Polyferric\|silicate\|sulfate(PFSS),as a new type of coagulant,was prepared by using sodium silicate, sulfuric acid and ferric sulfate as materials.The zeta potential of hydrolyzate of PFSS under different pH values w...Polyferric\|silicate\|sulfate(PFSS),as a new type of coagulant,was prepared by using sodium silicate, sulfuric acid and ferric sulfate as materials.The zeta potential of hydrolyzate of PFSS under different pH values was investigated.The effects of Fe/SiO\-2 molar ratio and dosage of PFSS on turbidity removal were studied. The relation between the optimum coagulation pH range and Fe/SiO\-2 molar ratio was found and the coagulation mechanism of PFSS was discussed.The experimental results showed that Fe/SiO\-2 molar ratio has an effect on the zeta potential of hydrolyzate, the coagulation performance and the optimum coagulation pH range of PFSS and that PFSS gives the best turbidity removal effect when its Fe/SiO\-2 molar ratio was 1.5.展开更多
The oxidation rate of ferrous sulfate was investigated in the preparation of polyferric sulfate(PFS) coagulant. It was proved that this reaction is zero order with respect to Fe2+, first order with respect to NO2(g) a...The oxidation rate of ferrous sulfate was investigated in the preparation of polyferric sulfate(PFS) coagulant. It was proved that this reaction is zero order with respect to Fe2+, first order with respect to NO2(g) and first order with respect to the interface area between gas phase and liquid phase. If the partial pressure of NO2(g) in gas phase is increased or the interface area is increased, the time needed to complete the reaction will be decreased.展开更多
Polyferric silicate sulfate （PFSS） with high concentration was prepared using the composite-poly method. The coagulation properties and mechanisms of this new complex were probed using TEM, Fe-Ferron timed complex-c...Polyferric silicate sulfate （PFSS） with high concentration was prepared using the composite-poly method. The coagulation properties and mechanisms of this new complex were probed using TEM, Fe-Ferron timed complex-colorimetric method, and infrared spectrum method. The results showed that the flocculating effect of polyferric silicate sulfate had an advantage over polyferric sulfate （PFS）, as the optimum coagulation effect could be obtained when the Si/Fe mole ratio was 0.75 in accordance with its macrostructure of PFSS. According to the Fe-Ferron timed complex-colorimetric method, the Si species was mainly Sic, whereas, the Fe species were Fea and Fec in the copolymerization system. The infrared spectra indicated that the structure of these new flocculants was formed by polymers, mainly by olation, which was different from polyferric sulfate, and the vibration of M-OH-M of around 1100 cm^-1, also proved that there existed Fe-OH-Fe and its polymers in some forms.展开更多
A crystalline polyferric sulfate(PFS) adsorbent was synthesized by oxidizing and precipitating ferrous ions in air atmospheric conditions. The morphology, structure, specific surface area(SSA), and adsorptive efficacy...A crystalline polyferric sulfate(PFS) adsorbent was synthesized by oxidizing and precipitating ferrous ions in air atmospheric conditions. The morphology, structure, specific surface area(SSA), and adsorptive efficacy of the adsorbent to As(Ⅲ) were characterized by scanning electron microscope(SEM) and transmission electron microscopy(TEM) images, X-ray diffraction(XRD) patterns, Fourier-transform infrared(FTIR) spectra, BET SSA analyses, and adsorption experiments. The adsorbent showed a near-spherical aggregate structure and had good crystallinity. A significant amount of α-goethite co-precipitated with PFS in the case of the initial ferrous concentration of 1 mol/L and increased SSA of the adsorbent. The stability region of ferric compounds in the process was drawn and applied to analyze the iron behavior during the synthesis. The adsorption of As(Ⅲ) in high As(Ⅲ)-containing solutions fitted the Langmuir isotherm model adequately. The absorbent with co-precipitation of α-goethite showed good adsorbability for As(Ⅲ) and good filtering performance in the high As(Ⅲ)-containing solution of 10–100 mg/L under acidic, neutral, and alkaline conditions(pH 2.09–9.01). After the adsorption process, the stability of the residues bearing As(Ⅲ) was evaluated by toxic characteristic leaching procedure(TCLP) tests. The results indicated that the residues were extremely stable, and the concentrations of arsenic in the leaching solutions were less than 0.01 mg/L.展开更多
Acid leaching solution was obtained after mixing pyrite cinders with H 2SO 4, then heating the mixture of pyrite cinders and H 2SO 4 at 200300 ℃, leaching the heated mixture with water and filtrating. Polyferric sulf...Acid leaching solution was obtained after mixing pyrite cinders with H 2SO 4, then heating the mixture of pyrite cinders and H 2SO 4 at 200300 ℃, leaching the heated mixture with water and filtrating. Polyferric sulfate (PFS) solution was produced by adding suitable amounts of FeSO 4·7H 2O and NaClO 3 into acid leaching solution. By concentrating and drying PFS solution, solid PFS with alkali degree of 6.40%22.4% was prepared. Fe 4.67 (SO 4) 6(OH) 2·20H 2O in the solid PFS was discovered by XRD analysis. FT IR spectroscopy shows that the absorption peaks at 3 400 cm -1 and 1 635 cm -1 arise from OH and absorption peaks at 998 cm -1 and 669 cm -1 come from Fe-OH in the solid PFS.展开更多
文摘Polyferric\|silicate\|sulfate(PFSS),as a new type of coagulant,was prepared by using sodium silicate, sulfuric acid and ferric sulfate as materials.The zeta potential of hydrolyzate of PFSS under different pH values was investigated.The effects of Fe/SiO\-2 molar ratio and dosage of PFSS on turbidity removal were studied. The relation between the optimum coagulation pH range and Fe/SiO\-2 molar ratio was found and the coagulation mechanism of PFSS was discussed.The experimental results showed that Fe/SiO\-2 molar ratio has an effect on the zeta potential of hydrolyzate, the coagulation performance and the optimum coagulation pH range of PFSS and that PFSS gives the best turbidity removal effect when its Fe/SiO\-2 molar ratio was 1.5.
