Volume 3 Issue 4

The capacity for removal of heavy metals from liquid streams by formation of complexes with lignins oxidized by acid treatment was studied. Lignins were obtained from different sources: sulfuric acid pre-treated cane bagasse, soda pulping bagasse, eucalypt Kraft lignin, and commercial Kraft lignin. These lignins were characterized using different techniques to determine Klason lignin, carbohydrates, total acids, ashes, and their main functional groups: phenolic-OH, carbonyls, etc. The studied lignins were determined spectroscopically using FTIR. In order to increase the metal adsorption capacity, lignins were oxidized at 100°C during 2 h, using aqueous solutions of H2O2 in distilled water solvent and HCl catalyst. Some lignin adsorption isotherms were constructed before and after the oxidation process to define Cd(II) ion removal capacity.

A theoretical method for prediction of cutting edge recession during milling wood and wood-based products, due to the presence of hard mineral contamination, High Temperature Tribochemical Reactions (HTTR), and frictional wearing, based on 3D random distribution of contaminant particles is presented and positively verified based on the example of three experiments from the literature, showing good correlation between the predicted and observed cutting edge recession.

The purpose of this study is to develop an analytical method to quantify the nitrogen present at the surface of paper by using X-ray photo-electronic spectroscopy (XPS). A sample of softwood thermomechanical pulp (TMP) was treated with a cationic starch containing primary amines, while another one was treated with a cationic polymer containing quaternary amines. We also grafted monomers containing a quaternary amine to the fiber. Sheets were prepared and analyzed by XPS. The technique used allowed us to identify the type of amine and to give a semi-quantitative evaluation.

Environmental pollution has a harmful action on bioresources, including agricultural crops. It is generated through many industrial activities such as mining, coal burning, chemical technology, cement production, pulp and paper industry, etc. The toxicity of different industrial wastes and heavy metals excess was evaluated using crop plant assays (germination and hydroponics seedlings growth tests). Experimental data regarding the germination process of wheat (from two cultivars) and rye seeds in the presence of industrial wastes (thermal power station ash, effluents from a pre-bleaching stage performed on a Kraft cellulose – chlorinated lignin products or chlorolignin), along with use of an excess of some heavy metals (Zn and Cu) are presented here. Relative seed germination, relative root elongation, and germination index (a factor of relative seed germination and relative root elongation) were determined. Relative root elongation and germination index were more sensitive indicators of toxicity than seed germination. The toxic effects were also evaluated in hydroponics experiments, the sensitivity of three crop plant species, namely Triticum aestivum L. (wheat), Secale cereale (rye), and Zea mays (corn) being compared. Physiological aspects, evidenced both by visual observation and biometric measurements (mean root, aerial part and plant length), as well as the cellulose and lignin content were examined.

The present work concerns the experimental evaluation of hazelnut shells as a low cost natural biosorbent. Adsorption of the direct azo dye Congo Red was performed within a concentrations range of 50-5000 mg/L. Hazelnut shells were employed as organic support for Phanerochaete chrysosporium cultures to study the best cultural medium composition for the MnP production. The capability of Phanerochaete chrysosporium to take macronutrients as carbon and nitrogen from hazelnut shells was demonstrated. Cultures of Phanerochaete chrysosporium were carried out with hazelnut shells coming from Congo Red adsorption tests, showing that 43% of the adsorbed dye was degraded.

Experiments were performed to evaluate a recent extraction process called the instantaneous controlled pressure drop process (briefly: DIC process: “Détente Instantanée Contrôlée”) for extracting some volatile compounds from red cedar wood. This process involves subjecting red cedar chips for a short time (30 s to 5 min) under a steam pressure (1 to 6 bars or from 100 to 165 °C). This first step is followed by a flash decompression toward vacuum (up to 50 mbar). This transition induces a fast evaporation of water and volatile compounds and a cooling effect. The effects of two processing parameters (steam pressure and heating time) on the total extraction yield and on yield of four volatile compounds were evaluated by response surface methodology. The results indicated that the processing pressure is the predominant parameter for global extraction yield of oil (E.O= Extracted Oil) and for yield of the four compounds investigated in this study. The processing time is also a significant parameter but less than processing pressure. Moreover, activated carbon produced from DIC-treated residue revealed larger pore sizes compared to untreated samples.

