Topics in Current Chemistry (2020) 378:2
1 3
Another strategy to apply ball milling during the formation of TiO 2 nanoparticles
was by mixing and ball milling of different precursors [36]. In 2007, Billik et al.
used either TiCl 4 with (NH 4 ) 2 CO 3 or TiOSO 4 ·xH 2 O with Na 2 CO 3 [127, 128]. After
ball milling, they received amorphous samples, and they linked this to no crystallization having occurred. After annealing, they obtained well-crystalized materials,
with higher photoreactivity compared to P25, determined by electron-paramagneticresonance (EPR) studies. They reported also that the presence of Fe impurities
plays a role in the photoactivity of the final material. In 2008, Salari et al. also used
TiOSO 4 ·xH 2 O as the Ti source but NaCl as diluent [129].
3.3 1‑D Ball‑Milling‑Derived Nanostructures
An important, abundant, and cheap source used for the industrial production of bulk
TiO 2 is the iron–titanium oxide mineral (FeTiO 3 ) mineral, known as ilmenite. A
high amount of ilmenite exists in the Earth’s crust on all five continents, and on
the Moon. The price of the raw material was around 80–107 USD per metric ton in
2004, while a peak was achieved in 2012 reaching even 350 USD per ton. In recent
years, the cost has been around 250 USD/ton. The global demand has grown moderately in recent years, since it was estimated at around 6.4 million tons in 2010 with
a prediction to reach above 8 million tons in 2025. The industrialized production of
bulk TiO 2 from minerals is based on chloride or sulfate processes. In recent decades,
there has been increased research effort to expand the use of this mineral in order to
prepare nanostructures of TiO 2 . The utilization of ball milling in order to promote
the formation of nanostructured TiO 2 for a “real-life” application by using ball milling dates from 2008.
Li et al. (2008) [130] reported the formation of meso- and/or micro-porous hydrolysate TiO 2 by an initial mechanical activation of ilmenite using BM, following by
a simultaneous dissolution and hydrolysis in a dilute sulfuric acid aqueous solution.
The effect of the acid concentration played a key role in the structural parameters,
with 10% sulfuric acid leading to a surface area of 258 m
2
/g. In order to obtain the
rutile-phased final material, calcination was applied. The importance of this work
was that the ball-milling pretreatment made feasible the dissolution of the mineral in
a dilute acidic solution. For an efficient decomposition in pigment production without mechanochemical utilization, an H 2 SO 4 solution of a concentration above 80
wt% is required [130].
In 2011, Tao et al. prepared flower-like FeTiO 3 by pretreatment of ilmenite with
high-energy BM followed by mild hydrothermal treatment in basic aqueous solution
(1 M NaOH) [131]. They stated that the nano-petals comprising the final obtained
flower-shaped particles had a thickness of 5–20 nm and sizes 100–200 nm. The
hydrothermal treatment at 120 °C, even with 2 M NaOH, did not lead to noticeable
changes in morphology. The obtained materials showed attractive capacitance values. Considering the above observations regarding the formation of NTBs, we can
derive two possible conclusions/proposals. First, the presence of Fe stabilizes the
layered structure of the nano-petals to roll to tubes. Second, the utilization of BM
58
Reprinted from the journal
1 3
Another strategy to apply ball milling during the formation of TiO 2 nanoparticles
was by mixing and ball milling of different precursors [36]. In 2007, Billik et al.
used either TiCl 4 with (NH 4 ) 2 CO 3 or TiOSO 4 ·xH 2 O with Na 2 CO 3 [127, 128]. After
ball milling, they received amorphous samples, and they linked this to no crystallization having occurred. After annealing, they obtained well-crystalized materials,
with higher photoreactivity compared to P25, determined by electron-paramagneticresonance (EPR) studies. They reported also that the presence of Fe impurities
plays a role in the photoactivity of the final material. In 2008, Salari et al. also used
TiOSO 4 ·xH 2 O as the Ti source but NaCl as diluent [129].
3.3 1‑D Ball‑Milling‑Derived Nanostructures
An important, abundant, and cheap source used for the industrial production of bulk
TiO 2 is the iron–titanium oxide mineral (FeTiO 3 ) mineral, known as ilmenite. A
high amount of ilmenite exists in the Earth’s crust on all five continents, and on
the Moon. The price of the raw material was around 80–107 USD per metric ton in
2004, while a peak was achieved in 2012 reaching even 350 USD per ton. In recent
years, the cost has been around 250 USD/ton. The global demand has grown moderately in recent years, since it was estimated at around 6.4 million tons in 2010 with
a prediction to reach above 8 million tons in 2025. The industrialized production of
bulk TiO 2 from minerals is based on chloride or sulfate processes. In recent decades,
there has been increased research effort to expand the use of this mineral in order to
prepare nanostructures of TiO 2 . The utilization of ball milling in order to promote
the formation of nanostructured TiO 2 for a “real-life” application by using ball milling dates from 2008.
Li et al. (2008) [130] reported the formation of meso- and/or micro-porous hydrolysate TiO 2 by an initial mechanical activation of ilmenite using BM, following by
a simultaneous dissolution and hydrolysis in a dilute sulfuric acid aqueous solution.
The effect of the acid concentration played a key role in the structural parameters,
with 10% sulfuric acid leading to a surface area of 258 m
2
/g. In order to obtain the
rutile-phased final material, calcination was applied. The importance of this work
was that the ball-milling pretreatment made feasible the dissolution of the mineral in
a dilute acidic solution. For an efficient decomposition in pigment production without mechanochemical utilization, an H 2 SO 4 solution of a concentration above 80
wt% is required [130].
In 2011, Tao et al. prepared flower-like FeTiO 3 by pretreatment of ilmenite with
high-energy BM followed by mild hydrothermal treatment in basic aqueous solution
(1 M NaOH) [131]. They stated that the nano-petals comprising the final obtained
flower-shaped particles had a thickness of 5–20 nm and sizes 100–200 nm. The
hydrothermal treatment at 120 °C, even with 2 M NaOH, did not lead to noticeable
changes in morphology. The obtained materials showed attractive capacitance values. Considering the above observations regarding the formation of NTBs, we can
derive two possible conclusions/proposals. First, the presence of Fe stabilizes the
layered structure of the nano-petals to roll to tubes. Second, the utilization of BM
58
Reprinted from the journal