Abstract: The conversion of lignocellulosic waste materials, such as sugar cane bagasse, to biofuels such as ethanol has attracted significant interest as a potential element for transforming transport fuel supplies to totally renewable sources. However, the refractory nature of the cellulosic structure of lignocellulosic materials has impeded progress on developing an economic process, whereby the cellulose component may be effectively broken down to glucose monosaccharides and then purified to allow downstream fermentation. Ionic liquid (IL) treatment of lignocellulosic biomass has been shown to disrupt the crystalline structure of cellulose thus potentially enabling the cellulose to be more readily hydrolysed to monosaccharides. Furthermore, conventional hydrolysis of lignocellulosic materials yields byproducts that are inhibitors for efficient fermentation of the monosaccharides. However, selective extraction of monosaccharides from an aqueous/IL phase into an organic phase utilizing a combination of boronic acids and quaternary amines has shown promise as a purification process. Hydrolysis of sugar cane bagasse immersed in an aqueous solution with IL (1-ethyl-3-methylimidazolium acetate) was conducted at different pH and temperature below 100 ºC. It was found that the use of a high concentration of hydrochloric acid to acidify the solution inhibited the hydrolysis of bagasse. At high pH (i.e. basic conditions), using sodium hydroxide, catalyst yields were reduced for total reducing sugars (TRS) due to the rapid degradation of the sugars formed. For purification trials, a supported liquid membrane (SLM) apparatus was constructed, whereby a synthetic solution containing xylose and glucose in an aqueous IL phase was transported across a membrane impregnated with phenyl boronic acid/Aliquat 336 to an aqueous phase. The transport rate of xylose was generally higher than that of glucose indicating that a SLM scheme may not only be useful for purifying sugars from undesirable toxic compounds, but also for fractionating sugars to improve fermentation efficiency.
Abstract: Lactulose is a synthetic disaccharide which has remarkable applications in food and pharmaceutical fields. Lactulose is not found in nature and it is produced by isomerization reaction of lactose in an alkaline environment. It should be noted that this reaction has a very low yield since significant amount of lactose stays un-reacted in the system. Basically, purification of lactulose is difficult and costly. Previous studies have revealed that solubility of lactose and lactulose are significantly different in ethanol. Considering the fact that solubility is also affected by temperature itself, we investigated the effect of ethanol and temperature on separation process of lactose from the syrup containing lactose and lactulose. For this purpose, a saturated solution containing lactulose and lactose was made at three different temperatures; 25⁰C (room temperature), 31⁰C, and 37⁰C first. Five samples containing 2g saturated solution was taken and then 2g, 3g, 4g, 5g, and 6g ethanol separately was added to the sampling tubes. Sampling tubes were kept at respective temperatures afterward. The concentration of lactose and lactulose after separation process measured and analyzed by High Performance Liquid Chromatography (HPLC). Results showed that ethanol has such a greater impact than operating temperature on purification process. Also, it was observed that the maximum rate of separation occurred at initial amount of added ethanol.
Abstract: The practical application of the Fenton-based treatment method for organic compounds-contaminated water purification is limited mainly because of the large amount of ferric sludge formed during the treatment, where ferrous iron (Fe(II)) is used as the activator of the hydrogen peroxide oxidation processes. Reuse of ferric sludge collected from clarifiers to substitute Fe(II) salts allows reducing the total cost of Fenton-type treatment technologies and minimizing the accumulation of hazardous ferric waste. Dissolution of ferric iron (Fe(III)) from the sludge to liquid phase at acidic pH and autocatalytic transformation of Fe(III) to Fe(II) by phenolic compounds (tannic acid, lignin, phenol, catechol, pyrogallol and hydroquinone) added or present as water/wastewater constituents were found to be essentially involved in the Fenton-based oxidation mechanism. Observed enhanced formation of highly reactive species, hydroxyl radicals, resulted in a substantial organic contaminant degradation increase. Sludge reuse at acidic pH and in the presence of ferric iron reductants is a novel strategy in the Fenton-based treatment application for organic compounds-contaminated water purification.
Abstract: As a by-product of the biodiesel industries, glycerol
has been vastly generated which surpasses the market demand. It is
imperative to develop an efficient glycerol valorization processes in
minimizing the net energy requirement and intensifying the biodiesel
production. In this study, base-catalyzed transesterification of
glycerol with dimethyl carbonate using microwave irradiation as
heating method to produce glycerol carbonate was conducted by
varying grades of glycerol, i.e. 70%, 86% and 99% purity, that is
obtained from biodiesel plant. Metal oxide catalysts were used with
varying operating parameters including reaction time, DMC/glycerol
molar ratio, catalyst weight %, temperature and stirring speed. From
the study on the effect of different operating parameters it was found
that the type of catalyst used has the most significant effect on the
transesterification reaction. Amidst the metal oxide catalysts
examined, CaO gave the best performance. This study indicates the
feasibility of producing glycerol carbonate using different grade of
glycerol in both conventional thermal activation and microwave
irradiation with CaO as catalyst. Microwave assisted
transesterification (MAT) of glycerol into glycerol carbonate has
demonstrated itself as an energy efficient route by achieving 94.2%
yield of GC at 65°C, 5 minutes reaction time, 1 wt% CaO and
DMC/glycerol molar ratio of 2. The advantages of MAT
transesterification route has made the direct utilization of bioglycerol
from biodiesel production without the need of purification. This has
marked a more economical and less-energy intensive glycerol
carbonate synthesis route.
