Study on the solidification performance and mechanism of heavy metals by sludge/biomass ash ceramsites, biochar and biomass ash.

Industrial by-products are stored in large quantities in the open, leading to wasted resources and environmental pollution, and the natural environment is similarly faced with phosphate depletion and serious water and soil pollution. This study uses these by-products to produce a new sludge/biomass ash ceramsite that will be used to adsorb nitrogen and phosphorus from wastewater, and solidify heavy metals in the soil while releasing Olsen P. The sludge/biomass ash ceramsites are made using sewage sludge and biomass ash in a certain ratio calcined at high temperatures and modified for the adsorption of nitrogen and phosphorus from wastewater. Sludge/biomass ash ceramsites before and after phosphorus adsorption, biochar and biomass ash were compared to analyze their heavy metal adsorption capacity and potential as phosphate fertilizer. After phosphorus adsorption, the sludge/biomass ash ceramsites released effective phosphorus steadily and rapidly in the soil, with a greater initial release than biochar and biomass ash, and the ceramsites were in a granular form that could be easily recycled. Biochar and biomass residue, due to their surface functional groups, are better at solidifying heavy metals than sludge/biomass ash ceramsites. Biochar, biomass ash and sludge/biomass ash ceramsites significantly reduced the concentrations of Cd, Cu, Pb and Zn in the soil. Correlation analysis demonstrated that there was a synergistic relationship between the increase in soil Olsen P content and the change in pH, with the increase in soil Olsen P content and the increase in pH contributing to heavy metal solidification.

Adsorption of nitrogen and phosphorus from wastewater by modified sludge/biomass ash ceramsite: Preparation, adsorption mechanism, and sustainable analysis.

Excessive ammonium and phosphate in aquatic settings may produce major eutrophication. Adsorbents can be used to reduce the eutrophication of natural water bodies. In this study, a sustainable and efficient ceramic adsorbent (sludge/biomass ash ceramsite [SBC]) was prepared by using sludge and biomass ash with a weight ratio of 1:1; the sintering parameters were 1070°C for 15 min. The NH4 + -N and P adsorption capabilities were improved by utilizing 1 mol L-1 NaOH and 1.6 mol L-1 La(NO3 )3 ·6H2 O for modification. When the pH and duration were 7 and 1440 min, respectively, the maximum bending capacity of ammonia nitrogen and phosphorus was 3.2 and 2.1 mg g-1 at 308 K. The pseudo-second-order kinetic model better describes the adsorption dynamics of NH4 + -N and P, whereas the Langmuir model better describes the adsorption isotherm models of NH4 + -N and P. The adsorption mechanism of SBC-NaOH on NH4 + -N is ion exchange between Na+ and NH4 + , whereas the adsorption mechanism of SBC-La on phosphorus is ion exchange and La3+ adsorption. SBC combines efficient wastewater purification with the reuse of solid waste. The findings gave rise to the possibility of recycling ceramics as a plant fertilizer with a delayed release in the future. PRACTITIONER POINTS: New ceramsite was made from sludge and biomass ash. NH4 + -N (3.2 mg g-1 ) and P (2.1 mg g-1 ) were effectively adsorbed by ceramsite. The mechanism of NH4 + -N and P adsorption by ceramsite was studied. Absorbed ceramsite can be used as slow-release fertilizer in plant cultivation.

The forkhead box protein P3 gene rs3761548 promoter polymorphism confers a genetic contribution to the risk of preeclampsia: A systematic review and meta-analysis.

Various studies have investigated the risk of preeclampsia with the forkhead box protein P3 (FOXP3) gene rs2232365 and rs3761548 polymorphisms. However, the results remained contradictory. A comprehensive literature search was conducted using the Cochrane Library, PubMed, and Web of Science (up to Oct 11, 2021). Meta-analysis was carried out in the R language environment for statistical computing and graphics. A fixed-effect or random-effects model was used according to the statistical significance of heterogeneity among included studies. The pooled odds ratios and corresponding 95% confidence intervals were calculated to estimate the strength of the effect. For the rs2232365 polymorphism, statistical significance was detected neither in the overall population nor among the East Asian and West Asian subgroups. However, for rs3761548, the summarized statistics revealed a significant association between the C allele carriage and preeclampsia risk in the homozygote, heterozygote, and dominant models. The further stratified analysis found this effect might be specific to West-South Asian ethnic subgroups. To sum up, this meta-analysis showed that the FOXP3 rs3761548 polymorphism was significantly associated with preeclampsia susceptibility, and it had a deleterious effect especially in the West-South Asian population. In contrast, rs2232365 may serve as neither a protective nor a risk factor for preeclampsia onset.

Green synthesis of ceramsite from industrial wastes and its application in selective adsorption: Performance and mechanism.

The increasing requirement and consumption of coal has resulted in a large accumulation of coal gangue. The reuse and recycling of coal gangue have become a high priority for sustainable development. A sustainable and efficient ceramsite adsorbent was prepared for copper ions adsorption by using coal gangue, coal fly ash, and copper slag as the main materials. The appropriate performance of the ceramsite could be obtained at a mixture of coal gangue, coal fly ash, and copper slag at a weight ratio of 3:4:1. The optimal sintering temperature and time were 1050 °C and 20 min, respectively. The main crystalline phases of ceramsite were quartz, mullite, and anorthite. Many micropores are connecting the interior on the surface of ceramsite under scanning electron microscope. The maximum copper ions adsorption capacity reached up to 20.6 mg/g at 303 K when pH and time were 5 and 1440 min, respectively. The adsorption kinetics and isotherm could be described by the pseudo-second-order model and Freundlich model, respectively. The adsorption mechanisms of Cu2+ with ceramsite were attributed to Cu(OH)2 precipitation formed on the alkaline surface of ceramsite and complexation reactions occurred between the O-containing groups (including C-O, Fe-O, and Si-O) from ceramsite and Cu2+. The prepared ceramsite may be also applied to other heavy metal wastewater treatments.