生物混凝土封存二氧化碳及其机理研究进展

Research Progress on Carbon Dioxide Storage and Its Mechanism in Bioconcrete

在地质系统或生物系统中发生的二氧化碳(CO_(2))转化为碳酸钙的过程可以达到封存CO_(2)的目的。与地质封存相比,生物封存速度较快且价格低廉。目前,已有研究利用微生物,如藻类等,将大气中的CO_(2)生物封存到土壤中,但藻类是光能自养型微生物,无法在生物混凝土中生存。相比之下,细菌是生物混凝土技术中更好的选择,在生物加气混凝土砖(B-ACB)中,应用细菌封存CO_(2)的潜力巨大。细菌可以通过加速碳酸化过程来捕获CO_(2),这是由于碳酸化过程通过碳酸酐酶(CA酶)和脲酶可以将CO_(2)转化为碳酸钙(CaCO_(3))。从文献中可以看出,采用生物混凝土可通过加速碳化过程吸收CO_(2)的同时加固自身。细菌加固混凝土的原理是微生物诱导碳酸钙沉淀(MICP),其机制有多种,其中一些已被认可,并运用于混凝土裂缝愈合中。但迄今为止其应用仍具有局限性,尤其是对处于不同环境条件混凝土结构的细菌种类选择。文章根据不同菌种的生存特性总结成表以供相关研究选择参考。

The process of converting carbon dioxide(CO_(2))into calcium carbonate that occurs in geological or biological systems can achieve the purpose of storing CO_(2).Compared with geological storage,biological storage has a faster speed and lower price.At present,research has utilized microorganisms,such as algae,to biologically store CO_(2)in the atmosphere into soil.However,algae are photoautotrophic microorganisms and cannot survive in biological concrete.In contrast,bacteria are a better choice in biological concrete technology,and the potential for using bacteria to store CO_(2)in biological aerated concrete bricks(B-ACB)is enormous.Bacteria can capture CO_(2)by accelerating the carbonation process,which converts CO_(2)into calcium carbonate(CaCO_(3))through carbonic anhydrase(CA enzyme)and urease.From the literature,it can be seen that using biological concrete can accelerate the carbonization process to absorb CO_(2)while strengthening itself.The principle of bacterial reinforcement of concrete is microbial induced calcium carbonate precipitation(MICP).There are various mechanisms for bacterial induced calcium carbonate precipitation,some of which have been recognized and applied to concrete crack healing.But so far,its application still has limitations,especially in the selection of bacterial species in concrete structures under different environmental conditions.This paper summarizes the survival characteristics of different bacterial strains into a table for selection reference.