K₂CO₃-Activated Pomelo Peels as a High-Performance Adsorbent for Removal of Cu(II): Preparation, Characterization, and Adsorption Studies

Table 1

Kinetic and isothermal models used in this study.

Kinetics model	Equation	Linear form	Plot
Pseudo first-order model			ln(qe − qt) vs. t
Pseudo second-order model			t/qt vs. t
Intraparticle diffusion model			qt vs. t^0.5
Isothermal model
Langmuir model			Ce/qe vs. Ce
Freundlich model			ln qe vs. ln Ce
Temkin model			qe vs. ln Ce
Dubinin–adushkevich (D-R) model			ln qe vs.