A simple procedure has been developed for the conversion of non-magnetic powder materials into their magnetic derivatives, which is based on the mixing of the material to be modified with water based magnetic fluid. After drying, aggregates of maghemite were deposited on the treated material, enabling its magnetic separation. In this paper we provide two examples of low-cost non-magnetic materials suitable for this type of simple one-step magnetic modification. Magnetically modified spent tea leaves efficiently adsorbed organic dyes; high maximum adsorption capacity (up to 100 mg g(-1)) was achieved. Magnetic montmorillonite was used as a carrier for the immobilization of lipase and beta-galactosidase; immobilized enzymes showed long-term stability without leaching of enzyme from the support and enabled their repeated use without significant loss of activity. (C) 2012 Elsevier B.V. All rights reserved.