posted on 2024-01-15, 06:30authored byAklima
A Akhi, Abid Hasan, Nakshi Saha, Sabbir Howlader, Sabonty Bhattacharjee, Kamol Dey, A. K. M. Atique Ullah, Farhana Rumzum Bhuiyan, Ashok Kumar Chakraborty, Umme Sarmeen Akhtar, Md. Aftab Ali Shaikh, Benu Kumar Dey, Samiran Bhattacharjee, Sumon Ganguli
Green synthesis of silver nanoparticles (AgNPs) using
a plant extract
has attracted significant attention in recent years. It is found as
an alternative for other physicochemical approaches because of its
simplicity, low cost, and eco-friendly rapid steps. In the present
study, Ophiorrhiza mungos (Om)-mediated AgNPs have been shown to be effective bioadsorbents
for methylene blue (MB) dye removal (88.1 ± 1.74%) just after
1 h at room temperature in the dark from an aqueous medium for the
first time. Langmuir and Freundlich isotherms fit the experimental
results having the correlation coefficient constants R2 = 0.9956 and R2 = 0.9838,
respectively. From the Langmuir fittings, the maximum adsorption capacity
and adsorption intensity were found to be 80.451 mg/g and 0.041, respectively,
indicating the excellent performance and spontaneity of the process.
Taking both models under consideration, interestingly, our findings
indicated a fairly cooperative multilayer adsorption that might have
been governed by chemisorption and physisorption, whereas the adsorption
kinetics followed the pseudo-second-order kinetics mechanism. The
positive and low values of enthalpy (ΔH0 = 4.91 kJ/mol) confirmed that adsorption is endothermic and
physical in nature; however, the negative free energy and positive
entropy value (ΔS0 = 53.69 J/mol
K) suggested that the adsorption is spontaneous. The biosynthesized
adsorbent was successfully reused up to the fifth cycle. A proposed
reaction mechanism for the adsorption process of MB dye onto Om-AgNPs is suggested. The present study may offer a novel
finding such as an effective and sustainable approach for the removal
of MB dye from water using biosynthesized Om-AgNPs
as reusable adsorbents at a comparatively faster rate at a low dose
for industrial applications.