What is Ferrous Sulfate (FeCl2)?
Ferrous sulfate (FeCl₂ — Iron(II) Chloride, CAS: 7758-94-3) FeCl₂ is an inorganic compound with strong coagulating and reducing properties, widely used in the treatment of industrial wastewater, electroplating, textile dyeing, and livestock farming. In a 15-30% solution, FeCl₂ is a clear, pale blue substance with a molecular weight of 126,75 g/mol. It is one of the essential chemicals that helps businesses meet the QCVN 40:2025/BTNMT wastewater discharge standards at optimal cost.
FeCl₂ Technical Specifications
| Parameter | Value |
|---|---|
| Formula | FeCl₂ |
| CAS number | 7758-94-3 |
| Molecular mass | 126,75 g / mol |
| Common concentrations | 15% - 30% |
| Optimal pH | 5 - 8 |
| Pack | 30kg can, 200kg drum, 1-ton tank, tanker truck |
| Certificate | MSDS, COA, ZDHC |
7 Main Applications in Industry
- Wastewater treatmentRemoves heavy metals (Cr, Ni, Cu, Zn), phosphorus, and reduces BOD/COD.
- H₂S removal: Fe²⁺ + H₂S → FeS↓ — effective odor treatment
- Electroplating: Recovery of Cr⁶⁺, Ni²⁺ by coagulation + precipitation
- Textile Dyeing (ZDHC): Dye coagulation, meeting ZDHC standards
- Livestock / AquaculturePond water treatment, algae control
- Chemical production: Catalysis, preparation of iron salts
- landfillTreatment of high COD leachate
Compare FeCl₂ vs FeCl₃ vs PAC
| Criteria | FeCl₂ | FeCl₃ | CAP |
|---|---|---|---|
| Heavy metals | ★ ★ ★ ★ ★ | ★ ★ ★ ★ | ★★★ |
| H₂S removal | ★ ★ ★ ★ ★ | ★★ | ★ |
| General Coagulation | ★★★ | ★ ★ ★ ★ ★ | ★ ★ ★ ★ |
| pH has an effect. | Low (pH 5-8) | Many (pH 2-4) | Medium |
Why Choose Ferrous Sulfate FeCl₂ from Loc Thien?
- ✅ Over 10 years of experience supplying industrial chemicals
- ✅ The product meets ZDHC standards and has complete MSDS and COA.
- ✅ 6 warehouses: Ho Chi Minh City, Binh Duong, Dong Nai, Da Nang, Can Tho
- ✅ Fast nationwide delivery using specialized tanker trucks.
- ✅ 24/7 Technical Support: (+84) 979 891 929
🛒 Need to buy FeCl2 (Iron II Chloride) for production?
Loc Thien provides FeCl2 15–30% Includes COA/MSDS, same-day delivery in Ho Chi Minh City, nationwide coverage. Discounts available for orders of 1 ton or more per month.
📞 Hotline: (+84) 979 891 929 | View pricing and specifications →
Mechanism of Action of FeCl2 in Wastewater Treatment
Ferrous sulfate (FeCl2) It operates through a complex physicochemical mechanism when introduced into wastewater. Understanding this mechanism helps engineers optimize dosage and treatment efficiency. For more information on calculating actual dosages, please refer to the relevant resources. Instructions on dosage and method of mixing FeCl2 our details.
1. Coagulation and Flocculation Mechanism
when the FeCl2 dissolve in water, ions Fe²⁺ It is partially hydrolyzed and oxidized to form Fe(OH)₂ —a colloidal precipitate carrying a positive charge. These colloidal particles neutralize the negative charge of suspended solids (TSS), colloidal organic matter, and bacteria present in wastewater, causing them to become unstable and clump together. floc Large floc particles settle easily. The effectiveness of coagulation depends strongly on the stirring speed — stir quickly in the initial stage to evenly disperse the chemicals, then stir slowly to allow the floc to grow in size.
2. H₂S Reduction Reaction — Odor Control
An important application of ferrous depression This involves controlling odors in wastewater collection systems and anaerobic tanks. The reaction proceeds as follows:
- Fe²⁺ + S²⁻ → FeS↓ (Black, insoluble precipitate, removal of sulfide from the liquid phase)
- Sulfide ions (S²⁻) are the direct precursors of H₂S gas—the cause of the characteristic rotten egg smell at pumping stations and sewers.
