ABSORBENT PARTICLES

An adsorbent which is made of iron oxyhydroxide and which has higher adsorption rate and adsorption efficiency than hitherto is provided. The adsorbent particle of the present invention comprises iron oxyhydroxide as a main component, wherein 90% or more of the volume of the particle is constituted of a granular crystal having a crystal grain size of 20 nm or less or a columnar crystal having a width of 10 nm or less and a length of 30 nm or less and the particle has a BET specific surface area of 250 m 2 /g or more. The above adsorbent particle is produced by a method comprising a step of generating iron oxyhydroxide by adding a base represented by YOH (wherein Y represents a monovalent atom or atomic group) to a solution comprising at least one selected from trivalent iron compounds represented by FeX 3 (wherein X represents a monovalent atom or atomic group other than OH) while adjusting the pH to pH 3 to 6, wherein the solution has a total concentration of FeX 3 , YOH and other electrolytes of 10% by mass or more at the completion of the step.