Efficient Removal of the Toxic Lead Ions from ContaminatedSandy Soils using Newly Engineered Carbon Black Nanoadsorbent

Abstract

Soils contaminated with heavy metals can embarrass a fatal risk to the environment and human life via the direct uptake of the heavy metal-contaminated agricultural crops. Hence, the treatment of metal-contaminated soils is attracting a lot of research activities to reduce the negative impact on the environment. In the current study, I have activated the surface of the carbon black (CB) adsorbent by introducing functional groups capable to efficiently capture the lead (Pb) metal ions from a Pb-contaminated sandy soil. The soil properties (e.g. electrical conductivity, acidity, carbon and nitrogen content, and organic matter) were studied before and after the treatment with the CB adsorbent. I also showed a comprehensive adsorption study in soil-batch extraction experiments, evaluating a series of factors such as the effects of soil pH (pH 3.0 to pH 7.0), Pb concentration into the soil (5-100 mg/L), and the soil temperature (15-50 °C).Furthermore, the recyclability of the adsorbent was highlighted to evaluate adsorption efficiency upon use. The results of the study were remarkable where a 100 % removal efficiency of Pb ions was obtained using only a 40 ppm of the oxidized CB compared to a 60% removal efficiency when using a pristine CB at the same concentration. The adsorption capacity of Pb ions was as high as 100 mg/g at 30 mg/L of oxidized CB adsorbent. The life cycle of oxidized CB adsorbent was also remarkable compared to that of pristine adsorbent. The recyclability data of the functionalized CB has showed an easy regeneration process with an efficient reusefor 5 cycles with 30 %a performance decline of 30 % only from the initial adsorption efficiency.