Abstract :
The use of plant-based biosorbents in water treatment is one of the scientific challenges. This present work
contributes to the valorization of Euphorbia prostata as a biosorbent of certain metals and its application for the
treatment of water in the coastal lagoon of Ouidah. The content of Cu2+, Pb2+, Cd2+ and Zn2+ of water taken from five
(05) sites around the coastal lagoon was measured by the atomic absorption spectrophotometer method. The
phytochemistry of the aqueous and ethanolic extract (70°) of Euphorbia prostata indicates the presence of flavonoids,
leucoanthocyanins, coumarins, reducing compounds and that they are rich in alkaloids and tannins, both catechic and
gallic. From the ETM analysis, it appears that the lagoon water contains high levels of heavy metals of Cu2+ (8.16 –
10.32 mg/L), Pb2+ (5.02 – 14.59 mg/L) and Cd2+ (6.52 – 8.71 mg/L) from one site to another. The removal of metals
from the samples by the different extracts revealed that they have an absorbent action where the ethanolic extract
(70°) of Euphorbia prostata expressed an efficiency of: Cu (96.07%), Pb (97.01%) and Cd (59.86%). It makes this
plant a good bio-sorbent candidate for heavy metals in water treatment.
Keyword :
Tannins, alkaloids, biosorbent, heavy metals, Euphorbia prostata, Ouidah lagoon