Congratulations to Brittany Multer Hopkins on the publication of her latest article in Science of the Total Environment. It can be accessed here: https://doi.org/10.1016/j.scitotenv.2024.177692
Abstract
The enhanced weathering of concrete in soil has potential to capture atmospheric CO2. The objective of this research was to conduct a laboratory experiment and evaluate the environmental impacts and carbon capture potential of concrete as an enhanced weathering material in soil. A column study was conducted with four treatments comprised of: 1) 100 % soil (S treatment), 2) 90 % soil and 10 % concrete by weight of 0.25–0.71 mm diameter fragments (S + Cfine treatment), 3) 90 % soil and 10 % concrete by weight of 8–25 mm diameter fragments (S + Ccoarse treatment), and 4) 100 % concrete composed of 8–25 mm diameter fragments (C treatment). Deionized water was added to the columns for 16 weeks. The S + Cfine treatment experienced a significant increase in soil pH (8.0 ± 0.07) compared to the S (6.9 ± 0.22) and S + Ccoarse (7.1 ± 0.08) treatments. The C treatment experienced a significant increase in leachate pH. Leachate NO3− concentrations in the S + Cfine (33 ± 18 mg L−1) samples were significantly greater than those in other treatments. Soil microbial community concentrations were significantly less in the S + Cfine treatment. The S + Cfine treatment had a calculated average HCO3− concentration of 350 ± 120 mg L−1 which was significantly greater than the S (230 ± 100 mg L−1), C (270 ± 170 mg L−1), and S + Ccoarse (260 ± 50 mg L−1) treatments. Increased concentrations of Ca2+, SO42−, H4SiO4, and HCO3− in the mixed concrete and soil samples are evidence that chemical reactions occurred due to the soil-concrete interaction and are likely capturing atmospheric CO2.