مجله تحقیقات علوم چوب و کاغذ ایران
سال سی و ششم شماره 2 (پیاپی 75، تابستان 1400)

Industrial wastewater is one of the major environmental pollutants. Many industries effluents, including leather industry, printing, plastics, paper, food industry, cosmetics and industries like these use dyes for dyeing their products and consequently the output wastewaters contain industrial dyes. In this study, Nano zeolite Clinoptilolite modified by Fe3O4 magnetic nanoparticles was used to remove acid green 20 dye in a batch system. In batch absorption studies of acid green 20 dye with Nano zeolite-Fe3O4 , the effect of factors such as pH, initial dye concentration, the amount of absorbent and sorption time was investigated on absorption efficiency in order to determine the optimal conditions for dye removal. In this study, the surface response method (RSM) using Box-Behnken design (BBD) was used to optimize the absorption of acid green 20. The results indicated that Nano zeolite-Fe3O4 is successfully absorbed the acid green 20 dye and has the ability to remove 99.47% of dye from 100 ml of the solution acid green 20 with the concentration of 50 mg/ l in optimal conditions of pH=3, time of 90 minutes and absorbent dose of 0.8 g/l. also, Freundlich and pseudo -second order models had the best fitting with the absorption process as isothermal and kinetic models, respectively. The results showed that the nanocomposite was significantly able to remove the acid green 20 dye from aqueous solutions in a short time. Therefore, it can be used as an effective absorbent to remove dye.

Considering the increase of environmental pollutant resulted from agglomerating rubbish and wastes containing stable petroleum-based polymers, substitution of these polymers with bio-polymers and solving their problems and defects in the production process as well as the final products is an important topic. In this study, the possibility of the production of poly lactic acid (PLA)-rice husk composite with acceptable properties, and also the effect of using flame retardant mineral fillers of aluminum three hydrates (ATH) and magnesium di-hydroxide (MDH) on physical and thermal properties of the produced composite were investigated. Results indicated that the density of PLA-rice husk composite was higher than petroleum-based polymers composites (PP/HDPE-rice husk composites); and flame retardant mineral fillers addition led to an increase in the composite density. Also, flame retardant mineral fillers addition decreased the composite water absorption and thickness swelling, in a way that they were comparable with petroleum-based polymers composites. Results of thermal gravimetric analysis (TGA) showed that flame retardant mineral fillers addition also decreased the temperature of the composite weight loss curve peaks, and the weight loss rate toward temperature rising.

In this study, the effect of thermal cycle on surface degradation and crackability of wood coatings reinforced with clay nanoparticles and changes in adhesion and gloss properties were investigated. In this study, solvent-based coatings (alkyd, polyurethane), water-based coatings (chromium and phosphorescence) and oil-based coatings (oil-based coatings) were used in Abies alba wood species. Also, techniques and tests for measuring surface cracks, tensile adhesion and gloss meter were used to analyze the results before and after thermal fatigue. The results showed that the best coating performance in all three tests of tensile adhesion, surface gloss and surface crack is chrome coating and the most unsuitable of them is alkyd coating. Moreover, the results showed that the use of clay nanoparticles before the thermal cycle did not differ much in the properties of the coating, but after the thermal cycle increased the strength of the coatings. This increase in adhesion resistance in chromium, phosphorescence, oil, polyurethane and alkyd coatings was rate nearly doubled. In addition, the use of clay nanoparticles could reduce the crackability of the coating due to thermal fatigue and improve the performance of the coatings.

