Optimization and Modeling of Cr (VI) Removal from Tannery Wastewater onto Activated Carbon Prepared from Coffee Husk and Sulfuric Acid (H<sub>2</sub>SO<sub>4</sub>) as Activating Agent by Using Central Composite Design (CCD)

<table class="table-group" id="tab3"><tr><td><table class="table"><tr><td class="thead-hr" colspan="3"><hr/></td></tr><tr class="thead"><td class="align_left">St.</td><td class="align_center">Physiochemical properties</td><td class="align_center">CHBAC values obtained</td></tr><tr><td class="thead-hr" colspan="3"><hr/></td></tr><tr><td class="align_left">1</td><td class="align_center">Bulk density (g/mL)</td><td class="align_center">0.71</td></tr><tr><td class="align_left">2</td><td class="align_center">pH</td><td class="align_center">5.2</td></tr><tr><td class="align_left">3</td><td class="align_center">pH<sub>PZC</sub></td><td class="align_center">4.19</td></tr><tr><td class="align_left">4</td><td class="align_center">Specific surface area (m<sup>2</sup>/g)</td><td class="align_center">1396</td></tr><tr><td class="align_left">5</td><td class="align_center">Porosity (%)</td><td class="align_center">58.4</td></tr><tr><td class="align_left">6</td><td class="align_center">The yield of CHAC (%)</td><td class="align_center">60.1</td></tr><tr class="table-tr"><td colspan="3"><hr class="tbody-hr"/></td></tr></table></td></tr></table>

<div>Physiochemical properties of CHAC.</div>

Journal of Environmental and Public Health

tab3

Table 3

Table 3: Optimization and Modeling of Cr (VI) Removal from Tannery Wastewater onto Activated Carbon Prepared from Coffee Husk and Sulfuric Acid (H<sub>2</sub>SO<sub>4</sub>) as Activating Agent by Using Central Composite Design (CCD) 

Table 3 | Optimization and Modeling of Cr (VI) Removal from Tannery Wastewater onto Activated Carbon Prepared from Coffee Husk and Sulfuric Acid (H2SO4) as Activating Agent by Using Central Composite Design (CCD) 