محمدهادی اریایی منفرد

In this research, the strengthening of wheat straw cold soda pulp produced in Iran using tomato stalk fibers prepared by soda-anthraquinone process was investigated. Length, diameter, cell cavity diameter, and fiber thickness; Runkle ratio, slenderness ratio and flexibility coefficient of tomato stalk fibers were measured. The chemical composition of tomato stalk including percentage of ash, lignin, cellulose and hemicelluloses were determined. Unbleached pulp was produced from tomato stalk in 180 minutes with optimal conditions of 170°C, 20% active alkali and 0.1% anthraquinone. The average yield percentage after screening and kappa number of tomato stalk pulp were measured as 43.09 % and 27.33, respectively. Hand sheets made from this pulp has the tensile index of 34.75 (Nm/g), tear index of 6.02 (mNm2/g) and burst index of 2.16 (kPam2/g), respectively. The combination of tomato stalk pulp with wheat straw cold soda pulp available in the market was done at three levels: 75:25, 50:50 and 25:75. The amount of tensile, tear and burst indices increased by 28, 63 and 36 % respectively after mixing. The most obvious effect of mixing in terms of mechanical properties is observed in the increase of tear index. The results show that the addition of unbleached soda-anthraquinone tomato stalk pulp as an unused agricultural waste to the unbleached wheat straw cold soda pulp can improve and increase the mechanical indices by reducing the weaknesses of the cold soda pulp and also leads to expanding the application and demand for this pulp.

One of the disadvantages of recycled fibers is the significant loss of mechanical strength of the paper due to the decrease in the bond between the fibers. So far, many types of research have reported the application of cellulose nanofibers in the production processes of paper products. The results of previous research show that the use of cellulose nanofibers strengthens paper products. However, the amount of this reinforcement is different according to the type of cellulose nanofibers used. Nano lignocellulosic fibers of paulownia fortune (Nano wood) consist of nanoscale fibers with the same chemical composition as wood, which is produced mechanically without the use of chemicals from lignocellulosic biomass at ambient temperature. This material is a brown gel, which has a completely environmentally friendly production process. The objective of this study was to investigate the effect of adding Paulownia nano-wood on the improvement of pulp from old corrugated containers (OCC).

The pulp was prepared from OCC collected and after refining and obtaining a flow rate of 380 ± 20 ml, different amounts of paulownias nano-wood (1, 2, and 3%) and cationic polyacrylamide (0.1, 0.2, and 0.3%) was added to it. Finally, standard hand sheet papers were made from these treatments, and their physical and mechanical properties were measured according to the TAPPI standards.

Using nano wood and cationic polyacrylamide simultaneously causes a significant increase in resistance properties. The results show that the simultaneous addition of cationic polyacrylamide-nano wood to the pulp obtained from old corrugated containers increases the resistance to air permeability and density due to the improvement of the content of the bond and also the reduction of the porosity of the paper structure. According to the results, the highest strength in the nano lignocellulosic fibers -cationic polyacrylamide system among different treatments was observed in samples containing 1 % of nano wood and 0.3 % of cationic polyacrylamide. The results of evaluating the physical properties of the papers showed that the density and air resistance of paper (Gurley method) increases with the addition of lignocellulosic nanofibers - cationic polyacrylamide in the paper. The results show that the simultaneous addition of lignocellulosic nanofibers - cationic polyacrylamide to the pulp obtained from Old corrugated container (OCC) increases the air resistance of paper and density due to the improvement of bonds and also the reduction of the porosity of the paper structure.

Due to its positive charge, cationic polyacrylamide improves the bonding between fibers and restores lost bonds, and also prevents the wastage of fine nano wood particles and thus improves the properties of the paper. The statistical analysis showed that 95 % confidence in accuracy between treatments in the mechanical strengths (burst, RCT, and tensile strengths) is different. Using optimum levels of nano lignocellulosic fibers improves these strengths. According to the results, the best’s amount of strength among different treatments in the lignocellulosic nanofibers-cationic polyacrylamide system is observed in samples containing 1% lignocellulosic nanofibers and 0.3% cationic polyacrylamide.

The reduction of forest wood resources has increased the necessity of using alternative primary resources including weedy non-wood plants, wood of fast-growing trees and agricultural residues in papermaking industries. On the other hand, most of the country's agricultural waste is consumed in animal husbandry industries, and wood farming also faces many challenges due to costs such as removing the roots after cutting the tree. Hence the need to use a weedy non-wood raw material seems essential. terjin (Saccharum ravennae) is one of the native weedy non-wood resources of the country, which has a good distribution in the country, and so far, its potential for use has not been evaluated. Therefore, the purpose of this research is to investigate the chemical and morphological characteristics of terjin, as well as the production and evaluation of refined and unrefined soda-anthraquinone pulp from it as a raw material to offer to papermaking industries.

