# Adsorption of Ammonium, Nitrate, and Phosphate on Hydrochars and Biochars
## 3 Results and Discussion
### Comparison with Other Adsorbents
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Carbonaceous** & **Conditions for the** & **Adsorbent** & **Solution** & **Adsorption** & **Ref.** \\
**Materials** & **Adsorbent** & **Adsorbed Ion** & **Concentration** & **Capacity** & **mg g\({}^{-1}\)** & **Ref.** \\ \hline Oak-based HC & Hydrothermal carbonisation 250 \({}^{\circ}\)C & NH\({}_{4}\)\({}^{*}\) & 43 & 6.0 & [62] \\ Oak-based BC & Slow pyrolysis at 450 \({}^{\circ}\)C & & & 9.2 & \\  & Slow pyrolysis at 650 \({}^{\circ}\)C & & & 8.9 & \\ \hline Peanut shell, cornob, or & Pyrolysis at 300, 450, or 600 \({}^{\circ}\)C for 2 h & NH\({}_{4}\)\({}^{*}\) & 50 & 16–18 & [63] \\ cotton stalk BC & & & & \\ \hline Wheat straw BC & Pyrolysis at 500 \({}^{\circ}\)C for 1.5 h & NH\({}_{4}\)\({}^{*}\) & 50 & 0.33 & [37] \\ Corn straw BC & & & & 0.92 & \\ Peanut shell BC & & & & 0.54 & \\ \hline Sugarcane bagasse BC & Pyrolysis at 500 \({}^{\circ}\)C for 1 h & NH\({}_{4}\)\({}^{*}\) & 50 & 4.46 & \\ Sugarcane bagasse HC30 & Hydrothermal carbonisation at & & & 1.37 & This study \\  & 250 \({}^{\circ}\)C for 30 min & & & \\ \hline Corn cob HC & 230 or 260 \({}^{\circ}\)C for 30 min & NH\({}_{4}\)\({}^{*}\) & 20–3000 & \(\approx\)34–107 & [64] \\ KOH-activated HC & Corn cob HC mixed with 200 mL of & & & \(\approx\)48–140 & \\
3 M KOH & 3 M KOH & & & \\ \hline Oak-based hydrochar & Hydrothermal carbonisation 250 \({}^{\circ}\)C & NH\({}_{4}\)\({}^{*}\) & 1000 & 109.7 & [11] \\ Oak-based BC & Slow pyrolysis at 450 \({}^{\circ}\)C & & & 129.4 & \\  & Slow pyrolysis at 650 \({}^{\circ}\)C & & & 123.5 & \\ \hline Macadamia nutshell BC & Pyrolysis at 1000 \({}^{\circ}\)C for 1 h & NO\({}_{3}\)\({}^{-}\) & 10 & & [65] \\ \hline Sugarcane bagasse BC & Pyrolysis at 800 \({}^{\circ}\)C for 2 h & NO\({}_{3}\)\({}^{-}\) & 10 & 0.06 & [66] \\ Bamboo chip BC & & & & 0.15 & \\ Japanese codar BC & & & & 0.23 & \\ Rice husk BC & & & & 0.07 & \\ Poultry manure BC & & & & 0.02 & \\ \hline Pine sawdust BC & Pyrolysis at 500 \({}^{\circ}\)C for 4 h & NO\({}_{3}\)\({}^{-}\) & 30 & 0.45 & [67] \\ Corn straw BC & & & & 0.15 & \\ Peanut hull BC & & & & 0.38 & \\ Rice straw BC & & & & 0.15 & \\ \hline Wheat straw BC & Pyrolysis at 500 \({}^{\circ}\)C for 1.5 h & NO\({}_{3}\)\({}^{-}\) & 50 & 0.021 & [37] \\ Corn straw BC & & & & 0.032 & \\ Peanut shell BC & & & & 0.024 & \\ \hline Sugarcane bagasse & Feedstock & NO\({}_{3}\)\({}^{-}\) & 50 & 2.1 & [68] \\ Sugarcane bagasse BC & Pyrolysis at 200 to 600 \({}^{\circ}\)C for 4 h & & & 11. 6 & \\  & Sugarcane bagasse BC added in & & & & 28.2 & \\  & epicichlorydin and & & & & \\  & N-dimethylformamide & & & & \\ \hline Sugarcane bagasse BC & Pyrolysis at 500 \({}^{\circ}\)C for 1 h & NO\({}_{3}\)\({}^{-}\) & 50 & 1.34 & \\ Sugarcane bagasse HC30 & & Hydrothermal carbonisation at & & 0.35 & This study \\  & 250 \({}^{\circ}\)C for 30 min & & & \\ \hline Pine sawdust BC & Pyrolysis at 550 \({}^{\circ}\)C for 15 min & PO\({}_{4}\)\({}^{3-}\) & 30 & 10 & [47] \\  & Pyrolysis at 750 \({}^{\circ}\)C for 15 min & & & 14 & \\ \hline Activated carbon residue BC & Downdraft gasifier 1000 \({}^{\circ}\)C & PO\({}_{4}\)\({}^{3-}\) & 50 & 21 & [69] \\ \hline Oak sawdust BC & Pyrolysis at 500 \({}^{\circ}\)C for 30 min & PO\({}_{4}\)\({}^{3-}\) & 61 & 11 & [19] \\ \hline Sugarcane BC & Pyrolysis at 300 \({}^{\circ}\)C for 20 min & PO\({}_{4}\)\({}^{3-}\) & 100 & 1.63 & [16] \\  & Pyrolysis at 700 \({}^{\circ}\)C for 20 min & & & 10.0 & \\ Miscanthus BC & Pyrolysis at 300 \({}^{\circ}\)C for 20 min & & & 1.83 & \\  & Pyrolysis at 700 \({}^{\circ}\)C for 20 min & & & 11.4 & \\ \hline Corn BC & Pyrolysis at 300 \({}^{\circ}\)C for 3 h & PO\({}_{4}\)\({}^{3-}\) & 100 & \(\approx\)35 & [17] \\  & Pyrolysis at 600 \({}^{\circ}\)C for 3 h & & & \(\approx\)40 & \\ \hline Sugarcane bagasse BC & Pyrolysis at 500 \({}^{\circ}\)C for 1 h & PO\({}_{4}\)\({}^{3-}\) & 100 & 2.76 & \\ Sugarcane bagasse HC30 & Hydrothermal carbonisation at & & & 0.45 & This study \\  & 250 \({}^{\circ}\)C for 30 min & & & \\ \hline Sewage sludge HC & & & & & \\  & 210 \({}^{\circ}\)C 21 and 24 bar & & & \\ KOH-activated HC & Produced sewage sludge HC was & & & 14.2 & \\  & washed with 1 M KOH & & & \\ \hline \hline \end{tabular}
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