Adsorptive Removal of Lead (II) Pollutants from Wastewater Using Corncob-Activated Carbon

Abstract

The level of contamination in industrial wastewater has been a serious environmental challenge of our time. Various researchers have reported that the adsorption process using different adsorbents is a promising technique for treating heavy metal-contaminated wastewater. This study investigated the adsorptive removal of lead (II) from wastewater using corncob-activated carbon. Activated carbon was synthesized from a raw corncob. The synthesized activated carbon was applied as a sorbent in batch lead (II) adsorption in an aqueous lead (II) solution. Scanning electron microscopy, Fourier transformed infrared (FTIR), and Brunauer–Emmett–Teller (BET) theory characterized the synthesized activated carbon. A batch adsorption study investigated the effects of dosage, contact time, and the initial concentration of lead (II) on the sorption of Pb2+ on the synthesized activated carbon. The highest removal of lead recorded was 95 % at an adsorbent dosage of 2.5 g/L in 2 h. The highest adsorption capacity was 16.46 mg/g at the same conditions. The results showed that percentage removal increased with dosage and contact time but decreased with the initial metal ion concentration. Adsorption kinetics were best described with the pseudo-second-order kinetics, while the Langmuir isotherm model best fitted equilibrium adsorption in the study. The FTIR results showed the presence of several functional groups like carboxyl, hydroxyl, and amino, indicating good interaction with lead metal ions. The BET characterization revealed the activated corncob’s specific surface area and pore volume to be 249 m2/g and 0.164 cm3/g. This work shows that activated carbon can be synthesized from agricultural waste such as corncob and be used as an effective adsorbent for heavy metal removal, such as lead, from wastewater.

Keywords

• metal-contaminated wastewater treatment
• adsorption
• corncob agro-waste
• lead ion
• adsorbent
• isotherm
• kinetics