摘要
Biomineralization has garnered significant attention in the field of wastewater treatment due to its notable cost reduction compared to conventional methods.The reinjection water from oilfields containing an exceedingly high concentration of calcium and ferric ions will pose amajor hazard in production.However,the utilization of biomineralization for precipitating these ions has been scarcely investigated due to limited tolerance among halophiles towards such extreme conditions.In this study,free and immobilized halophiles Virgibacillus dokdonensis were used to precipitate these ions and the effects were compared,at the same time,biomineralizationmechanisms and mineral characteristicswere further explored.The results showthat bacterial concentration and carbonic anhydrase activitywere higher when additionally adding ferric ion based on calcium ion;the content of protein,polysaccharides,deoxyribonucleic acid and humic substances in the extracellular polymers also increased compared to control.Calcium ions were biomineralized into calcite and vaterite with mul-tiple morphology.Due to iron doping,the crystallinity and thermal stability of calcium carbonate decreased,the content of O-C=O,N-C=OandC-O-PO_(3) increased,the stable carbon isotope values became much more negative,andβ-sheet in minerals disappeared.Higher calcium concentrations facilitated ferric ion precipitation,while ferric ions hindered calcium precipitation.The immobilized bacteria performed better in ferric ion removal,with a precipitation ratio exceeding 90%.Free bacteria performed better in calcium removal,and the precipitation ratio reached a maximum of 56%.This research maybe provides some reference for the co-removal of calcium and ferric ions from the oilfield wastewater.
基金
supported by the National Natural Science Foundation of China(Nos.42072136,41972108,and 42106144)
the Natural Science Foundation of Shandong Province(Nos.ZR2023MD063,ZR2020MC041,and ZR2020QD089)
the Key Laboratory of Marine Biogenetic Resources,Third Institute of Oceanography,Ministry of Natural Resources(No.SKDZK20230127)
the Foreign visiting scholar funded by Shandong Provincial government.
