This study showcases the successful synthesis of Saraca
asoca nanoparticles (SANPs) and their efficacy as adsorbents
for a range of cationic dyes, namely, malachite green (MG), methylene
blue (MB), and crystal violet (CV). SANPs have been characterized
through techniques such as powder X-ray diffraction, Fourier transform
infrared, dynamic light scattering, scanning electron microscopy,
and transmission electron microscopy. X-ray photoelectron spectroscopy
analysis confirms the different oxidation states of elements, including
carbon, potassium, calcium, phosphorus, silicon, and oxygen. Using
the Debye–Scherrer equation, the average crystallite size has
been estimated to be 27 nm. Synthesized SANPs illustrate highly effective
adsorption toward MB, CV, and MG, demonstrating maximum adsorption
efficiencies 495, 404, and 943 mg/g, respectively. Furthermore, the
adsorption mechanism follows the pseudo-second-order reaction, and
the Langmuir isotherm indicating adsorption follows chemisorption
and monolayer formation. Besides this, the high efficiency may be
due to the combined effect of diffusion and adsorption. To confirm
practical viability and feasibility, SANPs encapsulated within alginate
beads were developed that also exhibited a high MG removal efficiency
with significant regenerative ability for multiple consecutive cycles.
SANPs and their alginate-encapsulated beads, therefore, align with
current sustainable development goals.