Sorption of Inorganic Substances on the Porous Latvian Clay Ceramic

Abstract

Devonian clay of Liepa deposit (district of Cesis) and Quaternary clay of Laza deposit (district of Aizpute) was investigated. Pellets were fired at four different temperatures of 700, 800, 900, and 1050 °C. Porosity and surface area of pellets was determined by mercury porosimetry. The pH values after water immersion of fired pellets was determined with a pHmeter. The sorption ability of molecular substance (iodine) and ionic substances (ammonia and dichromate) were determined by titrimetric methods.The best sorption ability was found for iodine molecules. The entire amount of iodine in the water suspension was absorbed in two weeks, and the sorption ability reached 12.5 mg/g for samples fired at 700 and 800 °C temperature for the Liepa clay and 13.0 mg/g for the Laza clay. The sorption ability of these clay pellets for ammonia was lower and amounted to 3.0 and 2.5 mg/g, respectively. The sorption ability for dichromate ion was even less -only 0.6 mg/g for pellets of both clays.The investigated fired porous clay granules exhibited distinct sorption properties towards water-soluble ionic and molecular substances, which depended more on the firing temperature of granules and less on the source of clay.

Natural Radioactivity in Clay and Building Materials Used in Latvia

“…In Latvia, clay is obtained from two deposits (Fig. 3) belonging to Devonian and Quaternary periods [18]. With regard to the results obtained, we have undertaken a systematic study of natural radionuclide content in clay-based building materials produced by various firms in different years.…”

Celtniecības keramika, keramzīts un keramiskie sorbenti

“…Potenciālo keramikas sorbentu iegūšanai izmanto gan dažādu atradņu devona, gan dažādu atradņu kvartāra māli ar atšķirīgu ķīmisko un granulometrisko sastāvu [9], [10]. No devona māliem izmanto Liepas, Tūjas, Kupravas un Planču atradņu mālus, bet no kvartāra māliem Progresa, Lažas, Prometeja un Šļūcenieku atradņu mālus.…”

Valsts pētījumu programmas projekta “Zemes dzīles” svarīgākie rezultāti un perspektīvas

“…Savstarpēji salīdzinot devona un kvartāra mālus, labākās sorbcijas īpašības uzrāda kvartāra mālu keramikas granulas, kurām ir lielāks īpatnējās virsmas laukums, salīdzinot ar tajās pašās temperatūrās apdedzinātām devona mālu granulām. Granulu sorbcijas spēja ir atkarīga arī no sorbējamās vielas rakstura (vielas ar molekulāru vai jonu saiti), no jona vai molekulas izmēra, kā arī no tā, kāds ir vides pH ūdenī iemērktām granulām [4]. Kvartāra mālu 700 -900˚C temperatūrā apdedzinātu granulu immersija ūdenī uzrāda bāzisku vidi, kas saistīts ar kvartāra mālu mineraloģisko sastāvu.…”