Numerous low-cost adsorbents have been used for removal of harmful azo colorants from aqueous environment, but they frequently suffer from either low/limited adsorption capacity or slow adsorption kinetics; moreover, almost all of them become problematic on the regard of recycling and reuse. This research explores the possibility of using a novel low-cost biocomposite, i.e., magnetized chitosan-coated lignocellulose fiber, for biosorptive removal of acidic azo colorant from aqueous solution. This chitosan-decorated lignocellulose fiber (CS/LCF) was prepared for the first time via a facile "surface deposition-crosslinking' method, exhibiting a well-defined coating structure. Interestingly, the CS/LCF could be easily magnetized by simply blending it with magnetic nanopartide (MNP) in an aqueous solution because of the spontaneous adherence of MNP to CS/LCF surface. More importantly, the magnetized CS/LCF was found to be exceptionally effective and efficient in biosorptive removal of acidic azo compound (i.e., acid red 18), e.g., ultrahigh adsorption capacity (up to 1184 mg g(-1)), rapid adsorption rate, excellent reusability (with removal efficiency up to 99.48% in tenth cycle), and convenience in manipulation (magnetic separation). The inherent advantages of the magnetically retrievable CS/LCF may pave a new, inexpensive, efficient, and sustainable way towards removal of acidic azo colorants from Earth's water environments. (C) 2016 Elsevier B.V. All tights reserved.