Insight into the sulfonation conditions on the activity of sub-bituminous coal as acidic catalyst during the transesterification of spent corn oil; effect of sonication waves

Insight into the Effect of Sulfonation Techniques on the Adsorption Properties of −SO3H Surface-Functionalized Coal as Adsorbent for Malachite Green Dye: Steric and Energetic Investigation

“…Such modification processes involved demineralization, chemical activation, metal loading, and thermal activation of coal fractions. 19,22 The chemical activation of coal and carbonaceous materials is the most applied technique to support their surfaces by additional or new active chemical groups especially the oxygenated chemical groups such as the hydroxyl groups (−OH) and carboxyl groups (−COOH). 20,31 The sulfonation of coal was reported as a very effective method that can support its structure by different active oxygenated chemical groups in addition to the significant enhancement in its surface electronegativity.…”

“…30 Moreover, conducting the sulfonation reactions under the sonication source resulted in different surficial properties than the sulfonated product by normal stirring processes. 19,32,33 Unfortunately, the adsorption properties of sulfonated raw coal were not covered by the satisfied studies yet considering the sulfonation agent, sulfonation conditions, sulfonation techniques, and types of dissolved chemical contaminants. The sulfonation of raw coal without precarbonization processes will result in enhanced low-cost adsorbent of numerous active functional groups and high adsorption capacities to be used effectively in the decontamination of organic pollutants.…”

“…Therefore, the decolorization of the dye molecules by low-cost and innovative techniques was investigated recently in several studies recently. , The adsorption processes as a decolorization technique of the dissolved synthetic dyes were endorsed strongly for their high efficiency, simplicity, recyclability, and production cost considerations as compared to the other investigated methods including filtration, ion exchange processes, chemical precipitation, and coagulation. , Availability, fabrication cost, recyclability, biodegradability, safety, and adsorption capacity are the main parameter that controls the suitability of the selected adsorbent and its efficiency . Recently, natural-based carbonaceous materials and raw coal were assessed widely as potential adsorbents of some synthetic dyes as well as other types of dissolved chemicals. − The raw coal was applied effectively in the removal of some synthetic dyes such as methylene blue, methyl orange, basic blue 3 (BB3) dye, and basic yellow 2 (BY2) dye …”

“…The previous studies demonstrate that the physicochemical properties of coals as adsorbents depend essentially on their surface properties such as the dominant chemical groups, surface area, and porosity properties. , Therefore, several studies were introduced to follow the impact of the different surface modification processes on the chemical and textural properties of coal. Such modification processes involved demineralization, chemical activation, metal loading, and thermal activation of coal fractions. , …”

“…The chemical activation of coal and carbonaceous materials is the most applied technique to support their surfaces by additional or new active chemical groups especially the oxygenated chemical groups such as the hydroxyl groups (−OH) and carboxyl groups (−COOH). , The sulfonation of coal was reported as a very effective method that can support its structure by different active oxygenated chemical groups in addition to the significant enhancement in its surface electronegativity. ,, The sulfonation efficiency and the physicochemical properties of the modified coal as adsorbent depend essentially on the type of the used chemical activators, the activation conditions, and the used activation techniques. , The sulfonation of coal as an acidic heterogeneous catalyst by sulfuric acid (H 2 SO 4 ) as cost-effective and highly oxidizing acid resulted in a significant enhancement in its acid density and textural properties during its application in the transesterification reactions . Moreover, conducting the sulfonation reactions under the sonication source resulted in different surficial properties than the sulfonated product by normal stirring processes. ,, …”