Sulfonate-grafted porous polymer networks for preferential CO2 adsorption at low pressure.

A porous polymer network (PPN) grafted with sulfonic acid (PPN-6-SO(3)H) and its lithium salt (PPN-6-SO(3)Li) exhibit significant increases in isosteric heats of CO(2) adsorption and CO(2)-uptake capacities. IAST calculations using single-component-isotherm data and a 15/85 CO(2)/N(2) ratio at 295 K and 1 bar revealed that the sulfonate-grafted PPN-6 networks show exceptionally high adsorption selectivity for CO(2) over N(2) (155 and 414 for PPN-6-SO(3)H and PPN-6-SO(3)Li, respectively). Since these PPNs also possess ultrahigh physicochemical stability, practical applications in postcombustion capture of CO(2) lie well within the realm of possibility.

Unprecedented marriage of a cationic pentanuclear cluster and a 2D polymeric anionic layer based on a flexible tripodal ligand and a Cu(II) ion.

The anionic CdI(2)-type topological net, [Cu(2)(tci)(2)](2-), and the pentanuclear copper cluster cation [Cu(5)(tci)(2)(OH)(2)(H(2)O)(8)](2+) [tci = tris(2-carboxyethyl)isocyanurate] form a complementary 3D supramolecular framework. Interestingly, there exist centrosymmetric cyclic (H(2)O)(18) clusters in the cavities.

Anionic dye uptake via composite using chitosan-polyacrylamide hydrogel as matrix containing TiO2 nanoparticles; comprehensive adsorption studies.

In the present study, TiO2 nanoparticles dispersed in chitosan grafted polyacrylamide matrix (TiO2-PAM-CS) was synthesized using in situ technique, and applied for the uptake of Sirius yellow K-CF dye from aqueous solution. The synthesized nano-composite was characterized by FE-SEM, TEM, XRD and FT-IR analysis. The effect of significant parameters such as pH, dose, time and temperature in batch adsorption experiments were investigated. The adsorption process was pH dependent and the optimum value of pH was obtained 2 with 96.81% dye removal at 40 °C. The equilibrium data were compatible well with the Langmuir isotherm having qm value of 1000 mg/g. The Dubinin-Radushkevich (D-R) isotherm and thermodynamic studies prove that the adsorption is physical, endothermic and spontaneous. Kinetic study also verifies that pseudo second order kinetic model is the predominant model. The interactions between amin groups of polyacrylamide-chitosan (PAM-CS) composite in from of NH3+ and molecules of anionic dye via hydrogen bond formation (Dye-NH3+), also electrostatic interactions between Ti+4 available in PAM-CS composite and anionic dye (free energy of 1.66 kJ/mol calculated from D-R model) govern the adsorption mechanism. The reusability test showe that TiO2-PAM-CS composite can be renewed easily with HCl solution as an efficient adsorbent for practical wastewater treatment.

Cost-effective synthesis of amine-tethered porous materials for carbon capture.

A truly cost-effective strategy for the synthesis of amine-tethered porous polymer networks (PPNs) has been developed. A network containing diethylenetriamine (PPN-125-DETA) exhibits a high working capacity comparable to current state-of-art technology (30 % monoethanolamine solutions), yet it requires only one third as much energy for regeneration. It has also been demonstrated to retain over 90 % capacity after 50 adsorption-desorption cycles of CO2 in a temperature-swing adsorption process. The results suggest that PPN-125-DETA is a very promising new material for carbon capture from flue gas streams.

Hexagonal prismatic dodecameric water cluster: a building unit of the five-fold interpenetrating six-connected supramolecular network.

An experimental (H(2)O)(n) (n > 10) aggregate, similar to a theoretical hexagonal prismatic dodecameric water cluster structure, is characterized, the water cluster can be reversibly generated. The hydrogen bonds between the water clusters and bis(imidazolyl) ligand result in the formation of a five-fold interpenetrating six-connected supramolecular network.

In situ synthesis of Ag nanoparticles in aminocalix[4]arene multilayers.

The layer-by-layer (LbL) assembled thin films containing tetraamino-thiacalix[4]arenes (1) and tetraamino-calix[4]arenes (2) were used as nanoreactor to synthesize in situ Ag nanoparticles (Ag NPs). UV-vis spectra and AFM images demonstrate that Ag NPs are included in the (1/Ag NPs)(n) and (2/Ag NPs)(n) multilayer films. The silver ions are absorbed through cation-pi interaction and calix[4]arene-metal ion coordination interaction and are reduced into Ag NPs by calix[4]arenes. TEM images indicated that Ag NPs within aminocalix[4]arene multilayers were highly dispersed and uniform. Moreover, the mean size of Ag NPs is smaller than 10 nm.