In this study, a simple submersible device was tested to remove and recover Cd(II), Cu(II), Pb(II), and Zn(II) from model wastewater and real natural water. To obtain this device, fine particles (< 0.1 mm) of a new hybrid adsorbent based on the mesoporous carbon and Fenton-modified humic acids were fixed onto a highly porous polymeric matrix. The hybrid adsorbent was characterized by various methods. The main mechanism for Cd(II), Cu(II), Pb(II), and Zn(II) adsorption by the hybrid adsorbent is chemosorption by surface functional groups, the total concentration of which was found to be 1.56 mmol g−1. The adsorption capacity depends on pH, and at pH 6.0, it has the following order (mmol g−1): Cu(II) (1.14) > Pb(II) (0.86) > Zn(II) (0.59) > Cd(II) (0.50). The possibility of applying a submersible device for the removal and recovery of these metals from multi-metal wastewaters and reservoirs was studied. A high efficiency of metal removal (95–99.9%) and recovery (85–99%) from wastewater remained in at least six consecutive adsorption–desorption cycles. Effective removal of metals from the water of a contaminated reservoir contributed to the rapid restoration of the phytoplankton organisms after their oppression by metals. Thus, the use of a submerged device with the new hybrid adsorbent can be an effective way of remediating wastewaters and natural waters contaminated with metals.