Papers by Keyword: Absorption

Abstract: GO-PMMA solid was used to test its ability on absorbing the lead ion obtained from standard solution. Samples of the test solution were collected at 0 min, 10 min, 30 min, 50 min and 70 min. The results analyzed from ICP reveal that GO-PMMA solid could absorb lead (II) ion sup to 68.6%, which is 65.8% higher than the control setup, i.e. PMMA solid, at room temperature and pressure. The dry mass of GO-PMMA solid is around 119.82g and the mass after testing is around 124.21g. The ability of absorption could be easily refreshed by washing with ethanol and distillated water (80/20 v/v) several times. Structure of GO-PMMA solid was characterized by FRIR and optical microscope. The oxygen-containing functional groups and the rough surface of the GO-PMMA solid are determined to be the contributing factors of the adsorption of lead (II) ion onto GO-PMMA solid. The high removal efficiency of GO-PMMA suggests its adsorption capability on lead (II) ion and can be applied to remove lead (II) ions from water.

Abstract: Nowadays, the problems of climate change and global warming become more serious on environmental concern due to the higher amount of carbon dioxide in the atmosphere. Basically the main sources of carbon dioxide come from anthropogenic activities such as power generation, industries and so on. Currently, the effective technology to remove CO₂ from these sources is absorption especially chemical absorption. Also, the chemicals used are one of the key parameters for effective CO₂ removal. The widely used amine solutions are monoethanolamine (MEA) and diethanolamine (DEA). Nevertheless, they also have disadvantages such as low capacity, corrosion and high heat of regeneration thus making carbon capture technology more expensive. Therefore, many novel materials have been developed to improve the efficiency and compensate the disadvantages of some amines. Consequently, the objective of this work is to investigate the vapor-liquid equilibrium of CO₂ in novel materials of 2-(methylamino) ethanol or 2-MAE and 3-Amino-1-Propanol or 3-AP at the temperature from 40 °C to 80 °C and CO₂ partial pressures ranging from 5 to 100 kPa. The solubility results of CO₂ in novel materials are compared with those of aqueous solution of MEA and DEA. For cyclic capacity, the results present that novel materials provide higher performance than that of MEA with less cost. This means that novel materials can save more energy and cost for solution regeneration and making it more economically viable.

Abstract: The solution of poly [(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo [2,1,3] thiadiazol-4,8-diyl)] (F8BT) F8BT/TiO₂ nanocomposites were prepared using solution blending methods. The TiO₂ contents were fixed between 0 wt% - 35 wt%. Then, the solutions were spin coated at 1000 rpm for 30 s onto glass substrates to form thin film samples. The optical properties of the nanocomposites were determined using UV-Vis spectroscopy and photoluminescence spectroscopy. The absorption properties of the thin film increased due to existence of intermediate energy band which lead to higher space charge regions for electron insertion. Besides that, the λ_max for absorption and emission spectrum were systematically shifted due to incorporation of TiO₂ NPs indicating an interaction between nanoparticles and polymer matrix. Furthermore, the intensity of the emission spectrum were enhanced in the presence of TiO₂ NPs. This is due to the existence of TiO₂ NPs which trapped more electrons at the interface F8BT/TiO₂, resulted production of higher number of exciton formation in the nanocomposirte samples.

Abstract: Arsenical water pollution refers to the toxicity of arsenic. The form of trivalent arsenic has been seen as more toxic substances, which will be great improved by the manmade pollution. Compared with other technologies, adsorption is the main method of removal of arsenic pollution, for its higher efficiency and lower cost. Based on the adsorption theory and ion exchange method, the layered double hydroxides material containing ferric iron and manganese (Mn-Fe-LDH) was prepared to remove arsenic in this paper. We have designed some experiments for synthesis of this material. The reaction process and elemental compositions has been studied and the adsorption property of arsenic adsorption onto layered double hydroxides was verified through a series of experiments. Study shows that the Mn-Fe-LDH material can be used as a good adsorbent material for its high removal efficiency. The adsorption capacity of the Mn-Fe-LDH material is not affected by the interference of pH and Cl^-/SO₄^2- ion strength. It was a broad prospect for the development and application of arsenic removal materials.

