Soil contamination by heavy metals represents a major environmental challenge in tropical regions due to their toxicity, persistence, and bioaccumulation in ecosystems. This study investigates the potential of the tropical fern Nephrolepis biserrata for the phytoremediation of soils artificially contaminated with chromium, copper, zinc, and arsenic. Plants were cultivated for 56 d in moderately acidic, low-salinity soil and analysed by inductively coupled plasma mass spectrometry to quantify metal accumulation in roots and shoots. Results revealed strong bioaccumulation of zinc and copper, with bio concentration factors reaching 33.7 and 19.0 at 20 mg/kg, confirming hyper accumulation behaviour. Chromium showed moderate uptake, whereas as was weakly accumulated. Kinetic modelling indicated that chromium followed a first-order model, while copper and zinc fitted a pseudo-second-order model (R2>0.96), suggesting chemisorption through specific interactions with cell wall functional groups. Langmuir isotherms provided the best fits (R2>0.96), highlighting monolayer adsorption on homogeneous sites. Thermodynamic analysis demonstrated spontaneous (ΔG°<0), exothermic (ΔH°<0), and entropy-increasing (ΔS°>0) processes, confirming favourable metal-plant interactions. Overall, Nephrolepis biserrata emerges as a promising candidate for selective phytoremediation of tropical soils, particularly effective for copper and zinc contamination.
