Iranian Journal of Wood and Paper Science Research
Year:2021 | Volume:36 | Issue:2 (75)|Papers Count:7

Industrial wastewater is one of the major environmental pollutants. Many industrial effluents, such as leather, printing, plastics, paper, food industry, cosmetics and industries as such use dyes for dyeing their products and consequently the discharged effluents 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 on absorption efficiency was investigated 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 dye. The results indicated that Nano zeolite-Fe3O4 was successfully absorbed the acid green 20 dye and has the ability to remove 99. 47% of dye from the solution acid green 20 with the concentration of 50 mg/ l applying optimal conditions of pH=3, time; 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.

In respect to increase the environmental pollutants initiating from agglomerating rubbish and wastes containing stable petroleum-based polymers, the substitution of these polymers with biopolymers and solving their problems and the production process as well as the final products is an important topic. In this study, the possibility of the production of polylactic acid (PLA)-rice husk composite, and 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 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 against temperature rising.

In this study, the effect of thermal cycle on surface degradation and cracking of wood coatings reinforced with clay nanoparticles and changes in its adhesion and gloss properties were investigated. Solvent-based coatings (alkyd, polyurethane), water-based coatings (chromium and phosphorescence) and oil-based coatings (oil-based coatings) were applied on Abies alba wood. 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 coating is alkyd coating. Moreover, the results showed that the addition of clay nanoparticles before the thermal cycle did not differ much in the properties of the coating, but after the thermal cycle the strength of the coatings was increased. This increase in adhesion strength in chromium, phosphorescence, oil, polyurethane and alkyd coatings was nearly doubled. In addition, the use of clay nanoparticles could reduce the cracking of the coating due to thermal fatigue and improve the performance of the coatings.

In this research, surface properties and failure modes of hygrothermally modified poplar wood (Populus deltoides) were evaluated. For this purpose, the effect of variable factors including hygrothermal temperature (130, 150 and 170° C) and treatment time (20 and 40 minutes) on poplar wood 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.

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 elevations of 147 and 200 cm above the ground and on 8 tree 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-cellulosepolyacrylamide-nano-cellulose hybrid systems to replace the imported long chemical fibers in the production of durable 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 5% level as one treatment and other treatment were designed adding either 1% starch or 0. 1% with polyacrylamide to 5% nano-cellulose having another two treatments. Then another set of treatment using three levels of cationic starch (0. 5, 1, 1. 5%) and three levels of cationic polyacrylamide (0. 05, 0. 1, 0. 15%) were used. From each treatment, 60 gm-2 handsheet were made and the physical, mechanical and optical properties of handsheets from different treated pulps were measured and compared. The results showed that handsheets with increasing nanocellulose alone as compared to imported long fibers, showed increased surface smoothness, tensile strength, burst strength, tear but air resistance, folding resistance and opacity were decreased. Increasing nanocellulose in combination with cationic polyacrylamide increased the paper air resistance, surface smoothness, tensile, burst, tear, and folding strength compared to imported long fibers, and air resistance and opacity decreased. With the increase of nanocellulose in combination with cationic starch, surface smoothness, tensile strength, burst strength, and 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 is smoother and the pores are filled relatively, confirming the results of surface smoothness and air resistance measurement.

Microorganism damages or contamination of books and documents are the 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 the contamination to employees or vice versa. Current research was conducted as 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 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.