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Solid leather wastes as adsorbents for cationic and anionic dye removal
Nadini S Carvalho Pinheiro1, Oscar W Perez-Lopez2, Mariliz Gutterres1
1Laboratory for Leather and Environmental Studies - LACOURO, Chemical Engineering Department, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.
Environmental Technology
|September 17, 2020
Summary
Leather shavings effectively remove anionic and cationic dyes from wastewater. Vegetable-tanned leather shavings excelled at removing cationic dyes, while wet-white and pickled shavings efficiently removed anionic dyes.
Area of Science:
- Environmental Science
- Materials Science
- Chemical Engineering
Background:
- Leather industry generates substantial solid waste, including various types of leather shavings.
- Wastewater contamination by anionic and cationic dyes poses significant environmental challenges.
- Developing cost-effective and sustainable adsorbents for dye removal is crucial.
Purpose of the Study:
- To investigate the efficacy of different leather shavings (wet-blue, vegetable-tanned, pickled, wet-white) as adsorbents for removing anionic (Acid Brown 414) and cationic (Basic Red 2) dyes from aqueous solutions.
- To characterize the leather shavings, including point of zero charge, functional groups, shrinkage temperature, and surface area, to understand their adsorption properties.
- To evaluate the influence of tanning agents on the adsorption performance of the leather shavings.
Main Methods:
- Characterization of leather shavings: point of zero charge, functional groups, shrinkage temperature, and specific surface area.
- Adsorption experiments using Basic Red 2 (cationic dye) and Acid Brown 414 (anionic dye).
- Optimization of adsorption parameters including contact time and adsorbent mass for anionic dye removal.
Main Results:
- Vegetable-tanned leather shavings demonstrated high removal efficiency (96.7%) for the cationic dye Basic Red 2.
- Wet-white and pickled leather shavings exhibited excellent removal rates (above 96%) for the anionic dye Acid Brown 414 within 30 minutes.
- Optimized conditions using 20 mg of adsorbent achieved over 97% removal for Acid Brown 414 with wet-white and pickled shavings.
Conclusions:
- Leather shavings, particularly vegetable-tanned, wet-white, and pickled types, show significant potential as low-cost, sustainable adsorbents for dye removal from industrial wastewater.
- The type of tanning process influences the adsorption capacity of leather shavings for different dye types.
- This study highlights a promising application for leather industry waste, contributing to a circular economy and effective wastewater treatment.
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