Potential low-cost carbon-based adsorbent from gold mine tailings for anionic dye removal

Abstract

In this study, a mesoporous carbon (CMK-3) was successfully synthesized using mesoporous silica (SBA-15) prepared from gold mine tailings (sample CGMT) for removal of anionic dye from aqueous solution. For comparison, CMK-3 was prepared by the same method from pure silica (sample CT), and the other CMK-3 sample was prepared by a one-pot route mixing with Pluronic P123 (sample CP). The effect of the carbonization time on the synthesis of all CMK-3 samples was investigated, and the samples were characterized by X-ray diffraction and N2 adsorption–desorption. The sample with the highest surface area was chosen as an adsorbent, for each CMK-3 obtained from different methods. Batch adsorption experiments were studied to determine the influence of pH, contact time, and initial dye concentration. The adsorption kinetics obeyed the pseudo-second-order model. All carbon-based adsorbents were observed to be quite effective for the removal of dye with adsorption percentage in the order of CP > CT > CGMT. The maximum adsorption capacities were 188.99 and 204.57 mg·g−1 for CT and CGMT, respectively. The comparative results of all carbon-based adsorbents show that CGMT can be applied as a low-cost alternative to CT for dye removal. HIGHLIGHTS CMK-3 was synthesized from gold mine waste (CGMT) for the first time.; The usage of CGMT as low-cost adsorbent for the removal of dye was investigated.; For comparison, other adsorbents synthesized from different methods were investigated as an adsorbent in the dye adsorption.; The specific surface area, pore volume and pore size dominate the adsorption capacity.; CGMT can be applied as a novel, low-cost and alternative adsorbent for dye removal.;

Keywords

• cmk-3
• dye adsorption
• gold mine tailings
• low-cost adsorbent
• recycling waste