Effective Gas Separation Performance Enhancement Obtained by Constructing Polymorphous Core-Shell Metal-Organic Frameworks.

We reported a new polymorphous core-shell metal-organic framework (MOF) in the form of a three-dimensional MOF core wrapped in a two-dimensional layered MOF shell by applying a general acid-solvent synergy synthesis. This hybrid material can achieve high adsorptive selectivity/capacity simultaneously, which is validated by the unary isotherms of CO2 and N2 conducted at 273 K (0-1 bar). The MOF-S@MOF-C with a 7-day exchange showed the highest CO2/N2 selectivity (32.7) among our samples and a moderate CO2 capacity (2.3 mmol/g), which are 3 times and 1.6 times those of the MOF-C and MOF-S, respectively. We attributed the enhanced selective adsorption performance to the negligible N2 uptake exhibited by the outer shell of MOF-S@MOF-C. This study provides a new route for elevating gas separation performance by constructing multifunctional core-shell materials.

Converting 3D rigid metal-organic frameworks (MOFs) to 2D flexible networks via ligand exchange for enhanced CO2/N2 and CH4/N2 separation.

We report a synthetic strategy for constructing a novel flexible MOF from a rigid parent structure by ligand exchange. This is the first reported study on introducing flexible heterogeneity into a rigid structure via substantial structural rearrangement. The daughter material exhibits enhanced gas separation selectivity compared with the parent.

[Biodegradation of o-chlorophenol by photosynthetic bacteria under co-metabolism].

Photosynthetic bacterial strain PSB-1D cannot utilize o-chlorophenol (2-CP) as the sole carbon source for energy. In this paper, different carbon sources (malic acid, sodium propionate, sodium acetate, sodium citrate, phenol, glucose, and soluble starch) were taken as the co-metabolism substrates to study their effects on PSB-1D growth and 2-CP degradation under the condition of aerobic culture in darkness. Among the substrates, glucose was most efficient, which promoted the reproduction of PSB-1D, enhanced the 2-CP degradation efficiency, and shortened the degradation period. The optimization experiment of added concentration of glucose showed that when the added glucose concentration was 3 g x L(-1), the PSB-1D cell concentration deltaD560 after 168 h culture was 1.749, the half-time of 2-CP was shortened to 3.9 d, and the degradation rate constant was increased to 0.00864 h(-1). The SDS-PAGE analysis on the total microbial cellular protein showed that taking glucose as the co-metabolism substrate, PSB-1D could induce a specific 2-CP-degrading enzyme.

[Biodegradation characteristics of o-chlorophenol with photosynthetic bacteria PSB-1D].

A strain of photosynthetic bacteria named PSB-1D with degradation of o-chlorophenol (2-CP) was isolated and screened from the shallow substrate sludge in downstream side of the sewage outfall of an insecticide factory. The PSB-1D is identified preliminarily as Rhodopseudomonas sp. according to its colony and cell morphological properties, physiological biochemical characteristics and absorption spectrum analysis of living cells. The experiments results of relationship between PSB-1D growth and o-chlorophenol degradation showed that the degradation rate of o-chlorophenol was up to 57.26% after 7 days cultural time. The main environmental factors including way of illumination and oxygen, initial pH, cultural temperature, illumination intensity had distinctly influenced on the o-chlorophenol degradation with PSB-1D. The results showed that the optimum conditions were as following: an anaerobic light, pH 7.0, temperature 30 degrees C, illumination intensity 4000 lx,initial o-chlorophenol concentration 50 mg/L. Under that cultural condition, the degradation rate of o-chlorophenol could reach to 62.08%. The degradation kinetic data fitted the Andrews model well. In addition, the biodegradation process of o-chlorophenol can be well described by enzymatic reaction of high concentration inhibition, with the maximum substrate utilization rate 0.309 d(-1), Michaelis-Menten constant 2.733 mg/L, inhibitory constant 230.15 mg/L respectively.