斜生栅藻对镉、锌吸附性能研究

Study on the Adsorption Performance of Cadmium and Zinc by Scenedesmus obliquus

摘要: 鉴于水域中重金属污染的日益严重，开发有效的修复技术变得尤为紧迫。本研究调查了斜生栅藻(Scenedesmus obliquus)对Cd²⁺和Zn²⁺的吸附行为，重点关注其生物吸附机制及潜在的解毒途径。实验在不同的初始金属浓度(1~16 mg/L)和pH条件(3~7)下进行，以评估微藻对这两种金属离子的去除效率。结果显示，Cd²⁺在pH值为7和初始浓度为12 mg/L时表现出最高的吸附效率，达到58%；而Zn²⁺在pH值为6和1 mg/L浓度下的去除效果最佳。这些结果表明，斜生栅藻对两种金属离子具有一定程度的选择性吸附行为。通过傅里叶变换红外光谱(FTIR）、扫描电子显微镜(SEM)和X射线衍射(XRD)进一步分析，揭示了吸附机制。FTIR光谱显示，氢氧基、羧基和氨基是主要的金属结合功能基团。SEM图像表明，重金属暴露后藻细胞结构受损，Zn²⁺由于其作为微量元素的必需性，造成的损伤较小。XRD结果表明，Cd²⁺可以通过生物矿化形成稳定的CdS沉淀，而Zn²⁺则主要通过与羟基结合形成络合物。综合这些结果，揭示了斜生栅藻对Cd²⁺和Zn²⁺的不同反应，为未来基于藻类的水体重金属修复策略提供了理论依据和实践参考。

Abstract: Given the increasing severity of heavy metal contamination in aquatic environments, developing effective remediation technologies has become particularly urgent. This study investigates the adsorption behavior of Scenedesmus obliquus toward Cd²⁺ and Zn²⁺, with a focus on biosorption mechanisms and potential detoxification pathways. Experiments were conducted under varying initial metal concentrations (1~16 mg/L) and pH conditions (3~7) to evaluate the microalga’s removal efficiency for both metal ions. The results showed that Cd²⁺ exhibited the highest adsorption efficiency of 58% at pH = 7 and an initial concentration of 12 mg/L, while Zn²⁺ achieved optimal removal at pH = 6 with a concentration of 1 mg/L. These findings indicated a degree of selective adsorption behavior by S. obliquus toward the two metal ions. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) was conducted to elucidate the underlying adsorption mechanisms. FTIR spectra revealed that hydroxyl, carboxyl, and amino groups served as the primary functional groups responsible for metal binding. SEM images indicated structural damage to the algal cells after exposure to heavy metals, with Zn²⁺ causing less disruption due to its essential role as a trace element. XRD results indicated that Cd²⁺ can undergo biomineralization to form stable CdS precipitates, while Zn²⁺ primarily forms coordination complexes by binding with hydroxyl groups. Collectively, these results highlight the differential response of S. obliquus to Cd²⁺ and Zn²⁺, providing both theoretical insight and practical reference for future algal-based bioremediation strategies in contaminated water bodies.