Abstract
Adsorption is widely recognized as a reliable and cost-effective technique for the
removal of dye pollutants from aqueous environments. This study investigates a novel
adsorbent—ferrite composite of biochar (FCOB) for Congo red (CR) dye removal. It was
synthesized by pyrolyzing Suaeda monoica leaf powder to obtain biochar, followed by base treatment to produce base-treated
biochar, and subsequent coprecipitation with NiCuZnFe₂O₄ ferrite spinel. The XRD analysis
of FCOB confirmed the successful incorporation of spinel NiCuZnFe2O4 into FCOB, as evidenced by the presence of two prominent characteristic peaks of
the spinel structure. The SEM image revealed the irregular-crumpled structure of FCOB.
BET analysis revealed the mesoporosity in FCOB, with a surface area of 44.64 ± 0.2396
m2 g−1. The optimum adsorption was achieved at a pH of 2, adsorbent dosage of 20 mg, initial
CR concentration of 50 mg/L, contact time of 320 min, and temperature of 85 °C. The
maximum CR dye removal percentage (R%) was 99.75%. At pH = 2, the strong electrostatic attraction between protonated FCOB
adsorbent and anionic CR seemed to be the dominant adsorption mechanism. The adsorption
data was best (R
2 = 0.99) described by the Redlich–Peterson isotherm model, indicating a heterogeneous
surface with some degree of monolayer adsorption. The maximum adsorption capacity
estimated from the Langmuir model was q
max = 239.80 mg/g. The adsorption kinetics data was best described by pseudo-second-order
model (R
2 = 0.99), suggesting that chemisorption is likely the rate-limiting step. The CR adsorption
process was spontaneous and endothermic with ΔH° = 71.02 ± 1.41 kJ/mol. ANN analysis revealed that both BR and LM algorithms accurately
predicted removal efficiency and adsorption capacity, achieving R values greater than 0.995. FCOB could also be regenerated and recycled up to 5 cycles
retaining ≅65% removal efficiency for CR. Therefore, FCOB can serve as a biodegradable,
cost-effective, nontoxic, and renewable adsorbent in treating CR-dye contaminated
industrial wastewater, especially from textile and printing sectors.
Keywords
Congo red - Adsorption - Biochar -
Suaeda monoica
- Ferrite spinel
Bibliographical Record
Disha P. Mehta, Pragnesh N. Dave, Ruksana R. Sirach, Vijay V. Kumar. Modified Halophyte
Biochar for Congo red Removal: Adsorption and Neural Prediction. Sustainability &
Circularity NOW 2025; 02: a27052083.
DOI: 10.1055/a-2705-2083
