ABSTRACT
In this study, dopamine-modified graphene aerogel (DGA) is synthesized through a one-step hydrothermal method using graphene oxide as the precursor and dopamine as the reducing agent. Subsequently, in situ immersion synthesis is conducted to obtain ZIF-8 loaded on a dopamine-modified graphene aerogel skeleton (ZDGA), featuring a regular honeycomb interconnected mesoporosity and a high specific surface area of 532.8 m2/g. The synthesized ZDGA exhibited exceptional adsorption performance for the cationic dye malachite green. At room temperature, ZDGA achieved an impressive equilibrium adsorption capacity of 6578.34 mg/g. The adsorption process followed pseudo-secondary kinetics and adhered to the Langmuir model, indicating chemically dominated adsorption on a monomolecular layer. Intraparticle diffusion was the primary rate determinant, with π-π stacking, electrostatic adsorption, hydrogen bonding, and Lewis acid-base interactions serving as the key driving forces. It has an ideal specific surface area and good cycling performance, which highlights its potential application in dye wastewater treatment.
ABSTRACT
In order to understand the diversity of culturable bacteria, 44 bacteria strains inhabiting brines and salt crystals in the Kunming Salt Mine, P. R. China were isolated and cultured. Results showed that the numbers of the bacteria isolated from salt crystals (3.1 x 10(3) - 3.7 x 10(6) CFU/g) were higher than those from brines (1.3 - 6.3 x 10(3) CFU/L). A neighbor-joining tree of the partial 16S rDNA sequences (about 600bp of 5'-end) showed that 44 strains were phylogenetically clustered into 4 major groups and 44 distinct lineages or species (the similarities of 16S rDNA sequences <97%): 24 strains of Firmicutes (54.6%), 2 strains of alpha-Proteobacteria (4.6%), 4 strains of gamma-Proteobacteria (9.1%) and 14 strains of Actinobacteria (31.7%). Strains of the genus Bacillus (26.1% and 59.9%) were the most predominant microorganisms among brines and salt crystals. Additionally, seven potential novel species were found, based on the similarities of 16S rDNA sequences to those of previously published species, and seven strains with bioactivities against pathogenic microorganisms were isolated. The conclusion is that there are a number of novel species and bioactive strains, as well as great diversity in Kunming Salt Mine.