文摘The oxidation rate of ferrous sulfate was investigated in the preparation of polyferric sulfate(PFS) coagulant. It was proved that this reaction is zero order with respect to Fe2+, first order with respect to NO2(g) and first order with respect to the interface area between gas phase and liquid phase. If the partial pressure of NO2(g) in gas phase is increased or the interface area is increased, the time needed to complete the reaction will be decreased.
文摘Polyferric silicate sulfate （PFSS） with high concentration was prepared using the composite-poly method. The coagulation properties and mechanisms of this new complex were probed using TEM, Fe-Ferron timed complex-colorimetric method, and infrared spectrum method. The results showed that the flocculating effect of polyferric silicate sulfate had an advantage over polyferric sulfate （PFS）, as the optimum coagulation effect could be obtained when the Si/Fe mole ratio was 0.75 in accordance with its macrostructure of PFSS. According to the Fe-Ferron timed complex-colorimetric method, the Si species was mainly Sic, whereas, the Fe species were Fea and Fec in the copolymerization system. The infrared spectra indicated that the structure of these new flocculants was formed by polymers, mainly by olation, which was different from polyferric sulfate, and the vibration of M-OH-M of around 1100 cm^-1, also proved that there existed Fe-OH-Fe and its polymers in some forms.
基金financially supported by the National Natural Science Foundation of China(No.51574285)
文摘A crystalline polyferric sulfate(PFS) adsorbent was synthesized by oxidizing and precipitating ferrous ions in air atmospheric conditions. The morphology, structure, specific surface area(SSA), and adsorptive efficacy of the adsorbent to As(Ⅲ) were characterized by scanning electron microscope(SEM) and transmission electron microscopy(TEM) images, X-ray diffraction(XRD) patterns, Fourier-transform infrared(FTIR) spectra, BET SSA analyses, and adsorption experiments. The adsorbent showed a near-spherical aggregate structure and had good crystallinity. A significant amount of α-goethite co-precipitated with PFS in the case of the initial ferrous concentration of 1 mol/L and increased SSA of the adsorbent. The stability region of ferric compounds in the process was drawn and applied to analyze the iron behavior during the synthesis. The adsorption of As(Ⅲ) in high As(Ⅲ)-containing solutions fitted the Langmuir isotherm model adequately. The absorbent with co-precipitation of α-goethite showed good adsorbability for As(Ⅲ) and good filtering performance in the high As(Ⅲ)-containing solution of 10–100 mg/L under acidic, neutral, and alkaline conditions(pH 2.09–9.01). After the adsorption process, the stability of the residues bearing As(Ⅲ) was evaluated by toxic characteristic leaching procedure(TCLP) tests. The results indicated that the residues were extremely stable, and the concentrations of arsenic in the leaching solutions were less than 0.01 mg/L.
文摘Acid leaching solution was obtained after mixing pyrite cinders with H 2SO 4, then heating the mixture of pyrite cinders and H 2SO 4 at 200300 ℃, leaching the heated mixture with water and filtrating. Polyferric sulfate (PFS) solution was produced by adding suitable amounts of FeSO 4·7H 2O and NaClO 3 into acid leaching solution. By concentrating and drying PFS solution, solid PFS with alkali degree of 6.40%22.4% was prepared. Fe 4.67 (SO 4) 6(OH) 2·20H 2O in the solid PFS was discovered by XRD analysis. FT IR spectroscopy shows that the absorption peaks at 3 400 cm -1 and 1 635 cm -1 arise from OH and absorption peaks at 998 cm -1 and 669 cm -1 come from Fe-OH in the solid PFS.
