Mass Transport of Heavy Metals in Soil Columns Amended with Biochar Nanoparticles

Abstract

Biochar has potential as a valuable material for removing heavy metals from wastewater. The biochar obtained by pyrolysis of the Pomegranate Peel (PPBC) under an oxygen-limited atmosphere in a muffle furnace at 450°C. The biochar was also analyzed through SEM and FTIR for identification of particle size and functional groups. Therefore, the present work aims to study the effect of adding biochar to the soil columns (10 cm length and 2.8 cm diameter) amended with biochar at rates of 0, 0.5, 1, 2, and 4% (w/w) on the transport of heavy elements. The mass balance and removal percentage of heavy metals through soil columns were calculated. The results showed that removal percentages of Pb were 27.93, 38.38, 52.61, 74.66, and 98.12 % respectively. The removal percentages of Cd were 24.97, 38.24, 47.37, 70.02 and 96.60 %; for Co were 24.85, 37.21, 39.01, 64.34 and 95.98 % and for Ni were; 24.53, 35.62, 43.56, 62.52 and 94.64 %, respectively. In general, heavy metals were concentrated in the surface layer (0 – 4 cm) and increased with soil depth as the biochar rate increased.  Increasing biochar rate up to 4% increased the sorbed heavy metals on soil column and homogeneous distribution with depth found. 

Application of biochar at 4% showed high potential for remediation water contaminated with heavy metals when added to the soil by the sorption of heavy metals on its surface, thereby reducing the hazards of Pb, Cd, Co, and Ni. Biochar has a high potential to remove heavy metals. In comparison to activated carbon, the use of biochar in bio-filter is particularly viable because of its low cost and diverse environmental benefits. Based on biochar use at different sections of bio-filters, biochar can serve multiple functions such as filter media for contaminant removal. Biochar is particularly useful to remove heavy metal contaminants from wastewater, whereas removal of metals/metalloids, and nutrients vary by a wide range based on biochar surface properties, contaminant properties, and water chemistry.

Keywords: biochar, mass transport, heavy metals, water pollution, biocarbon, Pomegranate peel biochar