AbstractToday, eco‐friendly and cost‐effective nanomaterials are vital to ultimately removing contaminants from groundwater as an essential part of freshwater. In this study, polyvinylpyrrolidone (PVP)‐stabilized nano zero‐valent iron (nZVI) supported by hydrophilic wheat straw biochar (HWS) (PVP‐nZVI@HWS) was prepared and compared with the nZVI‐HWS sample for Cr (VI) removal from aqueous media. The morphology and functional group structure of PVP‐nZVI@HWS composites demonstrated that nZVI could be dispersed homogeneously on the hydrophilic biochar substrate by adding PVP (owing to a large number of −OH functional groups). Based on BET analysis, despite a minimal reduction in the surface area of the PVP‐nZVI@HWS hybrid material compared to the nZVI‐HWS sample (7.19 m2 g−1), the pore volume and adsorption average pore diameter increased. Superior reduction efficiency (99.63 % elimination in only 5 min) of 20 ppm Cr (VI) was achieved using the proposed hybrid material. Pseudo‐ second‐order kinetics (R2=1) and Langmuir isotherm models (R2=0.9407) were attained via the PVP‐nZVI@HWS (0.2 g L−1) under groundwater condition (sodium chloride solution at pH=3.2). In addition, on a large scale, the proposed hybrid material could reduce 97.22 % of Cr (VI) in 180 minutes from the water. The mechanism of catalytic and absorption behaviour for two catalysts was compared, and the investigations showed that absorption action for the nZVI‐HWS sample, and catalytic behaviour for the PVP‐nZVI@HWS hybrid material were predominant.