Sorption Of Mercury Ions Research Articles

Innovative pyrazole–phosphoramidate derivative for effective mercury adsorption and their application for Egyptian industrial waste samples

ABSTRACT Mercury, known for its severe health and environmental impacts even in trace amounts, necessitates effective removal from water systems. This research focuses on preparation of a novel adsorbent of 3,9−bis((4−amino−5−hydroxy−1 H−pyrazol−3−yl)amino)−2,4,8,10−tetraoxa−3,9−diphosphaspiro[5.5] undecane 3, 9−dioxide (PADP) for Hg(II) ions adsorption. To validate functionalization steps and elucidate PADP’s physical and chemical properties, a comprehensive array of assays, including FTIR, surface area, BET, TGA, 13CNMR, Mass spectra, 31PNMR and1HNMR were employed. The study systematically examined several factors controlling mercury sorption, including temperature, adsorbent dosage, pH, interaction time, and mercury concentration using the batch technique. Optimal sorption effectiveness was achieved at pH 5, with an interaction time of 50 min, an 80 mg adsorbent dose, at ambient temperature. The newly devised adsorbent exhibited an impressive adsorption capacity (qe) of 357 mg of Hg(II) per Litre, with empirical data fitting the Langmuir and Dubinin−Radushkevich adsorption isotherm models. The kinetics of mercury sorption followed second-order and Elovich kinetics models. Thermodynamic aspects, including ΔGº, ΔSº, and ΔHº, were also investigated, providing appreciated perceptions into the energetic dynamics of the sorption process. Thermodynamics has shown that the sorption of mercury ions is both endothermic and spontaneous. Additionally, mercury adsorption in the occurrence of other ions was explored, highlighting the selectivity of the modified Pyrazole – Phosphoramidate adsorbent for mercury removal. PADP demonstrates superior performance in removing Hg(II) from wastewater effluents, outshining a range of both natural and synthetic adsorbents previously used for this purpose. This superiority is evident when comparing its adsorption capacity (qo) against those of other adsorbents, showcasing its exceptional efficacy in purifying water from mercury contamination.

Polyaniline Nanofiber Electrodes for Reversible Capture and Release of Mercury(II) from Water.

π-Conjugated polyaniline nanofiber networks are an attractive material platform for reversible and selective capture and release of toxic heavy metal ions from water. The nanofiber geometry facilitates fastsorption kinetics, sulfur functionalization of the backbone for improved adsorption, and electrochemical control of the oxidation (charge) state for reversible triggered sorption/desorption of metal ions. These active materials also function as sensors in that the sorption of mercury ions can be detected by analysis of cyclic voltammograms. Calculations of binding energies between polyaniline and metal ions using molecular dynamics and density functional theory support the electrochemically controlled reversible sorption/desorption mechanism. These redox-active materials for removing Hg2+ from water create an attractive system that combines efficiency, capacity, selectivity, and reusability.

Mordanting of mercury on styrene-divinylbenzene copolymer beads from aqueous solutions

The sorption of mercury ions from aqueous solutions on styrene-divinylbenzene copolymer beads (St-DVB) has been investigated for the decontamination of mercury from aqueous media. Various physico-chemical parameters, such as selection of appropriate electrolyte, contact time, amount of adsorbent, concentration of adsorbate, effect of diverse ions and temperature were optimized to simulate the best conditions which can be used to decontaminate mercury from aqueous media using St-DVB beads as an adsorbent. The radiotracer technique was used to determine the distribution of mercury. The highest adsorption was observed at 0.001 mol L−1acid solutions (HNO3, H2SO4and HClO4) using 0.2 g of adsorbent for 5.14×10−5mol L−1mercury concentration in five minutes equilibration time. Studies show that the adsorption decreases with the increase in the concentrations of all the acids. The adsorption data follows the Freundlich isotherm over the mercury concentration range of 2.19×10−4to 5.90×10−3mol L−1. The characteristic Freundlich constants,i.e.1/n= 0.42±0.01 andA= (1.54±0.03)×10−3mol g−1have been computed for the sorption system. The sorption mean free energy from Dubinin–Radushkevich isotherm is 11.9±0.1 kJ mol−1indicating ion-exchange mechanism of chemisorption. The uptake of mercury increases with the rise in temperature. Thermodynamic parameters,i.e.ΔG, ΔSand ΔHhave also been calculated for the system.

Metal sorption properties of sulfur-chlorinated jojoba wax bound to polystyrene beads

A new solid extractant (designated PS-DETA-JS) in which sulfur-chlorinated jojoba wax is bound via an amine spacer group to polystyrene beads was synthesized. The absorption of mercury cations from acidic solutions and of chromate anions from saline solutions onto PS-DETA-JS was investigated. The sorption of mercury ions by the solid extractant was compared with that by liquid-sulfurized jojoba wax impregnated inside macroporous resins. The static and dynamic properties of dichromate sorption from 2–20 g/L NaCl solutions at pH 4.1 were studied. Selective sorption of Cr(VI) was obtained at low chromate concentrations (∼ 6 ppm) in saline aqueous solutions. Complete regeneration of the PS-DETA-JS resin was achieved after the reduction of Cr(VI) to Cr(III) and the elution of the Cr(III) with 1N HCl. © 1997 John Wiley & Sons, Inc.