Effect of airborne particle on SO2-calcite reaction

Boke, H
Göktürk, Emine Hale
Caner-Saltik, EN
Demirci, S
In modern urban atmosphere, sulphur dioxide (SO2) attacks calcite (CaCO3) in calcareous stone-producing gypsum (CaSO4 . 2H(2)O) which forms crust at rain sheltered surfaces and accelerates erosion at areas exposed to rain. The airborne particles collected on stone surfaces have always been considered to enhance the gypsum crust formation and thus it is believed that they should be removed from the surface to decrease the effects of SO2. In this study, our aim was to investigate this event by carrying out a series of experiments in laboratory using pure calcium carbonate powder to represent calcareous stone. Sodium montmorillonite, activated carbon, ferric oxide, vanadium pentoxide and cupric chloride were mixed in the pure calcium carbonate powder as substitutes of the airborne particles in the polluted atmosphere. The samples have been exposed at nearly 10 ppmv SO2 concentrations at 90% relative humidity conditions in a reaction chamber for several days. The mineralogical composition of the exposed samples were determined by X-ray diffraction (XRD) analysis and infrared spectrometer (IR). Sulphation reaction products, calcium sulphite hemihydrate, gypsum and unreacted calcite, were determined quantitatively using IR. Exposed samples have also been investigated morphologically using a scanning electron microscope (SEM). Experimental results reveal that calcium sulphite hemihydrate is the main reaction product of the SO2-calcite reaction. It turns out that airborne particles play an important catalytic role in the oxidation of calcium sulphite hemihydrate into gypsum, although their presence does not very significantly affect the extent of sulphation reaction. This behaviour of airborne particles is explained by the presence of liquid film on the calcium carbonate surface when a series of reactions in the gas-liquid-solid interfaces takes place.


Effect of some surfactants on SO2-marble reaction
Boke, H; Gokturk, EH; Saltık, Emine Nevin (2002-12-01)
In the polluted atmosphere, sulphur dioxide (SO2) reacts with calcite (CaCO3) in marble producing calcium sulphite hemihydrate (CaSO3.0.5 H2O) and gypsum (CaSO4.2H(2)O). Gypsum develops crust at rain-sheltered surfaces and then, being more soluble, accelerates erosion at areas exposed to rain. Eventually, all these lead to significant deformations in the appearance and structure of marble surfaces. Clearly, some precautions must be taken to stop or at least to slow down this deterioration process which dest...
Influence of biomass thermal pre-treatment on the particulate matter formation during pulverized co-combustion with lignite coal
Magalhaes, Duarte; Kazanç Özerinç, Feyza (2022-01-15)
This work investigated the particulate matter formation during co-combustion of thermally pre-treated biomass with coal. Olive residue was chosen as agricultural waste biomass, and Tunçbilek lignite as the coal. The biomass was thermally pretreated to assess the influence of the pretreatment temperature on particulate matter formation during co-combustion. Specifically, the olive residue was torrefied (at 275 °C) and pyrolyzed (at 500 °C) using a tubular oven. The biomass-coal blends in a 50:50 wt% ratio we...
Effect of calcium carbonate addition on carbothermic formation of hexagonal boron nitride
ÇAMURLU, HASAN ERDEM; SEVİNÇ, NACİ; Topkaya, Yavuz Ali (Elsevier BV, 2008-01-01)
Effect of CaCO3 on formation of hexagonal boron nitride (h-BN) was investigated by holding CaCO3 free and CaCO3 added activated carbon-boric oxide mixtures under nitrogen atmosphere at 1500 degrees C for 30-120 min. Amount of CaCO3 addition was varied in the range of 0-50 wt.% of the initial mixture. Products were characterized by powder X-ray diffractometry, FT-IR analysis, quantitative chemical analysis, scanning electron microscopy and BET specific surface area analysis. It was observed that calcium carb...
Effect of heat treatment on grindabilities of celestite and gypsum and separation of heated mixture by differential grinding
Sener, S; Bilgen, S; Ozbayoglu, G (Elsevier BV, 2004-03-01)
This study was conducted to determine thermal decomposition of gypsum (CaSO4 . 2H(2)O) and celestite (SrSO4), to examine the effect of heating on grindability and the possibility of celestite-gypsum separation by differential grinding after heating. The results indicated that no significant decomposition reaction was observed in celestite up to 900 degreesC whereas the decomposition of gypsum occurred within 100-450 degreesC.
Role of boron carbide in carbothermic formation of hexagonal boron nitride
Camurlu, H. E.; Sevinc, N.; Topkaya, Yavuz Ali (Springer Science and Business Media LLC, 2006-08-01)
Formation of hexagonal boron nitride by carbothermic reduction of boric oxide under nitrogen atmosphere at 1500 degrees C was investigated. Experiments were performed for durations in the range of 15 min to 3 h. Reaction products were subjected to powder X-ray diffraction analysis, chemical analysis and were examined by scanning electron microscope. Formation of hexagonal boron nitride was found to be complete in 3 h with most forming in the initial 2 h. Boron carbide was found to exist in the reaction prod...
Citation Formats
H. Boke, E. H. Göktürk, E. Caner-Saltik, and S. Demirci, “Effect of airborne particle on SO2-calcite reaction,” APPLIED SURFACE SCIENCE, pp. 70–82, 1999, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/56963.