It is very important to develop a cost-effective and environmentally friendly adsorbent for the efficient removal of indoor formaldehyde (HCHO). Herein we present the modified montmorillonite as adsorbents for HCHO. A series of alumina cross-linked montmorillonite with surfactant modification (Al-SCLM) were synthesized in the presence of polyvinyl alcohol (PVA). These adsorbents are safe and cheap, in rich sources, acceptable appearance for daily use. By the characterization such as XRD, FTIR, HCHO adsorption/desorption capacity measurement, it is found that the interlayer environment is a key factor for the superior adsorption capacity of the modified montmorillonite. The introduction of surfactant molecules is very favorable for the improvement of the montmorillonite's adsorption capacity. With optimization, the adsorbing capacity of HCHO over Al-SCLM is obviously superior to conventional inorgano-montmorillonite and organo-montmorillonite, and can be over 80% of that over activated carbon with the same volume. We can conveniently recover the adsorbents by heating them to 353 K. The strategy that improving the adsorbing capacity by increasing the interlayer distance of materials with surfactant modification will be crucial for developing highly effective adsorbents for hazardous wastes, and has a good prospect for getting rid of HCHO in industrialization. (C) 2015 Elsevier B.V. All rights reserved.