Pulp and Paper Research Division

Dhaka, Bangladesh

Pulp and Paper Research Division

Dhaka, Bangladesh
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Sarwar Jahan M.,Pulp and Paper Research Division | Shamsuzzaman M.,Pulp and Paper Research Division | Rahman M.M.,Pulp and Paper Research Division | Iqbal Moeiz S.M.,Dhaka College | Ni Y.,University of New Brunswick
Industrial Crops and Products | Year: 2012

The effect of hot-water and alkaline pre-extraction of rice straw on soda-anthraquinone pulping was carried out. The pre-extraction with hot water at 150 °C for 1. h dissolved 34.7% biomass and the pre-extracted liquor comprised of 16.6% sugars, 6.7% lignin, 6.6% acetic acid and other unknown products. But the pre-extraction with 1% NaOH at 100 °C for 1. h dissolved 10.2% sugars, 5.1% lignin and 10% acetic acid from rice straw. Pre-extracted rice straw was cooked by soda-anthraquinone process with varying alkali charges. The pulp from pre-extracted rice straw was low in kappa number with reduced pulp yield. The drainage resistance (°SR) improved obviously on pre-extraction of rice straw. Pulp strength properties such as the tensile index and the burst index were found to be lower, but the tear index was higher both with hot-water and alkaline pre-extraction. After bleaching, the gaps of the overall pulp yield and strength properties between pre-extracted and non-extracted rice straw became narrower. The alkaline pre-extraction showed improved yield and properties compared with hot-water pre-extracted rice straw. © 2011 Elsevier B.V.

Li H.,University of New Brunswick | Saeed A.,University of New Brunswick | Jahan M.S.,University of New Brunswick | Jahan M.S.,Pulp and Paper Research Division | And 2 more authors.
Journal of Wood Chemistry and Technology | Year: 2010

A pre-hydrolysis step to remove hemicelluloses from mixed hardwood chips consisting of maple, aspen, and birch with a ratio of 7:2:1 has been carried out. The effects of parameters on the pre-hydrolysis such as time, temperature, acetic acid addition, and raw material species, were determined. Different sugars, acetic acid, and furfural formation in the pre-hydrolysis liquor were quantified. The results showed that the pre-hydrolysis is a dynamic process, in which the removal of hemicelluloses increased with time while the conversion of extracted hemicelluloses to monosaccharides due to acid hydrolysis increased and part of the xylose was converted to furfural. The maximum temperature was the most critical parameter for hemicelluloses extraction and conversion, and a temperature of 170°C was the optimum for hemicelluloses extraction with relatively low conversion of xylose to furfural. About 11% of the xylan (in both monomeric and oligomeric forms) was removed at 170°C. Due to the presence of a high amount of xylan, birch produced the highest amount of xylose, followed by maple, and then aspen.

Jahan M.S.,Pulp and Paper Research Division | Jahan M.S.,University of New Brunswick | Chowdhury N.,Pulp and Paper Research Division | Ni Y.,University of New Brunswick
Bioresource Technology | Year: 2010

The chemical compositions and fiber morphology of stem and branch samples from Trema orientalis at three different sites planted in Bangladesh were determined and their pulping, bleaching and the resulting pulp properties were investigated. A large difference between the stem and branch samples was observed. The stem samples have consistently higher α-cellulose and lower lignin content, and longer fibers than the branch samples in all sites. T. orientalis from the Dhaka and Rajbari region had higher α-cellulose content and longer fiber length, resulting in higher pulp yield and better papermaking properties. The T. orientalis pulp from Rajbari region also showed the best bleachability. © 2009 Elsevier Ltd.

