A novel carboxymethylcellulose-g-poly(acrylamide)/montmorillonite (CMC-g-PAM/MMT) hybrid adsorbent with sufficient interconnected pores was prepared viathe Pickering medium internal phase emulsions (MIPEs) polymerization using eco-friendly inolenic acid oil (IAO) as the disperse phase and MMT as the stabilized particles. The effects of the dosages of MMT and Pluronic F68 on the pore structures were studied. It was found that the well-defined pore structure was obtained when the amounts of MMT and Pluronic F68 were 2% and 6%, respectively. The FTIR spectra analysis showed that MMT participates in the polymerization reaction. The porous adsorbent can rapidly reach adsorption equilibrium within 30 min, with the maximum adsorption capacities of 177.90 mg/g for Rb⁺ and 265.93 mg/g for Cs⁺. The fitting results confirmed that chemisorptions play a crutial role in the adsorption process, and the complexation of COO⁻ and Rb⁺ or Cs⁺ was the main driving force for adsorption. Cyclic adsorption experiment results in static and fixed bed column show that the porous adsorbent can be recycled for the adsorption of Rb⁺ and Cs⁺ions. The new porous adsorbent has the potential for rapid adsorption and removal of metal ions such as radioactive Rb⁺and Cs⁺.