Newly-Development of Synthetic MnCO3 and MnO2 Precipitate Through Biologically-Induced Mineralization for Effective Adsorption of As(V) in Aqueous Solution

Abstract

As(V) is becoming one of the dangerous and toxic chemicals causing the global issue of water pollution. Among several synthesis processes of adsorbent, biomineralization method has shown good potential. This study presented the biologically-induced synthetic Manganese Carbonate Precipitate (BISMCP) through biologically-induced mineralization method and formation change of BISMCP material after calcination process which is becoming MDSMCP. Herein, the potential ability of BISMCP and MDSMCP was performed for removal of As(V) in an aqueous solution. Characterization results showed both materials were successfully synthesized by the biomineralization process. TGA analysis showed the phase transition from MnCO3 to MnO2 significantly at 200-450 ºC. The BET surface area of the as-prepared nanocomposites was found to be 109.006 m2/g (BISMCP) and 91.672 m2/g (MDS-300). EDX analysis showed the elements in the crystal BISMCP and MDSMCP were Mn, C, and O. XRD result of BISMCP and MDSMCP determined the crystal structure, which are close to rhodochrosite (MnCO3) and pyrolusite (MnO2), respectively. Effects of pH, contact time, and varying pollutant concentration were studied in detail. The pHPZC value of BISMCP and MDS-300 was 5.5 and 1.50, respectively. According effect of pH, BISMCP and MDS-300 had better adsorption capacity at pH 6 and 2, respectively. The kinetic study for BISMCP and MDS-300 indicated that well fitted with pseudo-second-order (PSO). The experimental equilibrium data followed the Langmuir isotherm model with a maximum monolayer adsorption capacity of 119.331 mg/g (BISMCP) and 112.107 mg/g (MDS-300). This study implies that BISMCP and MDS-300 are potentially useful adsorbents for the adsorption of As(V).