Rice straw pulp obtained by using various methods

2018

This paper presents an efficient method for obtaining pulp from wheat straw. The influence of the chemical reagents used and of the duration of cooking in the formic acid–hydrogen peroxide solution on the quality of performic pulp was investigated. The selectivity indexes of lignin extraction from wheat straw by performic acid were calculated. The regression equations that described adequately the dependences of the straw pulp quality indexes on the key technological parameters were calculated. The optimal values of the technological parameters for the delignification process using performic acid were determined. The mechanical properties of organosolv straw pulp confirmed its suitability for being used in the production of paper and cardboard. A lignin–carbohydrate diagram, indicating the efficiency of different delignification methods for wheat straw, was proposed.

2005

(*) To whom correspondence should be addressed. E-mail: roshandeh@ ut. ac. ir paper machines as compared to wood pulp and the specific properties of the black liquors resulting from straw cooking in basic environments, makes them hard to use in recovery systems [2]. These deficiencies are primarily due to the presence of large amounts of pentosanes in the pulp and black liquors, which also contain silica [3].

1970

The influence of soda ratio on pulp properties was used as a guideline for calcn. of the min. dose of chems. for producing bleached pulps for writing and printing papers. Pulps obtained by the shortcycle pressure method were compared with those from a pressureless method. The short method produced pulps of higher screened yield, better opacity, brightness stability, and higher bulk more efficiently than the pressureles method. The strength characteristics were approx. the same for the 2 methods. In-creasing the pulping chem. ratio to >9% NaOH did not increase the delignification rate although bleachability was improved by ≤13% NaOH.

Bioresource technology, 2016

Rice straw is supposed to be one of the most important lignocellulosic raw materials for pulp mill in Asian countries. The major problem in rice straw pulping is silica. The present research is focused on the separation of silica from the black liquor of rice straw pulping by potassium hydroxide (KOH) and pulp evaluation. Optimum KOH pulping conditions of rice straw were alkali charge 12% as NaOH, cooking temperature 150°C for 2h and material to liquor ratio, 1:6. At this condition pulp yield was 42.4% with kappa number 10.3. KOH pulp bleached to 85% brightness by D0EpD1 bleaching sequences with ClO2 consumption of 25kg/ton of pulp. Silica and lignin were separated from the black liquor of KOH pulping. The amount of recovered silica, lignin and hemicelluloses were 10.4%, 8.4% and 13.0%. The papermaking properties of KOH pulp from rice straw were slightly better than those of corresponding NaOH pulp.

Carbohydrate Polymers, 2011

As their is an increase of global demand in oil, the production of bioethanol from renewable agricultural feedstocks is also on the rise. Ethanol can be produced from a number of renewable resources such as starches, sugars, or lignocellulosic materials. Lignocellulosic materials continue to be investigated as a source of fermentable sugars for biofuel (ethanol) production because of their high availability. The current research investigates the utilization of newspaper and a mixture with rice straw, banana plant waste and corn cob as a feedstock to produce a value-added product -fuel ethanol, where ethanol is nowadays an important product in the fuel market. A preliminary investigation was performed to assess the conversion of the cellulosic component of newspaper as well as their mixture with agricultural wastes to ethanol. Biomasses were first tested, then a laboratory experimental set-up was designed in order to perform the necessary conversions. Conversion of the cellulose to glucose was achieved by applying chemical pulping method as a pre-treatment method for the biomasses then followed by two processes, namely acid hydrolysis and enzyme hydrolysis. Sulfuric acid, 5%, was used in acid hydrolysis and Trichoderma reesei cellulases in enzyme hydrolysis. These experiments demonstrated that glucose concentration differs according to the type of the biomass and type of hydrolysis. Conversion of the glucose to ethanol during fermentation was accomplished by the action of yeasts from Saccharomyces cerevisiae. Ethanol production in the culture sample was monitored using gas chromatography. The results indicate that ethanol can be made from the above mentioned residues in a different yield.

Polymers

Inspired by nature, cellulose extracted from plant wastes has been explored, due to its great potential as an alternative for synthetic fiber and filler that contributes to structural performance. The drive of this study was to extract, treat, and evaluate the characteristics of rice straw (RS) (Oryza sativa L.) cellulose as a biodegradable reinforcement to be utilized in polymer base materials. Two routes of extraction and treatment were performed via the pulping (Route 1) and chemo-mechanical methods (Route 2), in order to discover comparative characteristics of the synthesized cellulose fiber. Comprehensive characterization of RS cellulose was carried out to determine crystallinity, surface morphology, and chemical bonding properties, using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and Fourier transform infra-red (FTIR), respectively. The XRD test results showed that the crystallinity index (CI) of cellulose powder (CP) decreased after the surf...

