Based on the composite pollution of atmospheric microbial aerosol, this paper selects the calcite/bacteria complex as the research object which was prepared by calcite particles and two common strains of bacteria (Escherichia coli, Staphylococcus aureus) in the solution system. The morphology, particle size, surface potential, and surface groups of the complex were explored by modern analysis and testing methods, with an emphasis on the interfacial interaction between calcite and bacteria. The SEM, TEM, and CLSM results showed that the morphology of the complex could be divided into three types: bacteria adhering to the surface or edge of micro-CaCO₃, bacteria aggregating with nano-CaCO₃, and single nano-CaCO₃ wrapping bacteria. The complex’s particle size was about 2.07 ~ 192.4 times larger than the original mineral particles, and the nano-CaCO₃/bacteria complex’s particle size variation was caused by the fact that nano-CaCO₃ has agglomeration in solution. The surface potential of the micro-CaCO₃/bacteria complex (isoelectric point pH = 3.0) lies between micro-CaCO₃ and bacteria, while the surface potential of the nano-CaCO₃/bacteria complex (isoelectric point pH = 2.0) approaches the nano-CaCO₃. The complex’s surface groups were based primarily on the infrared characteristics of calcite particles, accompanied by the infrared characteristics of bacteria, displaying the interfacial interaction from the protein, polysaccharides, and phosphodiester groups of bacteria. The interfacial action of the micro-CaCO₃/bacteria complex is mainly driven by electrostatic attraction and hydrogen bonding force, while the nano-CaCO₃/bacteria complex is guided by surface complexation and hydrogen bonding force. The increase in the β-fold/α-helix ratio of the calcite/S. aureus complex indicated that the secondary structure of bacterial surface proteins was more stable and the hydrogen bond effect was strong than the calcite/E. coli complex. The findings are expected to provide basic data for the mechanism research of atmospheric composite particles closer to the real environment.

基于大气微生物气溶胶的复合污染，本文选择方解石颗粒与两种常见细菌（大肠杆菌、金黄色葡萄球菌）在溶液体系中制备的方解石/细菌复合体作为研究对象。通过现代分析和测试方法探索了复合物的形态、粒径、表面电位和表面基团，重点是方解石和细菌之间的界面相互作用。 SEM、TEM和CLSM结果表明，复合物的形貌可分为三种类型：细菌附着在微米CaCO ₃表面或边缘、细菌与纳米CaCO ₃聚集、单个纳米CaCO ₃包裹。细菌。复合物的粒径约为原矿物颗粒的2.07～192.4倍，纳米CaCO ₃ /细菌复合物的粒径变化是由于纳米CaCO ₃在溶液中发生团聚造成的。微米CaCO ₃ /细菌复合物(等电点pH = 3.0)的表面电位介于微米CaCO ₃和细菌之间，而纳米CaCO ₃ /细菌复合物(等电点pH = 2.0)的表面电位接近细菌。纳米CaCO ₃ 。该复合物的表面基团主要基于方解石颗粒的红外特征，并伴有细菌的红外特征，表现出细菌的蛋白质、多糖和磷酸二酯基团的界面相互作用。 微米CaCO ₃ /细菌复合物的界面作用主要由静电引力和氢键力驱动，而纳米CaCO ₃ /细菌复合物的界面作用主要由表面络合和氢键力驱动。方解石/金黄色葡萄球菌复合物β-折叠/α-螺旋比例的增加表明细菌表面蛋白的二级结构比方解石/大肠杆菌复合物更稳定，氢键效应更强。该研究结果有望为更接近真实环境的大气复合颗粒物机理研究提供基础数据。