Removal of Fluoride Ions in Stored Drinking Water by Triethylamine Chemically Modified Polyethylene Containers

This paper reports the removal of fluoride ions in stored drinking water by a container made from chemically modified polyethylene material. To anchor triethylamine within the structure of the polyethylene material and improve its value, the polyethylene was first heated to melting. To the molten material, hot vegetable oil was added slowly with continuous heating followed by a strongly basic hydrogen peroxide solution and then activated with triethylamine to produce a water-insoluble material that is not a threat to life. The resulting synthesized products were characterized using FTIR and C-13 NMR after each step. The triethylamine-activated epoxy material was molded into a 1l container which was cured for 3h in an electric oven at 150 degrees C to form a hard mechanically strong container. It was then used for water storage and removal of dissolved fluoride ions. Its ability to remove fluoride ions was based on complexation reaction between the fluoride ions and quaternary ammonium compounds. The results obtained showed that sorption was best at pH values between 6.0 and 8.0. It was observed that a 40% removal efficiency was achieved from a solution containing 12.5mgl(-1) of fluoride ions in less than 7days of storage at the physiological pH of water. The existence of sulfate and nitrate ions had no observed significant effect on the fluoride removal process. However, chloride ions affected the removal of the fluoride ions and were therefore used to regenerate the container for reuse. The modification process is a sustainable method to manage the polyethylene pollution menace. This study revealed that the container has a potential application for the remediation of fluoride-laden waters in the rural areas during the water storage process to make it safe for domestic consumption. Article HighlightsTriethylamine chemically modified polyethylene containers have shown to have the potential of removing fluoride ions from the stored water.A 40% removal efficiency was achieved from a solution containing 12.5 mgl(-1) of fluoride ions in less than 7days.The removal mechanism was chemisorption.