Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, Fujian, China.
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, Fujian, China; State Key Laboratory of Grassland Agro-Ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, China.
Ecotoxicol Environ Saf. 2022 May 1;236:113489. doi: 10.1016/j.ecoenv.2022.113489. Epub 2022 Apr 4.
Glomalin-related soil protein (GRSP), a microbial product that can be used as a bioflocculant, is critical to metal sequestration in the ecosystem. However, the relationship between GRSP and heavy metal has not been well explored. In this study, the adsorption behaviors and mechanisms of Pb(II) and Zn(II) ions on GRSP were investigated. Results reveal that the Pb(II) and Zn(II) adsorption closely conform to the pseudo second-order model, which indicates that the chemisorption of GRSP occurred after intra-particle diffusion. The adsorption process is influenced by the degree of pollution, pH value, GRSP content in the environment. In addition, scanning electron microscopy coupled with microanalysis (SEM-EDX) reveals that the surface structure of GRSP is irregularly blocky or flaky and metal ions are uniformly distributed on the surface of GRSP. Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) analysis show that the carboxyl and nitro groups on GRSP act as ligands to form complexes with two divalent metal ions. The interaction between GRSP and the metals is mainly surface complexation. This research further reveals the dynamic response of its structural components when GRSP sequestrates heavy metals in mangrove sediment and aqueous ecosystems, demonstrating a new perspective for the transport and transformation of heavy metals onto GRSP.
胶磷矿相关土壤蛋白（GRSP）是一种微生物产物，可用作生物絮凝剂，对生态系统中重金属的固定至关重要。然而，GRSP 与重金属之间的关系尚未得到充分探索。在这项研究中，研究了 Pb(II)和 Zn(II)离子在 GRSP 上的吸附行为和机制。结果表明，Pb(II)和 Zn(II)的吸附很好地符合拟二级模型，这表明 GRSP 发生了化学吸附，然后才是颗粒内扩散。吸附过程受到污染程度、pH 值、环境中 GRSP 含量的影响。此外，扫描电子显微镜结合微分析（SEM-EDX）显示，GRSP 的表面结构不规则块状或片状，金属离子均匀分布在 GRSP 的表面。傅里叶变换红外（FT-IR）、X 射线光电子能谱（XPS）和 X 射线衍射（XRD）分析表明，GRSP 上的羧基和硝基作为配体与两种二价金属离子形成配合物。GRSP 与金属之间的相互作用主要是表面络合。这项研究进一步揭示了 GRSP 在红树林沉积物和水生态系统中螯合重金属时其结构成分的动态响应，为重金属在 GRSP 上的迁移和转化提供了新的视角。
