QIN Yong-lian1,2, DAI Qun-wei1, DONG Fa-qin1,2*, ZHAO Yu-lian1, ZHAO Pan1, TANG Jun1, CHEN Wu1, YANG Jie1, HOU Li-hua1
(1. Southwest University of Science and Technology, School of Environment and Resource, Mianyang 621010, China;
2. Key Laboratory of Solid Waste Treatment and the Resource Recycle (SWUST, Ministry of Education), Mianyang 621010, China)
Abstract: To investigate the influence of soil-resident bacteria contact modes on the interlayer spacing, layer charge and interlayer dielectric properties of montmorillonite, one strain of Bacillus pumilus was separated and selected from purple soil found in the Mianyang area of Sichuan Province, China. Dialysis bags were employed to establish direct and indirect-contact systems for interaction experiments between the soil-resident bacteria and montmorillonite. The results showed that after 5 days of bacteria interaction, the interlayer distances in the mineral samples decreased from 1.486 nm to 1.246 nm (M-1) and to 1.257 nm (M-2). Moreover, the per half unit cell layer charge also decreased. ξMMT> ξM-2> ξM-1. FTIR spectrometry showed that new characteristic peaks appeared on montmorillonite samples consisting amide Ⅱ methyl protein molecules and a shift of the interlayer water molecules peaks at 3434 cm-1 and 1637 cm-1. In addition, the cation exchange capacity of samples changed. Therefore, we concluded that the soil bacteria can change the layer spacing, layer charge and interlayer dielectric properties of montmorillonite, as well as alter its structure and other properties. Two modes of contact were compared and the effect of direct contact on changing the montmorillonite interlayer characteristics was stronger than the effect observed under indirect contact.
Keywords: montmorillonite; layer spacing; layer charge; interlayer water molecule; cation exchange capacity; soil bacteria; Bacillus pumilus
Email: fqdong@swust.edu.cn
ACTA MINERALOGICA SINICA Vol. 35, No. 2, 2015, Page 203-208
