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Functional Characterization of Green Sorption Media and Scaling of Pilot Studies for Copper Removal in Stormwater Runoff

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Date Issued:
2015
Abstract/Description:
Green adsorption media with the inclusion of renewable and recycled materials can be applied as a stormwater best management practice for copper removal. A green adsorption media mixture composed of recycled tire chunk, expanded clay aggregate, and coconut coir was physicochemically evaluated for its potential use in an upflow media filter. The results found that the use of the green adsorption media mixture in isolation or the coconut coir with an expanded clay filtration chamber could be an effective and reliable stormwater best management practice for copper removal. A suite of tests were conducted on the media mixture and the individual media components including studies of isotherm, reaction kinetics, column adsorption and reaction kinetics. Batch adsorption tests revealed that the media and media mixture follow both the Freundlich and Langmuir isotherm models and that the coconut coir had the highest affinity for copper. A screening of desorbing agents revealed that hydrochloric acid has good potential for copper desorption, while batch tests for desorption with hydrochloric acid as the desorbing agent showed the data fit the Freundlich isotherm model. Reaction kinetics revealed that the adsorption reaction took less than 1 hour to reach equilibrium and that it followed pseudo-second order kinetics for the mixture and coconut. Desorption kinetic data had high correlation with the pseudo-second order model and revealed a rapid desorption reaction. Batch equilibrium data over 3 adsorption/desorption cycles found that the coconut coir and media mixture were the most resilient and demonstrated that they could be used through 3 or more adsorption/desorption cycles. The coconut coir also performed the best under dynamic conditions, having an equilibrium uptake of 1.63 mg?g-1, compared to 0.021 mg?g-1 at an influent concentration of 1.0 mg?L-1 and a hydraulic retention time of 30 minutes. A physical evaluation of the media found the macro-scale properties, such as particle size distribution and mass-volume relationships, and observed the micro-scale properties such as surface and pore microstructures, crystalline structures, and elemental composition. FE-SEM imaging found a strong correlation between the porosity of the micro pore structure and the adsorptive capacity. The equilibrium and dynamic adsorption testing results were confirmed by elemental analysis, which showed measureable quantities of copper in the coconut coir and media mixture after adsorption followed by partial desorption. A new scaling-up theory was developed through a joint consideration of the Damk(&)#246;hler and P(&)#233;clet numbers for a constant media particle size such that a balance between transport-controlled and reaction-controlled kinetics can be harmonized. A series of column breakthrough tests at varying hydraulic residence times revealed a clear peak adsorptive capacity for the media mixture at a Damk(&)#246;hler number of 2.7. The P(&)#233;clet numbers for the column breakthrough tests indicated that mechanical dispersion is an important effect that requires further consideration in the scaling-up process. However, perfect similitude of the Damk(&)#246;hler number cannot be maintained for a constant media particle size, and relaxation of hydrodynamic similitude through variation of the P(&)#233;clet number must occur.
Title: Functional Characterization of Green Sorption Media and Scaling of Pilot Studies for Copper Removal in Stormwater Runoff.
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Name(s): Houmann, Cameron, Author
Chang, Ni-bin, Committee Chair
Wanielista, Martin, Committee Member
Lee, Woo Hyoung, Committee Member
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2015
Publisher: University of Central Florida
Language(s): English
Abstract/Description: Green adsorption media with the inclusion of renewable and recycled materials can be applied as a stormwater best management practice for copper removal. A green adsorption media mixture composed of recycled tire chunk, expanded clay aggregate, and coconut coir was physicochemically evaluated for its potential use in an upflow media filter. The results found that the use of the green adsorption media mixture in isolation or the coconut coir with an expanded clay filtration chamber could be an effective and reliable stormwater best management practice for copper removal. A suite of tests were conducted on the media mixture and the individual media components including studies of isotherm, reaction kinetics, column adsorption and reaction kinetics. Batch adsorption tests revealed that the media and media mixture follow both the Freundlich and Langmuir isotherm models and that the coconut coir had the highest affinity for copper. A screening of desorbing agents revealed that hydrochloric acid has good potential for copper desorption, while batch tests for desorption with hydrochloric acid as the desorbing agent showed the data fit the Freundlich isotherm model. Reaction kinetics revealed that the adsorption reaction took less than 1 hour to reach equilibrium and that it followed pseudo-second order kinetics for the mixture and coconut. Desorption kinetic data had high correlation with the pseudo-second order model and revealed a rapid desorption reaction. Batch equilibrium data over 3 adsorption/desorption cycles found that the coconut coir and media mixture were the most resilient and demonstrated that they could be used through 3 or more adsorption/desorption cycles. The coconut coir also performed the best under dynamic conditions, having an equilibrium uptake of 1.63 mg?g-1, compared to 0.021 mg?g-1 at an influent concentration of 1.0 mg?L-1 and a hydraulic retention time of 30 minutes. A physical evaluation of the media found the macro-scale properties, such as particle size distribution and mass-volume relationships, and observed the micro-scale properties such as surface and pore microstructures, crystalline structures, and elemental composition. FE-SEM imaging found a strong correlation between the porosity of the micro pore structure and the adsorptive capacity. The equilibrium and dynamic adsorption testing results were confirmed by elemental analysis, which showed measureable quantities of copper in the coconut coir and media mixture after adsorption followed by partial desorption. A new scaling-up theory was developed through a joint consideration of the Damk(&)#246;hler and P(&)#233;clet numbers for a constant media particle size such that a balance between transport-controlled and reaction-controlled kinetics can be harmonized. A series of column breakthrough tests at varying hydraulic residence times revealed a clear peak adsorptive capacity for the media mixture at a Damk(&)#246;hler number of 2.7. The P(&)#233;clet numbers for the column breakthrough tests indicated that mechanical dispersion is an important effect that requires further consideration in the scaling-up process. However, perfect similitude of the Damk(&)#246;hler number cannot be maintained for a constant media particle size, and relaxation of hydrodynamic similitude through variation of the P(&)#233;clet number must occur.
Identifier: CFE0005630 (IID), ucf:50205 (fedora)
Note(s): 2015-05-01
M.S.
Engineering and Computer Science, Civil, Environmental and Construction Engineering
Masters
This record was generated from author submitted information.
Subject(s): Stormwater management -- stormwater treatment -- best management practices -- green adsorption media -- copper -- desorption -- dimensional analysis
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFE0005630
Restrictions on Access: campus 2016-05-15
Host Institution: UCF

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