Grape waste as a biosorbent for removing Cr(VI) from aqueous solution

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Grape waste, a byproduct of winemaking, is rich in polyphenols and has a strong affinity for heavy metals.
• Cellulosic materials from agricultural waste present opportunities for developing novel adsorbents.
• Heavy metal contamination, particularly Cr(VI), poses significant environmental and health risks.

Purpose of the Study:

• To develop and characterize an adsorption gel from grape waste for Cr(VI) removal.
• To investigate the adsorption efficiency and selectivity of the grape waste gel for Cr(VI).
• To evaluate the potential of this bio-based adsorbent for wastewater treatment.

Main Methods:

• Grape waste was cross-linked using concentrated sulfuric acid to form an adsorption gel.
• Batch adsorption experiments were performed to study the effects of pH and contact time.
• Adsorption isotherms (Langmuir model) and the adsorption of various metal ions were analyzed.

Main Results:

• The grape waste gel demonstrated effective removal of Cr(VI) from synthetic aqueous solutions.
• Maximum adsorption capacity was 1.91 mol/kg at pH 4, following Langmuir adsorption behavior.
• The gel exhibited selective adsorption of Cr(VI) over other tested metal ions (Cr(III), Fe(III), Zn(II), Cd(II), Pb(II)).

Conclusions:

• Cross-linked grape waste gel is a viable and effective adsorbent for Cr(VI) removal.
• The material's selectivity offers advantages for treating complex contaminated water.
• Utilizing agricultural waste for heavy metal remediation presents a sustainable environmental solution.