Answer:
He planned to send them to the island as punishment for their crimes
Step-by-step explanation:
Mustapha Mond, the controller of the World State planned to banish both Helmholtz and Marx to the island - a place reserved for people who do not fit into the ideals of the World State.
Helmholtz was indifferent about his the sentence and actually chose the island he would like to be banished to. He chose the Falkland island where he said he would go and do some writing.
Marx on the other hand, pleaded against his banishment, prostrating on the floor in an effort to get Mond to change his mind. He was clearly still attached to the World State.
Mustapha Mond actually called their banishment a reward because on the island they would meet like-minded individuals selves who did not fit into what the World state believes and holds on to.