Membrane-based separations are the most ubiquitous unit operations in biotech processes. There are several key reasons for this. First, they can be used with a large variety of applications including clarification, concentration, buffer exchange, purification, and sterilization. Second, they are available in a variety of formats, such as depth filtration, ultrafiltration, diafiltration, nanofiltration, reverse osmosis, and microfiltration. Third, they are simple to operate and are generally robust toward normal variations in feed material and operating parameters. Fourth, membrane-based separations typically require lower capital cost when compared to other processing options. As a result of these advantages, a typical biotech process has anywhere from 10 to 20 membrane-based separation steps. In this article we review the major developments that have occurred on this topic with a focus on developments in the last 5 years.

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This work describes a platform technology being developed with the integration of low-power, miniature sensors with wireless technology to enable independent living by enhancing health and environmental monitoring and communication with healthcare providers for seniors, allowing them to lead a high quality life while maintaining their independence. The technology can help improve safety, productivity, and social integration along with reduced senior care costs associated with assisted living centers and hospitals.

The authors describe a technique that utilizes the fast heating rates (106K∕s) of a microhotplate sensor along with a calibrated thermal desorption system to determine the initial coverage and kinetic parameters using isothermal desorption on a millisecond time scale. Models for isothermal desorption including both pumping and desorption rate effects are presented for zero, first, and second order kinetics. Analysis of the first order model illustrates the domain of the desorption, pumping speed, and heating rate time constants that permit the desorption parameters to be estimated from the mass spectrometer signal. The technique is demonstrated using isothermal temperature programed desorption of benzoic acid from a single SnO2 covered microhotplate at surface temperatures ranging from 296to347K. The data indicate that desorption is best represented by first order kinetics. The first order preexponential factor and the desorption energy in the zero coverage limit are determined to be 1×1017s−1 and 97kJ∕mol, respectively, from desorption of 108molecules which corresponds to an initial coverage of 1012cm−2 (⩽0.005 ML).