A variety of compositions and materials are provided for water purification and remediation. The compositions including multiple functionalities for treating a variety of pollutants or contaminants. The compositions can include a porous organic polymer with one or more of a variety of functional groups for binding the contaminants and with a hierarchical pore size distribution over a range of pore sizes to facilitate enhanced removal of the contaminants. Functional groups can include one, two, or more different functional groups such as amines, halides, ammoniums, pyridiuiums, thiols, imidazoliums, salts thereof, or others. The range of pore sizes can be about 1 nm to 10 nm or more. Contaminants can include antimony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, mercury, selenium, technetium, thallium, uranium, radium, urea, and phosphate. Methods of removing the contaminants from water using the compositions are also provided.Energy & Environment