Spirulina platensis is one of the types of blue-green algae that was used as a biosorbent in this study. The aim of this study was to investigate the efficiency of S. platensis in removing MG from aqueous solutions and also to evaluate the biosorbent capacity using different kinetic models and isotherms. To obtain the optimum condition for MG biosorption using BBD, input factors included the initial level of MG 20–200 mg.L⁻¹), dose of S. platensis (0.1–1.5 g.L⁻¹), pH (4–9), and contaact time (5–80 min). The statistical method of BBD was considered to evaluate the removal rate of MG dye from aqueous solutions. The prediction of MG removal efficiencies and the evaluation of variable interactions were performed using a polynomial equation. The maximum removal efficiency of MG was obtained as 94.12% under MG level of 100.54 mg. L⁻¹, pH of 7.57, contact time of 52.43 min, and S. platensis dose of 0.98 g. L⁻¹. The removal MG efficiency enhanced with the increase in pH, reaction time, and S. platensis dose, and reduced with the decrease in MG level. The quadratic model suggested that the pH had a high impact on MG removal. The isotherms and kinetics data could be properly illustrated by the Freundlich model and the pseudo-second-order equation. Thermodynamic factors, including ΔG⁰, ΔH⁰, and ΔS⁰ showed the adsorption of MG onto S. platensis was spontaneous and exothermic. The acquired findings also showed that the physisorption mechanism mainly govern the MG sorption process. As a result, S. platensis showed excellent adsorptive properties and hence could be offered as a viable option for eliminating MG from aqueous solutions.

Spirulina platensis是本研究中用作生物吸附剂的蓝绿藻类型之一。本研究的目的是研究S. platensis从水溶液中去除 MG 的效率，并使用不同的动力学模型和等温线评估生物吸附能力。为了获得使用 BBD 进行 MG 生物吸附的最佳条件，输入因素包括 MG 的初始水平 20–200 mg.L ^-1 )、S. platensis的剂量(0.1–1.5 gL ^-1)、pH (4–9) 和接触时间 (5–80 分钟)。采用 BBD 统计方法评价 MG 染料从水溶液中的去除率。使用多项式方程进行 MG 去除效率的预测和变量相互作用的评估。在 100.54 mg 的 MG 水平下，MG 的最大去除率为 94.12%。L ^-1，pH 7.57，接触时间52.43 min，S. platensis剂量0.98 g。L ^-1。去除 MG 效率随着 pH 值、反应时间和S. platensis的增加而提高剂量，并随着 MG 水平的降低而降低。二次模型表明 pH 值对 MG 去除有很大影响。等温线和动力学数据可以通过 Freundlich 模型和准二级方程正确说明。^{包括ΔG 0}、ΔH ⁰和ΔS ⁰在内的热力学因素表明MG对S. platensis的吸附是自发的和放热的。获得的研究结果还表明，物理吸附机制主要控制 MG 吸附过程。结果，S. platensis表现出优异的吸附性能，因此可以作为从水溶液中消除 MG 的可行选择。