Researchers developed a silver nanoparticle composite cathode that accelerates nickel electrodeposition from dilute industrial wastewater. The Ag0@AC catalyst, made by anchoring zero-valent silver nanoparticles on activated carbon, achieved 96% nickel removal and 98% Faradaic efficiency in a simulated nickel sulfate electrolyte. This single-step process recovers metallic nickel as a solid film without generating secondary chemical sludge, unlike conventional precipitation or membrane methods. The study also mapped how pH, temperature, anion type, and agitation affect deposition kinetics. A neutral pH window minimized competing hydrogen evolution, while sulfate electrolytes provided stable operation without sulfur contamination. The composite's high surface area and microporous structure lowered charge-transfer resistance and improved electron transfer at room temperature. For industrial metal finishing, battery manufacturing, and metallurgy, this approach could turn a costly waste stream into a recoverable nickel resource. Pilot-scale testing is still needed to confirm performance on real effluents with mixed metals and organic contaminants.
