Lignitic Humic Acids as Environmentally-Friendly Adsorbent for Heavy Metals

Table 2

Average adsorption efficiencies for single Cu²⁺ ions and Cd²⁺, Cu²⁺, Pb²⁺, and Zn²⁺ ions adsorbed from their mixture.

Cu^2+ (single)	Cd^2+	Cu^2+	Pb^2+	Zn^2+
99.9%	90.3%	94.4%	92.8%	92.0%