Zinc removal efficiency ranged between 45% and 93% for
CACSC; 32% and 55 % for CCSC, and 12% and 50% for ACSC
over pH range of 2–6. Zinc, like other metals, such as chromium,
depending on the pH, is known to exist as anion. At low pH,
the amine group on chitosan is protonated to varying degree
[7]. The surface acidity was due to the introduction of several
oxygen-containing functional groups