Batch and Fixed-Bed Column Studies on Palladium Recovery from Acidic Solution by Modified MgSiO₃

Area of Science:

• Materials Science
• Environmental Chemistry
• Chemical Engineering

Background:

• Palladium's extensive industrial use necessitates efficient recovery from waste streams.
• High production costs of palladium from natural resources drive the need for recycling.
• Acidic waste solutions pose challenges for conventional palladium recovery methods.

Purpose of the Study:

• To synthesize and characterize a new adsorbent, MgSiO3 functionalized with DL-cysteine (cys), for palladium ion recovery.
• To evaluate the adsorption capacity and mechanism of the MgSiO3-cys material in both static (batch) and dynamic (column) regimes.
• To determine the optimal models for describing palladium adsorption kinetics and equilibrium.

Main Methods:

• Material characterization using BET, BJH, SEM, EDX, and FTIR spectroscopy.
• Batch adsorption studies to determine maximum adsorption capacity and isotherm modeling (Langmuir, Freundlich, Sips).
• Dynamic adsorption studies in a fixed-bed column to evaluate recovery efficiency and model fitting (Bohart-Adams, Yoon-Nelson, Thomas, Clark).

Main Results:

• The synthesized MgSiO3-cys material was characterized, confirming its suitability for adsorption.
• Equilibrium adsorption capacities were 9.3 mg g⁻¹ in batch and 3 mg g⁻¹ in column mode.
• The Sips and Clark models best described the adsorption process in batch and column regimes, respectively.

Conclusions:

• MgSiO3 functionalized with DL-cysteine is a promising adsorbent for palladium ion recovery from acidic waste solutions.
• The Sips isotherm and Clark model provide the best fit for describing palladium adsorption in batch and dynamic systems, respectively.
• This research offers a viable method for palladium recovery, contributing to resource sustainability and waste management.