Removal of Cr(VI) from aqueous solution using ball mill modified biochar: multivariate modeling, optimization and...

Area of Science:

• Environmental Science
• Materials Science
• Water Treatment

Background:

• Hexavalent chromium (Cr(VI)) poses significant environmental and health risks due to its toxicity and carcinogenicity.
• Conventional chemical modification of biochar for Cr(VI) removal is often complex, costly, and can cause secondary pollution.
• There is a critical need for environmentally friendly, cost-effective, and simple methods to produce modified biochar for water treatment.

Purpose of the Study:

• To develop a novel, simply processed modified biochar for efficient Cr(VI) removal from aqueous solutions.
• To investigate the adsorption characteristics and removal mechanisms of ball-milled wheat straw biochar (BM-WB) for Cr(VI).
• To optimize adsorption conditions and evaluate the practical application potential of BM-WB in water remediation.

Main Methods:

• Wheat straw biochar was modified using a simple ball milling technique to produce BM-WB.
• Characterization of functional groups, specific surface area, and particle size of BM-WB was performed.
• Adsorption experiments were conducted to analyze Cr(VI) removal kinetics, isotherms, and the influence of pH, temperature, and dosage, employing response surface methodology.

Main Results:

• Ball milling significantly reduced particle size, increased surface area, and enhanced oxygen-containing functional groups on biochar.
• BM-WB exhibited a 3.5-9.1 times increase in Cr(VI) adsorption capacity, reaching up to 52.21 mg/g.
• Optimal removal of 100% Cr(VI) was achieved at pH 2, 45°C, and 0.1 g adsorbent dosage, following pseudo-second-order kinetics and Langmuir isotherm models.

Conclusions:

• Ball-milled wheat straw biochar (BM-WB) is a highly efficient, cost-effective, and environmentally friendly adsorbent for Cr(VI) removal.
• The adsorption mechanism involves electrostatic attraction, redox reactions, and complexation.
• BM-WB demonstrates significant potential for the remediation of Cr(VI) pollution in water treatment applications.