The polyaminocarboxylated modified hydrochar for efficient capturing methylene blue and Cu(II) from water.

The polyaminocarboxylated modified hydrochar (ACHC) was synthesized to introduce abundant amino, hydroxyl and carboxylate multifunctional groups onto the surface of hydrochar by etherification, amination and carboxylated reaction. The ACHC was systematically characterized and used to evaluate adsorption properties of Cu(II) and methylene blue (MB) by batch sorption tests. The adsorption process toward Cu(II) and MB by ACHC obeyed the pseudo-second-order kinetic model and Langmuir model. Characteristic analysis indicated the surface chelation was mainly contribute to Cu(II) adsorption by large amounts of amino and carboxylate groups while π-π interaction, hydrogen bonding and electrostatic attraction dominated MB adsorption. The maximum adsorption capacities of ACHC were 140.65 and 1238.66 mg·g for Cu(II) and MB at 303 K, respectively. Approximately 97% of the adsorptive uptakes for two pollutants were removed within merely 5 min for kinetic experiment. Competitive adsorption of Cu(II) and MB, and treatment of electroplating wastewater by ACHC were also investigated.