Batch and Column Adsorption of Hexavalent Chromium on Household Filter Waste Activated Charcoal (HFWAC)

In this study, hexavalent chromium was removed from the wastewater using the household filter waste activated charcoal (HFWAC) by both batch and column mode studies. HFWAC of 106 μ size was characterized using FESEM/EDX, XRD and was applied to remove Cr(VI) from wastewater at room temperature. Batch mode study revealed that ~97% adsorption of dimerized Cr(VI) onto the HFWAC can be obtained at pH of 3.12, dose of 1.5 g/L of HFWAC, and contact time of 6 h at an initial concentration of 12 mg/L of Cr(VI). The adsorptive capacity of HFWAC was found to be 417.50 mg/g as per the Langmuir isotherm. Cr(VI) adsorption was pH dependent as was explained by pHZPC. A 20 cm bed-depth HFWAC packed column study was conducted in a continuous upflow mode (8 mL/min) with the batch-optimized Cr(VI) initial concentration and pH. The breakthrough (C/Co = 0.0083) and bed exhaust (90%) times were 40 and 65 h, respectively. The column design parameters, K (0.0135 L/mg h) and N (5088.79 mg/L) with the minimum bed-depth (xo) of 10.70 cm were understood from logit model. Finally, the application efficiency of HFWAC to remove Cr(VI) from the spiked pond water was evaluated.