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Chemical property and characteristics of polymer
Published in S. Thirumalai Kumaran, Tae Jo Ko, S. Suresh Kumar, Temel Varol, Materials for Lightweight Constructions, 2023
A. Sofi, Joshua Jeffrey, Abhimanyu Singh Rathor
Rice husks, also known as hulls, are the outer layer of rice grains that protect the rice seeds throughout the growth process. They are rich in lignin and amorphous silica, making them tough to digest for humans. Hence, they are discarded and burnt as a fuel source. The product of the ash that is created is called rice hull ash (RHA) and is mainly composed of silica. With almost three million tonnes of silica produced annually around the world, RHA silica is considered a significant waste stream. The ash is pulverized to a particle size of 0.1–2 m, a specific surface area of around 30 m2/g, and an oil absorption of 30–40 ml/100 g [44].
Toughening of Ceramics
Published in David W. Richerson, William E. Lee, Modern Ceramic Engineering, 2018
David W. Richerson, William E. Lee
Much of the exploratory work of whisker toughening of ceramics was conducted with SiC whiskers in Al2O3.61,62 This was first made possible when a source of SiC whiskers became available. The story of the development and eventual commercialization of these SiC whiskers is quite interesting. Whiskers were first produced on a research basis at the University of Utah by J. G. Lee and Dr. Ivan B. Cutler.63 They were studying ways of utilizing solid waste materials, specifically rice hulls. Chemical analysis showed that rice hulls contained about 14% SiO2, in addition to the normal carbon content one would expect for an organic material. The University of Utah team hypothesized that they could heat the rice hulls to around 1500°C in a nonoxidizing atmosphere and produce SiC powder. When they conducted their experiments to evaluate their hypothesis, they got SiC, but much of it was in the form of whiskers rather than particles. This technology was licensed and refined and ultimately ended up with Arco Chemical (later became Advanced Composite Materials). Individuals at Arco Chemical collaborated with researchers at Oak Ridge National Labs (ORNL) to evaluate the whiskers in Al2O3 and other matrix materials.
A novel basydiomycete isolated from mangrove swamps in the Colombian Caribbean shows promise in dye bioremediation
Published in Bioremediation Journal, 2022
Laura M. Jutinico-Shubach, Jesús D. Castaño, Tulio Juarez, Miguel Mariño, Javier Gómez-León, Lina M. Blandón
The effect of the carbon source, nitrogen source and inducer addition on laccase activity was evaluated using the one-factor-at-a-time method. For this purpose, the carbon source wheat bran, was substituted by other agro-industrial-wastes: corncob, banana peel and rice hulls (50 gL−1). The banana peel and corncob were washed with distilled water to remove impurities and dried at 60 °C for 3 days. The dried and sieved solid (size 300 μm) was used as a carbon source in the culture medium. The nitrogen source peptone, was replaced with ammonium sulfate, yeast extract and sodium nitrate (1.4 gL−1). On the other hand, the effect of different molecules reported as laccase activity inducers (Elisashvili et al. 2010) was evaluated. The compounds 2,5-xylidine, veratryl alcohol, vanillic acid (1 mM in 3% ethanol) and ethanol (3%) were added on the fourth day of growth. After addition, the flasks were incubated for eight days at 26 ± 3 °C in darkness. The supernatants were collected and evaluated as described above. ANOVA tests (p < 0.05) were run using the agricolae package (Mendiburu 2017) in R software (R version 4.0.3 (2020-10-10), R Foundation for statistical computing).
Bio-ethanol production from a mixture of rice hull and orange peel wastes
Published in Biofuels, 2022
Ahmad Taghizadeh-Alisaraei, Ahmad Abbaszadeh-Mayvan, Seyyed Hassan Hosseini
Banerjee et al. studied wet-air oxidation as a pretreatment strategy for bioethanol production from rice hulls. Results showed this pretreatment of rice hulls increased the cellulose content of the solid fraction by virtue of lignin removal and hemicellulose solubilization. They achieved 67% (w/w) cellulose content in the solid fraction, along with 89% lignin removal and 70% hemicellulose solubilization. In the liquid fraction, they detected 13.1 g/L glucose and 3.4 g/L xylose [20]. In another study, Dagnino et al. investigated the optimization of acid pretreatment of rice hulls to obtain fermentable sugars for bioethanol production. They reported that the performance of the enzymatic hydrolysis was about 50% (25% of total sugars present) over 48 h reaction time, and the efficiency of conversion of dissolved sugars to bioethanol was 84% [21]. Singh et al. studied the enzymatic hydrolysis of microwave alkali-pretreated rice hulls for ethanol production by Saccharomyces cerevisiae, Scheffersomyces stipitis, and their co-culture. They reported ethanol yields with S. cerevisiae of 0.3, 0.35, 0.40 and 0.39 g/g; with S. stipitis of 0.24, 0.27, 0.36 and 0.35 g/g; and with their co-culture of 0.33, 0.36, 0.42 and 0.40 g/g, with different sugar concentrations. The maximum ethanol yield was found to be 0.42 g/g with co-culture, 0.40 g/g with S. cerevisiae, and 0.36 with S. stipitis at an initial reducing sugar concentration of 50 g/L [15].
Determination of hydraulic retention time using a Piecewise linear regression analysis in the anaerobic digestion process
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
Hyeonsoo Jo, Jangwook Choi, Ishfaq Muhammad, Muhammad Usman Akhtar, Xiang Li, Jun Bao, Shinmook Choi, Syed Waqas Ali Shah, Abdul Qayum, Muhammad Altaf Hussain, Jaehee Lee
Substrate and inoculated sludge were used by S/I (Substrate/Inoculum) ratios 0.5, 1.0, 2.0, 4.0, and 50.0 based on the VS (Volatile solids). During the anaerobic digestion process, biogas yields were decreased linearly as increasing the level of lignin content in the biomass such as sawdust or rice hulls. If the lignin content increases from 15% (dry basis) to 25% (wet basis), biogas yield could decrease by about 45% (Liew, Shi, and Li 2012). In order to overcome these shortcomings, pre-treatment processes are recommended in the anaerobic digestion process and used such as inoculation for increasing the decomposition rate of organic material that increases the methane yield and results in shorten HRT.