Easy, Fast, Selective, and Simultaneous Separation of Hg(II) and Oil via Loofah-Sponge-Inspired Hierarchically Porous Membranes

Mercury abatement in the environment: Insights from industrial emissions and fates in the environment

Mercury's neurotoxic effects have prompted the development of advanced control and remediation methods to meet stringent measures for industries with high-mercury feedstocks. Industries with significant Hg emissions, including artisanal and small-scale gold mining (ASGM)-789.2 Mg year-1, coal combustion-564.1 Mg year-1, waste combustion-316.1 Mg year-1, cement production-224.5 Mg year-1, and non-ferrous metals smelting-204.1 Mg year-1, use oxidants and adsorbents capture Hg from waste streams. Oxidizing agents such as O3, Cl2, HCl, CaBr2, CaCl2, and NH4Cl oxidize Hg0 to Hg2+ for easier adsorption. To functionalize adsorbents, carbonaceous ones use S, SO2, and Na2S, metal-based adsorbents use dimercaprol, and polymer-based adsorbents are grafted with acrylonitrile and hydroxylamine hydrochloride. Adsorption capacities span 0.2-85.6 mg g-1 for carbonaceous, 0.5-14.8 mg g-1 for metal-based, and 168.1-1216 mg g-1 for polymer-based adsorbents. Assessing Hg contamination in soils and sediments uses bioindicators and stable isotopes. Remediation approaches include heat treatment, chemical stabilization and immobilization, and phytoremediation techniques when contamination exceeds thresholds. Achieving a substantially Hg-free ecosystem remains a formidable challenge, chiefly due to the ASGM industry, policy gaps, and Hg persistence. Nevertheless, improvements in adsorbent technologies hold potential.

Synthesis of salicylaldehyde tailored PAMAM dendrimers/chitosan for adsorption of aqueous Hg(II): Performance and mechanism

Water pollution caused by Hg(II) exerts hazardous effect to environmental safety and human health. Herein, a family of salicylaldehyde tailored poly(amidoamine) (PAMAM) dendrimers/chitosan composites (G0-S/CTS, G1-S/CTS, and G2-S/CTS) were prepared and used for the removal of Hg(II) from water solution. The adsorption performance of the as-prepared composites for Hg(II) was thoroughly demonstrated by determining various influencing factors. G0-S/CTS, G1-S/CTS and G2-S/CTS exhibited competitive adsorption capacity and good adsorption selective property for Hg(II). The maximum adsorption capacity of G0-S/CTS, G1-S/CTS and G2-S/CTS for Hg(II) were 1.86, 2.18 and 4.47 mmol‧g-1, respectively. The adsorption for Hg(II) could be enhanced by raising initial Hg(II) concentration and temperature. The adsorption process was dominated by film diffusion processes with monolayer adsorption behavior. The functional groups of NH2, CONH, CN, OH, CO and CN were mainly responsible for the adsorption of Hg(II). G0-S/CTS, G1-S/CTS and G2-S/CTS displayed good regeneration property and the regenerate rate maintained 95.00 % after five adsorption-desorption cycles. The as-prepared adsorbents could be potentially used for the efficient removal of Hg(II) from aqueous solution.