Adsorption of Chromium (VI) on Raw and Modified Carpathian Diatomite

• Main Authors: Alicja Puszkarewicz, Jadwiga Kaleta
• Format: Article
• Language: English
• Published: Polish Society of Ecological Engineering (PTIE) 2019-07-01
• Series: Journal of Ecological Engineering
• Subjects: adsorption; diatomite; removal of chromium(VI)
• Online Access: http://www.journalssystem.com/jeeng/Adsorption-of-chromium-VI-on-raw-and-modified-carpathian-diatomite,108640,0,2.html

The paper presents the research on the usability of natural Carpathian diatomite for removing chromate ions from water solutions. The concentration of chromium (VI) in test water was C0 = 1 g/m3. Both raw diatomite and diatomite modified with iron compounds of granulation 0.5 - 1.0 mm were tested. The process kinetics, as well as the effect of water reaction and the diatomite type on chromium sorption were determined in static conditions (no through flow). For both diatomite types, the chromium adsorption proceeded most effectively at pH 4. The effect of diatomite modification with iron compounds on the effectiveness of adsorption of chromium (VI) was determined on the basis of Freundlich adsorption isotherm. Compared to raw diatomite, the modified adsorbent (diatomite - Fe) exhibited much sorption capacity for chromate ions from water. When applied in dynamic conditions (v = 4 m/h), as filtration bed, it removed chromium compounds from water very effectively. It makes diatomite-Fe material a promising candidate for application in water treatment systems. Chromium concentration in the effluent oscillated within Ck = 0.001-0.002 mg/dm3, and the adsorption capacity of the bed, determined in the bed breakthrough point, reached Pp = 316.8 mg/kg.