Analog synthesis of artificial humic substances for efficient removal of mercury.

Author(s) Zhang, S.; Song, J.; Du, Q.; Cheng, K.; Yang, F.
Journal Chemosphere
Date Published 2020 Jul

A cost-effective artificial humic substances (humic acid-modified biochar, HA-BCs) is fabricated by using conventional hydrothermal-assisted pyrolysis technique, and then is considered as a promising adsorbent material for removing mercury ions from aqueous solution. Artificial humic acid (A-HA), humic acid-modified biochar (HA-BCs) are analyzed by using SEM, EA, XRD, FTIR, XPS, and BET techniques. The removal efficiency of mercury ions was greater than 95% after reaching the adsorption equilibrium. Meanwhile, the adsorption kinetics coincided with the pseudo-second-order model and the isotherms for mercury ion sorption can be best interpreted using Freundlich isotherm model, with high regression coefficients (R = 0.967-0.990). Furthermore, the surface properties of HA-BCs before and after mercury adsorption are compared and evaluated, realizing that the mechanisms of removal of mercury ions on HA-BCs mainly include surface complexation with oxygen/nitrogen functional groups (-OH, -COOH and -NH) and formation of precipitation with CO and OH. Furthermore, the used HA-BCs can be regenerated via 0.05 mol/L KI solution and the adsorption capacity of mercury still reaches at 32.57 mg/g after four cyclic utilization.

DOI 10.1016/j.chemosphere.2020.126606
Keywords Adsorption; Charcoal; Humic Substances; Hydrogen-Ion Concentration; Ions; Kinetics; Mercury; Spectroscopy, Fourier Transform Infrared; Surface Properties; Water; Water Pollutants, Chemical; Water Purification
ISSN 1879-1298
Citation Zhang S, Song J, Du Q, Cheng K, Yang F. Analog synthesis of artificial humic substances for efficient removal of mercury. Chemosphere. 2020;250:126606.