Dicyandiamide-Modified Ultrahighly Cross-Linked Polystyrene Resin for Selective CL-20 Adsorption from Explosive Waste...

Area of Science:

• Chemical Engineering
• Materials Science
• Environmental Science

Background:

• Industrial production of hexanitrohexaazaisowurtzitane (CL-20), a high explosive, generates significant acidic waste.
• CL-20 in waste streams leads to resource loss and complicates recovery processes.

Purpose of the Study:

• To develop a method for the preferential adsorption and recovery of CL-20 from acidic waste liquids.
• To investigate the adsorption mechanism and capacity of a modified resin for CL-20.

Main Methods:

• Synthesis of a dicyandiamide-modified highly cross-linked resin.
• Adsorption experiments using real acidic waste liquids.
• Kinetic and thermodynamic analyses (pseudo-second-order kinetics, Langmuir isotherm).
• X-ray photoelectron spectroscopy (XPS) and molecular dynamics simulations.

Main Results:

• The modified resin demonstrated strong interactions with CL-20 via hydrogen bonding, electrostatic attraction, and N-N interactions.
• Maximum adsorption capacity reached 30.68 mg·g⁻¹ under strongly acidic conditions (pH = 0.17).
• Adsorption followed pseudo-second-order kinetics and Langmuir isotherm, indicating spontaneous and endothermic processes.
• Highly efficient desorption (up to 100%) was achieved using ethyl acetate.

Conclusions:

• The dicyandiamide-modified resin is effective for adsorbing CL-20 from acidic waste.
• The resin facilitates resource recovery, addressing environmental concerns in CL-20 production.
• The study highlights the potential of this material for industrial application in waste management and recycling.