Comparative study of four different flavonoid compounds‐containing plant extracts functionalised waste wool for accelerating aqueous chromium(VI) reductive removal

Four different plant material extracts containing flavonoid compounds were prepared with fruits of Lycium ruthenicum Murray (LRM) and Vaccinium spp. (VS), Ginkgo biloba L. (GBL) leaves and grape seeds. On the basis of several characterisation, these extracts were then used for functionalising waste wool fibres by an exhaustion dyeing process. Content of deposited flavonoid compounds and aqueous chromium(VI) reductive removal capacity of four plant material extract dyed wool fibres were investigated and compared. The results indicated that LRM and VS extracts contained more flavonoid compounds (0.12‐0.15 mg ml −1 ) than the other two extracts (0.06‐0.08 mg ml −1 ), which led to high content of deposited flavonoid compounds and strong chromium(VI) reductive removal performance of their dyed wool fibres. Importantly, 0.10 mmol L −1 of chromium(VI) species could be almost completely removed by fallen GBL extract dyed wool fibre from water by increasing content of deposited flavonoid compounds up to 8.0 mg g −1 , which offer a novel strategy to produce cost‐effective, environmental‐friendly and renewable chromium(VI) removal material based on waste control by waste.