Nickel (Ni) in Water Treatment

Quick Answer

Nickel (Ni) is a transition metal with atomic number 28. PubChem lists its standard state as solid and its relative atomic mass as 58.693.

Nickel can originate from natural geology, plating, alloys and industrial wastewater. Treatment options include hydroxide or sulfide precipitation, adsorption, ion exchange and membrane separation, with pH and complexing agents strongly affecting removal.

Interesting Facts

• Nickel helps stainless steel resist corrosion, yet nickel can also leach from alloys or plating under unfavourable water chemistry.
• The name traces to the German Kupfernickel—“devil’s copper”—for an ore that looked copper-rich but yielded no copper.
• Cyanide, ammonia and organic chelants can keep nickel soluble, so a precipitation test with uncomplexed Ni²⁺ may overstate real wastewater performance.

Water-treatment Design Implications

An element name alone is not enough to select treatment equipment. Confirm chemical form or speciation, total and dissolved concentration, pH, alkalinity, competing ions and the product-water target. Send the water-analysis results to Watermart to identify additional testing and shortlist processes before equipment is specified.

Summary Data Sources

• PubChem — Nickel
• IUPAC Periodic Table of Elements
• WHO chemical hazards in drinking-water

1. Basic Information

Atomic Number	28
Symbol	Ni
Atomic Mass	58.69 g/mol
Electron Configuration	[Ar]3d⁸4s²
Category	Transition metal

2. Physical and Chemical Properties

Nickel is a silvery-white metal that is hard, malleable, and ductile. It has a melting point of 1453°C and a boiling point of 2913°C. Nickel is resistant to corrosion and is often used in alloys to improve corrosion resistance. In its compounds, nickel typically has an oxidation state of +2, although it can also form compounds with oxidation states of +1 and +3. Nickel dissolves slowly in dilute acids and becomes passive when treated with nitric acid.

3. Presence in Water and Health Effects

Nickel can enter water through rock weathering, mining, smelting, alloys and electroplating. Health evidence depends on route and compound: occupational inhalation cancer findings must not be presented as the effect of drinking dilute Ni²⁺. For potable projects, cite the current value and document of the competent authority rather than calling one international guidance value a universal “maximum limit.”

4. Water Treatment Applications and Removal Methods

Some methods used to remove nickel from water include:

• Ion exchange: Cation exchange resins can be used to remove Ni²⁺ ions from water. Special chelating resins such as AmberSep™ M4195 and AmberSep™ M4196 are particularly effective for removing nickel from acidic solutions.
• Reverse osmosis: RO systems can remove up to 97% of nickel from water.
• Chemical precipitation: The addition of bases such as lime or soda ash can precipitate nickel as hydroxide.
• Adsorption: Adsorption media such as activated carbon or zeolite can remove nickel from water.
• Membrane filtration: Nanofiltration and ultrafiltration can be effective in removing nickel.

5. Industrial Uses in Water Treatment

Nickel has several applications in the water treatment industry, although not as many as other metals:

• Catalysts: Some nickel-based catalysts are used in advanced water treatment processes such as catalytic oxidation.
• Corrosion-resistant alloys: Water treatment equipment such as pumps and pipes often use nickel-containing alloys for corrosion resistance.
• Electrodes: Nickel electrodes are sometimes used in water treatment electrochemical processes.

6. Case Study and Real World Application

An electroplating factory in West Java faced the problem of high nickel content in its wastewater. They implemented a multi-stage treatment system consisting of:

1. pH adjustment to precipitate most of the nickel as hydroxide
2. Filtration to remove sediment
3. Ion exchange using specialized chelating resins to remove residual dissolved nickel
4. Reverse osmosis as the final purification stage

This example is illustrative, not a verified case history. A real performance claim needs named feed chemistry, analytical methods, operating data, a cited discharge requirement and results across representative production cycles.

8. Environmental Impacts and Sustainability Considerations

Nickel can accumulate in sediments and aquatic organisms, causing toxic effects on aquatic ecosystems. Nickel removal from wastewater before discharge into the environment is essential to protect aquatic habitats. Treatment methods such as ion exchange enable nickel recovery and recycling, supporting a circular economy and reducing the environmental impact of new nickel mining.