Final Report: Nano Alumina Arsenic FilterEPA Contract Number: 68D02087
Title: Nano Alumina Arsenic Filter
Investigators: Tepper, Frederick
Small Business: Argonide Corporation
EPA Contact: Manager, SBIR Program
Project Period: October 1, 2002 through July 31, 2003
Project Amount: $99,923
RFA: Small Business Innovation Research (SBIR) - Phase I (2002) RFA Text | Recipients Lists
Research Category: Nanotechnology , Water and Watersheds , SBIR - Water and Wastewater , SBIR - Nanotechnology , Small Business Innovation Research (SBIR)
Argonide Corporation has developed filter media constructed of nano alumina (NanoCeram®) that is capable of retaining viruses and other pathogens. This research project was aimed at optimizing NanoCeram® to produce an improved arsenic sorbent for the purposes of a point-of-use (POU) filter. The objective is a commercially viable POU cartridge filter with the capability to remove the two predominant forms of arsenic (III and V) to below 10 ppb, when challenged by water that might contain contaminants or pH (acidity/basicity) that might occur in water sources.
The nano alumina fibers were found to have an arsenic absorption capacity substantially above that of activated alumina. Its capacity for arsenic was improved by formulating an iron-containing version, called Alfox™. Several compositional variations were evaluated, and one was chosen for more intensive study. Two different forms of filter media also were evaluated—a nonwoven fibrous media as well as a granular form. The granular version, which is a composite of nano alumina fibers and nano-sized iron compound, has a much higher density, and yet is capable of effective filtration when challenged by arsenic III and V solutions at flow rates typical of that in a POU. The preferred Alfox™ composition also was benchmarked versus competitive arsenic sorbents by challenging them with As III and V at a pH of 6.5 and 8.5 as well as at concentrations of 50 and 300 ppb arsenic. A model was developed that fits experimental data and describes the life of an Alfox™ sorbent bed as a function of challenge concentration and flow.
This project compared Alfox™ with competitive sorbents as they might be used in a POU filter as well as in a municipal water treatment plant. Alfox™ was found to have a dynamic capacity of up to four times that of competitive arsenic sorbents. The Alfox™ particle also was found to be more resistant to attrition under dynamic flow, minimizing the build up of pressure drop during service. It is projected that a conventional POU cartridge 2.75 inches in diameter and 12 inches in length can contain sorbent in excess of that to meet a 2,000 gallon ETV test, while still having capacity for adding components such as a biological (including virus) filter or activated carbon for chlorine removal.