You would have to start a fire and boil the water
Simple. Let the water heat in the light of the sun. It's a desert island.
The tap water has chlorine in it, so if chlorine cleans water it can clean things as well as water.
A desert island is uninhabitable, principally because there is no source of potable (fresh) water. No one lives on a desert island, so there are no homes.
To survive on a desert island, you could eatCoconuts (Also drink the milk)Fish/crabs/shrimpsFruitMeat- Bears etcWhat ever you do, don't drink sea water find clean water
A desert island is not specific to any climate; however it is unlikely that a desert island would have a desert climate... because it's an island; a chunk of land in the middle of water. The desert in desert island means that no-one lives there... it's deserted. Islands in the Arctic and Antarctica could be considered deserts, but one usually connotes desert islands as having tropical climates.
A small body if fresh water in the middle of the desert is known as an oasis.
Sand, rock, soil, water, air - are all nonliving things found in a desert.
That is not part of the island quest.
*food *water
They can't, it's much too big to do anything with. But the way to reclaim desert is to cultivate it, grow things on it, but that needs water, and the desert is there because there is no water.
They made crops on the water and they made aquaducts to bring clean water.
They made crops on the water and they made aquaducts to bring clean water.