Microfluidic synthesis of thiourea modified chitosan microsphere of high specific surface area for heavy metal wastewater treatment

Abstract An improved biosorbent of thiourea modified chitosan microsphere (TMCM) with high specific surface, favorable mechanical strength and excellent adsorption performance had been synthesized via microfluidic technology. Polyethylene glycol was used as a significant component added in aqueous solution of chitosan to produce such microspheres through droplets forming, chemical crosslinking and pores creating. For the improvement of adsorption capacity, thiourea was considered as an excellent choice in increasing amino functional group by graft modification. The SEM, FTIR and EDS were employed to detect distinct features of TMCM. Copper(II) was used to test the adsorption performance of TMCM. The experimental results indicated that TMCM exhibited higher adsorption capacity ( q e  = 60.6 mg g −1 ) and faster adsorption rate than that non-modified chitosan microsphere (NMCM). The adsorption kinetic was described well by the pseudo -second order kinetic model, which suggested that chemical adsorption along with electrons transferring was dominant in adsorption process.