Removal of Acetone Vapor from Air Using a Biotrickling Filter Packed with Polymeric Bioballs

Acetone released into the atmosphere can adversely affect human health and the environment. The aim of this work was to evaluate the performance of a laboratory-scale biotrickling filter (BTF) with bioball packing material to remove acetone vapor from contaminated air. The acetone removal efficiency was investigated in two different scenarios: with and without the inoculation of microorganisms. Three strains of bacteria, Pseudomonas putida, Rhodococcus aerolatus, and Aquaspirillum annulus, were used in the BTF. In both cases, the filter units were simultaneously operated for 100 days under three different inlet acetone concentrations (0.18 ± 0.01 g/m3, 0.25 ± 0.01 g/m3, and 0.40 ± 0.02 g/m3) and two different gas flow rates (2.54 and 5.09 m3/h). The results showed that acetone removal was greater in the filter with the inoculated bacteria. In the filter operated without inoculum, the acetone removal efficiency gradually decreased with filtration time from 90.1% to 6.1%. While employing three types of bacteria in the BTF, the efficiency of acetone removal remained relatively stable and varied between 70.2% and 97.6%. The study also revealed that bioballs can be successfully used as a packing material in air biofiltration systems designed for acetone removal from the air.

Acetone Bio-Sniffer (Gas-Phase Biosensor) for Monitoring of Human Volatile Using Enzymatic Reaction of Secondary Alcohol Dehydrogenase

We developed a highly sensitive acetone bio-sniffer (gas-phase biosensor) based on an enzyme reductive reaction to monitor breath acetone concentration. The acetone bio-sniffer device was constructed by attaching a flow-cell with nicotinamide adenine dinucleotide (NADH)-dependent secondary alcohol dehydrogenase (S-ADH) immobilized membrane onto a fiber-optic NADH measurement system. This system utilizes an ultraviolet light emitting diode as an excitation light source. Acetone vapor was measured as the fluorescence of NADH consumption by the enzymatic reaction of S-ADH. A phosphate buffer that contained oxidized NADH was circulated into the flow-cell to rinse the products and the excessive substrates from the optode; thus, the bio-sniffer enables the real-time monitoring of acetone vapor concentration. A photomultiplier tube detects the change in the fluorescence emitted from NADH. The relationship between the fluorescence intensity and acetone concentration was identified to be from 20 ppb to 5300 ppb. This encompasses the range of concentration of acetone vapor found in the breath of healthy people and of those suffering from disorders of carbohydrate metabolism. Then, the acetone bio-sniffer was used to monitor the exhaled breath acetone concentration change before and after a meal. When the sensing region was exposed to exhaled breath, the fluorescence intensity decreased and reached saturation immediately. Then, it returned to the initial state upon cessation of the exhaled breath flow. We anticipate its future use as a non-invasive analytical tool for the assessment of lipid metabolism in exercise, fasting and diabetes mellitus.

Polylactic Acid/Carbon Nanoparticle Composite Filaments for Sensing

Polylactic acid (PLA) is a bio-based, biodegradable polymer that presents high potential for biomedical and sensing applications. Ongoing works reported in the literature concern mainly applications based on 3D printing, while textile applications are hindered by the limited flexibility of PLA and its composite filaments. In the present work, PLA/multiwall carbon nanotube (MWCNT) composite filaments were produced with enhanced flexibility and electrical conductivity, which may be applied on a textile structure. A biodegradable plasticizer was incorporated in the nanocomposites, aiming at improving MWCNT dispersion and increasing the flexibility of the filaments. Filaments were produced with a range of compositions and their morphology was characterized as well as their thermal, thermomechanical, and electrical properties. Selected compositions were tested for sensing activity using saturated acetone vapor, demonstrating a suitable response and potential for the application in fabrics with sensing capacity.

A Novel Ceramic Sensing Material for Acetone Detection from Asphalt

A novel ceramic sensing material, orthorhombic molybdenum trioxide (a-MoO3) nanobelts, was successfully prepared through a simple hydrothermal strategy. And its crystalline phase and microstructures were characterized via X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). The results indicate that the size of the a-MoO3 nanobeltsis 180-250 nm in width and several microns in length. Gas sensing performances of the as-synthesized a-MoO3 nanobelts towards acetone vapor which was a representative VOCs in asphalt were investigated. The a-MoO3 nanobelts based gas sensor exhibits superior response at the optimum operating temperature of 300 °C for 200 ppm acetone vapor and excellent stability. The gas sensing mechanism for the a-MoO3 nanobelts to acetone vapor was also discussed.

Enhanced amperometric acetone sensing using electrospun non-stoichiometric WO3−x nanofibers

We report on a highly sensitive amperometric gas sensing device that employs electrospun tungsten oxide (WO3−x) nanofibers thus enabling trace levels (concentrations 1.2–12.5 ppm) of acetone vapor to be detected when operating at 350 °C.