Influences of pretreatment, extraction variables, and post treatment on bench‐scale rice husk black ash (RHBA) processing to bio‐silica

Abstract

Abundant availability and large silica content in rice husk black ash (RHBA) make the use of it very interesting to study. Many works only deal with lab‐scale rice husk ash extraction while the studies on bench‐scale RHBA extraction are still limited. This study, hence, presents the influence of pretreatment, extraction variables, and posttreatment on bench‐scale RHBA processing to bio‐silica. The pretreatment through acid leaching was carried out using HCl. The extraction was implemented under varying process variables such as alkaline‐to‐feed ratio (RA/F), extraction duration, and acid precipitation agent. According to this study, the highest extraction yield up to 98% was gained under RA/F 6 g/g and 1‐h extraction. The amorphous bio‐silica had an asymmetric siloxane bond and white appearance with a purity exceeding 95% and surface area up to 406.98 m2/g. Meanwhile, precipitation under HCl and H2SO4 had little impact on product purity and surface area. This study exhibits that acid leaching is executed to release mineral impurities but is still not sufficient to remove the remaining carbon content in bio‐silica. However, the contribution of refining process is able to do so. Moreover, the produced bio‐silica is suitable for adsorbent purposes which could adsorb up to 83.5% of 3‐monochloropropanediol compound.

Effects of nanobiosilica from rice husk ash application on rice growth, productivity, and milling quality

“…Inadequate washing/leaching of nanobiosilica gel might cause the increased concentrations of Na and Cl present in nanobiosilica powder. In general, the chemical composition of nanobiosilica obtained in the present study was in agreement with that reported in IOP Publishing doi:10.1088/1755-1315/1172/1/012021 4 previous studies [22,23]. Steven et al [24] reported that silica with SiO 2 concentration higher than 95% may be suitable for various industrial applications, other than agricultural purposes.…”

Digitalized turbulent behaviors of air and rice husk flow in a vertical suspension furnace from computational fluid dynamics simulation

“…At first, the escaped particle amount weakens from “0–100” to “50–50” and the value goes up drastically from “50–50” to “100–0,” both for temperatures 25°C and 700°C. This leads to the more escaped particle amount in the furnace containing rice husk ash compared to rice husk because ash is more brittle and easier to break into smaller fragments, 66,67 making them more easily entrained 62,64 . It can be said that the lowest escaped particle amount is found at the composition of “50–50.” This is supported by the calculation results from Equations and where the largest particle settling velocity is nominated to “50–50.”…”

“…The greater composition of rice husk ash in the feed mixture augments the particle density but decreases the particle diameter. At first, the escaped particle amount weakens from "0-100" to "50-50" and the value goes up drastically from "50-50" to "100-0," both for temperatures 25 C and 700 C. This leads to the more escaped particle amount in the furnace containing rice husk ash compared to rice husk because ash is more brittle and easier to break into smaller fragments, 66,67 making them more easily entrained. 62,64 It can be said that the lowest escaped particle amount is found at the composition of "50-50."…”

Rice Husk Silica Research in Indonesia: A Blibiometric Analysis Based on Scopus

“…This second cluster (green) discusses the application of nano silica as an adsorbent, filler and fertilizer. Studies of nano silica synthesis methods such as the sol-gel method involving the formation of sodium silicate as an intermediate compounds and morphological characteristics of the resulting silica nanoscale are also discussed in this cluster [22,[24][25][26][27]. Cluster 3.…”

“…This fifth cluster (violet) discusses studies related to silica synthesis as an adsorbent for removing iron metal from aqueous solutions and as a support catalyst for toxic compound removal is also discussed in this cluster. Studies related to crystal structure, electrical conductivity, energy gap and application temperature are also presented in this cluster [27,32,33].…”