مجله تحقیقات علوم چوب و کاغذ ایران
سال سی و نهم شماره 1 (پیاپی 86، بهار 1403)

Contamination in pulp mill wastewater and subsequently surface and underground water sources contamination with heavy metals is one of the most important problems which threatens the health of human being and other creatures. These metals penetrate and pollute the soil and water. In this regard, this study investigated and determined heavy metals in the pulp mill wastewater before and after the wastewater treatment process. In this study the newspaper adsorbent was prepared and the efficiency of the adsorbent in the adsorption of copper, lead and cadmium metals was studied. The adsorption experiments were performed to investigate the effect of the time of contact of the newspaper adsorbent and metals, and dose of the adsorbent. For this purpose, waste newspapers were first treated with sodium bicarbonate for one hour and then refluxed with 5% disodium hydrogen phosphate for 4 hours at 100 degrees Celsius and finally washed. Aqueous solutions with an initial concentration of 30 ppm for three metals lead, copper and cadmium were prepared by diluting the standard solution with distilled water. A specific amount of adsorbent was added to 10 ml of each solution and stirred in a mechanical shaker for specific times. Then they were filtered by filter paper purified and analyzed by atomic absorption spectroscopic device. After drying, the solid phase of the wastewater sample was subjected to acid digestion with nitric acid at a ratio of one to five. Then, the digested samples were analyzed with an atomic absorption spectrometer after washing.​ The results of wastewater analysis in the basins before and after treatment showed that the amount of lead, copper and cadmium in the wastewater before treatment were 0.2129, 0.5983 and 0.0004 ppm, respectively. The amount of metals after the treatment process was 0.0469, 0.134 and 0.0001 ppm for lead, copper and cadmium, respectively. Also, according to the results, taking into account that the absorption rate was high and the same in the amount of absorbent used and the treatment times; the amount and time of the desired treatment in this experiment were not effective factors in the amount of metal absorption.  The newspaper adsorbent is a good adsorbent for removing heavy metals from aqueous solutions due to high absorption capacity and low cost, which make the newspaper a potential adsorbent for the removal and wastewater treatment of the heavy metals. According to the results, the dosage and time of treatment with the newspaper adsorbent were not effective factors in metal removal.

Cellulosic industry organizations try to establish appropriate strategies to perform the main production processes and provide services to customers by improving productivity and reducing costs. Environmental concerns, energy scarcity, depletion of natural resources, and increased competition among organizations have made the study of a sustainable supply chain cost-effective for market success. The purpose of this study is to identify effective indicators for a stable supply chain sustainability model in the cellulosic industry with multi-objective decision making methods.

The present study is an exploratory research in terms of orientation, applied and in terms of method, quantitative-qualitative, which has used the data theory strategy of the foundation. The data collection tool in the qualitative section aimed at identifying the components and sub-components of stable supply chain sustainability, in-depth and semi-structured interviews with purposive sampling method. In the quantitative part of the research, a researcher-made questionnaire was designed. The obtained data were used to measure variables and weight by Vickor and Shannon entropy methods.

Eleven main components and thirty sub-components were identified by qualitative studies for stable supply chain stability. By examining the relationships and ranking of indices using quantitative methods, green storage indices with a numerical value of 0.133 and continuous improvement with a numerical value of 0.134 were considered as the top components. According to the Vickor index, the components of green warehousing, quality improvement, economic stability, intra-organizational pressures, information technology capabilities, company commitment and strategy, logistics optimization, social values, institutional pressures, strategic supplier cooperation and environmental protection, respectively. Stable supply chain stability affects the cellulose industry.

Due to the shortest distance to achieve sustainability in green warehousing and quality improvement, cellulose industry organizations in the country can use the results of this study to increase productivity and reduce organizational costs  .

Nowadays, the importance of treatments such as water washing and ethanol-acetone washing to improve the acoustic properties of wood has been noticed by the makers of musical instruments. Wood extractives are in the list of those materials that often do not have a construction role, and their purposeful and correct evacuation can lighten the wood without reducing the stiffness. Carrying out pre-treatments such as fermentation with bread yeast (before water washing and ethanol-acetone washing processes) can lead to the extraction of more extractable substances from wood. In this study, the effect of water washing and ethanol-acetone washing treatments as well as fermentation pre-treatment on the acoustic properties of Ash wood (Fraxinus excelsior) has been investigated.

Ash wood species (Fraxinus excelsior) was prepared from the wood of a commercial timber and 38 small radial beams with nominal dimensions of 150×12×2 mm (longitudinal×radial×tangential) were extracted from the hardwood. After reaching the equilibrium humidity of 12% in air-conditioned conditions, the selected samples were subjected to the forced vibration test in the free-free beam in order to measure the basic physical and acoustic characteristics. After that, the initial tests were randomly divided into two groups of 19 tests. The first group without pretreatment and the second group with fermentation pretreatment were placed in the process of removing the extractives by water and then by ethanol-acetone mixture. After each step of water washing and removing the extractive substances soluble in ethanol-acetone mixture, the forced vibration test in the free-free beam was performed on the samples and the acoustic properties of the samples were measured.