Fabrication of polymer composites reinforced with lignocellulosic materials has increased considerably during the last few years. This work reports the synthesis of natural fiber reinforced phenol-formaldehyde (PF) resin matrix based polymer composite using a compression molding technique. Initially the PF resin was prepared by varying the concentration of formaldehyde with a fixed weight of phenol. Polymeric resin of different P: F ratios were subjected for optimization of their mechanical properties. The sample ratio of 1:1.5 (P: F) was found to possess maximum mechanical strength. Then reinforcing of this optimized resin was done by taking different ratios of Hibiscus Sabdariffa (HS) fiber in short form (3mm) to prepare green polymer composites. Polymer composite materials thus prepared were subjected to evaluation of their mechanical properties such as tensile strength, compressive strength, flexural strength, and wear resistance, etc. Optimum mechanical properties were obtained with a fibre loading of 30%.Thermal (TGA/DTA/DTG) and morphological studies (SEM) of the polymeric resin, and composites thus synthesized have also been studied. The results obtained suggest that thesefiberscan be a superior candidate for the reinforcement of high performance polymer composites.

Polystyrene sulfonic acid (PSS), lignosulfonic acid (LS) sodium salts, and carboxymethylcellulose (CMC) were used as doping/dispersing agents in the chemical polymerization of polypyrrole (Ppy). Conductivity measure-ments performed on dry Ppy pellets showed a sharp increase in conductivity when adding the anionic polymers to the polymerization liquor. For a polyanion/pyrrole weight ratio ranging between 0.1 and 0.6, the highest conductivity was given by PpyCMC (82 S/m) and PpyPSS (80 S/m), followed by PpyLS (6 S/m). On the other hand, for a polyanion/pyrrole ratio higher than 0.6, the conductivity of PpyPSS systems sharply decreased, and for polyanion/pyrrole ratios higher than 1, the highest conductivity was given by PpyCMC (~10 S/m), followed by PpyLS (~7 S/m) and PpyPSS (~5 S/m). Zeta-potential measurements showed that the surface charge of Ppy was strongly affected by the polyanion type and amount. Cationic Ppy particles were obtained in the presence of the two polymers bearing strongly acidic moieties (PSS and LS). Anionic PpyPSS colloids were obtained at the highest PSS/Py ratio, after the degradation of the conducting properties. When using a weakly acidic dopant (CMC), PpyCMC colloids had a negative charge for all of the tested conditions.

The present study investigates the economical production of bacterial cellulose (BC) byGluconacetobacter subsp. Xylinus (ATCC 10245) in 250 ml Erlenmeyer flasks cultivated under static conditions. The fermentation media used contained food industrial by-product liquors, such as black strap molasses solution and corn steep liquor (CSL), which represents some of the most economical carbon and nitrogen sources. However, because of the presence of undesirable components in molasses (such as coloring substances, heavy metals, and other compounds) that may act as inhibitors, and in order to eliminate them, crude molasses has been treated with an acid, as an attempt to increase BC productivity. The amount of BC produced using these carbon and nitrogen sources was determined and compared to that produced using previously reported fermentation media. The characterizations of the bacterial cellulose (BC) pellicles obtained using either conventional or by-product media were studied by thermal and spectral techniques and compared to those of plant-derived cellulose such as cotton linter, viscose pulp, and microcrystalline cellulose.

Fibre flexibility is often anticipated to play a role in fibre flocculation phenomena. In this study, 3 thermomechanical pulps (TMPs) were sampled along a post-refining line. The only fibre morphological property that varied was fibre flexibility. These TMP samples were then tested for fibre flocculation and sheet formation tendency. The measurements clearly showed that fibre flocculation decreased and sheet formation uniformity increased with increasing fibre flexibility. The beneficial effect of fibre flexibility was larger at high consistency. These results support the elastic energy storage theory within flocs, which states that the more rigid the fibre, the stronger the flocs. Papermakers may take advantage of the beneficial effect of fibre flexibility on sheet formation through a careful tuning of post-refining.