Wenbo Wang,Guangyan Tian,Li Zong,Qin Wang,Yanmin Zhou,Aiqin Wang
A hierarchical mesoporous hybrid Zn-silicate adsorbent with superior adsorption performance for aureomycin (AMC) and tetracycline (TC) has been successfully synthesized by employing an “all-into-one” strategy and one-pot hydrothermal reaction , using naturally abundant, low-cost red palygorskite clay (RPAL), sodium silicate and zinc salts as raw materials. The morphologies and crystal forms of the Zn-silicates can be tuned by altering the dosage of Zn 2+ ions. Low-crystalline sheet-like Zn-silicates were formed at the Si/Zn ratio of 3:1 and 2:1, and zinc orthosilicates were obtained at the Si/Zn ratio of 1:1 and 1:2. A systematic study on their adsorption abilities for the antibiotics AMC and TC indicates that the sheet-like Zn-silicate has higher adsorption capacity for AMC and TC than zinc orthosilicate, and the Zn-silicate with Si/Zn ratio of 3:1 has the best adsorption capacity of 384 mg/g for AMC and 337 mg/g for TC, which is obviously higher than that of RPAL (154 mg/g for AMC and 140 mg/g for TC). The adsorption properties are dependent on the pore size and surface charges, instead of specific surface area. The average pore sizes of 10.62–11.50 nm and the negative surface charge (−42.54 mV) resulting from the –Si(M)O − groups are beneficial to the adsorption for both AMC and TC. The adsorption process mainly involves with monolayer coverage, and chemo-adsorption plays a key role for the enhanced adsorption capacity. The results suggest that the Zn-silicates derived from natural abundant clay mineral have superior performance, and could be candidates to remove AMC and TC from the wastewater with high amounts of AMC and TC.
Jiaxuan Liu,Wensi Ma,Xinyue Huang,Lei Jiang,Lin Yuan,Xiuling Ji,Yujiao Tu
Rapeseed oil residue (ROR) is the waste product of rapeseed oil extraction, mainly including protein and lignocellulose. In this study, we utilized waste ROR as the raw material to successfully prepare blue fluorescent carbon dots (ROR-CDs) by self-propagating synthesis. It demonstrated rapid preparation (20 min) with low energy consumption (400 °C) and without complicated purification processes. We analyzed the structural and optical properties of ROR-CDs. ROR-CDs exhibited exceptional fluorescence performance and stabilized, responding specifically to divalent mercury ions (Hg 2+ ) and aureomycin hydrochloride (CTC). Thus, we developed a high-sensitivity detection technique with a detection range and limit of detection (LOD) for Hg 2+ of 0–250 μg/L and 191.69 ng/L, respectively. For CTC, the detection range and LOD were 0–50 μM and 12.7 nM (S/N = 3), respectively. It is easy to operate and low-cost, ensuring efficient assistance for testing efforts in associated domains. Additionally, ROR-CDs-based detection technique can analyze Hg 2+ and CTC in the actual samples, demonstrating significant potential for application in environmental monitoring and food safety assessment.
Aureomycin (CTC) is a commonly used tetracycline antibiotic that causes water and soil pollution and greatly endangers the environment and human health. Microbial degradation to remove residual antibiotics in wastewater is of growing interest. Due to its unique structure and excellent oxidative properties, biogenic manganese oxides (BMO) has been widely studied in the field of water pollutant removal. However, the current preparation of BMO generally suffers from low yield and insufficient production efficiency. In this paper, an efficient manganese-oxidizing bacterium Bacillus sp. D-1 was isolated. Manganese-oxidizing engineering bacteria were constructed to achieve rapid and sufficient BMO production, and the structure and function of the BMO was characterized. SEM was used to characterize the layered structure of the nanoparticles. XPS and XRD were used to determine that the mixture was composed of manganese species with three valence states. BMO was used to degrade 10 mg·L −1 CTC, and the CTC removal rate reached 93.2 % in 24 h, with an optimal reaction pH of 7.6. Finally, LCMS and ECOSAR were used to analyze the oxidative degradation products of CTC and their biological toxicity. Therefore, this paper successfully constructed a high-performance manganese-oxidizing engineering bacterium, revealed the efficient degradation mechanism of CTC by BMO, provided a new strategy for the green treatment of combined pollution of manganese and antibiotics in water bodies, and realized the continuous removal of manganese and water pollutants.
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