ABSTRACT
What is already known about this topic?: The number of newly diagnosed human immunodeficiency virus (HIV) cases among Chinese youth 15-24 years of age shows an upward trend between 2010 and 2019. What is added by this report?: This survey is on a larger scale as compared to previous studies. It shows inadequate HIV knowledge - especially on HIV treatment, self-testing, and post-exposure prophylaxis - among college students. A significant gap exists between knowledge and behavior as indicated by the low condom use rate despite a high knowledge level. What are the implications for public health practice?: Findings suggest priorities for future HIV education and awareness creation of existing services. A low condom use rate at sexual debut suggests that HIV prevention education should start early.
ABSTRACT
Adsorption and improved biodegradation of dyes in wastewater was achieved with Fe3O4@MIL-100 core-shell bio-nanocomposites, which were prepared by a step-by-step strategy and attached to the surface of bacteria via zero-length carbodiimide chemistry. The Fe3O4@MIL-100 (Fe) nano-composite showed excellent dye adsorption properties and the overall dye removal process followed second-order kinetics. The dye AO10 was completely eliminated from solution by the combined effects of adsorption and biodegradation within 15 and 25 h from initial dye concentrations of 25 and 50 mg/L, respectively. The time to degrade the dye decreased from 11 h for the free microorganisms to 5 h for the bio-nanocomposite. The procedure was non-toxic, allowed for magnetic separation of the bio-nanocomposite from solution, and showed good cycling performance for the removal of dye. Hence, the strategy of surface-engineering bacteria shows great potential for the treatment of dyes from industrial effluents.
Subject(s)
Biodegradation, Environmental , Coloring Agents/chemistry , Ferric Compounds/chemistry , Water Pollutants, Chemical/chemistry , Adsorption , Kinetics , Magnetics , Nanocomposites/chemistry , Wastewater/chemistryABSTRACT
Microorganism immobilization has attracted great attention as a traditional method to overcome aqueous organic wastes containing N, N-dimethylformamide (DMF). In this approach, graphene oxide was modified with functional polymer firstly to obtain micro-composites material (PGO), and then the prepared composites were deposited on the surface of copper mesh (CM) to block the meshes and CM@PGO was achieved. Moreover, cage-shaped model was designed based on CM@PGO and P. denitrificans was packed inside the cage for batch experiments. This strategy could enrich the local concentration of DMF due to the formation of hydrogen bonds with the oxygen-containing groups from PGO and the character of bacteria in captivity could also contribute to the process of degradation. Results showed that the approach could remove DMF more efficiently about 15% compared with free microorganism and presented excellent cycling performance. Meantime, physical adsorption and chemical adsorption were both contributed to the process of PGO adsorption, and the adsorption isotherm fits Langmuir model well, furthermore, the theoretical maximum of adsorption ability calculated through Langmuir model is 95 mg/g. In other words, this cage-shaped CM@PGO provided a facile platform for treating various wastewaters by altering the species of packed microorganisms, which exhibited considerable prospects for wastewater treatment.
