A recyclable magnetic polyethyleneimine-functionalized cellulose aerogel for reducing cadmium (Cd) accumulation in acidic contaminated soil: Stress mitigation and soil improvement mechanisms

Currently, the reported stabilizers for soil remediation mainly focus on reducing the availability and migration of heavy metals, yet shifts in surrounding environmental factors can lead to the remobilization of these pollutants. Herein, a novel polyethyleneimine (PEI) cross-linked magnetic cellulose aerogel (MCA PEI ) was synthesized and employed for remediating cadmium (Cd)-polluted soil and alleviating the stress effects of Cd on green fertilizer (SV), a key biological fertilizer in southwest China. The cellulose derived from straw showed distinct characteristic peaks, with a substantial rise in functional group content following gelation, while the magnetized gel demonstrated easy recovery from soil. The synthesized MCA PEI demonstrated broad pH adaptability and rapid Cd(II) uptake, achieving a maximum binding capacity of 200.41 mg/g. The DTPA-Cd concentration was reduced by 89 % with a 3.0 % MCA PEI dosage under 40 % of soil moisture after 20 d. After 1 % MCA PEI remediation and recycling, the total amount of Cd in the soil decreased, which was conducive to improving soil properties, reducing the accumulation of Cd in SV, and promoting the growth of SV. In short, this study proposed a sustainable and effective remediation strategy for Cd-polluted soil using a magnetic functionalized aerogel that could be easily separated from the soil after remediation.