Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation

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Table 1 The adsorption constant rate of different kinetic models at 0.01 g of the activated carbon dosage and 16 mg L⁻¹

Pseudo first-order kinetic model \(\log (q_{e} - q_{t} ) = \log (q_{e} ) - \frac{{k_{1} }}{2.303}t\)		Pseudo second-order kinetic model \(\frac{t}{{q_{t} }} = \frac{1}{{k_{2} q_{e}^{2} }} + \frac{t}{{q_{e} }}\)		Intra particle diffusion kinetic model log(R) = log(k_id) + a log(t)
k₁	r²	k₂	r²	k_id	a	r²
0.0046	0.974	0.0415	0.998	62.80	0.174	0.965

q_e = uptake by the activated carbon at equilibrium, mg g⁻¹; q_t = uptake by the activated carbon at time t, mg g⁻¹; k₁ = rate of constant of pseudo first order adsorption, min⁻¹; k₂ = rate of constant of pseudo second order sorption, g mg⁻¹ min⁻¹; R = the fraction solute adsorbed; t = contact time; a = gradient of linear plots and depicts the adsorption mechanism; K_id = intra-particle diffusion rate constant (h⁻¹)