Chromium removal from tannery wastewater through activated carbon produced from Parthenium hysterophorus weed

Discharging volumes of leather tanneries' wastewater into the environment without proper treatment is causing severe environmental and public health problems. Therefore, this research aimed to remove chromium ion from tannery wastewater through the adsorption of activated carbon produced from the weed Parthenium hysterophorus. The activated carbon was characterized using proximate analysis, scanning electron microscope, Fourier transforms infrared spectroscopy and an iodine test. Full factorial experimental design of 2(4) was employed with four factors at two levels pH (2 and 6), contact time (45 and 90 min), initial chromium concentration (40 and 100 mg/L) and adsorbent dosage (9 g/L and 90 g/L), which resulted in 16 experimental runs. The average tannery effluent characteristics were described in terms of Five days biochemical oxygen demand: 1472.00 +/- 9.300 mg/L; chemical oxygen demand: 1800.00 +/- 50.00 mg/L; total solids: 29,000.00 +/- 1000.00; temperature: 21.50 +/- 2.01 degrees C; electrical conductivity (EC): 29.20 +/- 1.60 mS/cm and pH: 4.30 +/- 0.71. The mechanism of adsorption was tested by the Langmuir and Freundlich isothermal models. Maximum chromium removal of 90% was recorded at the optimum point of pH 2, contact time 90 min and adsorbent dose 90 g/L at initial chromium concentration 100 mg/L. Similarly, the treatment of the real tannery wastewater treatment was performed at the optimum point, which resulted in 89% chromium removal. Experimental data were best fitted with the Freundlich model at the adsorptive capacity 24.8 mg/g. This indicates that the application of this activated carbon for tannery wastewater treatment may be scaled up to mitigate industrial effluent pollution challenges, but detailed investigations of the adsorbent properties remain to be studied.