Table 1.
Some physicochemical properties of the experimental soil, solid biochar and chemically modified biochars.
| Soil | Solid biochar | H2O2 Modified biochar | KOH Modified biochar | H3PO4 Modified biochar | |||||
|---|---|---|---|---|---|---|---|---|---|
| Texture | Silty loam | N (%) | 0.52 | N (%) | 0.51 | N (%) | 0.48 | N (%) | 0.48 |
| pH | 6.2 | C (%) | 44.1 | C (%) | 38.23 | C (%) | 38.37 | C (%) | 40.31 |
| EC (dSm−1) | 1.32 | H (%) | 2.4 | H (%) | 3.51 | H (%) | 2.85 | H (%) | 2.96 |
| OC (g kg-1) | 11.1 | O (%) | 27.40 | O (%) | 30.20 | O (%) | 31.89 | O (%) | 33.40 |
| Total N (%) | 0.09 | P (mg kg-1) | 8250 | P (mg kg-1) | 8120 | P (mg kg-1) | 8212 | P (mg kg-1) | 8940 |
| P (mg kg-1) | 31.2 | S (mg kg-1) | 5790 | S (mg kg-1) | 4340 | S (mg kg-1) | 4360 | S (mg kg-1) | 5100 |
| K (mg kg-1) | 187.1 | Na (mg kg-1) | 2.30 | Na (mg kg-1) | 1.34 | Na (mg kg-1) | 1.12 | Na (mg kg-1) | 1.35 |
| Mg (mg kg-1) | 70.4 | K (mg kg-1) | 4070 | K (mg kg-1) | 3823 | K (mg kg-1) | 4150 | K (mg kg-1) | 3560 |
| Mn (mg kg-1) | 10.80 | Ca (mg kg-1) | 3750 | Ca (mg kg-1) | 3021 | Ca (mg kg-1) | 2980 | Ca (mg kg-1) | 3090 |
| SF (mg kg-1) | 8.30 | Mg (mg kg-1) | 166.4 | Mg (mg kg-1) | 102.7 | Mg (mg kg-1) | 110.4 | Mg (mg kg-1) | 105.3 |
| Cd (mg kg-1) | 0.13 | Mn (mg kg-1) | 37.30 | Mn (mg kg-1) | 35.8 | Mn (mg kg-1) | 32.2 | Mn (mg kg-1) | 22.40 |
| CEC (cmol kg-1) | 18.80 | Cl (mg kg-1) | N. A | Cl (mg kg-1) | N. A | Cl (mg kg-1) | N. A | Cl (mg kg-1) | N. A |
| Bulk density (g cm-3) | 1.43 | SF (mg kg-1) | 5.2 | SF (mg kg-1) | 4.3 | SF (mg kg-1) | 3.4 | SF (mg kg-1) | 3.7 |
| Moisture (%) | 1 | Cd (mg kg-1) | 0.06 | Cd (mg kg-1) | 0.06 | Cd (mg kg-1) | 0.06 | Cd (mg kg-1) | 0.06 |
| CEC (cmol kg-1) | 20.21 | CEC (cmol kg-1) | 24.60 | CEC (cmol kg-1) | 25.20 | CEC (cmol kg-1) | 26.10 | ||
| pH | 7.1 | pH | 7.5 | pH | 7.5 | pH | 7.5 | ||
| S BET (m2 g-1) | 14.2 | S BET (m2 g-1) | 48.1 | S BET (m2 g-1) | 69.3 | S BET (m2 g-1) | 77.3 | ||
| Vtot (cm3 g-1) | 0.024 | Vtot (cm3 g-1) | 0.082 | Vtot (cm3 g-1) | 0.063 | Vtot (cm3 g-1) | 0.089 | ||
| AVP (nm) | 3.43 | AVP (nm) | 3.57 | AVP (nm) | 3.22 | AVP (nm) | 3.24 | ||
| CA (mmol g-1) | 0.21 | CA (mmol g-1) | 0.39 | CA (mmol g-1) | 0.45 | CA (mmol g-1) | 0.62 | ||
| LA (mmol g-1) | 0.11 | LA (mmol g-1) | 0.19 | LA (mmol g-1) | 0.26 | LA (mmol g-1) | 0.18 | ||
| PA (mmol g-1) | 0.68 | PA (mmol g-1) | 0.95 | PA (mmol g-1) | 1.32 | PA (mmol g-1) | 1.14 | ||
| Fab (mg g-1) | 3.41 | Fab (mg g-1) | 4.59 | Fab (mg g-1) | 4.43 | Fab (mg g-1) | 5.17 | ||
| Cd ab (mg g-1) | 16.76 | Cd ab (mg g-1) | 24.78 | Cd ab (mg g-1) | 29.54 | Cd ab (mg g-1) | 41.3 | ||
| Stability (◦C) | 520 | Stability (◦C) | 505 | Stability (◦C) | 510 | Stability (◦C) | 505 | ||
| Moisture (%) | < 1 | Moisture (%) | < 1 | Moisture (%) | < 1 | Moisture (%) | < 1 | ||
EC, Electrical conductivity; OC, Organic carbon; CEC, Cation exchange capacity; SF, Soluble fluoride; NA, Not available; Fab, Fluoride absorbing capacity; Cd ab, Cadmium absorbing capacity; SBET, BET surface area; V tot, Total pore volume; AVP, Average pore size, CA, Carboxylic acid groups; LA, Lactonic acid groups; PA, Phenolic acid groups.