Liu Z.,Tianjin University of Science and Technology | Liu Z.,University of New Brunswick | Fatehi P.,University of New Brunswick | Jahan M.S.,University of New Brunswick | And 2 more authors.
Bioresource Technology | Year: 2011

In this paper, we proposed a new modification for an ethanol-based pulping process, which would consist of the pre-hydrolysis (pre-extraction) of wood chips for removing hemicelluloses; the ethanol extraction of pre-hydrolyzed wood chips for removing lignin; and the post purification of cellulose, leading to the production of pure cellulose. We also experimentally evaluated the separation of hemicelluloses from the pre-hydrolysis liquor (PHL) obtained from a pulp mill. To remove lignin from the PHL, it was acidified to a pH of 2, which resulted in 47% lignin precipitation. The lignin separation from the acidified PHL was further improved via adding polyethylene oxide and poly aluminum chloride or adding ethyl acetate. To recover the hemicelluloses from the acidified PHL, ethanol was added to the acidified PHL with a volumetric ratio of 4 to 1. The isolated lignin and hemicelluloses were characterized by a Fourier transform infrared spectroscopy (FTIR) and a gas permeation chromatography (GPC). © 2010 Elsevier Ltd.

Jahan M.S.,Pulp and Paper Research Division | He Z.,University of New Brunswick
Appita Journal | Year: 2010

An alkali source is needed to control the final pH of D1 and D2 stages in a conventional elemental chlorine free (ECF) chemical pulp bleaching sequence. This study evaluated the use of precipitated calcium carbonate (PCC) as an alternative alkali to caustic soda (NaOH) in the CIO 2 brightening of a hardwood kraft pulp. The PCC-based process showed improved brightening performance over the conventional NaOH-based process due to its lower initial pH and flat overall pH profile in the system. The pulp viscosity was also better than that of the control pulp. The PCC-based process can save up to 0.2% CIO2 in achieving the same target brightness as the control. PCC was also evaluated as the alkaline source for the alkaline extraction stage and the results showed that the final pulp brightness decreased but the COD in the effluent also decreased. However, at a 20% PCC substitution in the alkaline extraction stage, with the combination of the PCC-based D 1 and D2 stages, a fully bleached pulp with higher final brightness, less brightness reversion and better viscosity than the control can be produced.

Jahan M.S.,University of New Brunswick | Jahan M.S.,Pulp and Paper Research Division | Saeed A.,University of New Brunswick | He Z.,University of New Brunswick | Ni Y.,University of New Brunswick
Cellulose | Year: 2011

Cellulose was extracted at a yield of 59.8% from jute fibres based on the formic acid/peroxyformic acid process at an atmospheric pressure. The amounts of dissolved lignin and hemicelluloses were determined in the spent liquor. The results showed that the spent liquor contained 10.6% total sugars and 10.9% lignin (based on jute). Microcrystalline cellulose (MCC) was further prepared from the jute cellulose based on the acid hydrolysis technique. A very high yield, 48-52.8% (based on the jute raw material) was obtained. The acid hydrolysate of cellulose contained 2.7% glucose and 0.2% xylose. The MCC samples obtained from two different conditions, one at a low acidity and the other at a high acidity, were characterized by means of Thermo Gravimetric Analysis, Fourier Transform Infrared, X-ray detraction, Scanning Electron Micrograph, and Transmission Electron Micrograph techniques. © 2010 Springer Science+Business Media B.V.

Ahsan L.,University of New Brunswick | Jahan M.S.,University of New Brunswick | Jahan M.S.,Pulp and Paper Research Division | Ni Y.,University of New Brunswick
Bioresource Technology | Year: 2014

This work investigated the feasibility of recovering and concentrating sugars and acetic acid (HAc) from prehydrolysis liquor (PHL) of the kraft-based dissolving pulp process prior to fermentation of hemicellulosic sugars, by the combination of activated carbon adsorption, nanofiltration (NF) and reverse osmosis (RO) processes. To reduce the fouling PHL was subjected to adsorption on activated carbon, then the treated PHL (TPHL) passed through a nanofiltration (NF DK) membrane to retain the sugars, and the permeate of acetic acid rich solution was passed through a reverse osmosis membrane (RO SG). It was found that for NF process sugars were concentrated from 48 to 227. g/L at a volume reduction factor (VRF) of 5 while 80 to 90% of acetic acid was permeated. For the reverse osmosis process, 68% of acetic acid retention was achieved at pH 4.3 and 500 psi pressure and the HAc concentration increased from 10 to 50. g/L. © 2013.

