Method for removing heavy metals from wastewater

A method for removing a heavy metal from an aqueous solution, comprising:

• contacting a cross-linked polymeric resin with the aqueous solution comprising at least one heavy metal;
• wherein the cross-linked polymeric resin has the following formula (I)
• or a salt, solvate, tautomer or stereoisomer derived from the cross-linked polymeric resin of formula (I);
• wherein each R1 is independently selected from H, an alkyl, a cycloalkyl, and an aryl;
• each R2 is independently selected from H, —F, —Cl, —Br, —CN, —OR3, an alkyl, a cycloalkyl, and an aryl;
• each R3 is independently selected from —H, an alkyl, a cycloalkyl, and an aryl;
• n is a positive whole number in the range of 2-16;
• X is a positive whole number;
• and
• A1 forms a bond to A2 of another monomer unit;
• and
• adsorbing the heavy metal onto the cross-linked polymeric resin to form a heavy metal loaded cross-linked polymeric resin and a heavy metal depleted aqueous solution.