3
Figure 2 shows the surface images of a bare malachite
surface which has been soaked in nanopure water in an
AFM liquid cell for 10 minutes. Figure 2A is the 2 µm ×
2 µm height image, from which one can see that the solid
surface is still largely smooth in spite of minor adsorbate on
the sample surface detected by the AFM probe. Figure 2B
is the 3-D image of Figure 2A. Figure 2C is the section
analysis of Figure 2A. Figure 2D is the deflection image of
Figure 2A with a 10 nm data scale.
Figure 3A is the height image of a malachite surface
soaked in 5×10–5 M OHA solution for 10 minutes. By
comparing it to Fig.2A, one can see a lot of adsorbate show-
ing up on malachite when the mineral surface contacts
OHA solution for 10 minutes. Fig.3B is the 3-D image of
Figure 3A. Figure 3C is the section analysis of Figure 3A
and the surface roughness clearly increases due to the
adsorption. Figure 3D is the deflection image of Figure 3A
with a 10 nm data scale.
Figure 4A is the height image of a malachite surface
soaked in 5×10–5 M OHA solution at pH 6 for 60 minutes.
By comparing it to Fig.2A, one can see a lot of adsorbate
showing up on malachite when the mineral surface contacts
OHA solution for 60 minutes. In addition, by comparing
it to Fig.3A, one can find that the mineral surface becomes
only a little rougher, suggesting more adsorbate is forming
at solid/liquid interface, when the contacting time increases
from 10 minutes to 60 minutes. Figure 4B is the 3-D image
of Figure 4A. Figure 4C is the section analysis of Figure 4A
and it confirms that the surface roughness increases a lit-
tle bit due to the adsorption of collector. Figure 4D is the
deflection image of Figure 4A with a 10 nm data scale.
Figure 5A is the height image of a malachite surface
soaked in 5×10–5 M OHA solution for 120 minutes. By
comparing it to Figure 4A, one can find that the mineral
surface basically does not change much, suggesting similar
amount adsorbate is forming at solid/liquid interface, when
the contacting time increases from 60 minutes to 120 min-
utes. Figure 5B is the 3-D image of Figure 5A. Figure 5C
is the section analysis of Figure 5A and it confirms that the
surface roughness does not change much. Figure 5D is the
deflection image of Figure 5A with a 5 nm data scale.
Figure 6 shows the AFM images of a malachite sur-
face soaked in 1×10–4 M OHA solution for 10 minutes. By
comparing Figure 6A, the height image, to Fig.2A, one can
observe a lot of adsorbate showing up on malachite after
the mineral surface contacts OHA solution. In addition,
by comparing it to Figure 3A, one can find that, when the
OHA concentration increases, a lot of adsorbate is form-
ing at solid/liquid interface and the mineral surface is again
fully covered by the adsorbate. Figure 6B is the 3-D image
Figure 1. AFM images of malachite in air. A) 2 µm × 2 µm height
image with a data scale of 20 nm B) the 3-D image C) the section
analysis and D) the deflection image with a data scale of 5 nm
Figure 2 shows the surface images of a bare malachite
surface which has been soaked in nanopure water in an
AFM liquid cell for 10 minutes. Figure 2A is the 2 µm ×
2 µm height image, from which one can see that the solid
surface is still largely smooth in spite of minor adsorbate on
the sample surface detected by the AFM probe. Figure 2B
is the 3-D image of Figure 2A. Figure 2C is the section
analysis of Figure 2A. Figure 2D is the deflection image of
Figure 2A with a 10 nm data scale.
Figure 3A is the height image of a malachite surface
soaked in 5×10–5 M OHA solution for 10 minutes. By
comparing it to Fig.2A, one can see a lot of adsorbate show-
ing up on malachite when the mineral surface contacts
OHA solution for 10 minutes. Fig.3B is the 3-D image of
Figure 3A. Figure 3C is the section analysis of Figure 3A
and the surface roughness clearly increases due to the
adsorption. Figure 3D is the deflection image of Figure 3A
with a 10 nm data scale.
Figure 4A is the height image of a malachite surface
soaked in 5×10–5 M OHA solution at pH 6 for 60 minutes.
By comparing it to Fig.2A, one can see a lot of adsorbate
showing up on malachite when the mineral surface contacts
OHA solution for 60 minutes. In addition, by comparing
it to Fig.3A, one can find that the mineral surface becomes
only a little rougher, suggesting more adsorbate is forming
at solid/liquid interface, when the contacting time increases
from 10 minutes to 60 minutes. Figure 4B is the 3-D image
of Figure 4A. Figure 4C is the section analysis of Figure 4A
and it confirms that the surface roughness increases a lit-
tle bit due to the adsorption of collector. Figure 4D is the
deflection image of Figure 4A with a 10 nm data scale.
Figure 5A is the height image of a malachite surface
soaked in 5×10–5 M OHA solution for 120 minutes. By
comparing it to Figure 4A, one can find that the mineral
surface basically does not change much, suggesting similar
amount adsorbate is forming at solid/liquid interface, when
the contacting time increases from 60 minutes to 120 min-
utes. Figure 5B is the 3-D image of Figure 5A. Figure 5C
is the section analysis of Figure 5A and it confirms that the
surface roughness does not change much. Figure 5D is the
deflection image of Figure 5A with a 5 nm data scale.
Figure 6 shows the AFM images of a malachite sur-
face soaked in 1×10–4 M OHA solution for 10 minutes. By
comparing Figure 6A, the height image, to Fig.2A, one can
observe a lot of adsorbate showing up on malachite after
the mineral surface contacts OHA solution. In addition,
by comparing it to Figure 3A, one can find that, when the
OHA concentration increases, a lot of adsorbate is form-
ing at solid/liquid interface and the mineral surface is again
fully covered by the adsorbate. Figure 6B is the 3-D image
Figure 1. AFM images of malachite in air. A) 2 µm × 2 µm height
image with a data scale of 20 nm B) the 3-D image C) the section
analysis and D) the deflection image with a data scale of 5 nm