Effect of Acid and Alkali Treatments on Surface Areas and Adsorption Energies of Selected Minerals

Abstract

Bentonite, biotite, illite, kaolin, vermiculite and zeolite were acidified or alkalized with hydrochloric acid or sodium hydroxide at concentrations of 0.1, 1.0 and 5.0 mole dm−3 at room temperature for two weeks. In acid treatments, dissolution of Al prevailed over Si and the opposite was observed in alkali treatments. The XRD patterns showed severe alteration of the crystal structure after acid treatments, whereas sharpening of the XRD peaks after alkali treatments was observed. Illite and kaolin were most resistant to acid attack. with a few exceptions, the surface areas of the minerals computed from both water and nitrogen adsorption isotherms increased with acid and alkali treatments. with increasing reagent concentration, the nitrogen surface area increased faster than the water surface area. well-defined trends were not noted in either changes of average water or nitrogen adsorption energies or in relative amounts of adsorption sites, indicating that the effects of acid and alkali attack are controlled by the individual character of the minerals.

Effectiveness of urea nanofertilizer based aminopropyltrimethoxysilane (APTMS)-zeolite as slow release fertilizer system

“…Acidified zeolite was then cleaned up until neutral condition was obtained and was thereafter dried at a temperature of 120˚C. In the acid activation process, silica dissolution process was adopted, which is one component of the zeolite framework (Jozefaciuk and Bowanko, 2002). Silica dissolution will lead to changes in the structure of the zeolite and the decreasing ratio of Si/Al.…”

Reduction of Offensive Odor from Natural Rubber Using Zinc‐Modified Bentonite

“…Moreover, the high concentration of calcium and zinc (32.30 wt.%) in modi ed bentonite denotes limited ion exchange of Ca 2+ and preferred adsorption of Zn 2+ into the clay surface. Zinc modi cation also results in dealumination of bentonite [31] (Table 1) due to the weak acidity of zinc sulfate solution [32]. Zinc-and sulfur-free composition of zinc-modi ed bentonite shows considerable enrichment in silicon due to the dissolution of aluminum.…”

Influence of aggressive inorganic acids upon the strength parameters of glacial soil

“…Many previous investigations on how inorganic acids affect soils were committed to research changes in clay properties (Jozefaciuk, Bowanko, 2002; Umesh et al, 2011; Umesha et al, 2012). Changes in moraine soils have been almost uninvestigated.…”