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="tab8"><tr><td><table class="table"><tr><td class="thead-hr" colspan="7"><hr/></td></tr><tr class="thead"><td class="align_left">Parameter</td><td class="align_center">Goal</td><td class="align_center">Lower limit</td><td class="align_center">Upper limit</td><td class="align_center">Importance</td><td class="align_center">Optimized values</td><td class="align_center">Desirability</td></tr><tr><td class="thead-hr" colspan="7"><hr/></td></tr><tr><td class="align_left">A: pH</td><td class="align_center">Is in range</td><td class="align_center">1</td><td class="align_center">3</td><td class="align_center">3</td><td class="align_center">1.926</td><td class="align_center">1</td></tr><tr><td class="align_left">B: dose</td><td class="align_center">Is in range</td><td class="align_center">3</td><td class="align_center">5</td><td class="align_center">3</td><td class="align_center">4.209</td><td class="align_center">1</td></tr><tr><td class="align_left">C: contact time</td><td class="align_center">Is in range</td><td class="align_center">1</td><td class="align_center">3</td><td class="align_center">3</td><td class="align_center">2.101</td><td class="align_center">1</td></tr><tr><td class="align_left">Cr (VI) adsorption</td><td class="align_center">Maximize</td><td class="align_center">72.51</td><td class="align_center">97.46</td><td class="align_center">5</td><td class="align_center">97.645</td><td class="align_center">1</td></tr><tr class="table-tr"><td colspan="7"><hr class="tbody-hr"/></td></tr></table></td></tr></table>

<div>Summary of numerical optimization.</div>

Journal of Environmental and Public Health

tab8

Table 8

Table 8: 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 8 | 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) 