Trace ammonium removal by liquid–liquid membrane contactors as water polishing step of water electrolysis for hydrogen production from a wastewater treatment plant effluent

Abstract

© 2016 Society of Chemical Industry. BACKGROUND: This work evaluates hollow fiber liquid-liquid membrane contactors (HFMC) as a polishing step for the removal of low levels of ammonium from water purified by (or being supplied to) a membrane distillation unit in order to fulfil the conductivity requirements of hydrogen production by water electrolysis. RESULTS: The influence of the operating conditions (flow, pH, ammonium concentration, buffer capacity) were evaluated under a closed-loop setup in order to achieve a reduction of total ammonia concentration in water, from 15 to 1mgL-1 to assure the production of water in the membrane distillation with a conductivity lower than 1 µS cm-1. These values were used to validate a numerical algorithm describing the system performance. In order to reach the ammonia concentration requirements and considering the low concentration of bicarbonate (low pH buffer capacity) in the treated water a buffer agent was added to the working solution. CONCLUSIONS: HFMC technology is a suitable solution to remove low levels of ammonium from water to values as low as 1mgL- 1NH3 through appropriate control of pH. The ammonium removal efficiency of the HFMC was improved by raising the pH or the flow rate. Finally, the model proposed provides a good description of the membrane contactor performance with minimal deviations when compared with experimental results.Peer ReviewedPostprint (published version

Testing and Evaluation Performance of Borosilicate Glasses for Ammonia, Nitrate, and Total Nitrogen Removal from Industrial Wastewater

“…pH value was controlled after preparing solution samples by adding 0.1M NaOH or 0.1M HCl solution. The results of experimental work are illustrated in Figure (5). The best ammonia (NH3 + ) removal efficiency achieved at pH value of 8.9, as it observed in Figure (5a).…”

“…The non-homogeneous nature of the adsorbent surface is supported by Freundlich theory Equation (5). The underlying premise of the theory is that the adsorption sites on an adsorbent surface have various adsorption energies.…”

“…Most is used for fertilizer and agriculture while the remaining is used for other purposes including industrial processes and explosives [3], [4]. 40-50% of the total nitrogen (TN) in wastewater is converted to ammonia [5], [6]. Since there is too much ammonia in water streams, there is significant global pollution of drinking water.…”