This work created a new cross-linked hydrogel, Chitosan/Pol(acrylic acid-acryl amid-crotonic acid) (CS/(PAA-AM-CA)), using free radical polymerization. KPS catalysed the free radical reaction initiated by chitosan. A solution of acrylic acid (AA), acrylamide (AM), crotonic acid (CA), and N,N-Methylene-Bisacrylamide (MBA) was then added. FTIR and Field Emission Scanning Electron Microscopy were used to characterise the hydrogel (FESEM). These methods were used before and after adsorbing Azure A dye onto the hydrogel. Thermogravimetric analysis (TGA) showed that the hydrogel's adsorbed surface was thermally stable. XRD measurements showed the hydrogel's amorphous structure. Azure A dye equilibrated in 120 minutes. Adsorption kinetics were explored for pseudo-first-order and pseudo-second-order models. Correlation coefficient (R2) findings showed that the adsorption process followed the pseudo-second-order model. The adsorption process was also tested using three salts: sodium chloride (NaCl), potassium chloride (KCl), and calcium chloride (CaCl2). The quantity of colour adsorbed increased with pH. Adsorption capability decreased increasing salt content. This study produced and studied CS/AA-AM-CA, a cross-linked hydrogel, using free radical polymerization. The hydrogel has great heat stability and pH-dependent Azure A dye absorption. Salts decreased adsorption capability. Optimizing adsorption conditions and using this hydrogel for dye removal and environmental cleanup warrants further study.