China
Africa
Explore chapters and articles related to this topic
Prospects of Utilization of Various Solid Agro Wastes for Making Value Added Products for Sustainable Development
Published in Gunjan Mukherjee, Sunny Dhiman, Waste Management, 2023
J. Sharon Mano Pappu, Sathyanarayana N. Gummadi
Steam explosion: It is a hydrothermal pretreatment method in which the LCB is exposed to pressurized steam and depressurized immediately. It is considered as an important physical– chemical pre-treatment method that employs high pressure saturated steam which results in autohydrolysis reactions and converts hemicellulose and lignin to soluble oligomers (Hamelinck et al. 2005). Sudden reduction in pressure after treatment causes explosive decompression of biomass, which causes degradation of hemicellulose and disruption of lignin matrix. Generation of acetic acid from acetyl groups and action of water as acid at high temperature results in autohydrolysis. Steam explosion pretreatment increases cellulose crystallinity by promoting crystallization of amorphous structure, easy hydrolyzation of hemicellulose and progresses delignification of LCB. Moisture content of raw materials, residence time, chip size, temperature and moisture content are the factors that affect steam explosion. Hardwood such as oak and maple and agricultural wastes can be pre- treated by physical-chemical methods in a cost-effective manner but it is not much efficient for softwoods (Balat et al. 2008).
Advanced Biomass Pretreatment Processes for Bioconversion
Published in Prakash Kumar Sarangi, Sonil Nanda, Bioprocessing of Biofuels, 2020
Prakash Kumar Sarangi, Sonil Nanda
Steam explosion is one of the traditional and widely used physicochemical pretreatments for biomass hydrolysis. Steam explosion is a mild, chemical-free (typically) and cost-effective approach to pretreat lignocellulosic biomass. Water is involved to heat the biomass under pressure followed by a sudden decompression of the reaction vessel to explode the cellulosic fibers (Pielhop et al. 2016). Temperature involved in this process varies from 160 to 260°C and pressure varies from 0.69 to 4.83 MPa (Yu et al. 2012).
Integrated Approach for the Sustainable Extraction of Carbohydrates and Proteins from Microalgae
Published in Kalyan Gayen, Tridib Kumar Bhowmick, Sunil K. Maity, Sustainable Downstream Processing of Microalgae for Industrial Application, 2019
Sambit Sarkar, Mriganka Sekhar Manna, Sunil Kumar Maity, Tridib Kumar Bhowmik, Kalyan Gayen
The steam explosion is one of the pre-treatment processes of lignocellulosic materials. It offers both the mechanical and chemical disruption in unison. The technique has recently been proved to be effective in the disruption of the microalgal cell wall (Nurra et al. 2014), as polysaccharides are the main constituent of this organism. Steam explosion hydrolyzes the polysaccharides to monosaccharides (Lorente et al. 2017) that remains in the aqueous phase after solid–liquid separation, and the monosaccharides can eventually be concentrated using NF (Gerardo, Oatley-Radcliffe, and Lovitt 2014; Nelson and Barbano 2005; Vyas and Tong 2003; Morr and Brandon 2008; Pouliot 2008; Brans et al. 2004; Patel et al. 2013; Marcati et al. 2014). The dynamic tangential filtration has been introduced to avoid membrane fouling (Nurra et al. 2014a; Rios et al. 2011; Ríos et al. 2012).
