Browsing by Subject "sole amoniowe"

Now showing 1 - 1 of 1

Access status: Restricted ,
Interkalaty kaolinitu z solami amoniowymi i ich interakcja z anionami Cr(VI) i As(V)
(Data obrony: 2013-09-19) Matykowska, Lucyna Katarzyna
Wydział Geologii, Geofizyki i Ochrony Środowiska
The work shows structural characteristic of kaolinite with selected ammonium salts and their interaction with aqueous Cr(VI) and As(V) solutions. The modification process was carried out on the basis of a multi-stage intercalation procedure based on the introduction into the structure of kaolinite successively: dimethyl sulfoxide, methanol and ammonium salts. For the experiments the following chloride solutions were used: 2 mol/dm3 tetramethylammonium chloride (TMA), 2 mol/dm3 benzyltrimethylammonium chloride (B1) and 1 mol/dm3 benzyldimethylhexadecylammonium chloride (B5). The modification significantly improved the sorption capacity of the materials as compared to the raw kaolinite, where the sorption did not exceed 5 mmol/kg. Sorption of Cr (VI) on the obtained intercalates ranged from 23 to ~ 979 mmol/kg. In turn, the As(V) sorption varied between 26 and 322 mmol / kg. There are two possible mechanisms for the Cr(VI) and As(V) immobilization. The first is the ion-exchange of chromate(VI) and arsenate(V) with Cl- anion derived from an organic salt. The second is the precipitation of organic salts containing Cr(VI), which dominated in the case of MB5 material. The XRD and IR studies of the samples after sorption show that the structures of obtained intercalates are not stable in aqueous solutions.