Table 2 Evaluation for optimizing carbonization parameters.

From: Ultrahigh and kinetic-favorable adsorption for recycling urea using corncob-derived porous biochar

Variables

Levels

− 1

0

1

A: Carbonization temperature (°C)

300

400

500

B: Carbonization time (h)

1

3.5

6

C: Heating rate (°C/min)

5

10

15