Micro-Hole Membrane for Solid-Liquid Separation of Micron-Scale Particulate

Low pressure filtration and dewatering techniques for solid-liquid separation (SLS) of particulate material from dilute streams are of great importance in reducing the cost and energy consumption of processing materials in wide variety of food, water, pharmaceutical and energy related industries. SLS techniques can reduce energy consumption of these processes by over 90%. However, with current filtration membranes, the efficiency of the process drops greatly as pore size is reduced in an effort to retain high value, micron-scale particulate. In this SBIR project, MLPC will develop a membrane with closely spaced microholes appropriate for low energy SLS of hydrophilic compounds in dilute aqueous streams. The goal is to create a thin, inert, economical sheet material with micro-holes that provide at least 20% open area for water flow (compare to 5% for commercial weaves with 6 micron pores), while maintaining sufficient tensile strength and resistance to elongation for operation as an SLS belt. The microhole membrane will greatly increase the rate of water removal by the low pressure SLS process while maintaining a high retention of particulates on the order of 5 microns. In Phase I, specimens of thin sheet materials with microhole patterns will be produced by rapid laser hole drilling. These will then be tested for tensile strength and SLS performance such as water removal rate, particulate capture efficiency. Best embodiments will be selected and estimates of the production times and costs will be developed to support a go/no go decision for developing much larger belt membranes for industrial use. Phase II will then focus on fabrication and demonstration of a subscale prototype beltin a relevant SLS environment, along with design and specification of a laser workstation to economically produce arbitrary lengths of microhole membrane. The micro-hole membrane will enable higher rate, lower cost processing of a variety of bio-based products. Initial application will be to algae separation for biofuel, but other the technology will also apply to separation of corn solids in ethanol production, wastewater remediation, pharmaceutical separations and food and beverage processing