Hebei Messi Biology Co., Ltd. stated that carbonate rock is a widely distributed rock type on the earth. Its weathered products will enter the soil and sediments in the area and become the main component thereof. In the carbonate mineral-heavy metal-water solid-liquid system, carbonate minerals can interact with metal ions such as Cu, Pb, Zn, and Cd in the environment, affecting the properties of these ions through processes such as dissolution-precipitation, adsorption-desorption, etc. Environmental geochemical cycles.
Regarding the adsorption mechanism of heavy metals by carbonate, it has been found that, unlike the adsorption of heavy metal ions by other mineral materials (Freundlich type or Langmuir type adsorption isotherm), the adsorption isotherm of metal ions by carbonate minerals shows a typical The nonlinear characteristic (S-shaped or broken line) kinetic curve also shows rapid adsorption in the early stage and slow reaction in the later stage, reflecting the different types of surface reactions that occur at the solid-liquid interface. There are many studies on the reaction mechanism between calcium carbonate and heavy metals at home and abroad, but there are few studies on the solid-liquid interaction process between magnesium carbonate and heavy metals.
This paper uses magnesium carbonate (MgCO3) as the adsorbent, experimentally studies its interaction characteristics with lead under different pH values and initial lead concentrations, and discusses the effects of magnesium carbonate on lead from the aspects of the solid surface properties and structure after magnesium carbonate adsorption. The mechanism of transition between adsorption and precipitation. The experimental results can not only theoretically expand the surface reaction mechanism between carbonates and heavy metals, but are also of great significance for evaluating the migration and transformation of lead in soil and groundwater in the dolomite area and guiding environmental remediation.
Hebei Messi Biology Co., Ltd. stated that this article systematically studied the interaction of lead ions with magnesium carbonate under different initial pH values (4 and 7) and initial concentrations (0~3mmol/L). The research results show that due to the dissolution and neutralization of magnesium carbonate, the final pH value of the system is maintained at around 10.5; with the increase of the initial concentration of lead, the equilibrium pH value of the system has an increasing trend, and after reaching a value greater than 0.75 mmol/L The pH value does not change much; the equilibrium concentration of lead increases with the increase of the initial concentration and is basically stable after it is greater than 0.75mmol/L; the adsorption isotherm of magnesium carbonate for lead is a broken line type, and the reaction at low concentrations is mainly surface configuration. Site adsorption occurs, and at high concentrations, surface precipitation occurs and Pb3(C03)2(0H)2 is generated.