Heavy metal adsorbent, water purification material, and method of manufacturing heavy metal adsorbent

A method of manufacturing a heavy metal adsorbent consisting of a zeolite with a median diameter on a volume basis of 10.0 μm or more and a pore volume measured in a pore volume calculation range of 10 nm to 1000 nm by a mercury intrusion method of 0.1000 cm3/g or less,

• which comprises:
• adding a silicon-containing compound X and an aluminum-containing compound Y to a zeolite seed crystal-containing slurry A at a temperature of 60° C. to 200° C. simultaneously or in any order,
• wherein
• the addition of X satisfies the following (1), and the addition of Y satisfies the following (2):
• (1) a total addition amount of X is an amount such that a silicon element amount in X is 3.5 or more times amount of a silicon element amount in the zeolite seed crystals on a molar basis, and
• an addition amount of X per hour is 5.00 mol or less based on the silicon element amount in X with respect to 1 mol amount of silicon elements in the zeolite seed crystals;
• and
• (2) a total addition amount of Y is an amount such that an aluminum element amount in Y is 3.5 or more times amount of an aluminum element amount in the zeolite seed crystals on a molar basis, and
• an addition amount of Y per hour is 5.00 mol or less based on the aluminum element amount in Y with respect to 1 mol amount of aluminum elements in the zeolite seed crystals.