Methane, a renewable biofuel: from organic waste to bioenergy
Published in Biofuels, 2022
Mixtli J. Torres-Sebastián, Juan G. Colli-Mull, Lourdes Escobedo-Sánchez, Daniel Martínez-Fong, Leonardo Rios-Solis, María E. Gutiérrez-Castillo, Gloria López-Jiménez, María L. Moreno-Rivera, Luis R. Tovar-Gálvez, Armando J. Espadas-Álvarez
Steam explosion is a physicochemical pretreatment for lignocellulosic biomass that consists of placing it in a container with saturated steam (and pressure above atmospheric) for a certain time. The steam diffuses through the lignocellulose, which is heated and moistened, causing some acids to be released from the hemicellulose, lowering the pH, favoring autohydrolysis. At the end of the steam treatment, the pressure is released abruptly, for example, by opening a reactor valve. Due to this sudden pressure drop, usually down to atmospheric pressure, flash evaporation of superheated water occurs, which can be found in lignocellulose fibers, literally causing an explosion of biomass, causing fiber breakage. All this process globally increases the digestibility of the biomass [43]. Some of its advantages are that it is environmentally friendly, does not require dangerous chemicals, and requires relatively low capital to invest. In general, the steam explosion is accepted as one of the most efficient pretreatments [44]. Increases of up to 345% in specific methane production performance have been reported using the steam explosion. This depends on the operating conditions (temperature, time, and pressure drop), the substrate, and the digestion process [45]. For example, Steinbach et al., (2019), reported that to treat rice straw with too mild conditions, the methane yield remained constant compared to the untreated fraction of the substrate, in very severe conditions, the yield decreased significantly, and under moderate vapor explosion conditions, the methane yield increases by up to 32%.
Steam Explosion in alkaline medium for gelatine extraction from chromium-tanned leather wastes: time reduction and process optimization
Published in Environmental Technology, 2020
Bianca Santinon Scopel, Danielle Restelatto, Camila Baldasso, Aline Dettmer, Ruth Marlene Campomanes Santana
Making use of an auxiliary process that accelerates hydrolysis can reduce the gelatine extraction time. Steam explosion is widely known and used as pre-treatment of lignocellulosic biomass for ethanol production. It usually acts as a pre-treatment also for enzymatic hydrolysis, increasing its yield [18–19].
Biopolymer composites: a review
Published in International Journal of Biobased Plastics, 2021
Basheer Aaliya, Kappat Valiyapeediyekkal Sunooj, Maximilian Lackner
In plasma treatment, the surface of the fiber is exposed to very high voltage, which is supplied for ionizing the gas and to use it as plasma in vacuum conditions [4]. The treatment improved the surface strength of the fiber by crosslinking the fiber surface by introducing free radicals [11]. Oxygen plasma refers to plasma treatment by introducing oxygen to the plasma chamber. Oxygen plasma treatment removes the organic contaminants by chemical reaction with highly reactive oxygen radicals [4]. With this method, the surface of the fiber is cleaned by surface etching and improved the surface roughness for enhancing the adhesion and interfacial bonding by creating interlocks with the matrix [45]. Oxygen plasma treatment also promotes surface hydroxylation, oxidation, and increases the wetting property of the natural fiber surfaces [46]. Corona treatment carried out in a corona discharge reactor modifies the fiber surface oxidation to improve the interface between hydrophilic fiber and hydrophobic matrix [47]. The treatment improves the mechanical strength by changing the surface energy [42], and acidity of the fiber surface [48]. Steam explosion process is a high-pressure steaming, which requires heating of lignocellulosic fibers at high pressures and temperatures, followed by mechanical disruption of pre-treated fibers to a collecting tank by violent discharge (explosion). Steam explosion process resulted in reduced stiffness, smoother surface, better fineness distribution, and improved bending properties of the fibers. This process is used in lignocellulosic fibers to improve the dispersibility and adhesion with polymeric matrices [44]. The vacuum ultraviolet (VUV) irradiation is a widely accepted method for removing impurities from fiber surface. The fibers were placed in a stainless steel chamber and high energy radiations <200 nm and pressure of 2.5 Torr is applied at room temperature [49]. The treatment enhances the wettability, insulation, tribological properties, and biocompatibility of fibers with the matrix [3]. γ-rays treatment enhances the inter-crosslinking of cellulose molecules and improves the mechanical strength of the fibers [50]. Laser treatment is a way to remove the lignin content in plant fibers and to ameliorate the structural and tensile strength of the fibers [49]. Ozone or oxygen-fluorine gas is a successful method to enhance the surface of the natural fibers. The mechanical properties of natural fibers can be maintained for a long period by ozone treatment [51].