Polyvinylpolypyrrolidone Immobilized Cu, Cd and Zn in Soils and Reduced Their Uptake by Oilseed Rape

Organic amendments application has been proposed as an efficient method for remediation of heavy metals-contaminated soils. This study evaluated the performance of the water-insoluble organic material polyvinylpolypyrrolidone on decontaminating water and soil polluted by heavy metals Cu, Cd and Zn via batch trials, soil incubation and pot experiments with oilseed rape. The adsorption process of Cu, Cd and Zn by polyvinylpolypyrrolidone included a rapid step which achieved 92%, 76% and 87% of adsorption capacities within 10 min, followed with a slow step before reaching equilibrium which varied from 4 to 24 h among the three heavy metals. The maximum adsorption capacities were 327, 330 and 186 mg g−1 for Cu, Cd and Zn, respectively. With application doses of polyvinylpolypyrrolidone ranging from 10 to 60 g kg−1, the DTPA-extracted Cu, Cd and Zn showed 59–96%, 27–93% and 13–83% reduction compared to no addition. Moreover, the uptake of Cu, Cd and Zn by oilseed rape were significantly inhibited with polyvinylpolypyrrolidone amendments, and the effects improved with the accrual of polyvinylpolypyrrolidone. Intriguingly, the application of polyvinylpolypyrrolidone showed insignificant influences on nutrients taken up by oilseed rape. Results of the present study indicated that polyvinylpolypyrrolidone is a promising organic amendment for heavy metal (Cu, Cd and Zn) stabilization in polluted water and soil.