Iron (Fe) (oxyhydr)oxide minerals, which are amongst most reactive minerals in soils and sediments, are known to exhibit strong adsorption of inorganic phosphate (P-i) and organophosphate (P-o) compounds. Beyond synthetic Po compounds, much still remains unknown about the reactivity of these minerals to transform naturally-occurring P. compounds to Pi, particularly with respect to solution versus surface speciation of P-o hydrolysis. To investigate this reactivity with a ferrihydrite-type mineral and ribonu-cleotides, we employed high-resolution liquid chromatography-mass spectrometry (LC-MS), X-ray absorption near-edge structure (XANES), Fourier-transform infrared (FTIR) spectroscopy, and molecular modeling. Kinetic experiments were conducted with the mineral (1 g L-1) reacted with adenosine monophosphate, diphosphate, or triphosphate (respectively AMP, ADP, ATP; 50 mu M). Analysis of solution organic species by LC-MS implied that only adsorption occurred with AMP and ADP but both adsorption and dephosphorylation of ATP were evident. Maximum adsorption capacities per gram of mineral were 40.6 +/- 0.8 mu mol AMP, 35.7 +/- 1.6 mu mol ADP, and 10.9 +/- 1.0 mu mol ATP; solution dephosphorylated by-products accounted for 15% of initial ATP. Subsequent XANES analysis of the surface species revealed that 16% of adsorbed AMP and 30% of adsorbed ATP were subjected to dephosphorylation, which was not fully quantifiable from the solution measurements. Molecular simulations predicted that ADP and ATP were complexed mainly via the phosphate groups whereas AMP binding also involved multiple hydrogen bonds with the adenosine moiety; our FTIR data confirmed these binding confirmations. Our findings thus imply that specific adsorption mechanisms dictate the recycling and subsequent trapping of Pi from ribonucleotide-like biomolecules reacted with Fe (oxyhydr)oxide minerals. (C) 2019 Elsevier Inc. All rights reserved.