Metal–organic framework-808 has been functionalized with 11 amino acids (AA) to produce a series of MOF-808-AA structures. The adsorption of CO2 under flue gas conditions revealed that glycine- and dl-lysine-functionalized MOF-808 (MOF-808-Gly and -dl-Lys) have the highest uptake capacities. Enhanced CO2 capture performance in the presence of water was observed and studied by using single-component sorption isotherms, CO2/H2O binary isotherm, and dynamic breakthrough measurements. The key to the favorable performance was uncovered by deciphering the mechanism of CO2 capture in the pores and attributed to the formation of bicarbonate as evidenced by 13C and 15N solid-state nuclear magnetic resonance spectroscopy studies. On the basis of these results, we examined the performance of MOF-808-Gly in simulated coal flue gas conditions and found that it is possible to capture and release CO2 by vacuum swing adsorption. MOF-808-Gly was cycled at least 80 times with full retention of performance. This study significantly advances our understanding of CO2 chemistry in MOFs by revealing how strongly bound amine moieties to the MOF backbone create the chemistry and environment within the pores, leading to the binding and release of CO2 under mild conditions without application of heat.

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The diffusion mechanism and the concentration dependence of the mass transfer rate of water vapor adsorbing in the zirconium-based metal organic framework (MOF) UiO-66 has been determined using a concentration swing frequency response (CSFR) apparatus. The mechanism that best describes the adsorption of water in UiO-66 is micropore diffusion and the rate is dependent on the gas phase concentration of the water. Moreover, the results show that as the gas phase water concentration increases, a minimum in the water adsorption rate occurs near 4 mol/kg of water loading. Although the Darken relationship is unable to predict the concentration dependence, it agreed qualitatively with the experimental diffusivity data extracted from the CSFR analysis. The results demonstrate the ability of the concentration-swing frequency response technique to accurately determine adsorption rate mechanisms and quantify the adsorption kinetics of a slow to moderately fast diffusing component in MOFs.

A new volumetric frequency response (VFR) system was developed for studying the mass transfer characteristics of gases in microporous adsorbents. For this VFR system, the differential pressure response from a small perturbation in volume was measured in a closed system after equilibrium was established for a gas adsorbate–adsorbent pair at constant temperature and pressure. It operates over a wide range of frequencies from 10–5 to 10 Hz, from atmospheric pressure down to vacuum pressures of 100 Torr, and at temperatures from 5 to 80 °C. The sample chamber holds up to 100 g of adsorbent. These operating ranges make this new VFR system capable of measuring mass transfer characteristics of adsorbate–adsorbent systems at conditions relevant to many commercial separation processes using a relatively large volume of adsorbent in a unique packed bed arrangement. The apparatus and procedure were described in detail, including the use of runs with different gases and different porous and nonporous solid beads and pellets to fully characterize the system in terms of its dynamic behavior especially at high frequencies and in terms of various volumes required in the analyses. It was shown how to analyze these baseline runs to correct for gas compression heating and pressure drop effects in the high frequency region of the pressure change amplitude response curves and to determine intensity (or amplitude ratio) and phase shift (or lag) response curves from which fundamental thermodynamic and kinetic information for an adsorbate–adsorbent pair could be extracted. To demonstrate the utility of this new VFR system, experiments were carried out with CO2 in 13X zeolite beads at 25 °C and 100, 200, and 760 Torr using 32 frequencies at each pressure. Slopes of this isotherm estimated from the intensity response curves at low frequency showed very good agreement with those measured independently. The mass transfer time constant estimated from the maximum in the phase lag response curve also agreed well with that reported in the literature. Unique features of the intensity and phase lag response curves were revealed.

An experiment was carried out at farmer's field in Debigonj, Panchagorh during November 2009 to February 2010 to evaluate the effect of four levels of applied nitrogen on the growth and yield of carrot. The experiment was laid out in a Randomized Complete Block Design with three replications. The maximum plant height (47.36 cm), root length (16.17 cm), fresh weight of leaves (145.1 g), dry matter content (11.66 g) of leaves, fresh weight of root (68.33 g), dry matter content of root (15.90%), gross yield (22.55 t/ha) and marketable yield (20.67 t/ha) were found in 100 kg N/ha.