- The reaction occurs instantaneously in a neutral to slightly alkaline environment, requiring no additional energy.
3. Phosphate Precipitation — Nutrient Treatment
FeCl2 also used for processing phosphorus (P) According to the chemical precipitation mechanism:
- 3Fe²⁺ + 2PO₄³⁻ → Fe₃(PO₄)₂↓ (vivianite, blue precipitate)
- The phosphorus removal efficiency reaches 85–95% when the Fe:P (mol) ratio is ≥ 1,5:1.
- The Fe₃(PO₄)₂ precipitate is recovered along with the sludge, without generating any additional secondary pollutants.
4. Optimal pH Conditions
All of the above reactions are most efficient within the given range. pH 6–9Below pH 6, Fe(OH)₂ redissolves, reducing the coagulation efficiency. Above pH 9, Fe²⁺ rapidly oxidizes to Fe³⁺ and precipitates Fe(OH)₃, altering the working mechanism. Checking and adjusting the influent pH is a mandatory step before dosing. ferric sulfate 2.
Instructions for Safe Storage of FeCl2
Ferrous chloride The liquid form is a weak acid solution that is corrosive and sensitive to atmospheric oxygen. Proper storage not only ensures workplace safety but also maintains the quality of the chemical, preventing losses due to the oxidation of Fe²⁺ to Fe³⁺—which reduces its effectiveness in treatment.
Suitable Tank Materials
| Material | Rating | Note |
|---|---|---|
| HDPE (high density) | Suitable | Ideal for IBC tanks and small tanks ≤ 5.000 L |
| FRP (fiberglass reinforced plastic) | Suitable | Suitable for large tanks > 5.000 L, durable and long-lasting. |
| 316L stainless steel | ✅ Acceptable | Used for pipelines, valves, and metering pumps. |
| Ordinary carbon steel | ❌ Do not use | Severe corrosion, uncontrolled iron contamination. |
| Aluminum / Copper / Zinc | ❌ Do not use | The reaction releases H₂, posing a fire and explosion hazard. |
Storage Conditions
- Temperature: 5–40°C. Avoid storing at temperatures above 45°C — the solution will evaporate quickly and the concentration will change.
- Avoid direct sunlight: UV and heat catalyze the oxidation process of Fe²⁺ → Fe³⁺, causing the solution to turn yellowish-brown and reducing its effectiveness.
- Seal completely: Exposure to air is the primary cause of oxidation. Storage tanks must have airtight lids or an N₂ gas filling system for long-term storage.
- Expiry date: 6–12 months from the date of manufacture if stored properly.
Personal Protective Equipment (PPE)
- Eye: Chemical splash goggles are mandatory when pouring, diluting, or handling spills.
- Hand: Gloves nitrile Thickness ≥ 0,3 mm or neoprene; do not use thin latex gloves.
- Human body: Acid-resistant aprons or full-body protective clothing are recommended for handling large volumes of materials.
- Respiration: A well-ventilated area is sufficient for normal operation; a half-face mask with a P100/OV filter is required when dealing with concentrated acid vapors.
Spill Handling
- Evacuate the area, prevent FeCl2 It flows into drainage systems or surface water sources.
- Neutralize by NaHCO₃ (baking soda) Alternatively, sprinkle lime powder evenly over the flooded area — do not pour water directly over it as this will spread the lime more widely.
- Absorb the contents using dry sand or vermiculite, collect them in labeled HDPE containers, and dispose of them according to hazardous waste regulations.
- Rinse the affected skin area with clean water continuously for at least 15 minutes; for eyes: use an emergency eyewash station.
Legal Regulations & Standards for FeCl2 in Vietnam
The buying, selling, transporting, and using ferrous sulfate (FeCl2) In Vietnam, businesses are governed by numerous legal documents. Businesses need to understand this legal framework to avoid compliance risks and ensure continuous operation.
1. Decree 34/2024/ND-CP — Transport of Dangerous Goods
FeCl2 It belongs to hazardous goods category 8 (corrosive substances) according to the international ADR/IMDG. Decree 34/2024/ND-CP stipulates that transport vehicles must have warning labels conforming to GHS standards, drivers must possess a hazardous goods transport certificate, and the journey must include an emergency response plan. Violations may result in administrative fines of up to 50 million VND and suspension of operations.