In this research, terjin leaves were obtained from Gorgan region located in Golestan province. In order to measure the biometric characteristics of terjin, the samples were cut using the Franklin method, and then the dimensions of its fibers were measured using an optical microscope, and then their biometric coefficients were calculated. In order to measure the chemical properties of the fibers, the samples were first grinded and then their chemical properties, including the percentage of ash, extractives, lignin (klason) and cellulose were also measured based on the TAPPI standard. In order to prepare pulp from terjin, the samples were cooked at different levels of time (30 and 60 minutes) and chemical (alkalinity 14, 16 and 18%) under a temperature of 160 °C and 0.1% anthraquinone consumption, and then their yield, freeness and kappa number was measured. In the following, the pulps were refined to freeness of 350 ± 20 ml CSF, and then handsheet paper with a grammage of 60 g/m2 was prepared from refined and unrefined pulps, and their physical, optical and resistance characteristics were measured by TAPPI standards. Finally, the results were evaluated and analyzed using one-way analysis of variance and Duncan's test in SPSS software environment.

The results showed that the length, diameter, lumen diameter and wall thickness of the fibers were 1.85 mm, 10.82 µm, 5.32 µm and 2.75 µm, respectively; and biometric coefficients including Slenderness ratio, Flexibility coefficient and Runkel ratio were 171.14, 49.12 and 103.60 respectively. Its chemical composition included percentage of ash, extractive, lignin and cellulose were 5.75, 2.53, 26.73 and 44.63 respectively. The results of pulping showed that with the increase of alkalinity percentage and cooking time, yield, kappa number and freeness of pulp decreased. Also, the results showed that refining and increasing the alkalinity percentage and cooking time increase the density, decrease the opacity and increase the resistance characteristics of pulp. According to the results, the brightness increased with the increase in alkalinity percentage, while the increase in cooking time and the use of refining treatment did not have a significant effect on the brightness of the soda-anthraquinone pulp obtained from terjin. According to the results, the best characteristics were obtained after refining the pulp obtained from cooking at 18% alkalinity for 30 and 60 minutes, and also at 16% alkalinity for 60 minutes.

In general, terjin has better morphological and chemical characteristics than many non-woody plants, and in some cases, such as fiber length, its characteristics are comparable to hardwood. Also, refined and unrefined soda-anthraquinone pulp of terjin has relatively good and acceptable papermaking characteristics, and it can be suggested to the papermaking industry as a part of the raw material for the production of pulp.

One of the disadvantages of recycled fibers is the significant loss of mechanical strength of the paper due to the decrease in the bond between the fibers. The objective of this study was to investigate the effect of adding paulownia nano-wood on the improvement of pulp from old corrugated containers (OCC). Therefore, in this study, with the aim of preserving the mechanical properties of paper, a nano wood-cationic starch system was used. The pulp was prepared from OCC collected and after refining and obtaining a flow rate of 380 ± 20 ml, different amounts of nano-wood (1, 2, and 3%) and cationic starch (0.5, 1, and 1.5%) was added to it. Finally, standard hand sheet papers were made from these treatments, and their physical and mechanical properties were measured according to the TAPPI standards. The results showed that the density and air permeability increase with the addition of cation-starch nano-wood in the paper. Also, the results showed that there is a significant difference with 95% confidence between different treatments in terms of mechanical strength. The highest values of burst resistance index (2.173 kPa / g), crush resistance in ring mode (177.4 N), and air passage resistance (36.9 s) belonged to S3N 1.5 treatment. It can be concluded that the use of larger amounts of nano-wood with the help of cationic starch as retention aids improves the final paper strengths.

Nowadays, high dependence on fossil fuels for chemical and fuel production, and also, the severe shortage of these resources has raised serious concerns. Moreover, increasing in greenhouse gas emissions and environmental pollution are also an important reason for reviewing industries with conventional processes. In recent years, biorefinery has received much attention from the lignocellulosic industry, especially in the field of converting natural polymeric wastes (black liquor, sludge, etc.) to value-added products by supplying part of the chemicals and fuel required by industry. Many studies have been done on the conversion of hemicelluloses into high value-added materials. In most of these studies, the aim was to optimize the extraction conditions and then convert them. Furthermore, biorefinery can help to creating value-added products from black liqueur derived from pulping lignocellulosic materials in papermaking as by-products of pulp and paper. Finaly, economically, biorefinery will boost the economic sector of these plants. This paper discusses the main goals of biorefinery of natural polymer waste from paper mills that have multifaceted impacts on the economy, energy and the environment.

