Ion Imprinted Polymer for Removal and Monitoring of Arsenic

The threat of arsenic pollution in drinking water is a serious environmental and health concern because of the toxicity of arsenic on human and on other living organisms. In drinking water supplies, arsenic is usually naturally occurring although some pesticides and preservatives also contain arsenic. The US EPA recently lowered the maximum containment level (MCL) for arsenic to 10 µg/L (10 ppb) from 50 µg/L (50 ppb) in drinking water. This new MCL has created an urgent need of low capital and technology intensive arsenic removal and sensing in water, more particularly in small utilities and rural communities. Different technologies have been developed to remove arsenic from both water and wastewater. These technologies include the conventional processes of oxidation, co-precipitation and adsorption onto coagulated flocs, adsorption onto sorptive media, ion exchange, and membrane filtration. At pH 6-9, arsenic occurs in pentavalent form [As(v)] and, thus, this form of arsenic is more easily removed from water than trivalent arsenic [As(III)] by the conventional processes (e.g., ion exchange, reverse osmosis and electron diffraction). However, As(III) is the predominant form normally found in groundwater, and due to its weak dissociation constant, As(III) cannot be removed by the conventional processes. The present research proposes a method for treatment of arsenic which is based on the emerging ion imprinting technology that will have the ability to remove both As(III) and As(V) very efficiently without any pre-treatment. Again to date, arsenic in the environment is measured with spectroscopic techniques, including atomic fluorescence spectroscopy (AFS), graphite furnace atomic absorption spectroscopy (GFAAS), hydride generation atomic absorption spectroscopy (HGAAS), inductively coupled plasma-atomic emission spectrometry (ICP-AES), and inductively coupled plasma-mass spectrometry (ICP-MS). These techniques are well established but require samples to be collected and transported to a centralized laboratory for analysis because the equipment is bulky, expensive, and requires significant operator expertise. These techniques are time intensive and the sample handling procedure may introduce errors. In-situ and ex-situ measurements using simple hand-held instrument are highly desirable because they can provide quick detections of arsenic while minimizing errors, labor, and cost associated with the spectroscopic methods. Such a method has become even more relevant with the US EPA is new MCL of 10 µg/L, more particularly for small and rural utilities. This project proposes ion imprinted polymer based potentiometric sensor to measure As(III) and As(V) in environmental samples.