Aldehydes (e.g., formaldehyde, acetaldehyde) — properties & control
Volatility
High (C1–C2) → moderate
Water solubility
Moderate–high (hydrates)
Hazards
Irritant; sensitizer; some carcinogenic
Abatement
Oxidation / bisulfite
Toxicity
moderate (high for CH₂O)
Flammability
many are flammable
Chronic risk
sensitization / cancer (subset)
Environmental
VOC / ozone precursor
| Aspect | Detail |
|---|---|
| Chemistry | Hydrates in water; nucleophile addition (e.g., bisulfite); readily oxidised to acids. |
| Representative species | Formaldehyde (CH₂O), Acetaldehyde (CH₃CHO), Propionaldehyde, Butyraldehyde… |
| Absorption/abatement | Alkaline H₂O₂ (oxidation to formate/acetate) or NaHSO₃ (addition → hydroxymethanesulfonate, etc.); high-efficiency demisting. |
| Materials | For oxidants: FRP, PVC-C, PP, PTFE; stainless with care. Avoid copper/plain CS in oxidising liquor. |
| Monitoring | FTIR/UV for stacks; DNPH cartridge + HPLC for low-level ambient/formaldehyde. |
*Indicative ranges; confirm with process SDS, local limits, and vendor performance curves.