Masoumeh Mollaei; Mazaher Moeinaddini; Nematollah Khorasani; Mohammad Azadfallah; Amirhooman Hemmasi
Abstract
Sulfide ions (S-2 ) derived from Na2S remaining in black liqueur are the source of H2S gas production along the black liquor recovery cycle in the Kraft pulp and paper industry. In this study, we tried to prevent the production of H2S by removing the mentioned ions from black liquor by using of synthesized ...
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Sulfide ions (S-2 ) derived from Na2S remaining in black liqueur are the source of H2S gas production along the black liquor recovery cycle in the Kraft pulp and paper industry. In this study, we tried to prevent the production of H2S by removing the mentioned ions from black liquor by using of synthesized adsorbents (Cu-PAC and Cu-BWP100). The adsorbents were produced by immersing powdered activated carbon (PAC) and beech powder with 100 mesh (BWP100) in 0.1 M solution of CuCl2. The adsorbent properties were obtained before and after copper ion loading by FTIR, BET and SEM-FEI analyses. Finally, the performance of these adsorbents in the removal of S-2 from black liquor with three levels of sulfide (22%, 20, 18) was investigated. The results of FTIR, BET and SEM-FEI analysis showed that Cu+ 2 was located on the surfaces of raw organic material without any change in the structure of them. Experimental data for the Cu-PAC adsorbent showed that it was more agreement with the Freundlich equation and more follow to the pseudo-second-order kinetic model, whereas for Cu-BWP100 adsorbent it was the more consistent with the Langmuir equation and adherence to the pseudo-first-order kinetic model. The Cu-PAC adsorbent has the ability to remove 79.93% and Cu-BWP100 60.03% of S-2 from black liquor. The Cu-PAC, with its higher specific surface area, has a higher ability to remove S-2 from the black liquor than the Cu-BWP100. In general, the mentioned adsorbents will have a high ability to reduce H2S production by eliminating S-2.
Zahra Gholami; Mohammad Azadfallah; soheila izadyar; Mehdi Roohani
Abstract
In this research, deinked pulp (DIP) was modified with carboxymethyl cellulose (CMC) in order to introduce more charged groups on the surfaces of fibers which leads to improve strength properties. Modification of the pulp was conducted at mild reaction temperature conditions of 85, 95°C and 120°C ...
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In this research, deinked pulp (DIP) was modified with carboxymethyl cellulose (CMC) in order to introduce more charged groups on the surfaces of fibers which leads to improve strength properties. Modification of the pulp was conducted at mild reaction temperature conditions of 85, 95°C and 120°C at 60 and 90 minutes, and under sever conditions of 120°C for 120 minutes in the presence of calcium chloride as electrolyte. The drainage time, water retention value (WRV), tensile strength, burst strength, brightness and opacity of CMC-modified pulps were measured and compared with corresponding values of blank (untreated) pulp and CMC-treated pulps as conventional treatment. The results indicated that tensile strength and burst strength of CMC-modified pulps were improved in comparison with unmodified pulps. The behavior of pulps was different in terms of optimum reaction condition. However, no significant changes were observed for optical properties of CMC-modified pulps. Water retention value of CMC-modified pulps decreased unexpectedly in some conditions.
Management and Economics wood
Seyed Mahmoud Miri Tari; asghar tarmian; Mohammad Azadfallah; Abdolkhani Ali; Davood Efhamisisi
Abstract
DOR:98.1000/1735-0913.1398.34.45.66.1.1575.1575 Mold growth resistance of Polyurethane and Diotrol coatings containing natural (Thyme essential oil) and synthetic (IPBC) fungicides in both free and microencapsulated forms was studied. Polymethyl methacrylate (PMMA) microcapsules were prepared using solvent ...
