Formation of silicon carbide from rice husks using enzymatic methods for carbon control

Silicon-Based Materials from Rice Husks and Their Applications

“…Some research has even shown that the yield of SiC from raw RHs is higher than that from burned RHs. , The produced SiC is usually cleaned with an acid treatment to remove small amounts of amorphous material and wool . Because the ratio of silica and carbon is less than the optimum ratio for silicon carbide formation, usually either silica is added or carbon is removed to regulate this ratio. − According to whether pretreatment is performed and/or a catalyst is used, pyrolysis methods can be divided into three categories.…”

Review on the physicochemical treatments of rice husk for production of advanced materials

“…They claimed that CoCl 2 diffuses into the graphite and burned rice husk and opens up the layers of graphite by channeling. It has been reported that the SiC whisker formed in CoCl 2 treated burned rice husks is negligible.Alkali pre-treatment has also been reported [16].Patel et al [16] also showed that the concentrated (>9N) NaOH solution cannot penetrate through the holes of rice husk and the extraction of silica deacreses.Mizuki et al [80]proposed usinganenzymaticmethod for formation of SiC.Theground treated powders of rice husk with NaOH were hydrolyzed with a mixture of Acucelase and Meicelasein acetate buffer (pH 4-5, 20 ml).After treatment with enzymes the precipitate was dried and pyrolyzed in a two-stepprocess(at 500 ºC for 1h in N 2 atmosphere and 1600 ºC for 1hin Ar atmosphere).The cellulase treatment was developed to control excess carbon for silicon carbide formation from rice husks. Komatsu et al [225]demonstrated that sieving is an easily controlled method; however, the yield of carbon-controlled rice husks (45.5%) was lower than that for the enzymatic method (54.0%).…”

“…At present, RHs are the raw materials for the production of a series of silicon-basedmaterials including SiO 2 , SiC, Si 3 N 4 , Mg 2 Si and carbon enriched materials which can be used in metalmatix (MMCs) and ceramicmatrix (CMCs) composites [78][79][80][81][82].…”

Green routes to silicon-based materials and their environmental implications

“…SiC can also be formed directly from RHA as pioneered in the mid-1970s by Lee and Cutler (Lee and Cutler 1975;Lee et al 1977). Krishnarao et al 1998) as well as others (Mizuki et al 1993;Sujirote and Leangsuwan 2003;Niyomwas 2009;Li et al 2013) have developed methods for the direct conversion of RHA to SiC using less energy intensive processes. This is typically done by first pretreating the RHA with acid to remove impurities, via direct RHA insertion, or by pre-coking the samples.…”