Malyuba A. Abu-Daabes

[n]-Oligourea-Based Green Sorbents with Enhanced CO2 Sorption Capacity.

A new series of [n]-oligoureas ([n]-OUs, n=4, 7, 10, and 12) green solid sorbents was prepared following a base-catalyzed, microwave-assisted oligomerization reaction. The materials were characterized by NMR and IR spectroscopy, elemental analysis, thermogravimetric analysis, differential scanning calorimetry, and XRD. Decomposition temperatures at 50 % weight loss (Td50 ) were ca. 350 °C for all oligomers. Urea and urethane functional groups indicated by IR spectroscopy confirmed the formation of the sorbent. The CO2 capturing capacities were determined at 35 °C and 1.0 bar (gravimetric method). Accordingly, [10]-OU had the highest CO2 sorption capacity among the others (18.90 and 22.70 mg CO 2 gsorbent (-1) ) at two different activation temperatures (60 or 100 °C, respectively). Chemisorption was the principal mechanism for CO2 capture. Cyclic CO2 sorption/desorption measurements were carried out to test the recyclability of [10]-OU. Activating the sample at 60 °C, three stable CO2 sorption cycles were achieved after running the first cycle.

Ordered mesoporous silica prepared by quiescent interfacial growth method - effects of reaction chemistry

Acidic interfacial growth can provide a number of industrially important mesoporous silica morphologies including fibers, spheres, and other rich shapes. Studying the reaction chemistry under quiescent (no mixing) conditions is important for understanding and for the production of the desired shapes. The focus of this work is to understand the effect of a number of previously untested conditions: acid type (HCl, HNO3, and H2SO4), acid content, silica precursor type (TBOS and TEOS), and surfactant type (CTAB, Tween 20, and Tween 80) on the shape and structure of products formed under quiescent two-phase interfacial configuration. Results show that the quiescent growth is typically slow due to the absence of mixing. The whole process of product formation and pore structuring becomes limited by the slow interfacial diffusion of silica source. TBOS-CTAB-HCl was the typical combination to produce fibers with high order in the interfacial region. The use of other acids (HNO3 and H2SO4), a less hydrophobic silica source (TEOS), and/or a neutral surfactant (Tweens) facilitate diffusion and homogenous supply of silica source into the bulk phase and give spheres and gyroids with low mesoporous order. The results suggest two distinct regions for silica growth (interfacial region and bulk region) in which the rate of solvent evaporation and local concentration affect the speed and dimension of growth. A combined mechanism for the interfacial bulk growth of mesoporous silica under quiescent conditions is proposed.

Effect of Surface Oxygen Complexes of Activated Carbon on Phenol Adsorption from Single and Mixed Non-Aqueous Solvents

ABSTRACT The effects of heterogeneous oxygen groups of activated carbon on the adsorption of dissolved phenol in single and mixed solvents have been studied. Cyclohexane, heptane, and mixtures of cyclohexane and heptane with different volumetric ratios have been used as solvents. Solvent hydrophobicity, the capability of the molecules to H-bond, and dispersive/repulsive interactions were found to be the main factors that affect the adsorption capacity. In a homogeneous mixed solvent, all phenol isotherms were very close to the pure heptane rather than pure cyclohexane isotherm for the untreated carbon, which has the lowest surface oxygen concentration. However, as the concentration of surface oxygen increases, phenol isotherms from the mixed solvents are more evenly distributed. It is suggested that selective segregation of the different solvents molecules (cyclohexane and heptane) can occur in the adsorbed phase based on differences in hydrophobicity between solvent molecules.

Corporate Environmental Responsibility in Jordan: The Potential and Limits

The world is facing unique environmental challenges. There is a record loss of biodiversity and long-term damage to ecosystems; pol-lution of the atmosphere and the consequences of climate change; waste production and disposal; natural resource depletion; the impact of using chemicals and toxic substance disposal; damaged aquatic ecosystems and land degradation. There is a need to iden-tify the options to reduce and eliminate unsustainable volumes and patterns of production and consumption to ensure that the resource consumption per person becomes sustainable.