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DOR:98.1000/1735-0913.1398.34.45.66.1.1575.1575 Mold growth resistance of Polyurethane and Diotrol coatings containing natural (Thyme essential oil) and synthetic (IPBC) fungicides in both free and microencapsulated forms was studied. Polymethyl methacrylate (PMMA) microcapsules were prepared using solvent evaporation method by means of oil emulsion formation in water. Mold growth resistance against Aspergillus niger was determined by Filter Paper Disc method before and after aging process according to ASTM D 5590 Standard. Adhesion strength and surface roughness of coated samples were also measured. Results revealed that biocide-free coatings cannot provide adequate protection against mold growth, and addition of biocides, especially IPBC, significantly improved the mold growth resistance. Even after the aging process, microencapsulated biocides were able to provide better protection against mold growth due to controlled-release mechanism and shielding-effect of polymeric shell. Although the surface roughness of polyurethane coating was increased by using of biocides in both forms, especially microencapsulated ones, its adhesion strength reduced.
Pulp and paper
Ali Ahmadi ladjimi; Mohammad Azadfallah; Mehdi Rahmaninia; Yahya Hamzeh
Abstract
Stickies is among the major challenges in paper recycling mills. This substance deposits on paper machine components and cause to break paper web as well as loss of end product quality. So, it is necessary to control the stickies and lessen its detrimental effects. It is known that cationic polymers ...
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Stickies is among the major challenges in paper recycling mills. This substance deposits on paper machine components and cause to break paper web as well as loss of end product quality. So, it is necessary to control the stickies and lessen its detrimental effects. It is known that cationic polymers as fixing agents can control the stickies efficiently. Therefore, the control of stickies of OCC pulp using a commercial cationic polymer called GL at 0.4, 0.8 and 1.2 percent based on oven dry weight of pulp at pH 4 and pH 5 were investigated. Macro- and microstickies, dissolved and colloid substances (DCS), turbidity, and drainage time were measured to evaluate GL efficiency and compared with control sample. The results indicated that GL dosing at 0.4 and 0.8 percent in pH 4 and 7 due to flocculation and fixing the stickies onto the fiber caused to decrease in macro stickies, microstickies and DCS while improved the drainage time. Although, no efficient performance was observed in controlling stickies at higher content of GL i.e. 1.2 percent. Generally, it is concluded that with consuming at desired pH and dosage content, GL can be used as efficient agent to control stickies in processing of OCC pulp.
Chemical conversion
Mahmoud Rouhbakhsh Bidaei; Mohammad Azadfallah; Rasoul Yarahmadi
Abstract
Dyes release into waste water due to its toxicity for some organisms results in major environmental pollution problems. The activated carbon (AC) is an efficient adsorbent to remove this kind of pollutants from aqueous phase. Hence, in this research activated carbon was prepared from sound and rotted ...
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Dyes release into waste water due to its toxicity for some organisms results in major environmental pollution problems. The activated carbon (AC) is an efficient adsorbent to remove this kind of pollutants from aqueous phase. Hence, in this research activated carbon was prepared from sound and rotted beech wood by chemical activation method and its adsorption capacity for removal of Rhodamine B was assessed. The carbonization and activation steps were performed at single stage with impregnating the substrate by zinc chloride as activating agent and with the ratio of 75, 100 and 125 percent to raw material mass at 400 and 500 ºC. The results showed that with increasing the impregnating agent content, the iodine number of ACs from both woods enhanced. The yield of AC from sound wood decreased with increasing impregnating agent while it was not predictable for AC resulted from rotted wood. Scanning electron microscopic (SEM) studies revealed much morphological changes in the surface of rotted wood-AC in comparison with sound wood -AC after treatment with activating agent. Also, raising the activating temperature from 400 to 500 ºC caused to enhance the iodine number. All prepared ACs performed much efficient in removal of Rhodamine B from aqueous solution. The maximum adsorption of the dye was obtained for ACs prepared under impregnating ratio of 125 and activating temperature of 500 ºC.
Pulp and paper
Alireza Sukhtesaraie; Mohammad Azadfallah; Saeed Bastani
Abstract
Flexographic printing is the most usable technology in the packaging industry. But the lack of proper adhesion of water-based ink on cardboard coated with polyethylene is one of the most important problems. Silane adhesion promoters are considered among the best compounds used as the crosslinking and ...
