Changes in the structure of red mud and black nickel mud after activation

hazardous wastes from the production of metals, namely waste from
the production of aluminium - red mud and waste from the
production of nickel - black nickel mud. In environmental
applications, red mud and black nickel mud are likely to be used
after activation. The samples were activated using hydrochloric acid
to study the structure properties before and after the treatment. Both
of these wastes have suitable adsorption and catalytic properties that
could be positively affected by the activation of their surfaces. The
morphology of the samples was documented by scanning electron
microscope, phase analysis was performed using diffraction
techniques, and the content of elements was determined by EDX
analysis. Also, FTIR analysis of the samples was performed.
Activation increases the specific surface area of samples, which is
beneficial in many environmental applications, such as in the
adsorptive removal of pollutants. Treatment of samples changes the
surface properties of the adsorbent, such as electrostatic,
hydrophobic, and hydrophilic. The activation creates a new surface
structure and thus affects its properties. EDX analysis confirmed the
high content of Fe, Al, Si and Ti, which are responsible for good
adsorption and catalytic properties. X-ray diffractograms have
shown only slight changes in the structure of wastes after activation.
The results of SEM confirmed the changes in the surface structure
and the creation of new active centres necessary for the successful
adsorption process. The FTIR analysis determined the changes in
the structure of the samples mainly due to the thermal degradation
of C=O and O-Si-O bonds.