The development of the OH- sieving membranes is of extraordinary importance but challenging for treating alkaline effluents. Here, we propose the ionization engineering concept of two-dimensional (2D) laminated membranes to pursue promising OH- separation. This concept is exemplified via stacking the self-designed sulfonated graphene oxide (SGO) nanosheets to fabricate 2D membranes. The SGO membranes achieve synergetic improvements of OH- dialysis coefficients and separation factors towards the simulated NaOH/Na2WO4 alkaline wastewater in sharp contrast to the 2D GO membranes and the commonly adopted polymeric cation exchange membranes. Besides, the separation factor of the SGO membranes is far higher than most the existing alkali recovery membranes. The molecular dynamics simulation results hint the high-efficiency OH- separation originates from the 2D SGO confined channels, where the dehydration effects and intensified electrostatic repulsion jointly play critical roles. This study offers an alternative strategy to achieve fast OH- sieving by ionizing 2D confined channels.