Decorating metal organic framework on nickel foam for efficient Cu²⁺ removal based on adsorption and electrochemistry

The removal of heavy metal ions in wastewater has a great significance to human health and environment protection. Metal organic framework possesses high surface area, rich porosity, tunable pore size and abundant active sites. However, the intrinsic aggregation and fragility of MOF nanoparticles make its poor adsorption and undesirable reusage. Herein, a facile and unique hot-pressing method is adopted to decorate the MOF nanoparticles on nickel foam (ZIF-8/NF), which simultaneously serves as self-supporting substrate of ZIF-8 nanoparticles and electrode of a self-powered multifunctional purification system. In adsorption, the ZIF-8/NF composite presents high Cu²⁺ removal rate of 49.5% with the concentration of 10 mg/100 ml. More importantly, integrating with electrochemistry, the Cu²⁺ removal rate of the ZIF-8/NF composite reaches 54.7% in 5 min. The superior performance is attributed to the comprehensive effects of ion exchange, chemical bonding and physical adsorption. Moreover, the low-cost, fast and scalable preparation contributes to commercially fabricate MOF nanoparticles on self-supported substrate to treat wastewater with high efficiency and good recyclability.