High-performance removal of iron from aqueous solution using modified activated carbon prepared from corn cobs and luffa sponge

Abstract

Activated carbon prepared from corn cobs (CAC) and luffa sponge (LAC) modified with aluminum chloride (Al-CAC and Al-LAC) were investigated for the adsorption of Fe(III) from aqueous solution. Scanning electron microscopy, Fourier transform infrared, and N2 adsorption–desorption analysis were carried out to identify adsorbents characterization. The effect of operational parameters onto the adsorption performance was investigated in batch experiments mode. The modification method significantly improves the adsorption property of activated carbon. The optimum pH was found to be 8 for all adsorbents with maximum removal efficiencies of 89.3%, 99.1%, 79.7%, and 96.7% using CAC, Al-CAC, LAC, and Al-LAC, respectively, after a contact time of 5 min and initial iron concentration of 5 mg/L. The maximum adsorption capacity was 334.9, 366.7, 317.1, and 348.8 mg/g for CAC, Al-CAC, LAC, and Al-LAC, respectively, using adsorbent dosage of 0.1 g/L and initial iron concentration of 40 mg/L. The adsorption data fit well with Langmuir model for Al-CAC, Freundlich model for CAC and Al-LAC and Dubinin–Radushkevich model for LAC. The experimental data fitted well with the pseudo-second-order model (R2 = 0.999). The thermodynamic study confirmed the spontaneity with increased randomness of the adsorption process. The results showed that the prepared activated carbons are effective low-cost adsorbents for Fe(III) removal from aqueous solutions.