Abstract: There are many difficulties in the purification of raw components and products. However, researchers are seeking better ways for purification. One of the recent methods is extraction using supercritical fluids. In this study, the phase equilibria of benzoic acid -supercritical carbon dioxide system were investigated. Regarding the phase equilibria of this system, the modeling of solid-supercritical fluid behavior was performed using the Perturbed-Chain Statistical Association Fluid Theory (PC-SAFT) and Peng-Robinson equations of state (PR EoS). For this purpose, five PC-SAFT EoS parameters for pure benzoic acid were obtained using its experimental vapor pressure. Benzoic acid has association sites and the behavior of the benzoic acid-supercritical fluid system was well predicted using both equations of state, while the binary interaction parameter values for PR EoS were negative. Genetic algorithm, which is one of the most accurate global optimization algorithms, was also used to optimize the pure benzoic acid parameters and the binary interaction parameters. The AAD% value for the PC-SAFT EoS, were 0.22 for the carbon dioxide-benzoic acid system.
Abstract: The production of Dimethyl acetal, Isovaleradehyde and Pyridine were simulated using Aspen Plus simulation. Upgrading cleaning water from wine industrial production is the main objective of the project. The winery waste composes of Acetaldehyde, Methanol, Ethyl Acetate, 1-propanol, water, iso-amyl alcohol and iso-butyl alcohol. The project is separated into three parts; separation, reaction, and purification. Various processes were considered to maximize the profit along with obtaining high purity and recovery of each component with optimum heat duty. The results show a significant value of the product with purity more than 75% and recovery over 98%.
Abstract: We explore entanglement in composite quantum systems
and how its peculiar properties are exploited in quantum
information and communication protocols by means of Diagrams
of States, a novel method to graphically represent and analyze how
quantum information is elaborated during computations performed
by quantum circuits.
We present quantum diagrams of states for Bell states generation,
measurements and projections, for dense coding and quantum teleportation,
for probabilistic quantum machines designed to perform
approximate quantum cloning and universal NOT and, finally, for
quantum privacy amplification based on entanglement purification.
Diagrams of states prove to be a useful approach to analyze quantum
computations, by offering an intuitive graphic representation of the
processing of quantum information. They also help in conceiving
novel quantum computations, from describing the desired information
processing to deriving the final implementation by quantum gate
arrays.
Abstract: The implementation of Super-Ultra Low Emission
Vehicle standards requires more efficient exhaust gas purification. To
increase the efficiency of exhaust gas purification, an the adsorbent
capable of holding hydrocarbons up to 250-300 ОС should be
developed. The possibility to design such adsorbents by modification
of zeolites of mordenite type, ZSM-5 and NaY, using different
metals cations has been studied.
It has been shown that introducing Cr, Cs, Zn, Ni, Co, Li, Mn in
zeolites results in modification of the toluene TPD and toluene
sorption capacity.
5%LiZSM-5 zeolite exhibits the most attractive TPD curve, with
toluene desorption temperature ranging from 250 to 350ОС. The
sorption capacity of 5%Li-ZSM-5 is 0.4 mmol/g. NaY zeolite has the
highest sorption capacity, up to 2 mmol/g, and holds toluene up to
350ОС, but at 120ОС toluene desorption starts, which is not desirable,
since the adsorbent of cold start hydrocarbons should retain them
until 250-300ОС. Therefore 5%LiZSM-5 zeolite was found to be the
most promising to control the cold-start hydrocarbon emissions
among the samples studied.
Abstract: Resins are used in nuclear power plants for water
ultrapurification. Two approaches are considered in this work:
column experiments and simulations. A software called OPTIPUR
was developed, tested and used. The approach simulates the onedimensional
reactive transport in porous medium with convectivedispersive
transport between particles and diffusive transport within
the boundary layer around the particles. The transfer limitation in the
boundary layer is characterized by the mass transfer coefficient
(MTC). The influences on MTC were measured experimentally. The
variation of the inlet concentration does not influence the MTC; on
the contrary of the Darcy velocity which influences. This is consistent
with results obtained using the correlation of Dwivedi&Upadhyay.
With the MTC, knowing the number of exchange site and the relative
affinity, OPTIPUR can simulate the column outlet concentration
versus time. Then, the duration of use of resins can be predicted in
conditions of a binary exchange.