Abstract
For the protection of human and ecological receptors from the effects of soil pollution with chemical compounds, we need to know the behavior and transport of pollutants in soil. This work investigated the Congo red (CR) acid dye sorption on three natural soils collected from central and northeastern regions of Romania, symbolized as IS-65, IS-T, and MH-13. To define the mechanism of sorption and identify the rate governing step, various diffusion models such as Weber–Morris intraparticle diffusion, Boyd, film and pores diffusion, and mass transfer analysis have been verified. The intraparticle diffusion analysis of Congo red sorption onto soils has been described by a multi-linear plots, showing that the sorption process takes place by surface sorption and intraparticle diffusion in macro, meso, and micropores. The values of intraparticle diffusion coefficient kid increased with any rise of the initial concentration of pollutant. The results show that the values of pore diffusion coefficient (Dp) and film diffusion coefficient (Df) are found to be from 10−8 to 10−10 cm2 s−1, indicating that film diffusion influences the sorption rate limiting step. The intraparticle diffusion analysis shows that the plots did not pass through the origin and have two distinct parts, confirming that intraparticle diffusion is not the single determining mechanism involved in the sorption of Congo red on soils IS-65, IS-T, and MH-13. The results revealed that the sorption process has a complex nature, since both external diffusion and internal diffusion are involved in the sorption of CR from solution onto the investigated soils.
Highlights
Soil pollution and land degradation are emerging issues with consequences at local, regional and global scale [1,2,3]
The main purpose of this study was to assess the sorption mechanism involved in the uptake of Congo red azo dye onto three different soils
The sorption process has a complex nature and can be designated by the following consecutive steps: transport in the bulk of the solution, diffusion of solute across the liquid film surrounding the soil particles, and particle diffusion in the liquid contained in the pores and in soil along the walls of the pores
Summary
Soil pollution and land degradation are emerging issues with consequences at local, regional and global scale [1,2,3]. The main phenomena involved in soil and land degradation are erosion, chemical contamination, loss of soil’s organic matter, nutrient imbalance, salinization, surface sealing, loss of soil biodiversity, acidification, compaction, and waterlogging [4,5,6]. It is estimated that 1.9 billion hectares of land are affected globally [2]. Predicted that around 3 million sites in the EU Member States are affected by industrial activities, and on significant surfaces (250,000 sites) the urgent application of land remediation technologies is required. The number of recorded polluted sites is expected to increase by 50% until 2025 if no important changes in legislation and behavior are made [7].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