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Flexographic printing is the most usable technology in the packaging industry. But the lack of proper adhesion of water-based ink on cardboard coated with polyethylene is one of the most important problems. Silane adhesion promoters are considered among the best compounds used as the crosslinking and waterproofing agents in coating and ink industries. In this study, N-(2-Aminoethyl) (3-aminopropyl) methyldimethoxysilane and 2-(3, 4-Epoxycyclohexyl) ethyltriethoxysilane were used to improve the adhesion of water-based ink on paper boarded-coated with polyethylene. Results showed that highest amount of adhesion were achieved by adding 5% of N-(2-Aminoethyl) (3-aminopropyl) methyldimethoxysilane to ink. Adding silane compounds to ink formulation increased the contact angle of the ink film on the surface of cardboard coated with polyethylene which means that inks containing silane compounds act more successful in the formation of hydrophobic surface. It is worth noting that surface tension was decreased by addition of silane components to the formulation of the ink.
Pulp and paper
Bagher Ashrafi Rad; Mohammad Azadfallah; Fatemeh Kolaei Moakhar; Soheila Izadyar; Mehdi Rahmaninia
Abstract
Utilization of paper as packaging material and developing applied technological program on paper-based substrate are drastically dependent to control of cellulosic fiber hydrophilicity and to enhancement of its hydrophobic properties. Then this work carried out with the aim of developing hydrophobic ...
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Utilization of paper as packaging material and developing applied technological program on paper-based substrate are drastically dependent to control of cellulosic fiber hydrophilicity and to enhancement of its hydrophobic properties. Then this work carried out with the aim of developing hydrophobic surface on cellulosic fiber with layer by layer (LBL) method while keeping and enhancing the properties of paper network. The deposition was implemented by titanium dioxide nanoparticles and poly acrylic acid as cationic and anionic layer respectively on the fibers of unbleached hardwood Kraft pulp and using Zycosil and fluoroalkyl silane on the last layer. The hand-sheets were then made by this modified fiber. The contact angle and roughness were measured to evaluate the effect of layers on hydrophobicity. The results indicated that roughness increased with the number of layers. The instant contact angle was also increased with the number of layers and reached approximately to 110 degree at 7th layer. The dynamic contact angles dropped more lately with increasing the number of layers. The fluorosilane deposition as 8th layer in comparison with Zycosil showed more effect on surface energy reduction. The instant contact angle of Zycosil treated paper was measured 125 degree which dropped significantly to 48 degree after 30 seconds. However, fluorosilane modified paper exhibited contact angle of 140 degree at the same time. In addition, the presence of titanium dioxide nanoparticles on the surface of fiber was demonstrated by scanning electron microscopy (SEM) of paper surface.
Pulp and paper
Mohammad Azadfallah; Hamid Khodabandehlo; Amirabas Shaygani Akmal
Abstract
The oil-impregnated dielectric papers are the main components of distribution transformer which govern its service time. Therefore, durability enhancement of this grade of paper will cause to extend transformers life. Hence in this research long fiber unbleached Kraft pulp and mixture of it with bagasse ...
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The oil-impregnated dielectric papers are the main components of distribution transformer which govern its service time. Therefore, durability enhancement of this grade of paper will cause to extend transformers life. Hence in this research long fiber unbleached Kraft pulp and mixture of it with bagasse soda pulp with the ratio of 20% to 80% were used to make oil-impregnated dielectric papers with the grammage of 60 g/m2. The effect of dicyandiamide application with different content in paper structure and thermal aging were then assessed on dielectric properties and tensile strength of the insulation papers. The results showed that with increasing dicyandiamide content, the capacitance and tensile strength index decreased in comparison with untreated samples, but dielectric loss, insulation resistance, and breakdown voltage were improved. However, slight changes were observed in most dielectric properties during aging, but dicyandiamide caused to prevent loss of the tensile strength of insulated papers. Generally it could be concluded that dicyandiamide acts efficiently in thermal stabilization of insulation paper exposed to aggressive conditions inside the oil-filled transformer.
Pulp and paper
Mohammad Azadfallah; Hamid khodabandehlo; Amir abas Shayeghani akmal
Abstract
The properties of transformer electrical insulating papers are influenced by fiber chemical modification process. In this research, the effect of cyanoethylation of fibers and addition of cyanoethylated cellulose nanofiber (CNF) on dielectric properties including capacitance, dielectric ...
