Thiol-Functionalized Zr-Based Metal–Organic Framework for Capture of Hg(II) through a Proton Exchange Reaction

Rational design and facile synthesis of thiol-modified metal–organic frameworks (MOFs) for the efficient capture of highly toxic mercuric ions from water has attracted great attention. However, the corresponding adsorption mechanism is not well understood. In this paper, a thiol-modified Zr-based MOF (Zr-DMBD) with free-standing and accessible thiol groups was prepared. It exhibited remarkable performance in the capture of Hg­(II), and its maximum adsorption capacity was 171.5 mg·g^–1, approximately 9 times that of the pristine UiO-66. Impressively, the maximum value of the selective coefficient was as high as 28899.6. Additionally, 99.64% of Hg­(II) could be eliminated by Zr-DMBD from the actual wastewater, rendering the concentration of Hg (II) below 0.05 ppm (Emission Standard of Mercury (GB30770-2014)). The excellent adsorption capacity and outstanding selectivity were ascribed to the remarkable coordination between S^2– and Hg­(II), as supported by the results of FT-IR and XPS. Unexpectedly, a good correlation (R² = 0.982) between the increased H⁺ concentration after adsorption and its corresponding adsorption capacity was obtained. This result suggested that the thiol groups’ sulfur atoms coordinated with Hg­(II) while the hydrogen atoms in thiol groups were replaced and released as hydrogen ions in the solution, thus extending a proton exchange reaction mechanism for Hg­(II) adsorption

Reduction of cisplatin nephrotoxicity by sodium selenite. Lack of interaction at the pharmacokinetic level of both compounds

Administration of sodium selenite (Na2SeO3) 1 hr before cis-diamminedichloroplatinum(II) (referred to herein as cisplatin) can protect against the nephrotoxicity of cisplatin. The pharmacokinetic aspects of this interaction were studied in rodents with radiolabeled selenite and cisplatin. Total [75Se]selenium in plasma consisted of [75Se] selenium in plasma proteins and [75Se]selenite in plasma ultrafiltrate. After a short distribution phase, the elimination of [75Se]selenite and total [75Se]selenium proceeded biphasically in the rat, with an initial plasma elimination half-life of [75Se]selenite of 22 +/- 2 min. Coadministration of cisplatin had no effect on the initial nor on the much slower terminal elimination phase of [75Se]selenite nor of total [75Se] selenium. Sodium selenite, in doses protecting against the nephrotoxicity of cisplatin, did not significantly affect areas under the plasma concentration time curve from 0-6 hr nor the initial plasma half-lives of [195mPt]cisplatin (t1/2, 28 +/- 2 min) and total [195mPt]platinum (t1/2, 30 +/- 3 min) in plasma. The much slower terminal elimination phases in plasma and the cumulative urinary excretion of [195mPt] cisplatin and total [195mPt]platinum were neither influenced by sodium selenite. Sodium selenite does not react chemically with cisplatin in vitro. Apparently, bioactivation of selenite is required for its protective effect in vivo. Distribution studies in a mice tumor model indicated that [75Se]selenium is concentrated strongly in the kidney and that the bioactivation of selenite also most likely occurs primarily in the kidneys. We conclude that sodium selenite protects rodents against cisplatin-induced nephrotoxicity without influencing the systemic availability of cisplatin and total platinum.(ABSTRACT TRUNCATED AT 250 WORDS

N₂ adsorption isotherms of MPs and GAC.

<p>Herein, MPs 3–5 were synthesized by changing the molar ratio of ascorbic acid to Fe³⁺ from 0.1 to 0.15, 0.2, separately. MPs-3w was prepared at the molar ratio of 0.1 by acid wastewater digestion.</p

Parameters and the regression coefficients (R²) of the kinetic models.

<p>Parameters and the regression coefficients (R²) of the kinetic models.</p

Magnetic hysteresis loops of iron mud and MPs.

<p>MPs 1–5 were synthesized by changing the molar ratio of ascorbic acid to Fe³⁺ from 0.01 to 0.05, 0.1, 0.15 and 0.2, respectively. MPs-3w was prepared at the molar ratio of 0.1 with acid wastewater digestion.</p

Major elements in iron mud and MPs.

<p>MPs 1–5 were synthesized by changing the molar ratio of ascorbic acid to Fe³⁺ from 0.01 to 0.05, 0.1, 0.15 and 0.2, respectively. MPs-3w was prepared at the molar ratio of 0.1 with acid wastewater digestion.</p

Cation exchange capacity of MPs by NH₄-Na test.

<p>(Unit: Mmol/kg).</p

An Emission-Free Vacuum Chlorinating Process for Simultaneous Sulfur Fixation and Lead Recovery from Spent Lead-Acid Batteries

Spent lead-acid battery recycling by using conventional technologies is usually accompanied by releases of lead-containing wastewater as well as emissions of sulfur oxides and lead particulates that may potentially cause secondary pollution. This study developed a vacuum chlorinating process for simultaneous sulfur fixation and high-purity lead chloride (PbCl₂) recovery from spent lead paste by using calcium chloride (CaCl₂) and silicon dioxide (SiO₂) as reagents. The process train includes pretreatment, simultaneous PbCl₂ production and sulfur fixation, and PbCl₂ volatilization. The pretreatment eliminated chlorine emission from direct chlorinating reaction of PbO₂ in the initial S-paste (PbSO₄/PbO₂/PbO/Pb). During the subsequent PbCl₂ production and sulfur fixation step, lead compounds in the P-paste (PbSO₄/PbO) was converted to volatile PbCl₂, and sulfur was simultaneously fixed to the solid residues in the form of CaSO₄ to eliminate the emission of sulfur oxides. The final step, PbCl₂ volatilization under vacuum, is a physical phase-transformation process of ionic crystals, following a zeroth-order kinetic model. A cost estimate indicates a profit of USD $ 8.50/kg PbCl₂. This process offers a novel green lead recovery alternative for spent lead-acid batteries with environmental and economic benefits

Effects of Piecewise Electric Field Operation on Sludge Dewatering: Phenomena and Mathematical Model

Electro-dewatering (EDW) is an energy-efficient method for sludge dewatering. In this study, effects of piecewise electric field operation on EDW were investigated by experiments and simulation. Operational parameters were studied mainly in terms of sludge resistance variation during electro-dewatering process, which were evaluated by linear sweep voltammetry (LSV) analysis. Simulation of the sludge cake electro-dewatering processes was developed and validated, based upon time-dependent experimental data of electric currents and filtrate weights. The modeling results were in good agreement with experiments. It was proved by experimental and modeling results that the piecewise operation has positive effects on key performances of EDW devices, that is, limited water content, space-time yield, and mass specific energy consumption