Abstract: In this work, effects of catalysts (TiO2, and Nb2O5) were investigated on the hydrogen desorption of Mg(BH4)2. LiBH4 and MgCl2 with 2:1 molar ratio were mixed by using ball milling to prepare Mg(BH4)2. The desorption behaviors were measured by thermo-volumetric apparatus. The hydrogen desorption capacity of the mixed sample milled for 2 h was 4.78 wt% with a 2-step released. The first step occurred at 214 °C and the second step appeared at 374 °C. The addition of 16 wt% Nb2O5 decreased the desorption temperature in the second step about 66 °C and increased the hydrogen desorption capacity to 4.86 wt% hydrogen. The addition of TiO2 also improved the desorption temperature in the second step and the hydrogen desorption capacity. It decreased the desorption temperature about 71°C and showed a high amount of hydrogen, 5.27 wt%, released from the mixed sample. The hydrogen absorption after desorption of Mg(BH4)2 was also studied under 9.5 MPa and 350 °C for 12 h.
Abstract: This study was to investigate the performance of
hybrid solvents blended between primary, secondary, or tertiary
amines and piperazine (PZ) for CO2 removal from flue gas in terms
of CO2 absorption capacity and regeneration efficiency at 90 oC.
Alkanolamines used in this work were monoethanolamine (MEA),
diethanolamine (DEA), and triethanolamine (TEA). The CO2
absorption was experimentally examined under atmospheric pressure
and room temperature. The results show that MEA blend with PZ
provided the maximum CO2 absorption capacity of 0.50 mol
CO2/mol amine while TEA provided the minimum CO2 absorption
capacity of 0.30 mol CO2/mol amine. TEA was easier to regenerate
for both first cycle and second cycle with less loss of absorption
capacity. The regeneration efficiency of TEA was 95.09 and 92.89 %,
for the first and second generation cycles, respectively.
Abstract: Crystallization has been used for the separation of
chloronitrobenzene or CNBs, which are isomeric substances (o-, mand
p-CNB) and important intermediates in chemical productions. Effects of feed composition on the crystallization of m- and p-CNB was first studied. The results conform to the binary phase diagram of
m- and p-CNB. After that, effects of FAU zeolites (NaX, CaX, BaX, NaY and CaY) above the eutectic composition (63.5 and 65.0 wt% m-CNB in the feed) was also investigated. The results showed that
the FAU zeolites significantly affected the precipitates, the
composition of which was shifted from being rich in m-CNB to rich
in p-CNB. Effects of the number of FAU zeolites on the precipitate composition was then studied. The results revealed that the
precipitates from the lower number of the zeolites had higher p-CNB purity than those from the higher number of zeolite.
Abstract: To reduce the carbon dioxide emission into the
atmosphere, adsorption is believed to be one of the most attractive
methods for post-combustion treatment of flue gas. In this work,
activated carbon (AC) was modified by polyethylenimine (PEI) via
impregnation in order to enhance CO2 adsorption capacity. The
adsorbents were produced at 0.04, 0.16, 0.22, 0.25, and 0.28 wt%
PEI/AC. The adsorption was carried out at a temperature range from
30 °C to 75 °C and five different gas pressures up to 1 atm. TG-DTA,
FT-IR, UV-visible spectrometer, and BET were used to characterize
the adsorbents. Effects of PEI loading on the AC for the CO2
adsorption were investigated. Effectiveness of the adsorbents on the
CO2 adsorption including CO2 adsorption capacity and adsorption
temperature was also investigated. Adsorption capacities of CO2 were
enhanced with the increase in the amount of PEI from 0.04 to 0.22
wt% PEI before the capacities decreased onwards from0.25 wt% PEI
at 30 °C. The 0.22 wt% PEI/AC showed higher adsorption capacity
than the AC for adsorption at 50 °C to 75 °C.