科研之友
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摘要
In this study，a cadmium-tolerant bacterial flora was isolated from a sulfide tailings in Guangxi and immobilized on biochar to make an immobilized bacterial agent. The effects of biochar type，addition amount，solution pH and initial concentration of Cd2+ on the adsorption performance of the immobilized bacterial agent were investigated；the process and mechanism of Cd2+ adsorption by the immobilized bacterial agent were studied by combining adsorption kinetics，adsorption isotherm，16S rDNA，SEM，FTIR，XPS and other analytical tests. The results showed that immobilized bacterial agent prepared from bamboo biochar （ZBCM） prepared from bamboo biochar had the best Cd2+ adsorption performance. At a Cd2+ concentration of 20 mg·L-1，pH of 6 and biochar dosing of 3 g·L-1，Cd2+ adsorption by ZBCM reached 89.49%，which was 54.6% and 53.51% higher than that by biochar and bacterial flora. At the genus level，the flora consisted mainly of Clostridium_sensu_stricto，Lachnoclostridium_5 and Caproiciproducens，and the dominant bacteria became Paraclostridium，Lachnoclostridium_5 and Cupriavidus after the adsorption of Cd2+ by ZBCM，and the increase of Cupriavidus abundance enhanced the complexation and bioaccumulation of Cd2+ by ZBCM. The adsorption process of Cd2+ by ZBCM conforms to the pseudo-secondary kinetics and Langmuir model，indicating that the adsorption process was dominated by chemisorption within the single molecular layer. The FTIR and XPS results show that the mechanisms of action of ZBCM on Cd2+ include ion exchange，ligand complexation and cation-π bonding，and bioaccumulation. ? 2023 Science Press.
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