Research Articles

Creatinine is one of the major toxins in patients suffering from chronic renal failure. In this paper, cellulose dinitrobenzoate, with a degree of substitution (DS) of 0.15, was used as an oral adsorbent for creatinine adsorption. Cellulose dinitrobenzoate was prepared by modification of cellulose with 3,5-dinitrobenzoyl chloride in 1-butyl-3-methylimidazolium chloride (BMIMCl) ionic liquid as a homogenous medium. The effects of contact time, pH, adsorption temperature, and initial concentration of creatinine on the adsorption per unit mass of cellulose dinitrobenzoate were studied, comparatively. Results showed that the maximum adsorption per unit mass for creatinine was 3.88 mg/g. Furthermore, the adsorption process was spontaneous and exothermic. It was determined that the experimental results were well fitted to the pseudo-second-order rate equation and the Freundlich adsorption isotherm. Compared with traditional oral adsorbents, this cellulose-based adsorbent was biocompatible and could remove creatinine from dialysate effectively.

The present study shows that barley straw (Hordeum vulgare) can be a supplementary raw material of softwoods and hardwoods such as Pinus sylvestris and Eucalyptus camaldulensis, respectively,for the production of cellulose and paper, reducing an agricultural residue that has no added value. Barley straw has a lower content of cellulose at 36.4% than P. sylvestris and E. camaldulensis, but it contains a lower quantity of lignin, 15.9%. After pulping with soda anthraquinone (AQ), high contents of cellulose (56.5 to 67.5%) and holocellulose (>80%) were attained. Paper sheet properties were able to reach, and even improve upon, those of wood species (Pinus and Eucalyptus) pulped with kraft. Better values of total yield (56.5%), Kappa number (8.9), and ISO brightness (36.4%), were attained for paper sheets from barley straw pulp versus E. camaldulensis and P. sylvestris, respectively, and comparable values for viscosity, tensile, and burst index were obtained.

In China, alkaline peroxide mechanical pulping performed with refiner-chemical preconditioning (P-RC APMP) is well known to produce fiber with high bulk, opacity, and light scattering coefficient but weak bonding and strength properties. In this study, the characteristics of different P-RC APMP fiber fractions were investigated, and their effects on bonding strength properties were determined. The results showed that there was only 5.8% R30 fiber fraction and 14.1% P100/R200 fiber fraction, and the specific surface area increased from R30 to P100/R200. The tensile index increased by 51.85% and the bonding index increased by 15.35%, when the fibers were changed from the R30 fraction to the P100/R200 fraction. The short fiber fraction (P100/R200 fraction) had smaller fiber length and coarseness but larger specific surface area and greater surface charge density than the long fiber fraction (R30 fraction). The fiber specific surface area and surface charge density made significant contributions to the bonding capacity, whereas fiber coarseness and length were negatively correlated with the tensile index.

The causticizing calcium carbonate (CCC) produced in the causticizing stage of the chemical recovery process in alkaline pulping of wheat straw has a high silicate content and is difficult to convert to calcium oxide in the lime kiln. The CCC can be utilized as a paper filler to avoid costly lime re-burning, but the silicate content of the CCC can have a negative impact on the wet-end chemistry of the papermaking process. In this paper, the effect of the silicate content of the CCC filler on AKD sizing was investigated. CCC fillers of various silicate contents were prepared in the lab by causticizing green liquor from the soda pulping of wheat straw and were added to fiber suspensions at the wet end of the papermaking process. The results show that the impact of the CCC filler on AKD sizing was associated with its silicate content. As the silicate content increased, the specific surface area and negative charge density of the CCC particles markedly increased, resulting in more AKD adsorption onto the CCC particles instead of fibers.

Contents of silica and extractive substances in rice straw depending on rice varieties were investigated. The samples of amorphous silica were prepared, their microelement composition and morphology were investigated, and the values of true and bulk density were estimated. The porous structure of the samples was studied by the Brunauer-Emmett-Teller (BET) method and by water vapour sorption; the specific surface values, as well as the pore diameter and volume, were also determined. Sorption properties of the SiO2 surface were analyzed on a sample of Mn2+-ions and the organic dyes brilliant green and methylene blue.

