Environmental pollution occurs on a global scale as a result of various anthropogenic and natural events in recent decades. Particular interest has been given to metal ion pollution, seeing that they are persistent over time and very toxic, but at the same time non-biodegradable. Many functional materials are currently being developed for use in various areas. Macroporous hydrogels are prominent examples of such systems, their particular features including porosity, high elasticity, controlled swelling, fast stimuli responsiveness etc., being appropriate for pollutant removal, drug delivery, sensing or soft robotics [1-4]. In this work, the preparation of porous chitosan-based hydrogels stabilized by formaldehyde cross-linking under freezing conditions (-20 oC), in the absence or in the presence of thiourea as flexible spacer, is investigated. Optimization of synthetic conditions has been performed as a function of chitosan concentration, thiourea content in reaction mixture and molar ratio between amino groups and formaldehyde. The obtained hydrogels were characterized by scanning electron microscopy and FT-IR spectroscopy. The obtained hydrogels were tested as sorbents for the removal of Cu(II) and Pb(II) ions from simulated wastewater. The influence of pH, contact time and equilibrium concentration on the sorption process was studied. Experimental data was fitted with suitable kinetic and isotherm mathematical models.