Serpentine has weak immobilization capacity for Pb(II), especially under acidic conditions. In order to improve its application potential, a new biological modification method was adopted, i.e., the serpentine powder was weathered by Aspergillus niger and the fungus-serpentine aggregation (FSA) formed was investigated for its Pb(II) immobilization potential and underlying mechanism. Batch adsorption of Pb(II) by FSA closely followed the Langmuir model, while the maximum adsorption capacity of FSA (370.37 mg/g) was significantly higher than fungal mycelium (31.85 mg/g) and serpentine (8.92 mg/g). The adsorption process can be accurately simulated by pseudo-second-order kinetic model. Our data revealed the loading of organic matter is closely related to the adsorption of FSA, and the stronger immobilization capacity was mainly related to its modified porous organic-inorganic composite structure with extensive exchangeable ions. Moreover, FSA is an economical bio-material with excellent Pb(II) adsorption (pH = 1–8) along with significantly lower desorption efficiency (pH = 3–8), especially under acidic conditions. These findings provide a new perspective to explore the usage of fungus-minerals aggregation on heavy metals immobilization in acidic environments.

Key Points

• Co-culture of Aspergillus niger and serpentine produced a porous composite material like fungus-serpentine aggregation.

• Fungus-serpentine aggregation has a surprisingly higher adsorption capacity of Pb(II) and significantly lower desorption efficiency under acidic conditions.

• The loading of organic matter is closely related to the adsorption of FSA.

Graphical abstract

中文翻译：

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酸性条件下真菌-蛇纹石聚集体的形成及其对铅（II）的固定化

蛇纹石对Pb（II）的固定能力较弱，尤其是在酸性条件下。为了提高其应用潜力，采用了一种新的生物改性方法，即用黑曲霉将蛇纹石粉风化。并研究了形成的真菌-蛇纹石聚集体（FSA）的Pb（II）固定潜力及其潜在机理。FSA分批吸附Pb（II）的行为与Langmuir模型密切相关，而FSA的最大吸附容量（370.37 mg / g）明显高于真菌菌丝体（31.85 mg / g）和蛇纹石（8.92 mg / g）。吸附过程可以通过伪二级动力学模型精确地模拟。我们的数据表明，有机物的负载与FSA的吸附密切相关，而更强的固定能力主要与其具有广泛可交换离子的改性多孔有机-无机复合结构有关。此外，FSA是一种经济的生物材料，具有出色的Pb（II）吸附（pH = 1-8），并且解吸效率大大降低（pH = 3-8），特别是在酸性条件下。这些发现为探索真菌-矿物质在酸性环境中重金属固定化中的应用提供了新的视角。

关键点

•黑曲霉和蛇纹石的共培养产生了多孔复合材料，如真菌-蛇纹石聚集。

•真菌-蛇纹石聚集体在酸性条件下具有惊人的Pb（II）吸附能力，并且解吸效率显着降低。

•有机物的含量与FSA的吸附密切相关。

图形概要