A Multifunctional Microspheric Soil Conditioner Based on Chitosan-Grafted Poly(acrylamide-co-acrylic acid)/Biochar

A multifunctional microspheric soil conditioner based on chitosan-grafted poly(acrylamide-co-acrylic acid)/biochar [CS-g-P(AM-co-AA)/BC] was prepared. First, the P(AM-co-AA) was synthesized and successfully grafted onto CS, and the three-dimensional network structure of microspheres was formed with N,N-methylenebis(acrylamide) as the cross-linking agent according to the inverse suspension polymerization method. Meanwhile, BC and urea were encapsulated into the body of microspheres during the polymerization. The structure of the microspheres was analyzed by Fourier transform infrared spectroscopy, polarized optical microscopy, and scanning electron microscopy, and the mechanism of adsorption of Cu²⁺ on the microspheres was investigated by X-ray photoelectron spectroscopy. Furthermore, the experimental results demonstrated the excellent water absorption and retention capabilities of microspheres, and the release rate of urea was dramatically reduced. Importantly, the introduction of BC significantly enhanced the adsorption performance of the microspheres with respect to heavy metal ions. Consequently, the multifunctional soil conditioner held promise for use in soil improvement and agricultural production.