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Access status: Open Access ,
»Four-letters« (γ → ε → β → α) thermal transformation of Si-rich ferrihydrite
(Wydawnictwa AGH, 2015) Pieczara, Gabriela; Rzepa, Grzegorz; Gaweł, Adam; Tomczyk, Anna
Ferrihydrite is a poorly ordered iron (oxyhydr)oxide, ubiquitous in near-surface environments, where it is an important scavenger of numerous toxic metals and metalloids (Cornell & Schwertmann 2003).
Access status: Open Access ,
Weathering of siderite in the polar conditions
(Wydawnictwa AGH, 2014) Figura, Paulina; Manecki, Maciej; Rzepa, Grzegorz
Rapid retreat and thinning of glaciers perturb balance of polar ecosystems. These processes influence global climate (Anderson et al. 2000, Płonka 2009).
Access status: Open Access ,
Synthesis and preliminary characterization of 2-line ferrihydrite containing different amounts of Si
(Wydawnictwa AGH, 2012) Pieczara, Gabriela; Rzepa, Grzegorz
Ferrihydrite ($Fe_{5}HO_{8} \cdot 4H_{2}O$) is the reddish-brown, nearly amorphous hydrous ferric oxyhydroxide mineral with variable composition, widespread in various near-surface environments. Being thermodynamically unstable, it transforms with time into goethite ($\alpha-FeOOH$) or hematite ($\alpha-Fe_{2}O_{3}$). Due to its low crystallinity and high surface area, ferrihydrite is highly reactive and plays, through coprecipitation and adsorption reactions, an essential role in e.g. geochemical cycling of various trace elements and capturing of contaminants from streams and groundwater in such environments as ironladen springs, mine wastes and acid mine drainage.
Access status: Open Access ,
Tlenki manganu z diabazów Niedźwiedziej Góry koło Krakowa
(Wydawnictwa AGH, 2009) Muszyński, Marek; Rzepa, Grzegorz; Skowroński, Andrzej
Black manganese oxides from the polymineral veins found in 1998 in the so-called diabases of Niedźwiedzia Góra near Kraków have been identified (XRD, IR, DTA-TG, SEM/EDS, EPMA/WDS) as intermediate members of the rancieite-takanelite series. In comparison with the minerals of this series described in the literature, they reveal elevated contents of iron and barium and relatively low contents of calcium. In the probable succession of components of the veins mentioned, the Mn oxides occupy the before last position: goethite +/- saponite $\to$ <b>tension</b> $\to$ barite, thin prismatic-acicular quartz $\to$ <b>leaching</b> $\to$ Mn oxides, prismatic quartz. They must have crystallized from descensive waters associated with surface weathering of the diabases, which took place when overlaying Carboniferous rocks had been eroded. The weathering diabases were a probable source of manganese.
Access status: Open Access ,
Department of Mineralogy, Petrography and Geochemistry
(Wydawnictwa AGH, 2016) Matusik, Jakub; Rzepa, Grzegorz
Access status: Open Access ,
Manganese oxides from Zalas, Kraków area, southern Poland
(Wydawnictwa AGH, 2016) Polak, Marta; Gołębiowska, Bożena; Rzepa, Grzegorz
The Zalas quarry is located in the southern, marginal part of the Silesian-Cracovian Monocline.
Access status: Open Access ,
The using possibility of clay-rich overburden rocks from selected Polish deposits
(Wydawnictwa AGH, 2012) Bożęcki, Piotr; Rzepa, Grzegorz
The objective of this work was an assessment of the possibility of utilization of selected clay-rich overburden rocks from selected rock raw material found in Polish deposits.
Access status: Open Access ,
The influence of silicate content on thermal stability of 2-line ferrihydrite and properties of its transformation products
(Wydawnictwa AGH, 2014) Pieczara, Gabriela; Rzepa, Grzegorz; Gaweł, Adam
Naturally occurring ferrihydrite ($Fe_{5}HO_{8} \cdot 4H_{2}O$) is a poorly ordered iron (oxyhydr)oxide mineral, with non-stoichiometric composition and not fully understood structure. Because of its unique chemical and physical properties, such as low crystallinity, high surface area and surface reactivity, ferrihydrite plays significant role in e.g. inorganic weathering processes, biochemical cycling of iron and as a sorbent in various near-surface environments.
Access status: Open Access ,
Arsenic interactions with bog iron ores - As(III) and As(V) adsorption-desorption study
(Wydawnictwa AGH, 2016) Tuchowska, Magdalena; Bajda, Tomasz; Rzepa, Grzegorz; Dębiec, Klaudia; Drewniak, Łukasz
Arsenic is a toxic element, elevated concentration of which in the environment can result from both anthropogenic activity and natural geochemical processes.
Access status: Open Access ,
The results of multistage liming and lacustrine chalk application in AMD water reservoir in the Muskau Arch near Łęknica, W Poland
(Wydawnictwa AGH, 2012) Rzepka, Przemysław; Bożęcki, Piotr; Manecki, Maciej; Rzepa, Grzegorz; Bajda, Tomasz
The main goal of conducted experiment has been to examine the abilities of acid mine water remediation on the example of Muskau Arch lake named Africa. The chemical neutralization of acidic pH and removal of high salinity by precipitation was made by various substances application. The objective of this study was comparison of the potential effects of this treatments applied in several steps.

Rzepa, Grzegorz

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