Yang G.,Shandong Polytechnic University | Yang G.,University of New Brunswick | Jahan M.S.,University of New Brunswick | Jahan M.S.,Pulp and Paper Research Division | And 3 more authors.
Bioresource Technology | Year: 2013

Acetic acid was one of the main compositions of the pre-hydrolysis liquor (PHL), which was recovered by reactive extraction with triisooctylamine (TIOA) diluted with decanol. Dilution of TIOA played an important role in extracting acetic acid from the PHL. The recovery of acetic acid from the PHL by TIOA was increased from 10.34% to 66.60% with the dilution of TIOA to 20% by decanol at the HAc to TIOA molar ratio of 1, consequently, the equilibrium distribution coefficient K D increased. The effects of time, temperature and pH on the extraction process were also studied. The extraction process was very fast. The acetic acid extraction decreased from 65.13% to 57.34% with the rise of temperature to 50°C from 20°C. A higher pH increased the dissociation of acetic acid, as a result, decreased acetic acid extraction. The hemicelluloses in the PHL were unaffected on the extraction process of acetic acid. © 2013 Elsevier Ltd.

Liu H.,Tianjin University of Science and Technology | Liu H.,University of New Brunswick | Hu H.,Tianjin University of Science and Technology | Jahan M.S.,University of New Brunswick | And 3 more authors.
Bioresource Technology | Year: 2013

This study aimed to produce furfural from the PHL. Results showed best furfural yield of 32.8% and the furfural selectivity of 37.7% in the monophase system (170. °C, 100. min), while they were 60.1% and 69.8%, respectively in the biphase system. The lower furfural selectivity in the monophase system was explained by more side reactions, such as fragmentation, condensation reactions, resinification and others. Model compounds such as: xylose, furfural, syringaldehyde, were used to confirm/identify these side reactions. The addition of dilute sulfuric acid/acetic acid in the system under the same conditions decreased the recovery of furfural. The addition of syringaldehyde into the PHL also led to a decrease in the furfural yield, supporting the conclusion that lignin structures in the PHL may also be involved in the side reactions, thus decreasing the furfural yield. © 2012 Elsevier Ltd.

Jahan M.S.,Pulp and Paper Research Division | Rahman M.M.,Pulp and Paper Research Division
Carbohydrate Polymers | Year: 2012

The limited reserves of fossil fuel and trend of global warming increase interest in renewable resources. In this circumstance, significance has been developed on the production of fuels and chemicals from biomass that will replace fossil fuel. Corn stalks and Saccharum spontaneum (kash) are agricultural wastes, which are good raw materials for pulp production. However, there are limitations in achieving the desired pulp quality due to the presence of pith. The pith constitutes 20-35% of the dry matter of the raw materials. It must be removed prior to pulping to obtain good quality pulp. Chemically pith is similar to lignocellulosic, but it does not have fibrous structure. So the pith can be used in producing fuels and chemicals. Pre-hydrolysis prior to soda-AQ pulping of corn stalks and kash was carried out in order to remove pith as well as to extract hemicelluloses for use as fuel and chemicals. The pre-hydrolysis was performed at 150°C for 1 h. Pre-hydrolysis extracted 50-60 kg sugars, 28-34 kg lignin and 8-22 kg acetic acid per tonne of corn stalks/kash with the sacrifice of pulp yield. Pre-hydrolysed pulp had less fines resulting in lower drainage resistance ( 0SR) as compared to non-prehydrolysed counterpart. Pulp produced from the pre-hydrolysed corn stalks and kash had higher tear index but lower tensile index than the non-prehydrolysed counterpart. The pre-hydrolysis process requires careful optimization of the pulping process, and allows lower chemical charges. After D 0E pD 1 bleaching, the differences of pulp yield and physical properties were reduced. The pre-hydrolysed pulp showed almost similar bleachability to non pre-hydrolysed pulp. © 2012 Elsevier Ltd. All rights reserved.

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