Banana pseudo-stem fibers (BPSFs) have desirable tensile properties. In this study, BPSFs were extracted using mechanical, chemical, and enzymatic methods. The aim was to evaluate the effect of these three extraction methods on the tensile, thermal, and morphological properties of BPSFs. Microstructural analysis showed the presence of structural and arch fibers in banana pseudo-stem (BPS). The average tensile strength and elongation for mechanically, chemically, and enzyme-extracted BPSFs were 210, 333, and 235 MPa, and 0.8%, 1.6%, and 1.4%, respectively. Young’s modulus was enhanced by 19.1% in the mechanically extracted BPSFs compared with that of chemically extracted BPSFs. The morphology of BPSFs was correlated with their tensile properties via scanning electron microscopy (SEM) image analysis. Fourier transform infra-red (FTIR) and X-ray diffraction (XRD) analyses of fibers showed that chemically extracted BPSFs contained less hemicellulose and lignin with a crystallinity index of 61.2%. Chemically extracted BPSFs exhibited enhanced thermal properties over mechanically extracted BPSFs. Mechanically extracted BPSFs demonstrated similar thermal and tensile properties to chemically and enzyme-extracted BPSFs. Thus, mechanically extracted BPSFs could act as highly suitable reinforcing agents in bio-based composite material preparation. Given that mechanical methods need no chemicals and they are environmentally friendly, such techniques have potential applications.

The use of formaldehyde-free, biomass-based composites has gained increasing attention in recent years because of their environmental benefits and superior strength properties. In this study, oriented cotton stalk board (OCB) was fabricated with an environmentally friendly, water-based konjac glucomannan-chitosan-polyvinyl alcohol (KCP) blend adhesive using hot pressing technology. The effects of pressing parameters on the physical and mechanical properties of oriented cotton stalk board were examined in order to obtain optimal pressing parameters. Interfacial bonding surface was also examined with a scanning electron microscope and a fluorescence microscope. The optimal physical and mechanical properties were obtained at a pressing temperature of 150 °C for 15 min with a target density of 0.8 g/cm3 during hot pressing. Adhesive content and hot pressing pressure had significant influences on adhesion. Mechanical interlocking was also observed between cotton stalks and the adhesive. OCB with KCP blend adhesive has comparable mechanical properties to that with urea formaldehyde resin or phenolic formaldehyde resin. OCB resinated with KCP blend adhesive is environmental friendly and has potential applications in furniture and interior decoration with less stringent requirements for water resistance.

Fiber-reinforced polymer composites are widely used in various applications because of their mechanical properties and ease of manufacture. Fiber-reinforced plastics are being developed using synthetic fiber and natural fibers of bagasse, palm biomass, etc. In this study, the mechanical strength of bagasse fiber-reinforced epoxy composite was investigated using a Design of Experiment technique. The parameters of fiber volume percentage, alkali concentration, and treatment time with three levels were considered, and an L27 design matrix was developed using the Taguchi orthogonal array. The bagasse was first treated with sodium hydroxide solution (NaOH); subsequently, 27 specimens were developed for experimental investigation. The mechanical strength of newly developed bagasse fiber-reinforced epoxy composite was investigated using a three-point bending testing machine. The flexural strength was calculated using three-point bending strength for length versus load combination. The analysis and optimization was done using the Taguchi method, and a second-order mathematical model was developed using response surface methodology (RSM). A significant performance improvement in the flexural strength of the newly developed composite was found.

The construction industry is one of the largest and most active growth sectors worldwide. It presents an important environmental impact, and one way to reduce the impact of the construction activity is to substitute pozzolanic materials for ordinary Portland cement. In this work, barley straw, barley straw ash, and other natural and artificial pozzolans from Mexico were characterized and compared. Also, the pozzolanic activity of barley straw ash was compared with the pozzolanic properties of some natural and artificial pozzolans from Mexico. Materials considered included recycled dust of fired clay brick, fly ash, volcanic ash, and wheat straw ash.

In this study, effects of adhesive and additive’s type and ratio on burning characteristics of particleboard (PB) added glass wool (GW) and rock wool (RW) were researched. PB’s furnish was derived from 50% Crimean pine, 30% Eastern Black Sea oak, 15% quaking aspen, and 5% residues of wood machining, and moisture content of furnish was 1.5 to 3%. Seventy PBs with 0.64 g/cm3 density, urea formaldehyde (UF)/melamine formaldehyde (MF) fixed amount, 14 mm thickness, 45×45 cm2 dimensions and 10%, 15%, 20% SW/GW additives were produced. The 150 ºC pressing temperature with 25 kg/cm2 compression pressure was constant. Burning tests for determination of ignition time, flaming combustion temperature, flaming combustion duration, smoldering combustion duration, and mass loss during burning were made according to DIN4102 standards. According to the results of the tests, adhesive type did not affect ignition time and mass loss. While flaming combustion temperature of PB with UF was 19% higher, flaming combustion duration and smoldering combustion duration was 32% and 29% lower than those of PB with MF, respectively. While ignition time of PB with GW was 50% higher than that of PB with RW, changes in burning properties were similar for both PBs. An increase in the content of GW and RW affected burning properties of PB positively and an increase of ignition time up to 196% were obtained.