i vs one

i and one both are nouns.

Word	Noun	Adjective	Verb	Adverb
i	Yes	Yes	No	No
one	Yes	Yes	No	No

As adjectives, i and one are synonyms defined as:

Other synonyms of i include 1, ane.

i (noun)	one (noun)
the 9th letter of the Roman alphabet	a single person or thing
	the smallest whole number or a numeral representing this number

i (adjective)	one (adjective)
used of a single unit or thing; not two or more	used of a single unit or thing; not two or more
	being a single entity made by combining separate components
	(informal) very; used informally as an intensifier
	eminent beyond or above comparison
	indefinite in time or position
	of the same kind or quality
	having the indivisible character of a unit