Constructing CoNi-LDH/Fe MOF/NF Heterostructure Catalyst for Energy-Efficient OER and UOR at High Current Density.

The sluggish kinetics of the oxygen evolution reaction (OER) always results in a high overpotential at the anode of water electrolysis and an excessive electric energy consumption, which has been a major obstacle for hydrogen production through water electrolysis. In this study, we present a CoNi-LDH/Fe MOF/NF heterostructure catalyst with nanoneedle array morphology for the OER. In 1.0 M KOH solution, the heterostructure catalyst only required overpotentials of 275 and 305 mV to achieve high current densities of 500 and 1000 mA/cm2 for OER, respectively. The catalytic activities are much higher than those of the reference single-component CoNi-LDH/NF and Fe MOF/NF catalysts. The improved catalytic performance of the heterostructure catalyst can be ascribed to the synergistic effect of CoNi-LDH and Fe MOF. In particular, when the anodic OER is replaced with the urea oxidation reaction (UOR), which has a relatively lower thermodynamic equilibrium potential and is expected to reduce the cell voltage, the overpotentials required to achieve the same current densities can be reduced by 80 and 40 mV, respectively. The cell voltage required to drive overall urea splitting (OUS) is only 1.55 V at 100 mA/cm2 in the Pt/C/NF||CoNi-LDH/Fe MOF/NF two-electrode electrolytic cell. This value is 60 mV lower compared with that required for overall water splitting (OWS). Our results indicate that a reasonable construction of a heterostructure catalyst can significantly give rise to higher electrocatalytic performance, and using UOR to replace the anodic OER of the OWS can greatly reduce the electrolytic energy consumption.

Preparation of chlorine-resistant and regenerable antifouling nanofiltration membrane through interfacial polymerization using beta cyclodextrin monomers.

Constructing membrane with good chlorine resistance and antifouling properties is considered to be important challenges confronting membrane applications. In this study, a composite nanofiltration (NF) membrane (ß-CDx/y/PES) was prepared by interfacial polymerization using beta cyclodextrin (ß-CD) monomers. Subsequently, the ß-CD-based (AZ-ß-CDx/y/PES) membrane was prepared by assembling azobenzene labeled zwitterions into the hydrophobic internal cavity of ß-CD via host-guest interaction. The optimized membrane exhibited slight change in water flux and rejection under chlorine environment. The AZ-ß-CDx/y/PES membrane also displayed an evidently lower loss in water flux in the antifouling test in comparison with the ß-CDx/y/PES membrane. More interestingly, the trans azo groups in azobenzene labeled zwitterions can turn into the cis isomers as the visible light irradiation converted to the UV light irradiation, breaking the interaction between azobenzene labeled zwitterions and ß-CD. Hence, the contaminants upon the membrane surface can be simply eliminated by water washing under UV light irradiation. The antifouling membrane can be regenerated via immersing the reacquired ß-CD2/10/PES membrane into fresh azobenzene labeled zwitterions solution again.

Zwitterionic metal-organic frameworks modified polyamide membranes with enhanced water flux and antifouling capacity.

Antifouling properties are considered to be crucial parameter to polyamide (PA) composite nanofiltration (NF) membranes for practical applications. In this study, an antifouling material, surface zwitterionization of Metal-organic frameworks (Z-MIL-101 (Cr)) was firstly prepared by decorating zwitterionic polymer onto the MOFs surface. Subsequently, a novel type of MOFs-based hybrid membranes were fabricated via mixing the Z-MIL-101 (Cr) nanoparticle with the organic matrix by interfacial polymerization technique. The most optimal hybrid membrane had a high water permeation of 26 L m-2 h-1 bar-1, which was 2.1 times higher than that pristine PA membrane, while the retention for Na2SO4 was still kept at a considerably high value of 93%. The significant increased water flue can attribute to the existence of water channels generated by the Z-MIL-101 (Cr). More important, the antifouling property of the hybrid membrane was much better than that pristine PA, which was due to the formation of superhydrophilic liquid layer surrounding the zwitterionic groups. The combination of the micropore structure of the MOFs and the excellent antifouling properties of the decorated zwitterionic polymer effectively improved separation performances and antifouling ability, which makes these hybrid membranes promising for water purification.