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The properties of transformer electrical insulating papers are influenced by fiber chemical modification process. In this research, the effect of cyanoethylation of fibers and addition of cyanoethylated cellulose nanofiber (CNF) on dielectric properties including capacitance, dielectric loss, insulation resistance, breakdown voltage as well as tensile strength of two grade of handsheets made of unbleached long fibers and its mixture with bagasse soda pulp (with the ratio of 1:1) were evaluated after impregnating with mineral oil. Cyanoethylation of CNF and pulp fibers was performed by grafting of acrylonitrile under alkaline condition at 40 ̊C and room temperature respectively. Then, the nitrogen content of cyanoethylated samples was determined using Kjeldahl method and degree of substitution (DS) was calculated. The results showed that cyanoethylation of pulp fibers and CNF decreased the capacitance and tensile strength of insulated papers. It was also observed that the chemical modification imposed slight effect on dielectric loss, but insulation resistance and dielectric voltage were increased.
Pulp and paper
masoumeh mollaei; Mohammad Azadfallah; Yahya Hamzeh; faramarz khodaian chegini
Abstract
The Effect of Chitosan - Poly (vinyl alcohol) Coatings on Strength and Barrier Properties of Packaging PaperAbstract In this research the mechanical and barrier properties of hand-sheets made of virgin and recycled fibers were studied after coating by chitosan and poly (vinyl alcohol) polymer blends. ...
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The Effect of Chitosan - Poly (vinyl alcohol) Coatings on Strength and Barrier Properties of Packaging PaperAbstract In this research the mechanical and barrier properties of hand-sheets made of virgin and recycled fibers were studied after coating by chitosan and poly (vinyl alcohol) polymer blends. Therefore to evaluate coatings effects on barrier properties, water vapor transmission rate (WVTR), water absorbance, air resistance and grease proof of coated papers were determined. Moreover, mechanical strength including tensile strength and burst strength were measured. According to the results, the barrier properties and mechanical strength of coated papers improved dramatically than uncoated ones. The best results in WVTR and mechanical strength tests were obtained for coatings with the same ratio of polymers. On the other hand, coating with 75%chitosan - 25% poly (vinyl alcohol) composition exhibited excellent resistance against the grease penetration and water absorption.Keywords: Coating, chitosan, poly (vinyl alcohol), barrier properties, mechanical strength
Pulp and paper
farzaneh shiralizadeh; mohammad azadfallah; ali Abdolkhani; mohammad Layeghi; saeed mahdavi
Abstract
This study was conducted with the aim of producing laboratory samples of transparent paper using overbeating method. Hence, bagasse bleached soda pulp was subjected to post-bleaching sequence of DED to remove residual chromophores. Then this pulp was refined in a PFI mill to reach different ...
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This study was conducted with the aim of producing laboratory samples of transparent paper using overbeating method. Hence, bagasse bleached soda pulp was subjected to post-bleaching sequence of DED to remove residual chromophores. Then this pulp was refined in a PFI mill to reach different levels of 55, 130, 200, and 260 mL,CSF (Canadian standard freeness) freeness. Then handsheets were made according to TAPPI standard T 205 om– 8. Results indicated that refining has significant effect on optical properties especially transparency so that the maximum value was observed using pulp with the minimum freeness, i.e. 55 ml. The variations of transparency due to refining were also further explained by measuring scattering coefficient, opacity and brightness of the specimens. In addition, mercury porosimetry and analyzing the pictures of scanning electron microscopy (SEM) demonstrated the extensive variations of pore structure in paper during refining which impose great influence on developing transparency.
kezhal Moradyan Gilan; Mohammad Azad fallah; Amir abbas Shayghani akmal; Ali Abdolkhani
Abstract
This research was carried out with the aim of determining dielectric properties of bagasse unbleached soda pulp, long fiber kraft pulp and a mixture of both (20% kraft + 80% bagasse soda).The hand-sheets with 60 g/m2 basis weight were made after adjusting the freeness of pulps at levels of 200 ± ...
