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Cellulose nanocrystals (CNC) and succinic anhydride-modified CNC from bleached soda bagasse pulp under different parameters were used to remove Cd+2 and Pb+2 heavy metal ions from aqueous solution. The aim was to modify the chemical structure of cellulose nanocrystal using succinic anhydride and to investigate the effect of CNC and succinic anhydride-modified CNC on the adsorption capacity of heavy metal ions. The adsorption parameters included pH (3, 5, 6, and 8), contact time (30, 60, and 90 min), and initial metal ion concentration (40, 120, 200, and 280 ppm). It was found at all pHs that the adsorption capacity of the succinic anhydride-modified CNC adsorbent was much higher than that of the default CNC adsorbent, and this difference was greater at higher pHs. The results showed that the maximum metal ion adsorption was obtained at pH 6 for Pb+2 and Cd+2 ions. Both types of CNC had a higher adsorption capacity for lead ions than cadmium ions. To investigate the kinetic models of adsorption, the pseudo-first-order and pseudo-second-order kinetics model were used. Adsorption on unmodified adsorbent gave a better fit to the Langmuir model than the Freundlich model for both Pb+2 and Cd+2 metals. In addition, the adsorption mechanism was changed by modifying the adsorbent, and then it had better fit to the Freundlich adsorption model. Adsorption of cadmium and lead metals by adsorbents fit better to the pseudo-first-order kinetics model. [ABSTRACT FROM AUTHOR]

Effects of wollastonite substitution were investigated relative to the mechanical, physical, and microstructural properties of a wood fibercement composite. Wollastonite content of 0%, 3%, 6%, and 9% and lignocellulosic material (kraft fibers) content of 10%, 20%, and 30% were used based on the dry weight of cement. Then the lignocellulosic material and the resulting board samples were compared to a control (without wollastonite). Modulus of rupture (MOR), modulus of elasticity (MOE), water absorption, and fire resistance tests were conducted to examine the characteristics of the board composite. The results showed that the mechanical properties of wood fiber-cement composite were improved by the 9% wollastonite substitution. The fire-resistance of the composite board was improved when the wollastonite content was increased. Furthermore, cement boards with 9% wollastonite exhibited lower water absorption in comparison to the other specimens. Scanning electron microscopy (SEM) results showed that the calcium hydroxide formed hydrated calcium silicate gel (C-S-H gel) after the addition of wollastonite. The SEM images showed that the micro-structure of the boards were improved by increasing the nano-wollastonite content. [ABSTRACT FROM AUTHOR]

The flammability behavior of wood/plastic nanocomposites made from recycled polystyrene, wood flour, and nanoclay were investigated in this study. The wood flour was mixed, using the two weight ratios of 40 wt.% and 60 wt.% with recycled polystyrene, and nanoclay was added at 0 wt.% and 5 wt.%. A coupling agent was also added at up to 3 wt.% of the composite. The results showed that the oxygen index increased when higher contents of wood flour were added. Furthermore, it was found that the samples required more oxygen for ignition when the percentage of wood flour was increased. Similarly, it was found that the samples required a greater amount of oxygen for ignition with increasing nanoclay content. Therefore, the flammability of the sample decreased because the time to ignition took longer in the absence of sufficient oxygenation. X-ray analysis of the nanocomposites revealed that the morphological structure involved intercalation. [ABSTRACT FROM AUTHOR]

The effect of fungal pretreatment of Hornbeam (Carpinus betulus) wood chips on the performance of treated pulps was studied. The chips were pretreated with P. chrysosporium BKM-1767 fungus at 1, 2, and 4 weeks using an inoculation temperature and relative humidity of 39 °C and 65%, respectively with two pulping times (80 and 90 min) and three sodium sulfite charges (14, 18, and 22%). The cooking temperature of 165 °C, and liquor-to-wood ratio of 7:1 were kept constant. Beating energy consumption showed a maximum savings of 43% for four-week treatment of wood chips with the fungus. The screen yield of the unbleached CMP ranged between 76 and 84% depending on the chip inoculation time and cooking conditions. A decreasing trend in screen yield of the pulp after chips incubation could be explained by the enzyme action on the lignin or polysaccharides. Pulp strengths including tensile, burst, tear, and fold declined with an increase in chip treatment time. Applying 3% H2O2, 4.2% NaOH, 3% NaSiO3, and 0.3% DTPA for 1 hour in two similar stages and 2 weeks fungal pretreatment of chips showed the best optical properties of bleached pulp. After a two-stage H2O2-bleaching sequence, the maximal brightness value for the control and biopulps were 54.8% and 56.2%, respectively. Overall, two-week treatment showed the better performance of P. chrysosporium on Hornbeam chips. [ABSTRACT FROM AUTHOR]

Effects of chemical treatment on the potential for recycling of bagasse pulp were evaluated. The pulps were recycled three times with water (without treatment), sodium hydroxide, and ethylamine separately. Changes in crystalline structure of the pulp during recycling were investigated by x-ray diffractometry. Water retention content was measured by centrifugation. Morphological changes were investigated by scanning electron microscopy. The breaking length, burst index, fold number, water retention value, and density decreased continuously after recycling. Chemical treatment didn't have a positive effect on the swelling of the recycled pulp. But the light scattering coefficient increased continuously. The crystallinity index and crystallite size increased to an extent, compared to virgin pulp. Some particles on recycled fibers with chemical treatment and treated handsheets had more curled fibers than untreated handsheets. [ABSTRACT FROM AUTHOR]

Structural and chemical changes were investigated in Hornbeam (Carpinus betulus) chips that had been exposed to Phanerochaete chrysosporium BKM-1767 fungus. Samples subjected to fungal treatments for durations of 1, 2, and 4 weeks were investigated and compared with a control sample not subjected to fungal treatment. Results of scanning electron microscopy indicated that fungal hyphae were present on the surfaces of all chips exposed to the fungus. In the samples treated for a 2 or 4-week period, these hyphae additionally penetrated into vessels and lumens through ray cells, softening and destroying the cell walls. FT-IR spectra indicated that fungal treatment modified the chemical structure of the wood. Furthermore, there was a remarkable decrease in the amount of lignin in woods exposed to fungus. Lignin decreases after 1, 2, and 4 weeks of treatment were 2.83%, 11.4%, and 18.56%, respectively. Measurement of fiber dimensions indicated that cell wall thicknesses decreased after treatment, but that the lumen width increased compared with the control sample. [ABSTRACT FROM AUTHOR]