The preparation of thin-walled multi-cavities ß-cyclodextrin polymer and its static and dynamic properties for dyes removal.

Thin-walled multi-cavities ß-cyclodextrin polymers (Hß-CDs) were prepared by the suspension polymerization method using SiO2 nanoparticles as a template. The components and morphology structure of Hß-CDs were characterized by FTIR, BET, SEM, and TEM. The adsorption performances of the prepared nano-adsorbent Hß-CDs on crystal violet (CV), heavy metal ions, some cationic, neutral, and anionic dyes were investigated. The influences of the pH and ionic strength on CV adsorption by the Hß-CDs were explored. The correlation coefficient (R2) of pseudo-second-order kinetic model reached 0.9984 and the adsorption isotherm was closer to the Langmuir model. As the temperature increased, the R2 of the Freundlich isotherm model rose. Compared to anionic ones and heavy metal ions, Hß-CDs had a better adsorption efficiency for cationic dyes. Dynamic adsorption also indicated the thin-walled multi-cavities structure was beneficial for improving absorptivity and application of ß-cyclodextrin polymers. In addition, the Hß-CDs exhibited potentially applicable for the regeneration and reuse with the removal efficiency of CV was as high as 89% in the fourth cycle.

Proanthocyanidin prevents lipopolysaccharide-induced depressive-like behavior in mice via neuroinflammatory pathway.

Recent studies have demonstrated neuroinflammation and increased cytokine levels are associated with depression. Aware of the efficacy the potential anti-inflammatory and antioxidative activity of proanthocyanidin, the present study was designed to investigate the effects of proanthocyanidin on lipopolysaccharide (LPS)-induced depressive-like behavior in mice. In depressive behavior tests, the immobility time of forced swimming test (FST) and tail suspension test (TST) was increased when mice were administrated a single dose of LPS (0.83mg/kg, i.p.), whereas these alterations were reversed by proanthocyanidin treatment (80mg/kg, p.o.). In anxiety behavior tests, all the anxiety-related parameters, such as number of buried marble, time spent in the open arm and close arm did not show statistical differences between LPS and control groups. However, anxiolytic effects were observed in marble-burying test and elevated plus maze test in single proanthocyanidin treatment and proanthocyanidin treatment together with LPS group. Further assays indicated that LPS-induced overexpression of pro-inflammatory cytokines in the hippocampus, prefrontal cortex (PFC) and amygdala were reversed by proanthocyanidin treatment. Furthermore, proanthocyanidin inhibited the LPS-induced iNOS and COX-2 overexpression, via the modulation of NF-κB in the hippocampus, PFC and amygdala. Taken together, proanthocyanidin may be an effective therapeutic agent for LPS-induced depressive-like behaviors via its potent anti-inflammatory property.

Comparative transcriptional profiling of Gracilariopsis lemaneiformis in response to salicylic acid- and methyl jasmonate-mediated heat resistance.

Culturing the economically important macroalga Gracilariopsis lemaneiformis (Rhodophyta) is limited due to the high temperatures in the summertime on the southern Chinese coast. Previous studies have demonstrated that two phytohormones, salicylic acid (SA) and methyl jasmonate (MJ), can alleviate the adverse effects of high-temperature stress on Gp. lemaneiformis. To elucidate the molecular mechanisms underlying SA- and MJ-mediated heat tolerance, we performed comprehensive analyses of transcriptome-wide gene expression profiles using RNA sequencing (RNA-seq) technology. A total of 14,644 unigenes were assembled, and 10,501 unigenes (71.71%) were annotated to the reference databases. In the SA, MJ and SA/MJ treatment groups, 519, 830, and 974 differentially expressed unigenes were detected, respectively. Unigenes related to photosynthesis and glycometabolism were enriched by SA, while unigenes associated with glycometabolism, protein synthesis, heat shock and signal transduction were increased by MJ. A crosstalk analysis revealed that 216 genes were synergistically regulated, while 18 genes were antagonistically regulated by SA and MJ. The results indicated that the two phytohormones could mitigate the adverse effects of heat on multiple pathways, and they predominantly acted synergistically to resist heat stress. These results will provide new insights into how SA and MJ modulate the molecular mechanisms that counteract heat stress in algae.