Modification of Surface Charges on Ex-Gold Mining Soil Ameliorated with Activation of Sub-Bituminous Coal - NaOH

Abstract

The high mercury contamination in the ex-gold mining soil is the impetus for the development of soil remediation with amelioration technology that utilizes sub-bituminous coal activated with 10% NaOH (SC-NaOH) to modify the soil surface charge by affecting the chemical properties of the ex-gold mining soil. This research aimed to determine and study the modified surface charge of ex-gold mining soil ameliorated with SC - NaOH. The experimental design used in this study was a Completely Randomized Design with three replications. The treatment was implemented in a pot with equivalent dose: A = 0 (0.0g); B = 10 (0.5g); C = 20 (1.0g); D = 30 (1.5g), and (E) 40 t ha-1 (2g 100g-1 soil). The results showed amelioration technology with SC - NaOH, at the application of 40 t ha-1 on ex-gold mining soils, can modification of soil surface charge through changes in chemical characteristics by increasing the pH H2O EC, CEC, and SOM, respectively of 5.77; 4.33 dS m-1; 2.41 cmol(+) kg-1 and 17.15% compared to the control. Soil surface charge supported by soil minerals [Quartz (SiO2), Graphite (C), and Periclase (MgO)] and also happening decreases transmittance in the OH group (0.18%), which causes an increased adsorption capacity of the soil to Hg, which causes a decrease in total Hg of 2.84 mg kg-1 compared to the control. The correlation between total Hg and soil chemical properties in ex-gold mining soil ameliorated with SC – NaOH (Total Hg with SOM > ΔpH > EC > pH H2O > CEC).