Copper Ion Removal by Adsorption Using Fly Ash-Based Geopolymers: Process Optimization Insights from Taguchi and...

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Fly ash, a byproduct of coal combustion, presents an environmental challenge.
• Geopolymer materials synthesized from fly ash offer a sustainable solution for wastewater treatment.
• Copper ions in aqueous solutions pose significant environmental and health risks.

Purpose of the Study:

• To investigate the efficacy of geopolymer adsorbents derived from various fly ashes for copper ion removal.
• To optimize the adsorption process parameters using statistical methods.
• To characterize the fly ash and geopolymer adsorbents.

Main Methods:

• Characterization using energy-dispersive X-ray spectroscopy (EDS), Brunauer-Emmett-Teller (BET) analysis, and Scanning Electron Microscopy (SEM).
• Application of Taguchi and Analysis of Variance (ANOVA) methods to determine optimal working parameters.
• Experimental validation of copper ion removal under optimal conditions.

Main Results:

• The type of adsorbent was the most significant factor influencing copper ion removal, followed by solution pH, reaction time, adsorbent dose, and initial copper ion concentration.
• Optimal adsorption conditions were identified: fly ash C activated with 2 M NaOH at 70°C, pH 5, 300 mg/L initial copper concentration, 40 g/L adsorbent dose, and 120 min reaction time.
• Experimental results under optimal conditions demonstrated a high copper ion removal efficiency of 99.71%.

Conclusions:

• Geopolymer materials synthesized from fly ash are highly effective adsorbents for removing copper ions from aqueous solutions.
• The Taguchi and ANOVA methods successfully identified optimal parameters for the adsorption process.
• This study demonstrates a sustainable and efficient method for copper ion remediation using waste-derived geopolymer materials.