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[Removal of nickel from aqueous solutions using complexation-ultrafiltration process].
Shu Qin1, Jia-Hui Shao, Yi-Liang He
1School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. qinshu87@gmail.com
Huan Jing Ke Xue= Huanjing Kexue
|June 23, 2012
Summary
Complexation-ultrafiltration effectively removes nickel ions from water using polyacrylate (PAANa) or polyethylenimine (PEI) as complexing agents. Optimal conditions achieved over 99% nickel removal with minimal membrane flux decline.
Area of Science:
- Environmental Chemistry
- Water Treatment Technologies
- Polymer Science
Background:
- Nickel ion contamination poses environmental and health risks.
- Conventional water treatment methods may struggle with efficient nickel removal.
- Complexation followed by membrane separation offers a promising alternative.
Purpose of the Study:
- To investigate the efficacy of polyacrylate (PAANa) and polyethylenimine (PEI) as complexing agents for nickel ion removal.
- To optimize conditions (pH, polymer/Ni2+ ratio, time) for nickel removal via complexation-ultrafiltration.
- To evaluate the impact of complexing agents on membrane performance and nickel removal efficiency.
Main Methods:
- Complexation of nickel ions (Ni2+) with PAANa and PEI.
- Separation of nickel complexes using polyethersulfone (PES) ultrafiltration membranes at 0.1 MPa.
- Analysis of nickel removal rates, membrane flux, and complexation equilibrium constants (Langmuir isotherm).
- Systematic variation of solution pH and polymer/Ni2+ mass ratio.
Main Results:
- PAANa achieved the highest nickel removal rate (99.5%) at pH 8 and a PAANa/Ni2+ ratio of 5.
- PEI achieved a removal rate of 93.0% at pH 7 and a PEI/Ni2+ ratio of 5.
- Complexation equilibrium constants indicated pH 7 was optimal for the complex reaction.
- Membrane flux decline was less than 10% with PAANa over 12 hours, while PEI maintained constant flux.
- Nickel removal rates remained consistent throughout the ultrafiltration process for both agents.
Conclusions:
- Complexation-ultrafiltration is a highly effective method for removing nickel ions from aqueous solutions.
- PAANa and PEI demonstrate significant potential as complexing agents in this process.
- Optimized conditions, particularly pH and polymer/metal ratio, are crucial for maximizing nickel removal efficiency.
- The method shows good membrane stability, making it suitable for practical water treatment applications.
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