The activities of human civilization have imposed a high burden on the environment since the beginning of history on a global scale. That is why energy producers and consumers need to think deeply about the role that energy plays to achieve sustainable development. In this context, the maintenance of the environment, which cannot be replaced, should be taken into account precisely. Rising energy prices and market volatility, industry towards the use of energy management systems has led in order to compete reliable. Pulp and paper industry is not exception from this rule, Because the production of paper and paperboard demand is rising significantly on a global scale, that These factors lead to increased energy consumption and greenhouse gas emissions such as CO2 in this sector. In this context, a review of previous research and integrate them with the views of the experts, new methods for selecting the most appropriate technology in different sectors of the pulp and paper plant are provided.

This research was carried out with the aim of bleaching of soda-bagasse pulp, produced in the Pars paper industry, with oxygen (O), chlorine dioxide (D), and hydrogen peroxide (P) in the presence of titanium dioxide nanoparticle (T) as photo catalyzer and methylene blue (M) as an alternative to sodium hypochlorite (H). Bleaching of pulp was performed in sequences of O, OD, OD (Ep) T1, OD (Ep) T2, OD (EP) T1m and OD (Ep) T2m. The physical and mechanical properties of pulp and handsheets were measured as well as COD of effluents. According to the results, the kappa number of the pulp was reduced in two treatments of OD (EP) T1m, and OD (Ep) T2m and was the same as the control sample, bleached with HH conventional sequence in the Pars paper industry. However, the degree of polymerization of the two recent treatments was twice more than that of the control sample. The results of degree of brightness showed that the OD (Ep) T1, OD (Ep) T2, OD (EP) T1m, and OD (Ep) T2m sequences can result in the same degree as the bleached control sample of the Pars paper industry (75% ISO). Also, results showed that by replacing the HH sequence with OD (Ep) T1m and OD (Ep) T2m sequences with the same kappa number, an improvement in bleached pulp yield (3%), viscosity (207%), degree of polymerization (213%) of pulp, opacity (5%), tensile strength index (2.7%) and tear index (49%) of the paper can be expected, while the COD of effluent would decrease by 30%. In general, the use of titanium dioxide nanoparticles and aqueous methylene blue in OD (Ep) bleaching sequence can result in the higher pulp brightness and strength properties of paper.

Bacterial Nano-cellulose (BNC) due to special microscopic structures has a high potential in special used (such as medical and sanitary applications). BNC differs from plant cellulose in its higher purity, crystallinity, and degree of polymerization. The goal of this study was to investigate the production of BNC using Acetobacter xylinum bacteria and its characteristics evaluation.

In order to obtain BNC, the bacterium was cultured in a liquid culture medium under static and dynamic conditions and the resulting cellulose was washed and purified. Microstructures with field emission scanning electron microscopy (FE-SEM), crystallinity structure by X-ray diffraction (XRD), weight percentage, size and distribution of BNC with energy-dispersive X-ray spectroscopy (EDX), determination of viscosity and molecular weight by dissolving of cellulose in copper(II)-ethylenediamine complex (CED) solution, and BNC yield, using wet and dry samples weighed.

The results showed that yield of BNC static medium is more than BNC dynamic culture medium. Comparison of FE-SEM images showed that the culture method has a significant effect on the morphology structure of the BNCs fibers produced. Comparison of FE-SEM images of two cultivars showed that the morphology of BNC in static is porous and in dynamic is clustered together. The size of nanoparticles is generally below 60 n.m. for both BNC. The results of XRD test showed that the crystallinity of BNCs in the static and dynamic medium was 72.49% and 14.29%, respectively. Also, viscosity of BNCs in the static and dynamic medium was 110.7 centipoise (cP) and 97 cP, respectively.

In general, with respect to characteristics of BNC products and comparison with other studies, we concluded that suitable BNC is produced in this study that with respect to research needed in this field in the country and medical applications and engineering are important.

This study was aimed to investigate the possibility of using magnesium hydroxide as an alternative for sodium hydroxide in deinking of newsprint and magazine mixture. The old newsprint and magazine mixture (ONP/OMG -70/30) was treated by magnesium hydroxide at three levels: 1, 1.5 and 2 percent (based on oven dried pulp weight), for 20 min. Optical and mechanical properties and effluent COD load were compared to those of control and NaOH treated samples. Results showed that effluent COD load of Mg(OH)2 chemical treatments was less than that of NaOH treatment. Also, results indicated that 1.5% Mg(OH)2 treatment, which was done in pulp deinking, had better results compared to other treatments and also NaOH treatment. In the other words, it is the best treatment for both optical and mechanical properties. Thus, substitution of sodium hydroxide by magnesium hydroxide for deinking of newsprint and magazine wastepaper suggested.