Adsorption and Visible Photocatalytic Synergistic Removal of a Cationic Dye with the Composite Material BiVO4/MgAl-LDHs

Adsorption and photocatalysis are effective in removing organic pollutants from wastewater. This study is based on the memory effects of MgAl-layered double hydroxides (MgAl-LDHs) after high-temperature calcination. By introducing bismuth vanadate (BiVO4) during the reformation of the layered structure via contact with water, a composite material BiVO4/MgAl-LDHs with enhanced adsorption and visible light catalytic performance was synthesized. The effects of the calcination temperature, ratio, initial methylene blue (MB) concentration, and catalyst dosage on the adsorption and photocatalytic performance were investigated. The BiVO4/MgAl-LDHs showed better photocatalytic performance than the pure BiVO4 and MgAl-LDHs. Under the optimal conditions, the proportion of MB adsorbed in 20 min was 66.1%, and the percentage of MB degraded during 100 min of photolysis was 92.4%. The composite photocatalyst showed good chemical stability and cyclability, and the adsorption-degradation rate was 86% after four cycles. Analyses of the adsorption and photocatalytic mechanisms for the composite material showed that synergistic adsorption and visible light photocatalysis contributed to the excellent catalytic performance of the BiVO4/MgAl-LDHs. A highly adsorbent photocatalytic composite material exhibiting outstanding performance was prepared via a simple, cost-effective, and environmentally friendly method, providing reference information for the removal of organic pollutants from liquids.

Prevalence and determinants of home delivery among reproductive age women, Margibi County, Liberia

Background

The use of institutional delivery services is essential for improving maternal and child health. However, studies in Liberia reveal over 20% of women still deliver at home. We assessed the prevalence and associated factors of home delivery among women of reproductive age in Margibi County, Liberia.

Methods

We conducted a cross-sectional study among 438 women of reproductive age in Margibi County. Data were obtained using a semi-structured questionnaire. A simple random sampling approach was used to select the participants for the study. We performed binary logistic regression to identify factors influencing home delivery. Findings were summarized into tables displaying the frequencies, percentages, crude, and adjusted odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Prevalence of home delivery in the County was 90.6% (95% CI = 87.5 – 93.0). Women who were ≥ 31 years (aOR = 6.74, 95%CI = 2.86—15.90), women who had two or more children (aOR = 9.68, 95%CI = 4.07—22.99) and those who had rapid onset of labor (aOR = 6.35, 95%CI = 1.59 – 25.27) were associated with increased odds of home delivery. Good attitude of health workers (aOR = 0.01, 95%CI = 0.001 – 0.08) and the availability of transport to the nearest health facility (aOR = 0.01, 95%CI = 0.003 – 0.03) were factors associated with a decreased odds of home delivery among the study participants.

Conclusion

The high prevalence of home delivery in the county is a call for urgent interventions by the government of Liberia and various non-governmental organizations. The government may need to supply the county with ambulances and ensure in-service training of health workers on good attitudes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-022-04975-7.

Ammonium Polyphosphate Intercalated Yttrium-Doped Layered Double Hydroxides to Enhance the Thermal Stability and Flame Retardancy of Poly(Lactic Acid)

The flammability of the biodegradable plastic PLA limits its application in industrial fields with high flame-retardant requirements. This paper provides a novel strategy for constructing refractory and thermostable PLA composites using layered double hydroxides (LDHs) chemically modified with ammonium polyphosphate (APP). XRD, FT-IR, SEM-EDS, and TEM confirm that the goal of LDHs has been successfully prepared. The thermal stability and combustion behavior of PLA composites were evaluated by the thermogravimetric analysis (TGA) and cone calorimetry tests (CCT). The crystallization behavior and tensile performances were also examined. The results showed that the incorporation of 15 wt% MgAlY-APP-LDHs practically makes the PLA composites reach the UL-94 V-0 grade. There were 43% and 20% reduction in the PHRR and THR of PLA/15APP-LDHs respectively due to the catalytic effect of Y elements and barrier effects of LDHs, which was a major performance against fire hazards. Furthermore, the increase in crystallinity and the decrease in mechanical strength of PLA composites are attributed to the nucleation of LDHs. In short, this research introduces the production of multifunctional PLA composites through APP intercalation of LDHs, which are deemed as prospective candidates for the next generation of sustainable plastics products.