حمیدرضا مهری ایرائی

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.

Efficient use of waste papers and improve their quality has always been one of the targets in the pulp and paper industries. This study aimed to compare two stages bleaching of deinked pulp of newspaper and Magazine recycled pulp mixture using Sodium Dithionite (Y) and hydrogen peroxide (P).
Firstly, the pulp was bleached using 1% hydrogen peroxide and in the next stage bleaching was performed using 0.5 and 0.75 percent dithionite and of hydrogen peroxide Respectively for 60, 90 and 120 minute.
The results showed that with increase dosage of hydrogen peroxide in the second stage of PP sequence, decrease in bulk, opacity and increase in strength properties wasnt significant but increase in brightness and effluent COD showed significant changes. Prolongation of bleaching time in the second stage of PP sequence cause significant reduction in bulk, opacity and increase of effluent COD, brightness and strength properties. with increase the time of bleaching reactions in second stage of PY sequence, bulk and opacity reduction and increase in strength properties and brightness wasn’t significant, but with chemical dosage increasing, just brightness increasing was significant. Also, according to the results, with increase of chemical dosage in second stage of PY sequence, increase in the amount of Effluent COD load wasn’t significant, but with increasing of time of bleaching reactions in second stage of this sequence, increase in the amount COD load was significant.
Regarding to the results, effluent’s COD, brightness level and strength properties of PP sequence was higher than PY while bulk and opacity of that was lower than PY ones.

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.

In the present research, the effect of different peroxide charges and reaction times were investigated in hydrogen peroxide bleaching of mixed old newsprint and old magazine deinked pulp. In the beginning, mixed recycled papers were pulped using conventional method and then deinked by flotation. In addition, deinked pulps (mixture ratio of 70% ONP and 30% OMG) were bleached with hydrogen peroxide at different charges of 0.5, 0.75 and 1% from peroxide and times of 30, 60 and 90 min under constant process conditions. The bleached pulps refined with laboratory PFI mill to freeness of 300 ml, CSF and then standard handsheets (60gm-2) were made from them. The residual peroxide existing in bleaching liquor, chemical oxygen demand (COD) of bleaching effluent and also the paper quality properties (optical, physical and strength properties) were measured according to respected standards. Obtained results indicated that with increase in bleaching times, the residual peroxide in liquor was decreased but the differences of them was insignificant (P<0.01) with increase in peroxide charge. Also effluent COD was enhanced significantly with increase in the both peroxide charges and bleaching times. When the peroxide charge and also the bleaching time were added, the paper brightness had increased significantly but opacity was not significantly changed (P<0.01). Increasing the bleaching agent of peroxide has not been shown any significant influence on the paper strength properties. However increasing the bleaching time led to significant improve in these properties.

The migration of aluminum (Al) from aseptic laminated paperboard packages was studied by monitoring the Al content of orange juice (plain juice, no additives) filled into such packages and stored at ambient temperature (23ºC) for up to 1 year. Analytical procedure includes MW-assisted digestion of orange juice with concentrated nitric acid followed by determination of Al concentration by double-focusing sector field inductively coupled plasma mass spectrometry(ICP-SFMS). Special precautions were taken in order to reduce sample contamination at all stages of the procedure, resulting in a method detection limit of 5µ g L-1. In the concentration interval typical for orange juices reconstituted from concentrate, the combined measurement uncertainty of the method was within 10% RSD. Statistical tests performed on data setters presenting the storage period from 12 hto1 year revealed no time-depend etching's in A concentration. Through out all storage times, 3, 6, 9 and 12 months, the Al concentration is statistically un distinguish able from native concentration in the orange juice before fling in to the packages.