Comparison of Ni (II) ion biosorption onto Eupatorium Adinophorum and Acer Oblongum biomass using batch operations, response surface models, thermodynamics, kinetics, and equilibrium studies.

The batch operations, analysis of variance (ANOVA), and response surface quadratic models (RSM) were carried out for the biosorption of Ni(II) from synthetic aqueous solution onto treated Eupatorium adinophorum (AEA) and Acer oblongum (AAO) biomass. The impact of Ni-ion concentration, pH, adsorbent dose, contact time, and reaction temperatures was investigated. The maximum removal efficiency of the Ni(II) ion onto AEA and AAO biosorbent was 87.88 % and 91.1 %, respectively, at pH 5. The biosorption capacities for AEA and AAO biomass were determined to be 33.84 mg/g and 34.42 mg/g, respectively. The analysis of the morphology and the functional group of AEA and AAO was performed by scanning electron microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and Fourier transform infrared (FTIR) spectroscopy. Ni(II) ion biosorption was endothermic, spontaneous, and viable thermodynamically. The three adsorption isotherms, Freundlich, Dubinin-Radushkevich (D-R), and Langmuir, shows that the Langmuir model best matches the data, with regression coefficient values (Adj. R) of more than 0.99. The kinetic model demonstrated the biosorption via a chemisorption mechanism and gave the best correlation with pseudo-second-order kinetics. The findings showed that both biomass residues have the potential to be employed as inexpensive biosorbents, but AAO has a higher ability than AEA to remove Ni(II) from wastewater.