Engineering sustainable adsorption processes: batch vs. fixed-bed systems for pollutant removal.

Area of Science:

• Environmental Chemistry
• Chemical Engineering
• Materials Science

Background:

• Adsorption is crucial for pollutant removal, but selecting between batch and fixed-bed processes is complex.
• Optimizing adsorbent consumption while ensuring efficient removal is a key challenge in water treatment.

Purpose of the Study:

• To develop a practical framework for choosing between batch and fixed-bed adsorption processes.
• To introduce metrics for evaluating and comparing the efficiency of different adsorption systems.
• To minimize adsorbent usage in pollutant removal applications.

Main Methods:

• Introduced an experimental efficacy factor (rₑₓₚ) comparing batch (q_b) and fixed-bed (q_fb) adsorption capacities.
• Derived a theoretical efficacy factor (rₜₕₑₒ) using the Langmuir model for validation.
• Assessed performance using final critical concentration (C_fc) against a 5.0 mg/L threshold.
• Validated the model with data from 31 diverse adsorbents.

Main Results:

• The experimental and theoretical efficacy factors showed close agreement, validating the assessment approach.
• Tested adsorbents, including activated carbon and bioadsorbents, exhibited high dye uptake capacities.
• Polymeric resin demonstrated superior performance in both batch (1076.0 mg/g) and fixed-bed (917.0 mg/g) modes.
• Batch processes frequently showed lower C_fc values, indicating more efficient pollutant removal and adsorbent utilization.

Conclusions:

• The proposed framework effectively aids in selecting the most suitable adsorption process (batch or fixed-bed).
• The batch process offers advantages in pollutant removal efficiency and adsorbent minimization, particularly for costly synthetic adsorbents.
• This research supports informed decision-making for optimizing adsorption-based environmental remediation strategies.