 HP 产率，但会加快 HP 释放速率。磷酸盐去除动力学通过伪二级模型很好地模拟。批量实验表明，增加CP剂量提高了除磷能力，但不影响除磷率。此外，升高的温度加快了磷酸盐去除能力和速率。然而，低缓冲容量溶液的初始 pH 值不会显着影响 HP 的释放和磷酸盐的去除。根据实验室实验，从 CP 释放的 HP 会损害光合作用，导致微囊藻死亡率。此外，溶液中磷酸盐浓度的降低表明 CP 可以促进富营养化的控制，这直接减少了水华的形成。因此，我们的结果证实了 CP 是一种很有前途的微囊藻水华控制杀藻剂，值得开发基于 CP 的新型水华缓解方法。

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