Papers by Keyword: Mercury Ion

Abstract: The 2-thiol benzothiazole was blended in Polyvinylidene fluoride (PVDF) membrane to prepare a kind of PVDF modified ultrafiltration membrane that could be used to remove mercury ion in water treatment. The water flux and retention rate of BSA of obtained PVDF modified ultrafiltration membrane was 222 L/m²·h and 92.33% respectively. The membrane performance were characterized by infrared spectroscopy (FT-IR) and water contact angle measurement. The results showed that, the PVDF modified membrane presented better adsorption ability for mercury ion than the traditional PVDF membrane. After 4 phases of adsorption/desorption, the modified membrane maintained a mercury ion adsorption amount of 0.264 mg/cm² and the desorption rate could reached 94%.

Abstract: A new fluorescent probe, quinoline derivative DPQ bearing a methyl pyrrolidine-1-carbodithioate group, was synthesized and characterized by IR, Tof-MS and NMR. Its fluorescent behaviors toward transition metal ions were investigated. The results indicate that DPQ shows unique selective and high sensitive for Hg2+ in aqueous solution with a broad pH range 4-10. DPQ forms a 1:2 metal-ligand complex with Hg2+ ions with a limit of detection as low as 1.7×10-6 mol/L.

Abstract: The adsorption performance of mercury ion onto activated carbon prepared from rice husk with NaOH was carried out at initial concentration of 100 mg/L. The activated carbon obtained at 800 °C possessed the outstanding specific surface area of 2786 m²/g. And the results showed that the maximum adsorption capacity of Hg²⁺ was recorded as 342.0 mg/g due to abundant micropores of 1.076 nm. In addition, the adsorption data were well explained by the Langmuir model with the monolayer adsorption capacity of 555.6 mg/g.

Abstract: A new Hg²⁺-sensing and selective fluorescent sensor, 1-(1-pyrenecarboxaldehyd e)-thiocarbohydrazone, was synthesized and characterized by elemental analysis, FT-IR and ¹H NMR spectra. Its fluorescence and recognition properties to the mercury ion were studied by the fluorescence emission spectra. With adding mercury ion into solution, the fluorescence emission intensities at different characteristic wavelength changed continually. Hence the ratiometric fluorescence measurement was used for detecting the complex process. It was found that a 1:1 stoichiometry complex is formed between the mercury ion and the compound with the association constants were 2.04×10⁵ L/mol, respectively. And the detection limits of the mercury ion were 2.52×10^-8 mol/L.

Abstract: An electrochemical sensing device with a plasticized polyvinyl chloride (PVC) membrane electrode based on a porphyrin derivative of p-amino tetraphenyl porphyrin (p-NH₂TPP) for mercury ion (Hg²⁺) has been fabricated. The p-NH₂TPP based PVC membrane electrode exhibited a nice linear potential performance for responding to Hg²⁺ in the range of 1.0×10^-8 ~ 1.0×10^-3 mol/L with a slope of 27.54 mV/-pC (25°C) in citrate buffer solution (pH=2.5). The detection limit was evaluated to be 7.5×10^-9 mol/L. No obvious interferences were observed from Na⁺, K⁺, Ba²⁺, Mg²⁺, Ca²⁺, and Cr³⁺. The electrode possessed good stability and reproducibility. Comparing with atomic absorption spectroscopy (AAS), the electrode can be well applied to the determination of trace amount of Hg²⁺ in environmental waste water samples with a recovery rate of 94.83 ~ 104.78%. The sensing mechanism of the porphyrin derivative carrier for recognition of Hg²⁺ has also been expounded by the formation of nice complexation effect between the lone pair electrons provided by four nitrogen atoms of the porphyrin molecule and unoccupied orbitals provided by the mercury ion.

Abstract: The electrochemical behaviors and sensing application of 100nm-gold plate electrode based on 6-amino-1-hexanethiol (6-AHT) self-assembled monolayer (SAM) have been investigated in this paper. The 6-AHT assembled nano gold plate electrode exhibited a nice linear potential performance of responding to Hg2+ in the range of 1.0×10-8—1.0×10-6 mol/L with a slope of 42.57 mV/-pC (25°C) in Tris-HCl buffer solution (pH=5.0). No obvious interferences were observed from Na+, K+, Ba2+, Mg2+, Ca2+, and Cr3+. The detection limit can be evaluated to 8.0×10-9 mol/L. In addition, the electrode possessed good stability and reproducibility with a recovery rate of 96.50-103.67%, indicating that it can be used for the determination of Hg2+ content in environmental waste water samples. The sensing mechanism of 6-AHT monolayer has also been discussed by the formation of coordination structure between amino groups of the thiol molecules and the mercury ions.

Abstract: The thiol-functionalized eggshell membrane (TF-ESM) was prepared by esterification between thioglycolic acid (CH2SHCOOH) and oxygen-containing functional groups on eggshell membrane (ESM). A promising potential biosorbent, TF-ESM, was used for the removal of toxic mercury in wastewater. Aqueous of mercury ions removing properties by TF-ESM were studied through batch experiments. The results indicated that the modified ESM has greatly enhanced the adsorption capacity for Hg2+, the maximum capacity was increased more than 3-fold in comparison with the unmodified ESM, from 19.4 mg g-1 to 71.9 mg g-1. The optimum of pH value for Hg adsorption was in the range of 2-8, which the removing rate over 96%. The results obtained show that the novel thiol-functionalized eggshell membrane performed well the removal and recovery of mercury from low concentration wastewaters.

Abstract: Mercury sorption on chitosan was investigated in batch and continuous systems. Chitosan sorption properties were determined through sorption isotherms. Langmuir and Freundlich equations were used for the modeling of isotherms at pH 5. In batch systems, maximum sorption capacities reached 550 mg Hg/g. Sorption kinetics have been studied as a function of sorbent particle size and stirring rate. Dynamic removal of mercury was tested in a fixed bed reactor investigating the following parameters: particle size, column size, flow velocity and metal ion concentration. Clark and Adams-Bohart models were evaluated for the simulation of breakthrough curves. This study shows that chitosan is an effective sorbent for the treatment and recovery of mercury from dilute effluents at near neutral pH.