Carboxymethyl cellulose-based cryogels for efficient heavy metal capture: Aluminum-mediated assembly process and sorption mechanism.

Heavy metal ions pollution is a terrible issue that needs to be efficiently treated as a matter of priority to construct our sustainable society. However, the easy-to-handling of high-performance biomass-derived sorbents with fascinating features like high sorption capacity, favorable separation and recycling remain challenging. Herein, the development of a novel bead-like adsorbent with above features, that is, Al(III)-assembled carboxymethyl cellulose beads were used for the removal of Pb(II), Ni(II) and Co(II) from aqueous solution. Characterization methods like FT-IR, SEM, XPS and TGA were employed to confirm its physicochemical properties. Removal of the three heavy metal ions at different pH values, initial concentration and contact time were discussed at batch adsorption experiments. Meanwhile, regeneration was also discussed deeply. The results revealed that the adsorption capacity of the sorbents for three heavy metals increases with increasing pH and the initial concentration. The adsorption isotherm could be described well by the Freundlich model, and the maximum adsorption capacity for Pb(II), Ni(II) and Co(II) were 550, 620 and 760 mg/g, respectively. Kinetics study indicated that the Pseudo-second-order model described the best correlation with experimental data, this suggested that the complexation may participated in the adsorption process. More significantly, this type of bead-like adsorbents displayed excellent reusability after four sequential cycles.

Modifying alginate beads using polycarboxyl component for enhanced metal ions removal.

Designing desirable adsorbent for highly efficient removal of heavy metal ions is of practical significance, given the cost-effectiveness, environmental benign, natural abundance and easy-handling collection features. Herein, a bead-like adsorbent with high adsorption capacity was prepared by modifying alginate beads using polyacrylate with high density of carboxyl groups. The developed alginate/polyacrylate beads were collaboratively characterized by FT-IR, TGA, SEM, XPS, etc., and various adsorption conditions were tested including the pH of the solution, contact time and the initial concentration. The experimental data were fitted well by the Freundlich isotherm model, and the maximum adsorption capacity was obtained from the Langmuir model was 611.0 mg/g, and adsorption process followed the Pseudo-second-order kinetic model. The adsorption mechanisms conformed to multi-layer adsorption, and mainly dominated by chemical interactions. The bead-like adsorbent exhibited excellent reusability after eight sequential cycles and displayed higher adsorption capacity towards lead ions. This type of adsorbent might possess promising role in treating heavy metals from water by virtue of degradable, cost-effective component and high adsorption efficiency.

[Application of fetal echocardiography in detection of fetal arrhythmia and its clinical significance].

OBJECTIVE: To investigate application of fetal echocardiography in diagnosis of fetal arrhythmia and its clinical significance. METHODS: Fetal echocardiography was performed on 725 fetuses for evaluation of fetal heart structures and arrhythmias. Two-dimensional, M-mode, Color M-mode and pulsed Doppler echocardiography were used. RESULTS: Ninety fetuses were documented with fetal arrhythmia, the commonest fetal arrhythmia encountered in 72 cases extrasystole was (65 atrial extrasystoles, 7 ventricular extrasystoles), followed by bradycardia in 9 cases, tachycardia in 6 cases, 2:1 atrioventricular block in 2 cases, atrial flutter in 1 case. There were 4 fetuses with arrhythmias and structural heart diseases: 2 fetuses were found died in uterus within two-week follow-up (1 with single ventricle and pulmonary stenosis, 1 with cardiac rhabdomyoma, fetal echocardiographic findings were confirmed at autopsy), another 2 cases (1 with mitral atresia and 1 with atrioventricular canal defect, autopsy confirmed the fetal echocardiographic diagnoses) received termination of pregnancy later. One 38-week fetus with atrial flutter underwent cesarean section, neonatal ECG confirmed the arrhythmia, and Cedilanid D induced successful conversion. All the other 85 fetuses were with intermittent arrhythmia, normal heart structures, and had no fetal hydrops. After receiving routine treatment, all of them had term deliveries and follow-up monitoring showed normal neonatal heart rhythms (auscultation). CONCLUSIONS: Fetal echocardiography is the main diagnostic tool for prenatal evaluation of fetal arrhythmias. The outcomes of the vast majority of fetal arrhythmias are benign, especially for fetuses with extrasystoles. Their arrhythmias are always well tolerated and disappear during the perinatal period. Fetuses with intermittent arrhythmias without structural heart malformations, fetal hydrops or heart failure, can be followed up with routine prenatal care without the need for special intervention.