Synthesis, characterization and application of curcumin formaldehyde resin for the removal of Cd2+ from wastewater: Kinetics, isotherms and thermodynamic studies

•A green adsorbent (CFR) was used for the removal of Cd2+ from water samples.•The maximum monolayer adsorption capacity (Qm) was 322.58 mg g−1 at 45 °C.•CFR showed a good reusability up to 5 cycles.•Breakthrough capacity in tap water was 250 mg g−1.

The present work deals with the removal of highly toxic Cd2+from wastewater using ecofriendly curcumin (7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) formaldehyde resin (CFR). The CFR resin was characterized using several analytical techniques. The adsorption kinetics and isotherms were well fitted by pseudo-second-order and Freundlich models, respectively. The adsorption of Cd2+ onto CFR was increased with the ionic strength (NaCl). The regeneration studies demonstrated a decrease in the adsorption of Cd2+ from 94% to 80% after five consecutive cycles. All results illustrated that CFR was a promising adsorbent for the environmental pollution cleanup.

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