Selective removal of mercury from aqueous solutions using thiolated cross-linked polyethylenimine

Abstract

A successful approach to develop an insoluble form of polyethylenimine with a thiol-based functional group for selective removal of Hg(II) from aqueous solutions is reported. The selectivity of the modified polymer for Hg(II) as well as its ability to be regenerated for re-use has been studied. The synthesised polymer exhibited high selectivity for Hg(II) with high removal efficiency of up to 97 %, even in the presence of competing ions. The Freundlich isotherm was found to best fit and describe the experimental data. The pseudo-second-order equation explains the adsorption kinetics most effectively implying chemisorption. The thermodynamic study of the adsorption process revealed high activation energies [41 kJ mol-1 , further confirming chemisorption as the mechanism of interaction between mercury ions and the polymer surface. The polymer exhibited good potential for re-use after many cycles of regeneration, giving good removal efficiency up to the fifth cycle.

Efficient Mercury Capture Using Functionalized Porous Organic Polymer

“…The equilibrium adsorption data were well fitted with the Langmuir model, with a correlation coefficient equal to 0.989. The uptake capacities for each point were calculated and the maximum was found to be 1216 mg g −1 (with an equilibrium concentration of 200 ppm), outperforming many previously reported materials . Furthermore, with only a simple washing procedure POP‐SH could be fully regenerated, achieving a similar uptake capacity of 1250 mg g −1 .…”

“…Preliminary methods like ion‐exchange resins were explored but were found to be expensive and ineffective . Further research employed the strong soft–soft interactions between the thiol group (‐SH) and mercury, and much work has been done on thiol‐functionalized adsorbent materials including clays, activated carbon, mesoporous silica, cross‐linked polyethyleneimine, and others . However, these materials display low surface areas, small pore sizes, and a low density of functional groups.…”

Effective removal of mercury(II) ions from chlor-alkali industrial wastewater using 2-mercaptobenzamide modified itaconic acid-grafted-magnetite nanocellulose composite

“…K F and n are the Freundlich constants indicating the adsorption capacity and adsorption intensity of the system [29].…”

Investigation on Synthesis and Applications of Novel Polymeric Composites for the Removal of Heavy Metal Ion

“…Environmental contamination due to minerals and heavy metals is the major challenging problem in our country. The concentration of heavy metals due to industrial and agricultural waste materials have been increased to the levels of high risk [1][2][3][4] . Among the various metals like lead, mercury, chromium, arsenic, nickel, uranium, selenium, silver, cadmium, zinc and gold present in industrial waste water, discharge of Hg (II) ions cause severe environmental contamination as it is non-degradable and bio-accumulate in nature [5][6][7][8] .…”