Waste valorization of spent wastewater nanoadsorbents is a promising technique to support the circular economy strategies. The terrible rise of heavy metal pollution in the environment is considered a serious threat to the terrestrial and aquatic environment. This led to the necessity of developing cost-effective, operation-convenient, and recyclable adsorbents. ZnCoFe mixed metal oxide (MMO) was synthesized using co-precipitation. The sample was characterized using X-ray powder diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Factors affecting the adsorption process such as pH, the dose of adsorbent, and time were investigated. ZnCoFe MMO showed the maximum adsorption capacity of 118.45 mg/g for ceftriaxone sodium. The spent MMO was recycled as an adsorbent for malachite green (MG) removal. Interestingly, the spent adsorbent showed 94% removal percent for MG as compared to the fresh MMO (90%). The kinetic investigation of the adsorption process was performed and discussed. In addition, ZnCoFe MMO was tested as an antimicrobial agent. The proposed approach opens up a new avenue for recycling wastes after adsorption into value-added materials for utilization in adsorbent production with excellent performance as antimicrobial agents.