Stability and immobilizing potential of manganese oxide based adsorbents in contaminated soils under changing redox conditions

BcA. Miller Owusu Agyei

Master's thesis

Abstract:

The immobilizing efficiency of two novel engineered materials towards metals in contaminated soil has been studied. Metal(loid)s contamination of agricultural soils liable to flood presents a challenge in their remediation as redox conditions may change with seasonal floods. To this end, amorphous manganese oxide (AMO) and amorphous manganese oxide modified biochar (AMO/BC) were synthesized and tested for their stabilizing efficiency towards zinc (Zn), cadmium (Cd), lead (Pb) and arsenic (As) under oxic conditions (soil moisture of 70% water holding capacity) and over-saturated conditions (soil over-saturated with water) over time using an incubation experiment. A modified sol-gel procedure (without the heating step) was adopted in synthesizing the AMO whiles grape stalks were used in the biochar synthesis (600 °C). The results of the experiment determined that metal(loid)s dissolution and soil organic matter (SOM) degradation (suggested by increased concentrations of dissolved organic carbon (DOC)) were at least an order of magnitude higher in over-saturated conditions than more oxic conditions. Also, the application of both amendments increased metal(loid)s and DOC release in over-saturated conditions whiles being effective in immobilizing Zn, Cd and Pb in oxidic conditions. Both AMO and AMO/BC promoted increased arsenic (As), manganese (Mn) and DOC dissolution under both water regimes suggesting the influence of other factors such pH and amendment degradation. Not much significant difference was observed between the immobilizing efficiency of AMO and AMO/BC in both water regimes.

Keywords

cadmium, soil, stabilization, remediation, redox, comtamination, lead, zinc, arsenic

Jazyk práce: English

Datum vytvoření / odevzdání či podání práce: 15. 12. 2017

Obhajoba závěrečné práce

• Vedúci: Ing. Zuzana Michálková, Ph.D.

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme / odbor:
Geology / Environmental Geosciences