Sorption of urea hydrogen peroxide by co-pyrolysed bone meal and cow dung slowed-down phosphorus and nitrogen releases but boosted agronomic efficiency

Luyima, Deogratius; Sung, Jwakyung; Lee, Jae-Han; Woo, Seong-Ah; Park, Seong-Jin; Oh, Taek-Keun

doi:10.1186/s13765-020-00535-9

Applied Biological Chemistry

Table 2 Coefficients (R²) of the examined models and the rate constants for N and P release kinetics from co-pyrolysed biochar based fertilisers

From: Sorption of urea hydrogen peroxide by co-pyrolysed bone meal and cow dung slowed-down phosphorus and nitrogen releases but boosted agronomic efficiency

Kinetic models	N in Urea form			N in UHP form			Phosphorus
Kinetic models	CDTP	CDBM 1	CDBM 2	CDTP	CDBM 1	CDBM 2	TSP	CDTP	BC	CDBM 1	CDBM 2
Zero order \({[A]}_{t} ={[A]}_{0}-{k}_{0}t\)
\({\mathbf{R}}^{2}\)	0.239	0.195	0.218	0.168	0.138	0.209	0.283	0.386	0.197	0.816	0.894
\({\mathrm{k}}_{0}\)	−3.5733	−3.6761	−3.8937	−3.6511	−3.1932	−3.2819	−0.0785	−0.0142	−0.0004	−2 × 10^–5	−7 × 10^–5
First order \({Log [A]}_{t} ={Log [A]}_{0}- \frac{{k}_{1}}{2.303}*t\)
\({\mathbf{R}}^{2}\)	0.417	0.417	0.523	0.382	0.252	0.356	0.493	0.622	0.387	0.876	0.939
\({\mathrm{k}}_{1}\)	−0.0398	−0.0449	−0.0544	−0.0488	−0.0401	−0.0539	−0.0039	−0.0016	−0.0037	−0.0009	−0.0018
Pseudo first order \(In \left({q}_{e}-{q}_{t}\right)=In {q}_{e}-{k}_{1b}*t\)
\({\mathbf{R}}^{2}\)	0.995	0.987	0.981	0.976	0.998	0.971	0.924	0.984	0.930	0.979	0.956
\({\mathrm{k}}_{1\mathrm{b}}\)	−0.1079	−0.0787	−0.0825	−0.0659	−0.0952	−0.0675	−0.0050	−0.0035	−0.0052	−0.0029	−0.003
Second order \(\frac{1}{{ [A]}_{t}}=\frac{1}{{\left[A\right]}_{0}}+{k}_{2}t\)
\({\mathbf{R}}^{2}\)	0.659	0.737	0.873	0.755	0.528	0.587	0.866	0.841	0.707	0.926	0.918
\({\mathrm{k}}_{2}\)	0.0006	0.0008	0.0012	0.0012	0.0010	0.0015	0.0005	0.0002	0.0941	0.0375	1.1084
Pseudo second order \(\frac{t}{{q}_{t}}= \frac{1}{{{k}_{2b}q}_{e}^{2}}+\frac{1}{{q}_{e}}t\)
\({\mathbf{R}}^{2}\)	0.995	0.996	0.997	0.996	0.995	0.998	1.000	0.992	1.000	0.991	0.993
\({\mathrm{q}}_{\mathrm{e}}\)	997.33	914.29	866.67	800.00	654.78	644.83	303.03	135.86	1.59	0.48	0.92
\({\mathrm{k}}_{2\mathrm{b}}\)	0.00025	0.00030	0.00035	0.00041	0.00057	0.00062	0.00019	0.00010	0.05472	0.0165	0.0099
Elovich \({q}_{t}=\frac{1}{\beta }In (\alpha \beta )+\frac{1}{\beta } In t\)
\({\mathbf{R}}^{2}\)	0.990	0.984	0.984	0.985	0.979	0.980	0.840	0.983	0.762	0.971	0.819
Power function \(ln {q}_{t}=In k+v In t\)
\({\mathbf{R}}^{2}\)	0.988	0.985	0.980	0.989	0.991	0.957	0.710	0.976	0.654	0.969	0.966
Parabolic diffusion \({q}_{t}=A+C*{t}^{1/2}\)
\({\mathbf{R}}^{2}\)	0.968	0.959	0.946	0.961	0.975	0.972	0.629	0.957	0.559	0.972	0.956

R² values (in bold) are an important indication of the strength of the fit to the different kinetic models by the tested BFs fertilisers
\({[{\varvec{A}}]}_{{\varvec{t}}}\) is the concentration of N or P at time t, \({[{\varvec{A}}]}_{0}\) is the initial concentration of N or P, \({{\varvec{q}}}_{{\varvec{t}}}\) is the cumulative concentration of N or P at time t, \({{\varvec{q}}}_{{\varvec{e}}}\) is the cumulative quantity of N or P obtained at equilibrium of the experiment, \({[A]}_{t}\) = \({{\varvec{q}}}_{{\varvec{t}}2}-{{\varvec{q}}}_{{\varvec{t}}1}\) where q_t2 is the cumulative concentration of N or P at the current sampling and q_t1 is the cumulative concentration of N or P at the preceding sampling
BC bone char, TSP triple superphosphate, CDBM 1 75% cow dung + 25% bone meal (3:1 mixture), CDBM 2 50% cow dung + 50% bone meal (1:1 mixture), CDTP 75% cow dung + 25% bone meal.

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