Santhiya D., Subramanian S., Natarajan K. A.
Department of Metallurgy, Indian Institute of Science, Bangalore, 560 012, India
J Colloid Interface Sci. 2001 Mar 15;235(2):298-309. doi: 10.1006/jcis.2000.7256.
Biodissolution tests reveal the release of lead/zinc species from galena/sphalerite, respectively, while biosorption experiments confirm interaction of cells of Bacillus polymyxa (B. polymyxa) with the metal ions of interest. The amount of exo-polysaccharides is found to be the highest in the case of galena-interacted cells, followed by the Bromfield medium-grown cells while the sphalerite-interacted cells have the least, based on ruthenium red adsorption studies. In contrast, the sphalerite-interacted cells assay the highest amount of protein while the galena-interacted cells have the lowest amount, on a comparative basis. The adsorption of xanthate onto galena is found to be diminished in the presence of the cells whereas the xanthate adsorption density for activated sphalerite is unaffected in the pH range 9-11. Additionally, the cell surface hydrophobicity tests confirm that the sphalerite-interacted cells are more hydrophobic relative to the galena-interacted cells. FTIR spectroscopic data lend support to the higher adsorption density of the cells onto galena vis-à-vis sphalerite. The higher exo-polysaccharide and lower protein contents together with the hydrophilic nature of the galena-interacted cells could be the contributing factors to the selective flocculation and depression of galena. In a similar manner, the higher protein and lower exo-polysaccharide contents as well as the greater hydrophobicity of the sphalerite-interacted cells favor its floatability and dispersion. Copyright 2001 Academic Press.
生物溶解试验分别揭示了方铅矿/闪锌矿中铅/锌物种的释放，而生物吸附实验证实了多粘芽孢杆菌（B. polymyxa）细胞与目标金属离子之间的相互作用。基于钌红吸附研究发现，在与方铅矿相互作用的细胞中胞外多糖含量最高，其次是在布罗姆菲尔德培养基中生长的细胞，而与闪锌矿相互作用的细胞中胞外多糖含量最少。相比之下，在比较的基础上，与闪锌矿相互作用的细胞中蛋白质含量最高，而与方铅矿相互作用的细胞中蛋白质含量最低。发现在有细胞存在的情况下，黄药对方铅矿的吸附减少，而在pH值为9 - 11的范围内，活化闪锌矿的黄药吸附密度不受影响。此外，细胞表面疏水性测试证实，与闪锌矿相互作用的细胞比方铅矿相互作用的细胞更疏水。傅里叶变换红外光谱数据支持细胞对方铅矿的吸附密度高于闪锌矿。与方铅矿相互作用的细胞中较高的胞外多糖和较低的蛋白质含量以及其亲水性可能是导致方铅矿选择性絮凝和抑制的因素。同样，与闪锌矿相互作用的细胞中较高的蛋白质和较低的胞外多糖含量以及更大的疏水性有利于其可浮性和分散性。版权所有2001年学术出版社。