Water washing without pretreatment with bread yeast caused a slight decrease and with pretreatment, it caused a significant decrease in density values (respectively: 1.75 and 7.39%). While the process of removing extractives (with and without pretreatment) by ethanol-acetone mixture caused a significant decrease in density values (Respectively: 2.27 and 8.71%). The modulus of elasticity values showed a significant decrease due to water washing without pretreatment and with pretreatment. (Respectively: 11.37 and 16.47%). The process of removing the extractives by ethanol-acetone mixture also resulted in a significant decrease in the modulus of elasticity values in untreated and pretreated samples (Respectively: 13.87 and 20.93%). Water washing without pre-treatment with bread yeast and with pre-treatment has caused a significant decrease in the values of damping factor, among which the pre-treated samples had a greater percentage of drop in the values of damping factor (Respectively: 13/87 and 20.93%). The process of removing the extractive materials by ethanol-acetone mixture as washing has caused a significant decrease in the damping factor values, which among the pre-treated samples showed a greater percentage drop in the values resulting from this property (Respectively: 3.03 and 18.01%). In this factor, the process of removing the extractive substances soluble in ethanol-acetone mixture (with and without pretreatment) has resulted in a greater drop in damping values (respectively: 6.67% and 20.85%). Acoustic conversion efficiency due to water washing process without pretreatment with baker's yeast caused a slight increase, while pretreatment caused a significant increase in acoustic conversion efficiency values (Respectively: 0.44 and 25.24%). The process of removing extractive materials by ethanol-acetone mixture also caused a significant increase in the acoustic conversion efficiency values, which among the pre-treated samples showed a higher growth percentage in the values of this characteristic (Respectively: 3.41 and 28.90%). Both water washing methods and ethanol-acetone mixture washing were effective in improving the physical (density) and acoustic properties (modulus-elasticity, damping and acoustic conversion efficiency). Meanwhile, the effect of ethanol-acetone mixture washing was more than the effect of water washing. Fermentation pretreatment with bread yeast improved the performance of water washing and ethanol-acetone mixture washing treatments.

Some medicinal herb extracts have the antibacterial capability. On the other hand, herb extract is one of the organic, natural, and environmentally friendly substances. In recent years, the production of environmental and safe packaging materials has attracted the attention of scientists and industrialists. Paper is one of the biodegradable and less cost options for packaging in various industries, including the food industry. Also, the raw materials of paper can be modified and changed with different materials. As a result, paper fibers can be treated with herb extracts and used in the production of renewable papers with antibacterial properties.

In this research, thyme (Zataria Multiflora) was used for extraction. The thyme obtained from the research farm was dried and then powdered. Powdered thyme was treated via ultrasonication. In this method, two amplitudes of 40 and 60 amplitudes and three time levels of 3, 6, and 9 minutes were used for extraction. Then the papers were treated with herbal extract prepared in two amounts of 15 and 20% based on the dry weight of the paper by spraying. The antibacterial properties of the papers were investigated with Escherichia coli and Staphylococcus aureus bacteria. The chemical structure of materials extracted from the thyme extract investigated by fourier transform infrared spectrum (FTIR) analysis. Also, gas chromatography (GC-MASS) analysis was used to investigate the components of thyme extract. The optical properties of the paper, including brightness and opacity, and the strengths properties of the produced papers were measured by tensile, tear, and burst strengths.

The highest inhibition zone diameter in the treated paper with the thyme extracted by ultrasonic method was 20 mm in 40 amplitude and 9 minutes for Escherichia coli bacteria. Also, the highest inhibition zone diameter for Staphylococcus aureus bacteria was 14 mm in 60 amplitude and 6 minutes. According to the results of the papers analysis, the papers showed better antibacterial properties and higher inhibition zone against the Escherichia coli bacteria. The chemical compounds in the thyme extract including various substances such as hexane and furans. The most important chemical components that caused the antibacterial properties of the papers is carvenone, which was observed in the thyme extract. The results of the strength test of the treated papers showed that the sample of the thyme extracted by the ultrasonic method at 40 amplitudes, 3 minutes, and the 20% consumption amount based on the dry weight of the paper has the highest tensile and burst index. As well as, the highest tear index of the treated papers was in the treated sample with the thyme extracted at 60 amplitudes, 3 minutes, and 15% consumption amount based on the dry weight of the paper. The results of the optical tests showed that the opacity of the papers decreased and the brightness increased.

The results of this research showed that the paper as a biodegradable and environmentally friendly material has the ability to be treated with herbal and natural antibacterial materials such as the thyme extract. Also, the herbal extracts are a suitable alternative to inorganic and metallic materials in the production of materials with antibacterial properties due to the herbal extracts are cheap, available and natural materials.

 Today, with the increase in population, increasing demand for paper, as well as greater restrictions on raw materials, the production of pulp from high-yield pulps and mechanical pulps has found a special place. These pulps have a high yield greater than 85%, but due to the presence of lignin, extracts, and metal ions, their use is limited to short-term usage, as in the long run they suffer from brightness reversion and photo-yellowing. This study aimed to investigate the effect of DTPA, nano-cellulose, and nano-chitosan spray on the optical properties of chemical-mechanical pulp (CMP).

