This model is less preferred by scholars, who usually do not find evidence of its existence such as data from colorimeters or IV spectrometers. Although there is currently no general consensus in favor of copper chelation with chitosan, the balance seems to tip in favor of the leaning model. However, scholars suggest that chelation is extremely dependent on factors such as contact time, temperature, pH and adsorbent dose [36, 37], so it is conceivable that this type of chelation occurs under some specific conditions, but probably not so commonly like the pendant