微生物介导碳酸盐矿物合成过程中溶液pH值及主要阳离子变化及其地质意义  

CHANGES OF pH VALUE AND MAJOR CATIONS IN SOLUTION MEDIATED BY MICROORGANISMS DURING CARBONATE MINERAL SYNTHESIS AND THEIR GEOLOGICAL SIGNIFICANCE

作　　者：王勇 刘沛杰 孟兴平 田亚铭 施泽进[3] 贺海燕 陈安超 WANG Yong;LIU Peijie;MENG Xingping;TIAN Yaming;SHI Zejin;HE Haiyan;CHEN Anchao(State Key Laboratory of Oil and Gas Reservoir Geology and Erploitation,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Applied Nuclear Techniques in Geosciences Key Laboratory of Sichuan Province,Chengdu,Sichuan 610059,China;College of Earth Sciences,Chengdu University of Technology,Chengdu,Sichuan 610059,China)

机构地区：[1]成都理工大学地球科学学院地球化学系,四川成都610059 [2]地学核技术四川省重点实验室,四川成都610059 [3]成都理工大学、油气藏地质及开发工程国家重点实验室,四川成都610059

出　　处：《矿物岩石》2023年第1期118-130,共13页Mineralogy and Petrology

基　　金：国家自然科学基金(项目批准号:41872137)。

摘　　要：微生物介导碳酸盐矿物沉淀为“白云岩”问题的解决带来了希望。本次研究利用好氧、中度嗜盐细菌,在Mg^(2+)/Ca^(2+)值分别为3,5和7的溶液中合成碳酸盐,记录了每隔24 h溶液中的pH值,并取样分析了溶液中主要阳离子的变化情况。了解溶液pH值和阳离子变化,有利于我们了解微生物作用下碳酸盐矿物形成的过程,对理解微生物作用下碳酸盐的形成机制具有重要意义。实验结果表明,合成的矿物主要为一水碳酸钙、方解石及原白云石。3种溶液的pH值在前4 d均明显降低,溶液整体呈酸性,4 d后溶液pH值降低的趋势减缓,10 d后溶液pH值缓慢上升,呈近中性或弱碱性。Ca^(2+),Mg^(2+)均呈现先下降后略微上升的趋势,Ca^(2+),Mg^(2+)后期略微上升可能是由于细菌活性降低后不再消耗Ca^(2+),Mg^(2+),溶液中的H^(+),Na^(+)和K^(+)等阳离子在阳离子交替吸附的作用下替换出了一部分吸附在培养基上的Ca^(2+)和Mg^(2+)所致;3种溶液中,Ca^(2+)的消耗量随着Mg^(2+)/Ca^(2+)值的增大而减小,而Mg^(2+)的消耗量则随着Mg^(2+)/Ca^(2+)值的增大而增大,但这并不意味着高Mg^(2+)/Ca^(2+)有利于原白云石的形成。Sr^(2+)浓度的变化与Ca^(2+),Mg^(2+)浓度整体趋势一致,但明显与Ca^(2+)浓度变化具有更好的相关性,这可能与Sr^(2+)在进入碳酸盐晶格中时,更容易取代Ca^(2+)而非Mg^(2+)有关。Understanding pH value and cation change of solution is helpful to recognize the process and formation mechanism of carbonate mineral formation under the action of microorganisms.In this paper,aerobic and moderately halophilic bacteria are used to synthesize carbonates in solutions with Mg^(2+)/Ca^(2+)values of 3,5 and 7,respectively.Then,pH values in the solution are recorded every 24 hours,and the changes of major cations in the solution are analyzed.The experimental results show that the synthesized minerals are mainly calcium carbonate monohydrate,calcite and prodolomite.The pH value of the three solutions decreased significantly during the first 4 days,and the overall solution is acidic.After 4 days,the decrease trend of the solution pH value slowed down,and after 1o days,the solution pH value rose slowly,indicating a near neutral or weakly basic property.Both Ca^(2+)and Mg^(2+)decreased initially and then slightly increased later.The slight increase of Ca^(2+)and Mg in the later period may be due to the fact that bacteria no longer consume Ca^(2+)and Mg^(2+)after the decrease in bacterial activity.The cations such as H^(+),Na^(+)and K^(+)in the solution replaced some of the Ca^(2+)and Mg^(2+)adsorbed on the medium under the action of cation alternating adsorption.In the three solutions,the consumption of Ca^(2+)decreased with the increase of Mg^(2+)/Ca^(2+)value,while the consumption of Mg^(2+)increased with the increase of Mg^(2+)/Ca^(2+)val-ue,but this does not mean that high Mg^(2+)/Ca^(2+)is conducive to the formation of prodolomite.The change of Sr^(2+)concentration is consistent with the overall trend of Ca^(2+)and Mg^(2+)concentration,but obviously has a better correlation with the change of Ca^(2+)concentration,which may be related to the fact that Sr^(2+)is more likely to replace Ca^(2+)rather than Mg^(2+)when entering the carbonate lattice.

关 键 词：碳酸盐矿物合成 中度嗜盐细菌 PH值变化 阳离子变化 地质意义 

分 类 号：P579[天文地球—矿物学]