 For this purpose, first, a quantity of bleached chemical-mechanical pulp (CMP) was selected as a control sample from ‎Mazandaran wood and paper industry.‎ Papers with a base weight of 60 gr/m2 were prepared from the mentioned paper pulp. In this study, the nano-fibrillated cellulose (NFC) was purchased from Nano Novin Polymer Co. (Sari, Iran), which was prepared from softwood alpha cellulose pulp with an average fiber diameter of 32 nm. The NFC was loaded at 2% by spraying onto papersheets. Nanochitosan (“Seafresh”, Thailand), obtained from exoskeletons of crustaceans, with a deacetylation degree of 93% and a molecular weight of 270 kDa was used. Nanochitosan was loaded at 1 and 2% of the dry pulp weight. Diethylene triamine penta acetic acid (DTPA) was prepared from DIPER-Samchun (South Korea), with a 50% solid content and 25 cps viscosity. To spray the DTPA onto the paper surface, 0.5% DTPA was prepared. To prepare samples for the surface modification, paper sheets with a basis weight of 60 g/m2 were made. Then, 0.5% DTPA, 2% nanochitosan, and 2% nanocellulose were sprayed separately on the papersheets. In addition, another treatment named mixed-solution (containing 0.5 % DTPA + 2% nanochitosan + 2% nanocellulose) was sprayed onto the handsheets. The spraying time and distance were 20 s and 20 cm, respectively, and the treatment process was named “spray-coated”. Then, the optical properties (brightness, opacity, yellowness, and greenness) of the hand-‎sheets were measured according to ASTM and TAPPI standard methods. ‎

The results showed that by DTPA, nano-cellulose, and nano-chitosan spray in the handsheet paper, brightness, yellowness, greenness, L* factor, and the opacity increased and the a* factor decreased. By spraying nano-cellulose on the test samples, most of the optical properties were significantly improved except for the yellowness of the hand-sheet paper. In addition, the most appropriate properties were observed in the paper obtained from DTPA spray and also in the simultaneous spray treatment of DTPA, nano-cellulose, and nano-chitosan on hand-sheet papers. Therefore, it has caused a very sensible increase and improvement in all the optical properties, which can be selected and suggested as the best treatment. The evaluation results of the brightness reversion of the hand-sheet paper from CMP pulp showed that most of the treatments led to a relative reduction of the return of the paper brightness. On the other hand, the lowest and highest brightness return values in the hand-sheet paper were obtained from 0.5% DTPA spray and nano-chitosan spray, respectively. The evaluation results of the SEM images of the test samples compared to the control sample showed that the hand-sheet paper with nano-chitosan and nano-cellulose spray and also in the simultaneous spray treatment of DTPA, nano-cellulose, and nano-chitosan had more favorable surface and structural properties. The existence of less empty spaces (cavity) and more overlap of fibers in the test samples can be a reason for the higher quality of the properties, as well.

The results showed that by spraying nanocellulose, nano- chitosan and DTPA on the test samples, the optical properties, brightness, greenness, opacity, a* factor, l* factor , yellowness and brightness ‎‎durability improved. In ‎addition, among the various treatments, the DTPA treatment in long-term thermal aging and the use of nano-chitosan and nano-cellulose in the short-term aging had noticeable effects on brightness ‎‎durability and decrease in the color reversion. As a result, there was an increase in the durability of the paper ‎against thermal deterioration.

Plant extractives show unique properties. They impart colors and change the color of wood and generates attractive appearance. Since early days, societies have been utilizing plant extractives in industrial, medical and even as fungicides and biocides. In early times this application was based on the professional experiences, but as the sciences were advanced, then the technical and experimental identification and utilization was employed. In general, people look at walnut tree wood and fruit as its economic values. However, scientific research has proved the values of walnut tree extractives. In this study the chemical composition of walnut tree extractives and its variation in two periods of spring and summer as well as the impact of the drying on quantity and quality of the extractive components are investigated.

Walnut tree leaves from a selected location of an old walnut tree (100 years old) in mountain region of Karaj were collected in spring and summer. One part of the samples was air dried and another portion was used at green moisture condition. Totally four samples were obtained. Ethanol-acetone extraction was according to Tappi T204-05 procedure. The extractive was identified using GC-MASS spectroscopy and the chemical components in the extractives were identified and tabulated. 

The results revealed that the dried leaves contain fewer chemical compounds compared to green samples which can be an indication that some of the compounds in green sample are volatile and vaporize upon drying. Furthermore, the extractives chemical composition and content varies between spring and summer samples. The major chemical compounds identified were 2-methylneptaline, tri-decan, tetradecan, 2,3-dimethyl naptaline and methylcyclobenzen.

The results indicated the seasonal variation of walnut tree extractives. These is also considerable variation in wet and dry samples which can be attributed to the presence of volatile compounds. The odor of walnut leaves is the consequence of existence of such volatile extractives. The absence of some of the compounds in summer samples indicate the seasonal changes of the extractives.