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Developing different architectures of capacitive deionization for enhanced removal of heavy metals from wastewater |
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| รหัสดีโอไอ | |
| Title | Developing different architectures of capacitive deionization for enhanced removal of heavy metals from wastewater |
| Creator | Nguyen Tan Thong |
| Contributor | Sandhya Babel, Advisor |
| Publisher | Thammasat University |
| Publication Year | 2567 |
| Keyword | Capacitive deionization, Wastewater, Heavy metals, Nanostructures, Activated carbon, Membrane |
| Abstract | Capacitive deionization (CDI) is an emerging technique in water treatment due to its simplicity, energy saving, and environmental sustainability. It has been widely studied for desalination; however, its potential for heavy metals (HMs) removal is an area of ongoing research. In this study, several actions were implemented to assess the feasibility of employing CDI for remediating wastewater with HMs. To achieve the specified goals, lab-scale CDI cells were constructed and operated continuously. The study analyzed synthetic wastewater for the removal of Cr6+, Cr3+, Cu2+, and Ni2+, (with concentrations from 50 to 1000 mg/L) and then assessed real electroplating wastewater. Two approaches were utilized, including a modified electrode nanostructure and a fabricated cation exchange membrane. The effects of operational conditions in the CDI system were also analyzed. The following is a summary of the results and findings of this study: (1) Grafting MnO2 nanostructures onto activated carbon cloth (ACC/MnO2) significantly increased the capacitance of the material, enhancing removal of chromium. The adsorption amount of ACC/MnO2 was 7.86 mg/g, which was greater than the adsorption amount of pristine ACC (6.65 mg/g) for Cr6+ removal. (2) The modification of the activated carbon fiber surface with ZnO nanorods (ACC/ZnO-nRs) resulted in enhanced the electric field, leading to higher adsorption capacity of Cu2+ removal. The ACC material presented a specific capacitance of 38.43 F/g, while ACC/ZnO-nRs demonstrated a higher value of 45.08 F/g. (3) Using fabricated heterogeneous cation exchange membranes in a membrane capacitive deionization (MCDI) cell exhibited more significant adsorption of Ni2+ than the CDI cell, reaching 3.42 mg/g, while the CDI cell achieved 2.15 mg/g. (4) Increasing potential improved adsorption capacity and recovery rates for Cr6+, Cr3+, Cu2+, and Ni2+, while initial concentrations, pH, and flow rates notably influenced adsorption capacity. (5) The utilization of ACC/ZnO-nRs electrodes and commercial ion exchange membranes in the MCDI cell showed significant promise in treating real electroplating wastewater, meeting Thailand's industrial wastewater discharge regulation. This study found successful performance in eliminating HMs through appropriately configured and operated capacitive deionization systems. The findings of this study highlight the potential of CDI technique to effectively mitigate HMs contamination in wastewater, including synthesis and electroplating wastewater. |
