Provided is a composition that may include an alkylamine modified graphene having a formula R[—CH2-alkylamine)]x, where R is a graphene core, [—CH2-alkylamine)] is an alkylamine functional group, and x is a non-zero integer. The alkylamine functional group may include [—CH2-n-propylamine)], [—CH2-n-hexylamine)], or [—CH2-n-dodecylamine)]. Trace amounts of an oxygen and nitrogen functional group may be coupled to the graphene core. Further provided is a method that may include introducing alkylamine modified graphene into a hydrocarbon-contaminated water. The method may further include separating a hydrocarbon-absorbed alkylamine modified graphene from the recovered water. Further provided is a system that may include a holding tank, a pump, a membrane housing, and a collection tank. The membrane housing may include membranes and a filtration media.