Abstract: Researched the influence of the pore structure and water absorption on the carbonization property with sulphoaluminate foamed cement as an example. The results showed that: Under the same levels of dry density, the smaller pore size, the higher the carbonation coefficient and the integrity of pore had the same effect. After the surface water-proofing, water absorption decreased by 10% on average, the time of carbonizing completely become longer, and carbonation coefficient was increased. And put forward the methods of improving the carbonation resistance properties of sulphoaluminate cement foam materials.

Abstract: The oxygen absorption and diffusion properties are studied in γ-TiAl and TiAl₃ alloys within density functional theory using projector augmented wave method in the plane-wave basis. It is shown that the octahedral site inside the Ti-rich octahedron is preferable for oxygen in case of γ-TiAl alloy whereas the Al-rich octahedron is more favorable environment for oxygen in TiAl₃. It is shown that the energy barriers for oxygen jumps between different sites in bulk alloys depend significantly on the local environments of oxygen and increase for its jump from Ti-rich sites. The trajectories with minimum energy barriers are determined for both Ti-Al alloys. It is shown that the increase of Al content in alloy leads to the decrease of barriers for oxygen jumps.

Abstract: The paper studies the effect of technological parameters of the deposition process from the gas phase to the thickness of the carbon layers and their functional characteristics. Graphene and graphite layers have been synthesized by varying total pressure, methane partial pressure and temperature of synthesis. The synthesized films demonstrate an absorption in the range from 4.4% to 99.5% and electrical resistivity varying from 0.14 to 2 kΩ/sq. The obtained results make possible controllable synthesis of carbon films with specified characteristics for use as a photodetectors.

Abstract: The hydrogenation of TbNi_0.4Co_0.6 was studied by means of neutron diffraction and calorimetric method with use of the differential heat-conducting Tian-Calvet type calorimeter. It was determined that TbNi_0.4Co_0.6H_3.8 crystallized in orthorhombic CrB-type structure (S.G. Cmcm). The hydride formation is accompanied with strong lattice expansion. In the structure TbNi_0.4Co_0.6D_3.4 deuterium atoms occupy tetrahedral 8f-intersices, trigonal bipyramidal 4c-interstices and octahedral 4b-interstices. Dependence of the differential molar enthalpy of absorption (ΔH_abs) vs. the hydrogen concentration in the metallic matrix was obtained at 50°C. It was ascertained that in the range of 0<X<2.0 (X=H/ TbNi_0.4Co_0.6) ΔH_abs =-102.0±2.3 kJ mol^-1H_2. The value of the integral enthalpy of hydrogen absorption by TbNi_0.4Co_0.6 equals -99.5kJ mol^-1H₂ for the composition TbNi_0.4Co_0.6H_3.8.

Abstract: The spectra and kinetics of pulsed cathodoluminescence buildup and decay in LiF-TiO₂ and LiF-WO_3.crystals have been studied in the temperature range of 20–300 K. It is found that all the LiF crystals doped with metal oxides (Fe, Ti, W) have a similar structure of the luminescence centers – oxygen centers excited by impurities in Fe₂O₃, WO₃ and TiO₂ complexes. In all types of the crystals, the processes of energy transfer to luminescence centers are similar (buildup stage).

Abstract: In order to improve the stealth performance of antenna, a metamaterial absorber with high absorption, polarization-insensitive and wide angle based on the electromagnetic resonance is designed. Using of ultra-thin characteristic of absorber, they are attached to the microstrip antenna to reduce its radar cross section. The simulation results show that the new microstrip antenna’s radiation performance remains unchanged compared with conventional microstrip antenna and it has obvious RCS reduction in its working band. While the maximum reduction can reach 28dB at working frequency, and the in-band reduction of antenna is above 3dB. This indicates that the absorber can be used for antennas’ in-band stealth.