2. QCVN 40:2011/BTNMT — Industrial Wastewater
When using ferrous depression In wastewater treatment, the effluent must meet certain requirements. QCVN 40:2011/BTNMT. Specifically:
- Content Total iron (Fe) Output: ≤ 1 mg/L (column A) or ≤ 5 mg/L (column B).
- Total phosphorus: ≤ 4 mg/L (column A) / ≤ 6 mg/L (column B) — directly related to the phosphate precipitation efficiency of FeCl2.
- Businesses need to conduct periodic monitoring and maintain records at the prescribed frequency.
3. Decree 113/2017/ND-CP — Chemical Business
Supplier ferric sulfate 2 must have Chemical business license According to Decree 113/2017/ND-CP (amended by Decree 82/2022/ND-CP), the technical manager must have a chemical safety certificate. The storage facility must meet fire safety standards and have warning signs in accordance with regulations.
4. MSDS/SDS according to International GHS Standard
Each lot FeCl2 The supply must be accompanied by Safety Data Sheet (SDS) 16 items according to the standard GHS/OSHAThis includes: chemical composition, hazard index, first aid measures, and information on transport and disposal of waste. The SDS is a mandatory document for import customs clearance and environmental agency inspections.
5. ZDHC MRSL — Textile Industry Compliance
Textile and dyeing businesses use FeCl2 In wastewater treatment, it is necessary to ensure that the input chemicals are on the approved list. ZDHC MRSL (Manufacturing Restricted Substances List)The use of chemicals not found in MRSL could lead to violations of the standards of international brands such as H&M, Adidas, and Zara.
Legal Documents Provided by Loc Thien Palace
Loc Thien is committed to providing complete legal documentation for every order. ferric sulfate 2:
- ✅ CO (Certificate of Origin) — Certificate of Origin
- ✅ CQ (Certificate of Quality) — Batch quality inspection certificate
- ✅ MSDS/SDS — Vietnamese and English, GHS 16-item standard
- ✅ VAT bill — Electronic invoices in accordance with Decree 123/2020/ND-CP
- ✅ We provide consulting support for compliance with QCVN 40:2011 and ZDHC MRSL upon request.
Top Q&A
What is ferric sulfate (FeCl2) and what is it used for?
Ferrous sulfate (FeCl₂, Iron(II) Chloride, CAS: 7758-94-3) is a coagulant used in industrial wastewater treatment. FeCl₂ is particularly effective in removing heavy metals (Cr, Ni, Cu), eliminating odor-causing H₂S, and removing phosphorus. Common dosages range from 100-500 mg/L depending on the type of wastewater.
Where can I buy reliable ferrous sulfate (FeCl2)?
Loc Thien is a leading distributor of ferric sulfate (FeCl₂) in Vietnam, offering products that meet ZDHC standards, with complete MSDS documentation, and a nationwide network of 6 warehouses. Contact our hotline at (+84) 979 891 929 for the best price quote.
What is the difference between FeCl2 and FeCl3?
FeCl₂ (iron II) is more effective at reducing H₂S and removing heavy metals, with an optimal pH of 5-8. FeCl₃ (iron III) is more effective at general coagulation and water treatment, with an optimal pH of 2-4. FeCl₂ should be used for electroplating wastewater, while FeCl₃ or PAC should be used for domestic wastewater.
How much does ferric sulfate (FeCl2) cost?
FeCl₂ prices depend on concentration (15-30%), quantity, and time of purchase. Loc Thien commits to competitive prices and nationwide delivery by tanker truck. Contact (+84) 979 891 929 or email locthien@locthien.vn to receive the latest wholesale price list.
To Buy large quantities of liquid FeCl₂ (ferrous sulfate). Available in 1.000L IBC containers, 200L drums, or nationwide delivery via tanker trucks. Contact Loc Thien Chemicals: 0979.89.1929.
Related products
- FeCl2 15-30% — Product page
- Instructions on FeCl2 dosage for wastewater treatment and detailed mixing instructions.
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- Wastewater treatment chemicals
Updated: 07/07/2026
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