Selection of macrophytes with Cu-enriched root biomass intended for ecocatalyst production

[Display omitted] •Cyperus eragrostis roots stop to grow as Cu exposure exceeds 20 μM.•Root Cu content of Phalaris arundinacea do not reach the Cu-ecocatalyst level.•At 40 μM Cu, Iris pseudacorus roots reach the Cu-ecocatalyst level.•Above 10 μM Cu, Arundo donax roots meet the Cu-ecocatalyst level. Four macrophytes commonly used to clean up Cu contaminated effluents, i.e. Arundo donax L., Cyperus eragrostis Lam., Iris pseudacorus L. and Phalaris arundinacea L., were assessed to produce Cu–rich plant biomass intended for ecofriendly catalyst preparation. 7-month-old plants were exposed to a Cu gradient (0.08, 2, 10, 20 and 40 µM Cu) in batch conditions during 2 months. Copper exposure affected the root DW yield of C. eragrostis from 2 µM Cu, whereas I. pseudacorus and A. donax developed well. Maximum Cu concentration in the biomass of C. eragrostis and P. arundinacea (i.e. 255 and 838 mg Cu kg−1 DW respectively) did not reach the 1000 mg Cu kg−1 DW threshold value needed to produce Cu-ecocatalysts. Copper concentrations in the roots of I. pseudacorus and A. donax exceeded this threshold value at 40 µM and over 10 µM Cu, i.e. 1099 and 1809 mg Cu kg−1 DW, respectively, making them relevant candidates for producing Cu-ecocatalysts.