The remediation efficiency of heavy metal pollutants in water by industrial red mud particle waste

This study aims to treat heavy metal pollutants in water by applying red mud particle waste. An experiment on the static adsorption of heavy metal ions Pb2+ (or Cd2+ and Cu2+) by red mud particles was carried out, and the influences of the type of heavy metal ion, ion concentration, pH value, red mud dosage, reaction time, and temperature on adsorption performance were explored. The competitive adsorption mechanisms of various coexisting heavy metal ions by red mud particles were compared. The red mud samples loaded and not loaded with heavy metal ions were detected by zeta potential measurement, scanning electron microscopy, and Fourier transform infrared spectrometry. The adsorption strength of red mud particles for heavy metal ions was ranked in the sequence of Pb2+, Cd2+, and Cu2+, while increasing temperature enhanced their adsorption. When the initial pH values were 4.3, 5.0, and 3.6 for Pb2+, Cd2+, and Cu2+ solutions, the removal peaks were 94.5%, 92.8%, and 78.1%, respectively. The preferred order of adsorption for red mud was Pb2+, Cd2+ and then Cu2+ under the competitive mechanism of binary/ternary systems due to the discrepancy in the functional groups of red mud particles loaded with different heavy metal ions.