The pH effect of sulfuric acid on the physico-mechanical properties of Atashkuh travertine, Central Iran

• Published in: Environmental earth sciences 2022-03, Vol.81 (5), Article 159
• Main Authors: Parvizpour, Shahla, Jamshidi, Amin, Sarikhani, Ramin, Ghassemi Dehnavi, Artimes
• Format: Article
• Language: English
• Subjects: Acid rain; Air pollution; Biogeosciences; Cycles; Data analysis; Decay rate; Drying; Durability; Earth and Environmental Science; Earth Sciences; Environmental Science and Engineering; Geochemistry; Geology; Hydrology/Water Resources; Industrial pollution; Mechanical properties; Original Article; pH effects; Pollutants; Porosity; Quarries; Rain; Rainfall; Sulfur; Sulfur dioxide; Sulfuric acid; Sulphur; Sulphur dioxide; Sulphuric acid; Tensile strength; Terrestrial Pollution; Toughness; Travertine; Wetting
• ISSN: 1866-6280; 1866-6299
• DOI: 10.1007/s12665-022-10282-3

Sulfur dioxide (SO 2 ) is one of the most hazardous pollutants in the atmospheres of industrial cities. This pollutant, in combination with rainfall, forms acid rain. Acid rain can affect the physico-mechanical properties of stones and decrease their durability over time. In this paper, the pH effect of sulfuric acid was investigated on the physico-mechanical properties of travertine, including porosity ( n ), point load index (PLI), and Brazilian tensile strength (BTS). For this purpose, a travertine sample was obtained from the Atashkuh quarry in Mahallat (central Iran). Next, 30 cycles of wetting and drying were performed on the sample in H 2 SO 4 solutions with pH values of 2, 3.5, and 5, followed by measuring its physico-mechanical properties after every 5 cycles. Parameters of the decay constant ( λ ) and half-time ( N 1/2 ) were obtained from regression curves developed between the measured physico-mechanical properties and cycles of wetting and drying in H 2 SO 4 solutions. The N 1/2 and the rate of loss (RL) these properties were used for comparing the effect of H 2 SO 4 solutions with pH of 2, 3.5, and 5 on the sample. The results of data analysis showed that with an increase in the number of wetting and drying cycles in H 2 SO 4 , the n increased while PLI and BTS decreased with varying degrees. Furthermore, the variations in the physico-mechanical properties of the sample and their λ and N 1/2 indicated that the durability of the sample changes after the interaction of the H 2 SO 4 solution with various pH values.