Insights on ball milling enhanced iron magnesium layered double oxides bagasse biochar composite for ciprofloxacin adsorptive removal from water.

Both ciprofloxacin (CIP) and sugarcane bagasse have brought enormous pressure on environmental safety. Here, an innovative technique combining Fe-Mg-layered double oxides and ball milling was presented for the first time to convert bagasse-waste into a new biochar adsorbent (BM-LDOs-BC) for aqueous CIP removal. The maximum theoretical adsorption capacity of BM-LDOs-BC reached up to 213.1 mg g-1 due to abundant adsorption sites provided by well-developed pores characteristics and enhanced functional groups. The results of characterization, data fitting and environmental parameter revealed that pore filling, electrostatic interactions, H-bonding, complexation and π-π conjugation were the key mechanisms for CIP adsorptive removal. BM-LDOs-BC exhibited satisfactory environmental safety and outstanding adsorption capacity under various environmental situations (pH, inorganic salts, humic acid). Moreover, BM-LDOs-BC possessed excellent reusability. These superiorities illustrated that BM-LDOs-BC was a promising adsorbent and created a new avenue for rational placement of biowaste and high-efficiency synthesis of biochar for antibiotic removal.

Comprehensive understanding the impacts of dietary exposure to polyethylene microplastics on genetically improved farmed tilapia (Oreochromis niloticus): tracking from growth, microbiota, metabolism to gene expressions.

Microplastics (MPs) pollution has been recognized as a threat to sustainable fisheries due to the risks of MPs contamination in the process of feed production and susceptibility of fish to ingest MPs from the aquatic environment. In this study, we applied comprehensive approaches to investigate the impacts of polyethylene microplastics (PE-MPs) on juvenile genetically improved farmed tilapia (GIFT, Oreochromis niloticus) through 9-week dietary exposure based on growth performance, gut microbiota, liver metabolism, and gene expressions in brain and liver tissues. Dietary exposure to two kinds of PE-MPs with different median size (27 µm and 63 µm, respectively) concentration-dependently decreased weight gain (WG), while increased feed conversion ratio (FCR) and hepatosomatic index (HSI) of the tilapia. Dietary administration of PE-MPs also significantly reduced the activities of intestinal protease and amylase. PE-MPs particles of the larger size groups (63 µm) were mainly detected in feces, but those of the smaller ones (27 µm) tended to be accumulated in intestine. PE-MPs ingestion resulted in the alteration of gut microbiota composition, with Fusobacteria, Verrucomicrobia and Firmicutes as the overrepresented bacterial taxa. Metabolomic assays of liver samples in fish fed the diets containing 8 % of PE-MPs revealed the particle size-specific variations in composition of differential metabolites and metabolism pathways such as amino acid and glycerophospholipid metabolism. Gene expressions of brain and liver samples were analyzed by RNA-seq. Photoperiodism and circadian rhythm were the representative biological processes enriched for the differentially expressed genes (DEGs) identified from the brain. Citrate cycle (TCA cycle) was the most enriched pathway revealed by a joint transcriptomic and metabolic pathway analysis for the liver, followed by propanoate and pyruvate metabolism. Furthermore, an integration analysis of the gut microbiome and liver transcriptome data identified significant associations between several pathogenic bacteria taxa and immune pathways. Our findings demonstrated that the sizes and concentrations of PE-MPs are critically related to their toxic impacts on microbiota community, metabolism, gene expressions and thus fish growth.