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Removal of lead from aqueous solution with native and chemically modified corncobs
Guangqun Tan1, Hongyan Yuan, Yong Liu
1College of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
Journal of Hazardous Materials
|October 30, 2009
Summary
Corncobs effectively remove lead (Pb(II)) from water. Base hydrolysis significantly enhances corncob adsorption capacity, while esterification reduces it, highlighting the role of specific functional groups in lead binding.
Area of Science:
- Environmental Science
- Materials Science
- Chemistry
Background:
- Lead (Pb(II)) contamination in aqueous solutions poses significant environmental and health risks.
- Developing cost-effective and sustainable adsorbents for heavy metal removal is crucial.
Purpose of the Study:
- To investigate the use of corncobs as a low-cost adsorbent for Pb(II) removal.
- To evaluate the impact of chemical modifications (base hydrolysis and esterification) on Pb(II) adsorption capacity.
- To elucidate the adsorption mechanism and identify key functional groups involved.
Main Methods:
- Corncob biomass was chemically modified using methanol and sodium hydroxide.
- Adsorption experiments were conducted varying pH, contact time, and initial Pb(II) concentration.
- Adsorption data were analyzed using Langmuir and Lagergren-second-order models.
- Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) were used for surface analysis.
Main Results:
- Pb(II) adsorption by corncobs is pH-dependent and follows pseudo-second-order kinetics.
- The maximum Pb(II) binding capacity (qmax) from Langmuir isotherm was 0.0783 mmol/g.
- Base hydrolysis increased the binding capacity to 0.2095 mmol/g (43.4 mg Pb/g), while esterification decreased it to 0.0381 mmol/g.
- FTIR and XPS analyses confirmed the involvement of hydroxyl and carboxylate groups in Pb(II) binding as Pb(2+) ions.
Conclusions:
- Corncobs are a viable biosorbent for Pb(II) removal from aqueous solutions.
- Base hydrolysis is an effective pretreatment to enhance the adsorption capacity of corncobs for lead.
- Surface functional groups, particularly hydroxyl and carboxylate, are critical for the adsorption mechanism.
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