College of Civil Engineering and Architecture, Wenzhou University, Wenzhou, 325035, China.
Jiangsu Key Laboratory of Construction Materials, Nanjing, 211189, China.
Environ Sci Pollut Res Int. 2022 Jan;29(1):1314-1323. doi: 10.1007/s11356-021-15750-0. Epub 2021 Aug 5.
Urease-producing bacteria (UPB) could be used to cement loose sand particles. The UPB would produce free ammonia and carbon dioxide during the process of hydrolyzing urea, and part of the free ammonia would be discharged into the air to cause certain pollution to the atmospheric environment. The carbon dioxide could react with alkaline oxide to form carbonates and improved the strength in GGBS comparing with medium containing different concentrations of urea. By adding hydrogen phosphate ions and magnesium salts, free ammonia could be converted into environmentally friendly magnesium ammonium phosphate. The mixture of biological magnesium ammonium phosphate and basic magnesium carbonate could be synthesized through the bio-mineralization process. Through the pre-precipitation mixing process, the loose sand particles could be cemented into a whole. Scanning electron microscopy (SEM) images of the sand column showed that the mixture of biological magnesium ammonium phosphate and basic magnesium carbonate could better fill in the pores of sand grains. In the pre-precipitation mixing process, the optimal standing time and dosage of the bio-cement slurry prepared by the bio-mineralization method were 6 h and 30%, respectively. The average interface bonding force between CJ2 and glass slide was 2.12 N.
产脲酶细菌（UPB）可用于胶结松散的砂粒。在尿素水解过程中，UPB 会产生游离氨和二氧化碳，其中部分游离氨会排放到空气中，对大气环境造成一定的污染。二氧化碳会与碱性氧化物反应生成碳酸盐，从而提高 GGBS 中的强度，与含有不同浓度尿素的介质相比。通过添加磷酸氢根离子和镁盐，可以将游离氨转化为环保的镁铵磷酸盐。通过生物矿化过程，可以合成生物镁铵磷酸盐和碳酸镁的混合物。通过预沉淀混合过程，可以将松散的砂粒胶结成整体。砂柱的扫描电子显微镜（SEM）图像表明，生物镁铵磷酸盐和碳酸镁的混合物可以更好地填充砂粒的孔隙。在预沉淀混合过程中，生物矿化法制备的生物水泥浆的最佳静置时间和用量分别为 6 小时和 30%。通过界面剪切试验得到 CJ2 与玻璃片之间的平均界面结合力为 2.12N。
