Analog synthesis of artificial humic substances for efficient removal of mercury. (July 2020)

• Record Type: Journal Article
• Authors: Zhang, Shuaishuai; Song, Jingpeng; Du, Qing; Cheng, Kui; Yang, Fan
• Is Part Of: Chemosphere. Volume 250(2020)
• Publication Date: 2020-07
• Subjects: Mercury ions -- Waste biomass -- Artificial humic substances -- Removal mechanisms -- Recycling; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2020.126606
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: 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 2 = 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 –NH2 ) and formation of precipitation with CO3 2− 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. Graphical abstract: Image 1 Highlights: Humic acid-modified biochar nanocomposite is successfully prepared. HA-BCs show higher effectiveness for Hg 2+ removal than BC. Adsorption kinetics data is well described with the pseudo-second-order model. Removal mechanisms for Hg 2+ on HA-BCs are investigated and illustrated. HA-BCs exhibit good regeneration ability with 32.57 mg/g after four cycles.