Research Bulletin of the National Technical University of Ukraine "Kyiv Polytechnic Institute", 2015

Background. Decreasing of wood consumption and hazardous wastes in environment due to ecologically safe methods of plant raw material delignification. Objective. Identification of technological parameters influence on obtaining of organosolvent straw pulp and impact of catalysts (anthraquinone and hydrazine) on the delignification process, main quality indices of pulp, kinetic characteristics. Methods. Pulping of organosolvent straw pulp with using of catalysts was performed in 0.25 dm 3 steel autoclaves placed in glycerol bath heated at temperature 140-180 °C and 30-150 minutes duration. Results. Obtained organosolvent straw pulp with anthraquinone and hydrazine catalysts are characterized by such physical and mechanical properties: breaking length-7900-6900 m; burst index-4.33-4.52 kN/g; folding strength-128-600 double folds. It was established that using of hydrazine catalyst allows obtaining pulp with lesser lignin, ash and pentosans content then with anthraquinone. It was determined that delignification in isobutanol-KOH-watercatalyst system is described by second-order kinetic equation. Kinetic characteristics (reaction rate and energy of activation) of wheat straw delignification and characteristics of lignin removal from plant raw material were calculated. Conclusions. Obtained organosolvent straw pulp is suitable for production of paper and cardboard products and after bleaching and alkali treatment-for further chemical treatment into different cellulose derivatives.

Tropical Agricultural Research

In the recent years, natural fibres have gained greater attention to replace synthetic fibres in producing environmentally friendly green products. These are currently considered as one of the most promising areas of scientific and technological development due to strong global demand for creating a resource circulating society. Rice is one of the largest crops in the world. Sri Lanka being an agricultural country holds twentieth position in the worldwide rice production with 2.4 and 3.9 million metric tons in the years 2017 and 2018 respectively. However, a large amount of rice straw is generated per annum as a by-product of rice production in the country. Even though rice straw is utilized in various ways, there is a possibility for a value addition by extracting its constituents such as cellulose fibres from this underutilized waste material. In this work, cellulose fibres were extracted from locally available rice straw varieties via a series of chemical treatments. Technically modified variety BG352 and traditional variety Murunkan were used for this purpose. The material obtained after chemical treatment was carefully characterized and its chemical composition was determined. Fourier transform Infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analyses showed the progressive and complete removal of non-cellulosic constituents from the rice straw. Morphological investigation was performed using scanning electron microscopy (SEM). Thermal stability of the fibres was investigated using thermogravimetric analysis (TGA). The results showed around 26 and 33 percent cellulose fibres were extracted from rice straw varieties BG352 and Murunkan respectively.

Biomass and Bioenergy, 1996

Hemicellulose alkaline extraction was integrated prior to the well-known soda-anthraquinone (soda-AQ) pulping process. The resulting integrated process is called the integrated soda pulping (ISP) process. By the means of central compositely designed experiments, the ISP process was optimized in order to produce a good quality pulp from barley straw along with a significant amount of xylan-containing hemicellulose. The identified pre-extraction parameters to be optimized were the NaOH charge (dry straw basis), operating temperature, and extraction time. For comparison purposes, a reference soda-AQ pulp was also produced under the same cooking conditions.

Wood Science and Technology, 1999

A central composite design was used to investigate the in¯uence of the cooking conditions (time, temperature and butanol concentration) for wheat straw with butanol-water mixtures on the properties of the pulp obtained (yield and holocellulose, a-cellulose, lignin and ethanol-benzene extractives contents) and the pH of the resulting waste water. A second-order polynomial model consisting of three independent process variables was found to accurately describe the organosolv pulping of wheat straw. The equations derived predict the yield, the holocellulose, a-cellulose, lignin and ethanol-benzene extractives contents of the pulp, and the pH of the waste water with multiple-R, R 2 , adjusted-R 2 and Snedecor' F values of 0.99, 0.99, 0.99 and 310.33; 0.98, 0.97, 0.95 and 56. 63; 0.91, 0.84, 0.74 and 9.14; 0.99, 0.98, 0.96 and 70.52; 0.97, 0.94, 0.92 and 40.42; and 0.98, 0.95, 0.93 and 49.33, respectively. The process variables must be set at low values in order to ensure a high yield and pH. On the other hand, if a high holocellulose content and low lignin and ethanol-benzene extractives contents are to be obtained, then the process variables must be set at high values. Finally, obtaining pulp with a high a-cellulose content entails using a long cooking time and a high temperature, as well as a low butanol concentration.