 In the current research, surface properties and failure modes of modified poplar wood (Populus deltoides) by hygrothermal treatment were evaluated. For this aim, the effect of variable factors included hygrothermal temperature (three levels: 130, 150 and 170°C) and holding time (two levels: 20 and 40 minutes) on poplar wood specimens properties (contact angle and surface roughness) prior to and after planning were investigated. The surface characteristics and failure modes were evaluated for both treated and untreated wood specimens. The results revealed that surface roughness of poplar wood was enhanced due to the hygrothermal treatment in both states of before and after planning. It was also found that the hygrothermal treatment decreased contact angle of distilled water. The bending strength of specimens was reduced by hygrothermal treatment. According to the results, failure modes of hygrothermally treated specimens were simple and compression types in bending strength test. Keywords: Surface roughness, contact angle, bending strength, failure mode

Ensuring the quality and stability of trees as the most important components of the plant community has attracted the attention of foresters to identify and measure defects and ensure safety coefficients. Therefore, in the present study, the use of acoustic tomography to calculate the extent of decay, the area of the woody section and the safety factor of black pine was studied. Acoustic tomography was performed using 16 sensors at two heights of 147 and 200 cm above the ground and on 8 tree specimens in the Sopron region of Hungary. The results showed that the stress wave technique was an accurate method for determining safety coefficients and determining the amount of internal decay in the tree and also had the ability to identify compression areas in cross section. Resistography of the studied sections in different geographical directions assisted to locating the woody areas, which was compatible with the information of acoustic tomography. The findings of this study showed that the area of the canopy has a significant role in the safety of the tree and the possibility of tree fall, so that in some trees due to their condition, with doubling the area of the canopy, the torque increased from 80827 to 161655 N.m and the condition of the tree changed from low-risk to high-risk.

This study aimed to investigate the use of cellulose nanofibers and starch-nano-cellulose and polyacrylamide-nano-cellulose hybrid systems for the replacement of imported long chemical fibers in the production of these papers. In this study, imported long fiber chemical pulp was added to cotton pulp at 4 levels. Cellulose nanofibers were added to cotton pulp at a 5% level with 1% starch and 0.1% with polyacrylamide. Three levels of cationic starch and three levels of cationic polyacrylamide were also used. From each of the treatments, 60 gm-2 handsheet were made finally the physical, mechanical and optical properties of the paper made from different pulps were compared. The results showed that with increasing nanocellulose individually, compared to imported long fibers, surface smoothness, tensile strength, bursting, tearing of paper increased and air resistance, folding resistance and opacity decreased. Increasing nanocellulose in combination with cationic polyacrylamide increased the paper air resistance and surface area, tensile, burst, tear, and folding strength of the paper compared to imported long fibers, air resistance and opacity. With the increase of nanocellulose in combination with cationic starch, as compared to imported long fibers, surface smoothness, tensile strength, bursting, folding increased but opacity decreased. FE-SEM results also showed that with increasing percentage of cellulose nanofibers, the pores decreased significantly. As a result of the addition of 5% cellulose nanofibers the surface of the paper became smoother and the pores were filled relatively, confirming the results of surface smoothness and air resistance.

Book and documents damaged or contaminated by microorganisms are a serious threat to the health of users and librarians. This research was aimed to identify the different species of fungi in the archive of museums and their effects on manuscripts and also reviewing the possibility of transferring them to employees or vice versa. Method Current research was conducted in a field experiment. First the manuscripts (Aldoa, Resale Haj and Kholase Alfieh) were examined based on the visual effects of the fungal deterioration, then sampling was performed to cultivate and identify fungi under sterile conditions. Sabouraud dextrose agar medium was used for cultivation and finally, after 10 to 14 days, directs smears were prepared from grown colonies, and fungal genera were identified. the fungi were identified based on microscopic and morphological properties. The results of the studies showed that the fungi on the paper works in the archives of the Malek museum include Aspergillus flavus, Cladosporium, Acremonium, Trichophyton schoenleinii and Sterile hyphae, respectively. Aspergillus, Cladosporim and Acremonium fungi are common allergenic fungi which are identified in the libraries and can cause lung allergies in human. So these fungi can be dangerous for people who suffer from tuberculosis or background lung diseases. T.schoenleinii fungus is a pathogenic fungus in humans and is not common in books. This pathogenic fungus can be probably transferred to the manuscript by one of the librarians or a person who has frequently accessed to this book. Sterile hyphae are usually scattered in the surrounding and are not worth diagnosing and pathogenic.