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Topics in Current Chemistry (2020) 378:3
Table 1
Summary of main harmful reagents and energy-consuming processes during the synthesis of waste-derived photocatalysts
a
Metal precursors and washing solutions (e.g. ethanol) are not included
Sample
Waste
Main harmful reagents
a
Main energy-consuming processes
References
TiO
2 -based
Spent catalytic reduction catalyst
NaOH, H
2 SO
4 or HCl
Autoclave (180 °C, 1 h)
[56]
N-doped-TiO
2
Waste milk-like electrolyte
–
Furnace (500–600 °C, 3 h)
[58]
ZnO
Zinc-dust
NaOH, HNO
3
Autoclave (170 °C, 8 h)
[60]
ZnO/graphite
Plastic water bottles, zinc-dust
–
Furnace (700 °C, 1 h)
[62]
ZnO/diatomite
Zinc-dust
NaOH, H
2 SO
4 , HNO
3
Furnace (400–700 °C)
[63]
pb-Cu
2 S
Pig bristles
Ethylene glycol, NaOH
Microwave (500 W, 3 min)
[67]
CQDs
Citrus limetta pulp
Acetic acid,
Pyrolysis (190 °C, 20 min)
[75]
CQDs
Orange peel
H
2 SO
4 , NaClO
Autoclave (180 °C, 12 h)
[81]
Polysaccharide-templated ZnO
Polysaccharides
–
Ball mill (350 rpm, 30 min)
Furnace (600 °C, 3 h)
[88]
Natural fiber-templated TiO
2 microtubes
Platanus acerifolia
seed fibers
–
Furnace (500 °C, 2 h)
[89]
Lignin-templated TiO
2
Lignin
NaOH, HCl, NH
3
Furnace (300–900 °C, 2 h)
[90]
Lignin-based carbon/ZnO
Lignin
NaOH
Furnace (550 °C, 2 h)
[91]
g-C
3 N
4 –Fe
2 O
3
Waste toner powder
–
Furnace (450–600 °C, 2 h)
[95]
TiO
2 -BEW
Boron-enriched waste (BEW)
–
Furnace (400 °C, 4 h)
[96]
PT (processed skin)
Leather skin residues
–
Microactivity reactor (180–350 °C, 1 h)
[97]
21
Reprinted from the journal