Acetate anions intercalated Fe/Mg-layered double hydroxides modified biochar for efficient adsorption of anionic and cationic heavy metal ions from polluted water.

The simultaneous removal of anionic and cationic heavy metals presents a challenge for adsorbents. In this study, acetate (Ac-) was utilized as the intercalating anion for layered double hydroxide (LDH) to prepare a novel biochar composite adsorbent (Ac-LB) designed for the adsorption of Pb(II), Cu(II), and As(V). By utilizing Ac- as the intercalating anion, the interlayer space of the LDH was enlarged from 0.803 nm to 0.869 nm, exposing more adsorption sites for the LDH and enhancing the affinity for heavy metals. The results of the adsorption experiments showed that the adsorption effect of Ac-LB on heavy metals was significantly improved compared to the original FeMg-LDH modified biochar composites (LB), and the maximum adsorption capacity of Pb(II), Cu(II), and As(V) were 402.70, 68.50, and 21.68 mg/g, respectively. Wastewater simulation tests further confirmed the promising application of Ac-LB for heavy metal adsorption. The analysis of the adsorption mechanism revealed that surface complexation, electrostatic adsorption, and chemical deposition were the main mechanisms of action between heavy metals (Pb(II) and Cu(II)) and Ac-LB. Additionally, Cu(II) ions underwent a homogeneous substitution reaction with Ac-LB. The adsorption process of As(V) by Ac-LB mainly relied on complexation and ion-exchange reactions. Lastly, the modification of the LDH structure by Ac- as an intercalating anion, thereby increasing the affinity for heavy metals, was further illustrated using density-functional theory (DFT) calculations.

Half-metallic antiferromagnets induced by non-magnetic adatoms on bilayer silicene.

Transition metal-free magnetism and two-dimensional p-state half-metals have been a fascinating subject of research due to their potential applications in nanoelectronics and spintronics. By applying density functional theory calculations, we predict that bilayer silicene can be an interlayer antiferromagnetic ground state. Interestingly, the half-metallicity is realized by adsorbing non-magnetic atoms on the antiferromagnetic bilayer silicene in the absence of transition magnetic atoms, nanoribbons, ferromagnetic substrates and magnetic field. Then, on the basis of first principles calculations and theoretical analysis, we show that the realization of half-metallicity is induced by the split of antiferromagnetic degeneracy due to the localization of transfer charge from the adatom to silicene. Our findings may open a new avenue to silicene-based electronic and spintronic devices.

Effectiveness of traditional Chinese medicine in treating gastrointestinal dysfunction in patients with acute stroke: a systematic review and meta-analysis of 16 randomized controlled trials.

BACKGROUND: Gastrointestinal dysfunction is one of the complications after stroke. If it is not treated in time, it will affect the rehabilitation process after stroke and reduce the quality of life of patients. In this study, we conducted a systematic review and meta-analysis of the reports on the treatment of gastrointestinal dysfunction after stroke with traditional Chinese medicine (TCM) in recent years to provide evidence for clinical diagnosis and treatment. METHODS: The clinical randomized controlled trials (RCTs) published in Chinese Biomedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), Medline, and Web of Science databases from January 2010 to August 2021 were searched. After screening the qualified literatures, literature quality evaluation was performed. The software Stata 16.0 was used to analyze and compare the outcome indicators of TCM and conventional western medicine treatment, and the utility of TCM in the treatment of gastrointestinal disorders after stroke was comprehensively evaluated. RESULTS: A total of 16 studies were finally selected including a total of 1,589. Meta-analysis showed that TCM treatment of gastrointestinal disorders after stroke was more effective than conventional western medicine treatment [odds ratio (OR) =3.94; 95% confidence interval (CI): 2.63 to 5.89; P=0.000]. It was also shown that TCM can reduce the recovery time of bowel sounds and is superior to conventional western medicine [standard mean difference (SMD) =-1.92; 95% CI: -2.51 to -1.34; P=0.000]; reduce defecation and flatulence recovery time (SMD =-2.51; 95% CI: -3.41 to -1.61; P=0.000); increase gastrin level (SMD =0.80; 95% CI: 0.35 to 1.25; P=0.001); increase motilin level (SMD =2.27; 95% CI: 1.55 to 3.00; P=0.000); increase serum albumin level (SMD =0.72; 95% CI: 0.54 to 0.90; P=0.000); increase transferrin levels (SMD =1.11; 95% CI: 0.86 to 1.36; P=0.000); and it can increase serum prealbumin levels (SMD =1.50; 95% CI: 0.78 to 2.22; P=0.000). DISCUSSION: The use of TCM in the treatment of gastrointestinal dysfunction after stroke can effectively reduce symptoms, shorten the recovery time of bowel sounds, the first defecation and flatulence time, promote gastric motility and gastrointestinal hormone secretion, and improve the nutritional status of patients.

[Degradation 2,2',4,4'-Tetrabromodiphenyl Ether by Activated Peroxymonosulfate Using Magnetic Biochar Supported α-MnO2].

Polybrominated diphenyl ethers(PBDEs) are potentially harmful to human health and the ecological environment. It is, therefore, of great significance to develop efficient, economic, and environmentally-friendly advanced oxidation systems for their effective degradation. Here, a magnetic biochar supported manganese dioxide composite(α-MnO2/MWB) synthesized by hydrothermal methods was used as a catalyst to activate peroxymonosulfate(PMS) in the degradation of 2, 2', 4, 4'-tetrabrominated diphenyl ether(BDE-47). The prepared materials were characterized by SEM, XRD, FT-IR, and BET. The results showed that α-MnO2/MWB had the best catalytic performance, and the highest degradation efficiency reached 94% under optimal conditions(α-MnO2/MWB mass ratio=1:2, catalyst dosage=0.05 g·L-1, PMS concentration=5 mmol·L-1, BDE-47 concentration=1 mg·L-1). The effect of initial pH on the system was not distinct, while chloride ions(Cl-) and humic acid(HA) inhibited the degradation of BDE-47. In comparison, nitrate ions(NO3-) and bicarbonate ions(HCO3-) had no notable effect on the degradation. SO4-· and·OH were the key free radicals in the degradation of BDE-47 in this system, with SO4-· being dominant. As showed by the XPS characterization of the materials before and after the reaction, a change in the valence states of Mn and Fe was the main reason for the activation of PMS. It was also revealed that α-MnO2/MWB composites maintained high catalytic performance after being reused up to four times.