**Author details**

*Trace Metals in the Environment - New Approaches and Recent Advances*

Let the percentage of release defined as following Eq. (3):

*Variation of the release percentage according to the nature of the metal.*

tion of metals; Ce: concentration of ions at equilibrium.

**Table 12**, indeed the percentages of release are equal.

the raw chitin has undeniable qualities of fixing heavy metals. For the regeneration tests, we chose the raw chitin of shrimp origin. Finally, the regeneration is carried out by HCl and focused on four metals, the regeneration conditions are optimized.

**Metal CM2+ fixed (mg/l) C(metal) (mg/l) Percentage of release** Pb2+ 98.91 14, 820 149.8 Cd2+ 86.77 23.17 26.70 Cu2+ 94.09 23.35 24.82

CM2+ fixed: concentration of M2+ fixed on the adsorbent before regeneration, C(metal): concentration of the released amount of M2+ after regeneration. Concentration CM2+ fixed is calculated according to the following Eq. (4):

Mo: initial mass before treatment; Ms: mass saturated with heavy metals; Vi: volume used for saturation; Vr: volume used for regeneration; Ci: initial concentra-

The amount released by HCl remains relatively stable from a concentration of 0.08 mol/l HCl, if we increase the concentration of HCl. It should be noted that all the metals studied are easily displaced by a low concentration of H, this shows that the interactions established between the metals and the raw chitin are not strong

case of Cu and Cd, it is almost constant and neighbor. These results are grouped in

The incineration of raw chitin has led to metal oxides that can be recycled in other industries; in addition, it is a fast and perfectly hygienic process. It allows a significant reduction of waste in weight and volume. Therefore, it is the best solution in the case of effluents less loaded with heavy metals and whose composition is complex. However, the regeneration of raw chitin is a cumbersome process that requires the addition of reagents (acid, salt), and the use of material, in addition, it modifies the structure of the material, but in spite of this, the regeneration is the best solution in the case of mineral effluents heavily loaded with heavy metals and

The isothermal study and kinetics of adsorption of metal ions on crude chitin has shown that the adsorption capacity of a metal depends on the origin of the latter

**9.3 Comparison between the two processes and interpretation of results**

ions. The released quantity is maximum in the case of Pb. In the

% of release = C(metal)/CM2+fixed (3)

CM2+fixed = [(CiVi − CeVr) Ms]/MoVr (4)

**256**

with

**Table 12.**

with

to resist the H+

whose composition is simple.

**10. Conclusion**

Boukhlifi Fatima Faculty of Science, MY Ismail University, Meknes, Morocco

\*Address all correspondence to: boukhlifi1@yahoo.fr

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
