ABSTRACT
As an energy-efficient and eco-friendly technique, capacitive deionization (CDI) has shown great potential for uranium (U(VI)) capture recently. However, extracting U(VI) with high kinetics, capacity and selectivity remains a major challenge due to the current surface active sites-based material and co-existing ions in aqueous solution. Here we rationally designed a layered 2D/2D niobium phosphate/holey graphene (HGNbP) electrode material, and originally demonstrated its efficient U(VI) capture ability via an electro-adsorption and electrocatalytic reduction coupling process. The less-accumulative loose layered architecture, open polycrystalline construction of niobium phosphate with active phosphate sites, and rich in-plane nano-pores on conductive graphene nanosheets endowed HGNbP with fast charge/ion transport, high electroconductivity and superior pseudocapacitance, which enabled U(VI) ions first to be electro-adsorbed, then physico-chemical adsorbed, and finally electrocatalysis reduced/deposited onto electrode surface without the limitation of active sites under a low potential of 1.2 V. Based on these virtues, the HGNbP exhibited a fast adsorption kinetics, with a high removal rate of 99.9% within 30 min in 50 mg L-1 U(VI) solution, and a high adsorption capacity up to 1340 mg g-1 in 1000 mg L-1 U(VI) solution. Furthermore, the good recyclability and selectivity towards U(VI) were also realized.
ABSTRACT
Objective: Emerging evidence shows that high blood pressure (BP) level even below 140/90 mmHg during pregnancy is associated with increased risk for maternal and infant complications. The meta-analysis evaluated the associations between prehypertension (BP 120-139/80-89 mmHg) during pregnancy and the risk of small for gestational age (SGA), as well as the impact of prehypertension on birth weight (BW).Methods: Databases (PubMed, Embase, and Cochrane Library) were searched for cohort studies with data on prehypertension in pregnancy and adverse obstetrical outcomes, including SGA and/or BW. The relative risks (RRs) of SGA and weighted mean differences (WMD) in BW were calculated and reported with 95% confidence intervals (95% CIs). We calculated pooled RRs using fixed- and random-effects models.Results: A total of 143,835 participants from five cohort studies were included. Prehypertension in pregnancy increased the risk of SGA (RR 1.59, 95%CI 1.44 to 1.76, p < .00001) and lowered BW (WMD -13.71, 95% CI -83.28 to 55.87, p = .70) compared with optimal BP (<120/80 mmHg). In subgroup analyses, for prehypertension in late pregnancy, the risk of SGA was significantly higher than for optimal BP (RR 1.60, 95% CI 1.44 to 1.78).Conclusion: BP within the range of 120-139/80-89 mmHg during pregnancy, as previously defined as prehypertension, particularly in late pregnancy, was associated with a 59% increase in the risk of having an SGA birth.
