Effective removal of organic and inorganic pollutants from abattoir wastewater using magnesium oxide/activated carbon nanocomposites

Abstract

This study investigated the development and characterization of activated carbon (AC), magnesium oxide (MgO), and a combination of AC and MgO nanocomposite for abattoir wastewater treatment. Activated carbon was derived from Hura crepitans pods, whereas MgO nanoparticles were produced through biosynthesis. Different composite (AC/MgO) ratios (1:1, 1:2, and 2:1) were prepared using a wet impregnation technique. The efficiency of these nanoadsorbents in eliminating heavy metal pollutants were tested through batch adsorption experiments under the influence of the dosage, temperature, and contact time. Various analytical tools were used to characterize the prepared nanoadsorbents. XRD confirmed the formation of a pure MgO periclase phase, indicating a reduction in particle size with the increase in pH. The HRSEM images of the nanocomposites showed porous carbon structures with regular mesopores and spherical MgO nanoparticles. The uniform granules with agglomerated spherical shapes were confirmed by the SAED patterns, suggesting the core/shell structure of MgO from the HRTEM images. Further imaging confirmed the dispersion of carbon and magnesium in the nanocomposites, without the formation of distinct dopant oxides. The specific surface areas were determined as 2.74 m2/g for activated carbon, 27.57 m2/g for MgO, and 40.82 m2/g for activated carbon/MgO, indicating enhanced surface area due to the addition of activated carbon. Batch adsorption studies indicated that the AC/MgO nanocomposite in the 1:2 ratio exhibited the highest pollutant adsorption rate under similar conditions. The adsorption study was calculated by the pseudo-second-order and Langmuir isotherm models. The AC/MgO nanocomposite demonstrated reusability over six cycles, with a slight reduction in removal efficiency from the first cycle (98.05 % for Fe, 96.50 % for Cd, and 94.32 % for Pb) to the sixth cycle (91.10 % for Fe, 86.56 % for Cd, and 84.03 % for Pb). Overall, these findings suggest that AC/MgO nanocomposites can effectively eliminate pollutants from abattoir wastewater.