**4. Conclusions**

The experimental results obtained lead to the following conclusions:


**Table 3.** Italian legal concentration limit for chromium (VI), iron, and copper for disposal in both superficial water and drainage systems. (All. 5, P. Terza, D. Lgs n.152 del 03-04-06).


The NiAl-NO3 compound reduces the Cr(VI) content at a value close to the legal limit, but is not sufficiently low. Some improvements of the methods (reaction time, sorbent/wastewater ratio) could help in reaching the goal.

The MgAl-CO3 LDH demonstrates to be very effective in lowering the Cu(II) and Fe(III) concentration to below the legal limit.

For all of the above, the next step will be to test the effectiveness of a combined use of the two metal getters and their transformation into a spinel-like structure after heating for a potential reuse.

**Author Contributions:** Conceptualization: A.M.C., C.C.; investigation: A.M.C., S.C., M.F., N.P.; methodology: A.M.C., S.C.; writing—original draft preparation: A.M.C., S.C.; writing—review and editing: A.M.C., S.C.; resources: A.M.C., C.C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Conflicts of Interest:** The authors declare no conflict of interest.
