Pervaporation Membrane System for the Removal of Ammonia from Water

Abstract

Regenerated cellulose and chitosan membranes were studied for the pervaporation separation of an aqueous solution of urine component (ammonia, uric acid or creatinine). The permeation rate of water increased with increase of the temperature of feed solution induced into the upstream side of membrane module. Uric acid, creatine and creatinine were not found in the permeate through the all membranes investigated. Selective permeation of water and ammonia depends on membrane. The removal of ammonia through the chitosan membrane was from 57% to 59%. Adsorption of ammonia from the downstream vapor by silica gels was carried out. And desorption of ammonia from the adsorbents by heating under the reduced pressure to regenerate the capacity of adsorption was also confirmed. In the case of new pervaporation system, the combination of pervaporation and adsorption/desorption process, ammonia was almost completely removed, and finally the pure condensed water was obtained in the cold trap.

A Pervaporation Study of Ammonia Solutions Using Molecular Sieve Silica Membranes

“…In this case, the membrane exhibited higher selectivity toward NH 3 (molecular size ~0.326 nm) at low temperatures (<100 °C), because of stronger competitive adsorption between silica and NH 3 over H 2 . Other studies have reported a novel two-step system [ 25 ] using a cellulose membrane pervaporation (PV) system to separate water and ammonia from urine, followed by a silica adsorption column to completely remove ammonia and recover pure water. In recent years, the application of molecular sieve silica membranes has been broadened to the water treatment industry [ 26 , 27 ].…”

Pervaporation of ammonia solution with γ-alumina supported organosilica membranes

“…However at the same time, there is a strong adsorption between silica and ammonia which competes against water if ammonia can enter the silica micropores. The competing size exclusion and adsorption between water and ammonia in silica-based microporous materials is already well-known, and has shown ammonia selectivity over hydrogen in gas phase due to the natural adsorption affinity in the tight pore spaces [9,28,29]. It is therefore viable, but still a new concept in membrane research for fabricating suitable membranes to separate ammonia from aqueous solution.…”