Adsorptive-Oxidative Removal of Sulfides from Water by MnO2-Loaded Carboxylic Cation Exchangers

Abstract

Hybrid ion exchangers (HIX) containing manganese(IV) oxide (MnO2) based on macroporous and gel-type carboxylic cation exchangers as supporting materials were obtained. The hybrid materials were characterized using scanning electron microscopy with energy dispersive spectrometry (SEM/EDS), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD) and nitrogen adsorption isotherms at 77 K and mercury porosimetry. HIX with introduced MnO2 (20.0–32.8 wt% Mn) were tested for removal of dissolved sulfides from anoxic aqueous solutions with 100–500 mg S2−/dm3 concentrations. The process proceeded effortlessly at pH 10–13 despite unfavorable electrostatic interactions of the reactants. The highest exhibited sorption capacity was 144.3 ± 7.1 mg S2−/g. Approximately 65% of dissolved sulfides were oxidized to S2O32− ions and repelled from HIX structure. On average, 13% of sulfide removal products were adsorbed by the MnO2 surface. The impact of MnO2 load and the ionic form of HIX functional groups on removal of sulfides and resulting products was examined. The mechanism of the process is suggested.

Coral sand from hydraulic reclamation for the remediation of acid sulfate soil

“…9 compared the structural characteristics of several neutralizing materials. Montmorillonite shows IV type isotherm [19] and H3 type hysteresis loop [20] , which indicated that it has complex mesoporous structure and irregular pore structure. Shell powder, coral sand, calcite and dolomite showed I-type isotherm [21] , and there was no hysteresis loop, which indicated that they had the characteristics of microporous adsorbent [22] , and the saturated adsorption value was equal to the filling volume of micropores.…”

Decorated reduced graphene oxide transfer sulfides into sulfur and sulfone in wastewater

“…Sulfides can be formed spontaneously by the anaerobic decomposition of sulfur-containing organic matter or the reduction of biological sulfates under the action of septic bacteria and sulfate-reducing bacteria, which usually occurs in natural systems such as marine, river and lake sediments as well as in the treatment of municipal and agricultural sewage and waste. 5 Moreover, the majority of manufactured dissolved sulfide and gaseous H 2 S pollutants are discharged into the natural environment. The average sulfide concentrations in wastewater from the petrochemical and leather industries are around 150 g L −1 and 360 mg L −1 , respectively.…”

Copper Rich Composite Materials Based on Carboxylic Cation Exchangers and Their Thermal Transformation

“…Due to their form of porous spherical beads with mechanical strength and due to overcoming the propensity of parent nanoparticles to aggregate (by isolating them within the polymeric skeleton), HIXs are suitable for batch and flow-through systems, providing a highly accessible surface area, high sorption capacity, fast kinetics, and enhanced selectivity in purification processes (the Donnan membrane effect controls what type of ions can enter inside the resin structure) [ 11 ]. The different morphology of the host materials (ion exchanger macroreticular vs. gel-like structure), the diverse nature and concentration of the ionogenic functional groups (strongly or weakly acidic vs. strongly or weakly basic), the various methods of dispersing metal oxide NPs inside the polymer support, and the specific properties of immobilized metal oxide nanoparticles all contribute to the diversity of their applications, including separation processes, catalysis and biocidal actions [ 12 , 13 , 14 , 15 , 16 , 17 ]. The most popular HIXs are FeOOH, MnO 2 , and ZrO 2 doped anion exchangers.…”