. 2020 Nov 11;6(11):e05388. doi: 10.1016/j.heliyon.2020.e05388

Table 4.

Linear models which describe biochar sorption capacity (q_m) for Pb(II), Zn(II) and Cd(II).

PTE	Type of linear model	Graph	Coefficients	Estimate	Signif. codes	Multiple R²	Adjusted R²	F-statistic	p-value
Zn	Single variable^a	Figure 6B	Intercept	0.5 ± 0.2		0.99	0.99	747	< 0.001
Zn	Single variable^a	Figure 6B	EC (dS.m⁻¹)	3.4 ± 0.1	∗∗∗
Pb	Single variable^a	Figure 6E	Intercept	-129 ± 15	∗∗	0.98	0.97	123	<0.01
Pb	Single variable^a	Figure 6E	pH	18 ± 2	∗∗
Cd	Single variable^a	Figure 6D	Intercept	2 ± 3		0.88	0.84	21.9	0.02
	Single variable^a	Figure 6D	EC (dS.m⁻¹)	7 ± 2	∗
	Two variables^b	Figure 6C	Intercept	-29 ± 5	∗	0.99	0.99	163	0.01
			EC (dS.m⁻¹)	11.4 ± 0.8	∗∗
			H.C (molar ratio)	74 ± 12	∗

∗∗∗ = coefficients are significant 100%, ∗∗ = coefficients are significant 99.9 %, ∗ = coefficients are significant 99%.

formula, y = mx + b.

formula, y = m₁x₁ + m₂x₂ + b.