A critical review on graphene oxide membrane for industrial wastewater treatment.

An important way to promote the environmental industry's goal of carbon reduction is to promote the recycling of resources. Membrane separation technology has unique advantages in resource recovery and advanced treatment of industrial wastewater. However, the great promise of traditional organic membrane is hampered by challenges associated with organic solvent tolerance, lack of oxidation resistance, and serious membrane fouling control. Moreover, the high concentrations of organic matter and inorganic salts in the membrane filtration concentrate also hinder the wider application of the membrane separation technology. The emerging cost-effective graphene oxide (GO)-based membrane with excellent resistance to organic solvents and oxidants, more hydrophilicity, lower membrane fouling, better separation performance has been expected to contribute more in industrial wastewater treatment. Herein, we provide comprehensive insights into the preparation and characteristic of GO membranes, as well as current research status and problems related to its future application in industrial wastewater treatment. Finally, concluding remarks and future perspectives have been deduced and recommended for the GO membrane separation technology application for industrial wastewater treatment, which leads to realizing sustainable wastewater recycling and a nearly "zero discharge" water treatment process.

Microplastics contamination in groundwater of a drinking-water source area, northern China.

Although the contamination of microplastics (MPs) in groundwater has been anticipated, their occurrence, distribution, and composition require further understanding. In this study, the occurrence and distributions of MPs were investigated in shallow groundwater from an important water source district in Tianjin city of northern China. The abundance, the physical morphology, the chemical composition, and the potential correlations of the determined MPs with human activities were thoroughly characterized. MPs were determined from all ten sampling sites with the abundance ranged between 17.0 ± 2.16 to 44.0 ± 1.63 n/L, revealing the ubiquitous existed MPs contamination. Based on the physical categorization, fiber (44.74%) was the most abundant shape, while blue (31.02%) and transparent (26.09%) were the most prevalent colors. The dominant size of MPs was smaller than 200 µm which accounted for 73.10%. A total of seven types of MPs were determined with polyethylene, polyethylene terephthalate, and polystyrene as the main types, of which, polypropylene showed strong positive correlations with polystyrene, indicating the possible similar sources of them. Besides, the determined MPs in groundwater were greater in areas with the high population density and strong population activity, indicating their high correlation with human activity. The study highlighted the presence of MPs in groundwater of drinking water source in northern China and provided useful information for evaluating the potential ecological effects on water quality safety and human health brought by MPs.

Clinical-grade human dental pulp stem cells suppressed the activation of osteoarthritic macrophages and attenuated cartilaginous damage in a rabbit osteoarthritis model.

BACKGROUND: Although increasing evidence has demonstrated that human dental pulp stem cells (hDPSCs) are efficacious for the clinical treatment of skeletal disorders, the underlying mechanisms remain incompletely understood. Osteoarthritis (OA) is one of the most common degenerative disorders in joints and is characterized by gradual and irreversible cartilaginous tissue damage. Notably, immune factors were newly identified to be closely related to OA development. In this study, we explored the modulatory effects of clinical-grade hDPSCs on osteoarthritic macrophages and their protective effects on cartilaginous tissues in OA joints. METHODS: The cell morphology, immunophenotype, and inflammatory factor expression of osteoarthritic macrophages were explored by phase contrast microscope, transmission electron microscopy, immunostaining, flow cytometry, quantitative polymerase chain reaction, and enzyme linked immunosorbent assay, respectively. Additionally, the factors and signaling pathways that suppressed macrophage activation by hDPSCs were determined by enzyme-linked immunosorbent assay and western-blotting. Furthermore, hDPSCs were administered to a rabbit knee OA model via intra-articular injection. Macrophage activation in vivo and cartilaginous tissue damage were also evaluated by pathological analysis. RESULTS: We found that hDPSCs markedly inhibited osteoarthritic macrophage activation in vitro. The cell morphology, immunophenotype, and inflammatory factor expression of osteoarthritic macrophages changed into less inflammatory status in the presence of hDPSCs. Mechanistically, we observed that hDPSC-derived hepatocyte growth factor and transforming growth factor ß1 mediated the suppressive effects on osteoarthritic macrophages. Moreover, phosphorylation of MAPK pathway proteins contributed to osteoarthritic macrophage activation, and hDPSCs suppressed their activation by partially inactivating those pathways. Most importantly, injected hDPSCs inhibited macrophage activation in osteochondral tissues in a rabbit knee OA model in vivo. Further histological analysis showed that hDPSCs alleviated cartilaginous damage to knee joints. CONCLUSIONS: In summary, our findings reveal a novel function for hDPSCs in suppressing osteoarthritic macrophages and suggest that macrophages are efficient cellular targets of hDPSCs for alleviation of cartilaginous damage in OA. hDPSCs treat OA via an osteoarthritic macrophages-dependent mechanisms. hDPSCs suppress the activation of osteoarthritic macrophages in vitro and in vivo and alleviate cartilaginous lesions in OA models.