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This research was carried out with the aim of determining dielectric properties of bagasse unbleached soda pulp, long fiber kraft pulp and a mixture of both (20% kraft + 80% bagasse soda).The hand-sheets with 60 g/m2 basis weight were made after adjusting the freeness of pulps at levels of 200 ± 25 ml and 400± 25 ml and dried under mild condition around zero moisture content. Then the impregnation processes were carried out with mineral oil under vacuum at certain temperature. Finally the dielectric properties of impregnated papers including capacitance, insulation resistance, dielectric constant, and loss tangent were measured. The results showed that the refining give rise to enhance the dielectric properties in particular capacitance value. The dielectric properties of oil impregnated paper also increased. According to the preliminary results, unbleached soda bagasse pulp and its mixture with kraft pulp (20% Kraft -80% bagasse soda) found to be the suitable alternative with respect of dielectric applications for replacing kraft pulp, providing successful performance of the aging test.
Pulp and paper
Amir hooman Hamasi; Mehdi Sabor; Mohammad Talaeipoor; Mohammad Azadfallah
Abstract
The aim of present study was to investigate the effects of xylanase enzyme obtained from Trichoderma viride on APMP pulp from Populus nigra wood. Treatment temperature, time, enzyme dosage and pulp consistency were varied. The results demonstrated that treating by xylanase has considerable effects on ...
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The aim of present study was to investigate the effects of xylanase enzyme obtained from Trichoderma viride on APMP pulp from Populus nigra wood. Treatment temperature, time, enzyme dosage and pulp consistency were varied. The results demonstrated that treating by xylanase has considerable effects on pulp. Paper brightness improved in average 2.5% ISO and the highest gain was 4.5%. Also, using enzyme resulted in enhancement of tear and burst indices. Breaking length of paper from enzyme treated pulp was increased to 4098 meters. Further treatment by xylanase reduced the pulp yield by 2.78% as compared to sample without enzyme treatment. The impact of other treatment such as washing by distilled water and alkaline extraction revealed that these treatments did not have significantly effect on the results of enzyme treatment. The optimum temperature, time, enzyme dosage and pulp consistency were 40-50° C, 70 minutes, 10 U/g of oven dried pulp and 10% respectively.
Composite wood products
Hamid Hatefnia; Ali akbar Enayati; Kazem Dost hosseini; Mohammad Azadfallah
Abstract
Poplar wood chips were treated by steaming in different conditions. The chemical composition changes of milled wood were studied. The obtained results indicate hemicelluloses degradation, reduction of acetyl groups and formation of organic acid during the treatment. It was also found that steam treatment ...
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Poplar wood chips were treated by steaming in different conditions. The chemical composition changes of milled wood were studied. The obtained results indicate hemicelluloses degradation, reduction of acetyl groups and formation of organic acid during the treatment. It was also found that steam treatment has led to degradation of low-molecular lignin units, decrease in cellulose amorphous regions, increase of acetone extractives and hot water solubility as well as one percent sodium hydroxide solubility. The FT-IR spectra indicated a structural change of aromatic polymers in the wood, cleavage of the acetyl group of hemicelluloses and formation of organic acid.
Pulp and paper
Mohammad Azadfallah; Arezo Noori
Abstract
Yellowing of lignin-rich mechanical pulp is mainly attributed to light-induced changes in lignin structure. Hence, in this study the photodegradation of milled wood lignin (MWL) prepared from hardwood bleached chemimechanical pulp (BCMP) was investigated. The lignin preparation was then impregnated on ...
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Yellowing of lignin-rich mechanical pulp is mainly attributed to light-induced changes in lignin structure. Hence, in this study the photodegradation of milled wood lignin (MWL) prepared from hardwood bleached chemimechanical pulp (BCMP) was investigated. The lignin preparation was then impregnated on Whatman filter paper and irradiated with UV light during 4 hour exposure time. Then, photodegraded lignin was recovered and characterized by 13C-NMR.Irradiation caused to β-O-4 bonds cleavage, increase in carboxylic and phenolic hydroxyl groups, decrease in methoxyl, primary and secondary hydroxyl group. The amount of β-β and β-5 condensation structures was increased during irradiation.
