Agricultural Wastes Derived Activated Carbon for the Removal of Iron from Car-Wash Wastewater

Over the past few decades, car-washing centres have increased due to the increase in the number of vehicles. Car-wash effluents are highly polluted with non-biodegradable, toxic, and carcinogenic heavy metals, including iron, lead, chrome, cadmium, and zinc. The focus in this study is on iron removal from car-wash wastewater due to its toxicity to the food chain, health, and environment. In comparison with the costly wastewater treatment technologies, adsorption is a widespread, simple, and cheap method that has been applied for the metal removal from car-wash wastewater. Since the conversion of agricultural waste into valuable sorbents is a renewable and eco-friendly approach, activated carbon was used in this research to assess iron removal performance from car-wash wastewater applying the adsorption technique. The impact of the following parameters: contact time (0 min to 120 min), iron concentration (8 mg/L to 14 mg/L), dose of adsorbent (0.2 g to 1 g per 25 mL wastewater), and pH (4 to 10) on the adsorption efficiency of activated carbon was studied. Fe was efficiently removed (98 %) at the optimum values of contact time 120 min, concentration 12 mg/L, dose 1 g, and pH 8, respectively. The investigated parameters (particularly dose of adsorbent and pH) need to be studied in a broader range as they did not show a potential difference in terms of iron removal efficiencies. Turbidity, TDS, and TSS were removed from car-wash wastewater after 2 hours of contact time, with removal efficiencies of 88 %, 75 %, and 55 % respectively. Effluent characteristics of car-wash stations are usually variable due to the differences in the amount of dirt from vehicles, size and number of washed vehicles, and type of used detergents.