Simultaneous remediation of soil contaminated by mercury ions and acetochlor using CTAB and DTAB modified bentonites

The study focused on the simultaneous adsorption of heavy metal ions and organic pollutants by two organo-modified bentonites (MMTs), with mercury ion (Hg²⁺) and acetochlor (ACR) serving as representative substances of heavy metal ions and organic pollutants in soil. The two MMTs were prepared by employing cetyltrimethyl ammonium bromide (CTAB) and dodecyltrimethyl ammonium bromide (DTAB) cationic surfactants as modifiers. The results indicate that both CTAB-modified bentonite (CTAB-MMT) and DTAB-modified bentonite (DTAB-MMT) are effective in removing Hg²⁺ and ACR from real soil samples, and can simultaneously remediate soil contaminated by Hg²⁺ and ACR. When the mass fraction of Hg²⁺ is less than 0.4 mg/kg and the mass fraction of ACR is less than 15 mg/kg in the soil, the removal rates of Hg²⁺ and ACR by both CTAB-MMT and DTAB-MMT are more than 80%. Compared to previously reported modified bentonites, which were only capable of adsorbing single heavy metal ions or organic molecules, CTAB-MMT and DTAB-MMT demonstrate the ability to simultaneously remove Hg²⁺ and ACR from soil, thereby offering a solution for the simultaneous remediation of soil contaminated by Hg²⁺ and ACR.