Origin v 2018

The results of all equilibrium and kinetic models used in this study were evaluated through the least-square method and correlation coefficient (R²) analysis. The statistical evaluation was performed using Origin v.2018 (OriginLab Corporation, Northampton, MA, USA). The root mean square error function was also determined in order to establish the best-fitting models [59 (link)]: $$\mathrm{RMSE} =\sqrt{\frac{1}{\mathrm{n}}· {{\displaystyle \sum }}_{\mathrm{i}=1}^{\mathrm{n}}{\left({\mathrm{q}}_{\mathrm{calc}\left(\mathrm{i}\right)}-{ \mathrm{q}}_{\exp \left(\mathrm{i}\right)}\right)}^2}$$
where RMSE represents the root mean square error; q_calc is the calculated amount of pollutant adsorbed per unit mass of material (mg g⁻¹); q_exp is the measured amount of pollutant adsorbed per unit mass of material (mg g⁻¹).

The data were checked for normal distribution and equal variance, then analyzed with one-way ANOVA and Duncan’s multiple range tests, and their interactions at p ≤ 0.05 using SPSS v.14.0 (SPSS Inc., Chicago, IL, USA). Correlations were examined using Pearson’s correlation coefficient. SigmaPlot v. 12.5 (Systat Inc., San Jose, CA, USA) was used to correlate and plot indicators. A principal component analysis (PCA) was performed on all measured physiological parameters in Origin v. 2018 (OriginLab, Northampton, MA, USA).

The equilibrium sorption study was achieved using 3 mL of CV solutions of 38 different concentrations (0.45–500 mg L⁻¹) for an adsorbent amount of 3.33 g L⁻¹ and 30 min contact time. Experimental data were fitted on both the linear and non-linear forms of Langmuir, Freundlich, Temkin, Dubinin-Radushkevich and Khan isotherm models (Table S1) [30 ,31 ,32 (link),33 (link),34 ]. Equation (3) defines one of the most important attributes of the Langmuir isotherm, namely the separation factor (R_L), which shows the type of adsorption process and the isotherm profile: ${\mathrm{R}}_{\mathrm{L}}=\frac{1}{{1+\mathrm{K}}_{\mathrm{L}}{\times \mathrm{C}}_{\mathrm{i}}}$
where: R_L is the separation factor, and K_L is the Langmuir constant (L mg⁻¹).
According to [35 ,36 (link)], the adsorption mechanism can be categorized as: irreversible (if R_L = 0), favourable (if 0 < R_L < 1), linear (if R_L = 1) and unfavourable (if R_L > 1).
Descriptive statistics was performed using Origin v.2018 (OriginLab Corporation, Northampton, MA, USA) and Anscombe’s quartet model was developed by using Anaconda v.2–2.4.0 (numpy library) (Anaconda, Inc., Austin, TX, USA) and Python programming (Python v. 3.9.2, The Python Software Foundation, Beaverton, OR, USA).