Affordable adsorbent for arsenic removal from rural water supply systems in Newfoundland

Shadbahr, Javid (2017) Affordable adsorbent for arsenic removal from rural water supply systems in Newfoundland. Masters thesis, Memorial University of Newfoundland.

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Abstract

Fly ash from the Corner Brook Pulp and Paper (CBPP) mill was used in this study as the raw material for preparation of a low-cost adsorbent for arsenic removal from the well water in the Bell Island. The CBPP was physically activated in two different ways: (a) activation with pure CO₂ (CAC) with the iodine number and methylene value of 704.53 mg/g and 292.32 mg/g, respectively; and (b) activation with the mixture of CO₂ and steam (CSAC) with the iodine number and methylene value of 1119.98 mg/g and 358.95 mg/g, respectively, at the optimized temperature of 850ºC and the contact time of 2 hours of activation. The surface area of CAC and CSAC, at the optimized conditions, was 847.26 m²/g and 1146.25 m²/g, respectively. The optimized CSAC was used for impregnation with iron (III) chloride (FeCl₃) with different concentrations (0.01M to 1M). The study showed that the adsorbent impregnated with 0.1M FeCl₃ was the most efficient one for arsenic removal. According to the scanning electron microscopy images and BET surface area analysis, it was revealed that the impregnation with 0.1M FeCl₃ would not significantly decrease the surface area and pore blockage was also negligible. Isotherm analysis showed that the Langmuir model better described the equilibrium behavior of the arsenic adsorption for both local well water and synthesized water than the other models. Based on this model, the maximum arsenic adsorption capacity was 35.6 μg/g of carbon for local well water and 1428.6 μg/g of carbon for synthesized water. Furthermore, the kinetic data of the arsenic adsorption from synthesized and local well water was best fitted with the pseudo-second order kinetic model.

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