Comparison of the article with published article.

Article	Aspect
	Preparation method	Adsorb object	Adsorption evaluation	Adsorption mechanism	Novelty	Emphasis
The article	Coprecipitation method, crosslinking method, spray drying method, photochemical method and electrostatic drop method	Heavy metal ions (Cu, Pb, Cr)	BET surface area, adsorption capacity, pH, temp, cycles, kinetic and isotherm model	Physical adsorption, chemisorption and collaborative adsorption	Evaluate properties of magnetic chitosan prepared by different modification methods	Modification and application
Briao et al.15	Co-precipitation and crosslinking method	Toxic metal ions (Pb, Cd, Hg, As)	Kinetics, equilibrium and thermodynamics	—	Adsorbent regeneration	Magnetization method
Shaumbwa et al.16	Co-precipitation, crosslinking method and electrochemical crosslinking	Heavy metal ions, organic/inorganic dyes, fluorides and pesticides	Adsorption capacity, active sites and the surface area	—	Magnetic separation techniques	Application
Michailidou et al.17	Hydrothermal-crosslinking and hydrothermal-precipitation method	Uranium, mercury and rare earth elements	Kinetics and thermodynamics	Interaction between the functional group and the adsorbed substance	Adsorb uranium, mercury, and rare earth elements	Absorption efficiency