Journal of Lignocellulose
Volume:3 Issue: 1, 2014

Bank-notes have been an integral part of buying and selling for many years. There are about 7 billion Bank-note leaves in Iran that have been in circulation in a 5-year period. This amount of Bank-notes and the frequency with which they are touched can promote transmission of many pathogenic factors, especially bacteria. Based on scientific research results, Bank-notes are seriously contaminated and must be considered a potential danger to society. In this study, for antibacterial Bank-note paper production, 100 ppm of Nanosilver was used as an antibacterial agent accompanied by cationic polyacrylamide at the 0, 0.3, 0.5, 0.7, 1 percent (based on O.D. pulp) as a retention aid of Nanosilver particles on cotton fibers. Then standard handsheets (90 g/m2) were made from the above-mentioned pulps and tested for physical and mechanical properties. Also, for antibacterial tests of handsheets, Escherichia coli and Staphylococcus aureus were used as Gram-negative and Gram-positive bacteria, respectively. The results showed that handsheets strengths decreased with increasing of Nanosilver absorption. But antibacterial properties of handsheets increased by increasing of Nanosilver absorption so that the most antibacterial properties for handsheets were achieved at the 1% level of retention aid addition.Keywords: Cationic polyacrylamide; Nanosilver; Antibacterial paper; Escherichia coli;Staphylococcus bacteria

In this study, the effect of priming on the adhesion strength of coating in ash (Fraxinus excelsior L.), sycamore (Platanus orientalis), pine (Pinus halepensis mill), and walnut (Juglans regia) wood species was investigated. For this means, specimens were prepared at the size of 200×100 ×12 mm, and an 8% moisture content (in the radial direction). After sanding the specimen’s surface with sandpaper, they were separately covered with shapan, oil, and bars primers. After priming, an acid catalyzed clear coat was applied to the specimen surfaces. To analyze the effect of priming on the adhesion strength, the primed specimens were compared with control specimens. The obtained results from this study indicated that coating the surfaces of wood specimens with oil and bars primers does not have a negative impact over the adhesion strength, but the shapan primer significantly reduced the adhesion strength of coating. The highest adhesion strength on the wood surface was from the walnut species without priming, and coated with bars and oil primers.

A granular activated carbon, derived from olive stones, was oxidized with nitric acid for different periods of time in order to create more oxygenated functional groups without deeply affecting its framework. The changes in porous texture and morphology of carbon during acid treatment were evaluated by scanning electron micrograph (SEM), as well as N2 and CO2 adsorption. The surface functional groups on carbon surface were confirmed by FTIR spectroscopy, multibasic titration method of Boehm, pH of the point of zero charge measurement (pHPZC), and temperature programmed desorption (TPD-MS) technique. Batch adsorption experiments were conducted to study the effect of nitric acid oxidation on the removal of Pb2+ and 2-nitrophenol molecules from aqueous solution at 30°C. The results showed that the acidic character of the plain carbon was enhanced by the creation of carboxyl, lactone and phenol groups from the first two hours of oxidation. These created groups were located at the entrance of narrow micropores. The reduction in specific surface area was not very significant. Furthermore, the raw material showed excellent Pb2+ adsorption capacity (318 mg.g-1), which was improved by acid treatment. However, the uptake of the phenolic compounds decreased as a result of formation of new oxygen functionalities.

The present study highlights a simple and novel method for the production of ligninolytic enzymes on wheat straw (a cheap agricultural waste) extract and employing cell free enzyme extracts of seven white-rot fungal cultures to decolourise Poly R– 478 (a standard dye). The ligninolytic enzyme activities were correlated with dye degradation ability. The study has also been consolidated using immobilized fungal bioreactor at laboratory scale. The affectivity of degradation was assessed by analyzing the dye decolourisation with US-visible spectroscopy, studying decrease in chemical oxygen demand and toxicity of treated samples. The production of three ligninolytic enzymes was independent of incubation conditions with exception of laccase which was in general, better produced under stationary conditions. The Irpex flavus, Dichomitus squalens and Phlebia brevispora were the better dye degraders at bioreactor level. The ligninolytic enzyme maxima coincided with the maximum dye degradation rate. The chemical oxygen demand of the dye sample was lowered significantly by the D. squalens, P. brevispora and P. floridensis.

Today recycled paper is used to reduce the environmental impact of paper production. Starch as a dry strength additive improves the properties of recycled paper. Starch in combination with Poly-lactic Acid (PLA), a product from the biorefinery process, has the potentialto act as a promising strength additiveto further improve paper strength. In this study, PLA with molecular weight of 20,000, recycled pulp (OCC) with kappa number of 56.6, and cationic starch containing 0.43% nitrogen content were employed. Three machine conditions were run: Condition 1 – only pulp; condition 2 - pulp plus 1% starch; condition 3 - pulp plus 0.9% starch and 0.1% PLA. Selected paper properties were tested in accordance to TAPPI standards. The results showed that tensile index in the cross direction (CD) increased about 26 % for the paper made in condition 3 compared to condition 2. Tear strength of paper in condition 3 also showed a slight increase in the machine direction (MD), while it remained the same in CD, compared to the condition 2. There was no improvement seen for air and water resistance. Therefore, this study suggests that a blend of PLA – starch represents a promising approach in improving the strength properties of recycled paper.

In response to the increasing use of lightweight and durable raw materials in the manufacture of furniture for home and office, in this study, the effect of the skin type (MDF with a thickness of 3, 6 and 8 mm, particle board, plywood with 3 and 5 layers), the core type (polyurethane foam and Kraft paper honeycombs), and core thickness (3 and 4 cm) on mechanical strength of lightweight panels, were examined. The mechanical tests included bending strength, modulus of elasticity, impact bending, and compression. The results showed that the mechanical strength of lightweight panels made of polyurethane foam core, due to the higher density and good bonded with the skin, was better than lightweight panels made of kraft paper honeycomb core. By increasing the core thickness, the strengths of the panel was reduced. The best results were obtained in lightweight panels made of polyurethane foam core with a thickness of 3 cm and plywood skin.

This article reviews various adjustments in chemical additives and process conditions that can be used in the course of papermaking to manipulate either the efficiency of the process or the attributes of the resulting paper. Published studies show that the effects of certain chemical additives to the fiber suspension can be understood based on the forces of interaction between surfaces, i.e. the colloidal forces. There are opportunities to use such concepts to optimize the efficiency of retention of fine particles and the rate of water release during papermaking. It is proposed that – for easier understanding – the papermaking process should be viewed as a series of pairwise interactions, for which the outcomes depend on the ionic charges of surfaces, the hydrophobic or hydrophilic character of those surfaces, the balance of charges of dissolved polyelectrolytes, and conditions of hydrodynamic shear inherent in the unit operations of papermaking.