Papers by Keyword: Pore Volume

Abstract: This study is to examine and clarify the quality of polymer-modified mortars using a VA/E/MMA terpolymer powder as compared with polymer-modified mortars using a VAE copolymer powder. Polymer-modified mortars using general commercial redispersible polymer powders are prepared with various polymer-cement ratios, and tested for flexural and compressive strengths, tensile strength, water absorption, chloride ion penetration, carbonation and pore size distribution by mercury porosimetry. Overall, the properties of polymer-modified mortars using a VA/E/MMA terpolymer powder were superior to those of polymer-modified mortars using a VAE copolymer powder. And VA/E/MMA terpolymer powder-modified mortars showed significantly improved mechanical properties and durability in comparison with unmodified mortar. It is concluded from the test results that the modification of cement mortar with redispersible polymer powder improves the properties of unmodified mortar, and VA/E/MMA terpolymer powder has higher quality than VAE copolymer powder.

Abstract: Carbon Nanotubes (CNT) have emerged and gained great interest for research in many applications because of their unique specific characteristics such as having high porosity, high surface area and the existence of a wide spectrum of surface functional groups through chemical modification. Multiwalled carbon nanotubes (MWCNT) is a type of CNT that comprises of multiple layers of concentric cylinders. The overall study of this research work is to modify MWCNT to become a good adsorbent that can adsorb CO₂ at its optimum capacity. In order to make MWCNT as an efficient adsorbent, surface treatment on pristine MWCNT is necessary to overcome the hydrophobicity issue by the introduction of carboxyl group. Upon the surface treatment, functionalization of MWCNT with 3-Aminopropyl triethoxysilane (APTS) was conducted to obtain the attachment of amine group that will assist MWCNT in adsorbing CO₂. The surface treatment and functionalization process undergone by MWCNT changed the physical properties of MWCNT such as the surface area, pore volume, and pore size distribution. These properties can be determined using surface area and pore analyzer (SAP). Sample that treated with the mixture of nitric and sulfuric acid (HNO₃/H₂SO₄) and functionalized with APTS gives the lowest surface area (22.07 m²/g) and pore volume (0.06 cm³/g). The pore size distribution also decreases due to the most presence of functional group onto the surface of modified MWCNT. This research paper is focusing on the effect of surface area, pore volume, and pore size distribution on the modified MWCNT.

Abstract: Pulverizing problem, low mechanical strength and poor wear resistance of desulfurization sorbent limit the further development and industrialization of hot coal gas desulfurization technology. The present paper highlighted on the recent progress of hot gas desulfurization researches and gave a fully detailed introduction on physical parameters that reflect the texture of desulfurizer: specific surface area, pore volume, pore size and its distribution, porosity, fractal dimension and so on. Different from the traditional physical parameters, fractal dimension, as a comprehensive physical parameter describing a fractal structure, reflects the regularity degree of a porous structure. With the increase of sorbent fractal dimension, the complexity of pore spatial geometrical features increases, and the porosity and average diameter for pore decrease. The specific surface area also increased consequentially with the increase of micro-pore. Besides, this paper also investigated the proper texture of desulfurization sorbent that is favorable for desulfurization process on the basis of desulfurization mechanism for fuel gas.

Abstract: High Pressure Grinding Roll (HPGR) is a modern and energy-efficient surface area and pore volume of HPGR and jaw crusher comminuted products. The results indicate that HPGR products have lower work index, higher specific surface area and pore volume than its counterpart. Therefore HPGR is capable of lowering the energy consumption on plants, as well as improving the utilization of bauxite. In total, the HPGR is a better crushing solution than jaw crusher, at least in the perspective of energy efficiency.

Abstract: Three commercial resins (NDA150, NDA88 and NDA77) with different physicochemical properties were selected to investigate the adsorption behavior and primary factors controlling the adsorption of oxytetracycline (OTC) onto the resins. The adsorption kinetics of OTC onto all resins were fitted well to pseudo-second-order model. NDA150 had the largest adsorption capacity due to its higher surface area and larger total pore volume. Moreover, all of the three resins exhibited nearly the same equilibrium time because of their nearly the same particle size. The suitable pH for the effective adsorption of NDA150 and NDA77 is from 4 to 7, while the ideal pH for NDA88 is 10. OTC adsorption on all of the three resins increased with the increasing ionic concentration.

Abstract: Huadian oil shale and its spent char were selected to explore the adsorption properties of oil shale and oil shale char. A bench-scale adsorption system was established for capturing hydrogen sulfide in this test. What’s more, the nitrogen adsorption isotherms test was made in automatic and rapid specific surface-area-analyzer of American’s Gemini2380, which found the adsorption curve and desorption loop of the modified oil shale and oil shale char. Meanwhile, the experiment calculated and analyzed the specific surface area and pore size distribution of samples with BJH theory. The result shows that the adsorption capacity of oil shale char is greater than oil shale. The rougher the pore structure of the adsorbent samples the greater the pore volume, the larger the specific surface area, the better the adsorption effect of H2S.

Abstract: Activated carbon fibers were prepared from stabilized PAN-based fibers by chemical activation using hydroxides at different concentrations. The experimental data showed variations in specific surface area, microstructure, pore size distribution, and amounts of iodine adsorbed by the activated carbon fibers. Specific surface area of about 2244m2/g and iodine adsorption of 1202mg/g were obtained in the KOH 1.5M. However, the use of NaOH in the activation process rather than KOH and using the same time/ temperature profiles resulted in a carbon with a much lower surface area. KOH is a more developed pore structure than NaOH, which means that KOH is a better activation agent in producing ACF than NaOH.