Sodium Hypochlorite Supplier in the UAE

Technical guide · Prepared by the Hazchem Chemicals technical team · Last reviewed 10 October 2026

What Is Sodium Hypochlorite?

Sodium hypochlorite (NaOCl) is a chlorine compound supplied as a pale greenish-yellow alkaline liquid and used worldwide to disinfect water, sanitise surfaces and bleach materials. It is the active ingredient in household bleach (typically 3–8% NaOCl). Industrial grades are stronger, usually 10–15% available chlorine, and are the most common liquid chlorine source for drinking water, wastewater, swimming pools and cooling towers.

It is made by bubbling chlorine gas through sodium hydroxide (caustic soda) solution: Cl₂ + 2 NaOH → NaOCl + NaCl + H₂O. A small excess of caustic soda is left in the product to keep it stable, which is why commercial solutions are strongly alkaline.

How Sodium Hypochlorite Disinfects Water

When dosed into water, NaOCl forms hypochlorous acid, which kills microorganisms by oxidising their cell walls and enzymes.

1. DosingNaOCl is added to the water, usually by a dosing pump, in proportion to flow.
2. HOCl formsNaOCl + H₂O → HOCl + NaOH. Hypochlorous acid and the hypochlorite ion together are called “free chlorine”.
3. Contact timeFree chlorine needs time to act. WHO recommends at least 0.5 mg/L free chlorine after 30 minutes’ contact, at pH below 8.
4. ResidualA measured residual is kept in the water to protect it through storage and distribution.

Why pH matters: hypochlorous acid (HOCl) is a far stronger disinfectant than the hypochlorite ion (OCl⁻), and the balance between them depends on pH (pKa ≈ 7.5 at 25°C). At pH 7.0 about three-quarters of free chlorine is HOCl; at pH 8.0 only about a quarter is. That is why pools are kept at around pH 7.2–7.6: the same dose disinfects far more effectively than at pH 8 or above.

What Is Sodium Hypochlorite Used For?

• Drinking water disinfection: primary disinfection and residual chlorine in municipal, RO and bottling plants.
• Wastewater and sewage: effluent disinfection before discharge or reuse as irrigation (TSE) water, and odour control by oxidising hydrogen sulphide.
• Swimming pools: continuous liquid chlorination through automatic dosing systems, and algae control.
• Cooling towers and district cooling: controlling biofouling, slime and Legionella.
• Food and beverage: sanitising equipment, surfaces and clean-in-place (CIP) systems.
• Healthcare and facilities: surface disinfection and infection control.
• Bleaching: laundry, textiles and pulp, and as the base for household bleach and cleaning products.

How Much Sodium Hypochlorite to Add to Water

To raise free chlorine by a target amount, use:

Litres of NaOCl = (water volume in m³ × target dose in mg/L) ÷ available chlorine in g/L

Worked example: to raise a 500 m³ pool by 1 mg/L using 12.5% sodium hypochlorite (about 125 g/L available chlorine): 500 × 1 ÷ 125 = 4 litres. With 10% (about 100 g/L), the same job needs 5 litres.

Use the actual available chlorine on your batch COA, since strength falls in storage. Real systems also have a chlorine demand (organics, ammonia, iron) that must be met before a residual appears, so confirm the result with a free chlorine test.

Sodium Hypochlorite vs Calcium Hypochlorite vs Chlorine Gas

All three release free chlorine in water. They differ in strength, handling and how they are dosed.

Many pool operators use both hypochlorites: sodium hypochlorite for routine automatic dosing and calcium hypochlorite for shock treatment.

Why Sodium Hypochlorite Loses Strength in UAE Heat

• Temperature: the decomposition rate rises by a factor of about 2 to 4 for every 10°C increase. Product stored at 45°C in a UAE summer loses strength many times faster than product kept at 25°C.
• Concentration: stronger solutions decompose faster, so 12–15% loses strength faster than 10%.
• Sunlight: UV light breaks hypochlorite down, which is why tanks and containers should be opaque and shaded.
• Metals: traces of copper, nickel, cobalt and iron catalyse decomposition, so storage and dosing equipment should be HDPE, FRP or PVC.
• Chlorate by-product: as hypochlorite decomposes it forms sodium chlorate. WHO sets a provisional drinking-water guideline of 0.7 mg/L for chlorate, so fresh product matters most for potable water.

Sources: WHO Guidelines for Drinking-water Quality · Olin Sodium Hypochlorite Safe Handling · PubChem

Key Terms

Available chlorine

The amount of chlorine a product can release for disinfection, used to state strength. Industrial NaOCl is sold as 10% or 12–15% available chlorine.

Free chlorine

Hypochlorous acid plus hypochlorite ion in water: the chlorine still available to disinfect.

Combined chlorine

Chlorine that has reacted with ammonia to form chloramines. It is a weaker disinfectant and causes the “chlorine smell” in pools.

Chlorine demand

Chlorine consumed by organics, ammonia, iron and other substances before a residual can be measured.

Residual chlorine

Free chlorine remaining after the contact time, maintained to protect water in storage and distribution.