Chromium removal from aqueous solution using bimetallic Bi⁰/Cu⁰-based nanocomposite biochar

Area of Science:

• Environmental Science
• Materials Science
• Nanotechnology

Background:

• Chromium contamination in aquifers poses significant environmental and toxicological risks.
• Developing efficient adsorbents for chromium removal is crucial for water purification.

Purpose of the Study:

• To synthesize and characterize novel nano-biocomposites using almond shells biochar (BC) integrated with zerovalent bismuth (Bi⁰) and/or copper (Cu⁰).
• To evaluate the efficacy of these nanocomposites (Bi⁰/BC, Cu⁰/BC, and Bi⁰-Cu⁰/BC) in removing chromium (Cr) from aqueous solutions.

Main Methods:

• Nanocomposites were synthesized and characterized using XRD, FTIR, SEM, and EDX.
• Adsorption experiments were conducted varying Cr concentration, adsorbent dose, pH, and contact time.
• Adsorption data were analyzed using Freundlich isotherm and pseudo-second-order kinetic models.

Main Results:

• Characterization confirmed the successful formation of Bi⁰/Cu⁰ integrated with BC.
• The Bi⁰-Cu⁰/BC nanocomposite achieved the highest Cr removal efficiency (92%), outperforming Cu⁰/BC (85%), Bi⁰/BC (76%), and BC (67%).
• Optimal removal occurred at low Cr concentrations (25 mg/L) and acidic pH (4.0), with Cr(VI) adsorption favored at low pH and Cr(III) at high pH.

Conclusions:

• The synthesized Bi⁰-Cu⁰/BC nano-biocomposite exhibits excellent Cr removal potential and stability.
• This material offers a sustainable and effective solution for removing chromium from contaminated water sources.
• The adsorption process follows Freundlich isotherm and pseudo-second-order kinetics, indicating chemisorption mechanisms.