Methanol Vapor Research Articles

False Positive Results of Phosphatidylethanol (PEth) Quantitation in Dried Blood Spots (DBS): The Influence of Alcohol Vapors

The role of phosphatidylethanol (PEth) as an alcohol consumption marker is increasing in clinical and forensic medicine. During the COVID-19 pandemic, the role of hygiene increased, and it became common practice to use disinfectants almost everywhere. This paper highlights a possible source of false positive results (by the vapors of alcohols during the blood spot drying process) in dried blood spots (DBS) by LC-MS/MS quantitation of PEth. To achieve this, the PEth quantitation method was validated according to FDA guidelines. Additionally, the synthesis of phosphatidyl derivatives by phospholipase D (PLD) in the presence of methanol and 2-propanol vapors during the DBS process was determined. Each PEth-negative sample from a healthy male patient incubated in the presence of ethanol vapor becomes PEth-positive. After 4 h of DBS drying, teetotalers become “moderate drinkers”. It is necessary to avoid using alcohol-containing disinfectants in treatment rooms, where DBS is sampled.

Electrospun PVC-nickel phthalocyanine composite nanofiber based conductometric methanol microsensor

A conductometric microsensor for measuring methanol vapor was conceived, based on electrospun composite nanofibers of polyvinyl chloride (PVC) doped with nickel phthalocyanine (NiPc) deposited on interdigitated electrodes (IDEs) as transducers. The nanofiber’s shape, structure, percent atomic content and thermal properties were studied. The methanol sensor showed good sensitivity (505µS.cm−1.(v/v)−1), low limit of detection (LOD = 15 ppm), short response time (13 s), and short recovery time (25 s). The sensor was 4 times more sensitive to methanol than to ethanol and 19 times more sensitive to methanol than to acetone. Furthermore, the sensor response was unaffected by the interfering water vapor, making it more suitable for volatile organic compound (VOC) sensing in the presence of humidity. The sensor was applied for conductometric detection of methanol in rubbing alcohol.

Optically Clear Silk Fibroin Films with Tunable Properties for Potential Corneal Tissue Engineering Applications: A Process-Property-Function Relationship Study.

Owing to the shortage of donor corneas and issues associated with conventional corneal transplantation, corneal tissue engineering has emerged as a promising therapeutic alternative. Biocompatibility and other attractive features make silk fibroin a biomaterial of choice for corneal tissue engineering applications. The current study presents three modes of silk fibroin film fabrication by solvent casting with popular solvents, viz. aqueous (aq), formic acid (FA), and hexafluoroisopropanol (HFIP), followed by three standard modes of postfabrication annealing with water vapor, methanol vapor, and steam, and systematic characterization studies including corneal cell culture in vitro. The results indicated that silk fibroin films made from aq, FA, and HFIP solvents had surface roughness (Rq) of 1.39, 0.32, and 0.13, contact angles of 73°, 85°, and 89°, water uptake% of 58, 29, and 27%, swelling ratios of 1.58, 1.3, and 1.28, and water vapor transmission% of 39, 26, and 22%, respectively. The degradation rate was in the order of aq > HF > FA, whereas the tensile strength was in the order of aq < HF < FA. Further, the results of the annealing process indicated notable changes in morpho-topographical, physical, degradation, and tensile properties. However, the films showed no detectable changes in chemical composition and remained optically clear with >90% transmission in the visible range, irrespective of fabrication and postfabrication processing conditions. The films were noncytotoxic against L929 cells and were cytocompatible with rabbit cornea-derived SIRC cells in vitro. The study demonstrated the potential of fine-tuning various properties of silk fibroin films by varying the fabrication and postfabrication processing conditions.

Gas-Phase External Solvation of Protonated Benzonitrile by Eight Methanol Molecules.

The gas-phase sequential association of methanol onto protonated benzonitrile (C6H5CNH+) and the proton-bound dimer (C6H5CN)2H+ have been examined experimentally by equilibrium thermochemical measurements and computationally by density functional theory (DFT). The bonding enthalpy (ΔH°) for the association of methanol with protonated benzonitrile (25.2 kcal mol-1) reflects the strong electrostatic interaction provided by the formation of an ionic hydrogen bond in the C6H5CNH+OHCH3 cluster in excellent agreement with a DFT-calculated binding energy of 24.9 kcal mol-1. The sequential bonding enthalpy within the (C6H5CN)H+(OHCH3)n clusters decreases from 25.2 to 10.6 kcal mol-1 for the eighth solvation step (n = 8), which remains more than 25% above the enthalpy of vaporization of liquid methanol (8.4 kcal mol-1). The nonbulk convergence of ΔH°n-1,n with eight solvent molecules is attributed to the external solvation of a benzonitrile molecule by an extended hydrogen bonding network of protonated methanol clusters H+(CH3OH)n. In the external solvation of protonated benzonitrile by methanol, the proton resides on the methanol subcluster and the neutral benzonitrile molecule remains outside and bonded to the surface of the protonated methanol cluster. The bonding enthalpy of methanol to the proton-bound benzonitrile dimer (C6H5CN)H+(NCC6H5) is measured to be 18.0 kcal mol-1, in good agreement with a DFT-calculated value of 17.1 kcal mol-1, which reflects the association of the proton with the lower proton affinity methanol molecule, thus forming a highly stable structure of protonated methanol terminated by two ionic hydrogen bonds to the two benzonitrile molecules. The external solvation of benzonitrile by methanol ices in space allows benzonitrile to remain on the ice grain surface rather than being isolated inside the ice. This could provide accessibility for reactions with incoming ions and molecules or for photochemical processes by UV irradiation, leading to the formation of complex organics on the surface of ice grains.

MD studies of methanol confined in the metal-organic framework MOF MIL-88B-Cl

• The shapes of the inner voids of MOF, MIL-88B-Cl, vary widely. • These variations depend on the loading with methanol. • The structure of the included methanol depends on the shape of the voids. • The methanol structure becomes liquid-like only at the highest loadings. • At low loadings, the dynamics of the methanol is very slow. The lattice of the flexible Metal–Organic Framework (MOF) MIL-88B(Fe)-Cl is strongly modified when it is subjected to methanol vapor, increasing its volume by more than 130 %. We use a newly developed interaction model belonging to the extended MOF-FF family to perform classical Molecular Dynamics (MD) simulations of this MOF with varying amounts of methanol guest molecules. This work focuses on the evolving intermolecular structure of the counterions and guest molecules when their number is increased from 1 to 30 per cavity. Two mobile Cl − -counterions are, on the average, present in each lattice cavity to neutralize the framework charges. At low loadings (in the closed (or semi-closed) systems), the methanol molecules aggregate around these ions, which are themselves pegged, at the time scale of the simulation, to the Fe 3 -centers of the MOF. At loadings just below the transition, such methanol aggregates may link two counterions on opposite Fe 3 -centers, thus preventing the MOF from opening unless more methanol is added. In all closed systems, the methanol self-diffusion is almost two orders of magnitude lower than in the bulk liquid. Once the MOF opens, i.e., at loadings higher than about 12 to 13 methanol molecules per cavity, structural features typical of liquid methanol become more and more apparent. However, the evolution is not monotonous, there is a transitional region up to about 22 molecules par cavity. Increasing the loading further, all features more and more resemble the ones of bulk liquid methanol.

Water Vapor and Alcohol Vapor Induced Healing of the Nanostructured KBr Surface.

Using atomic force microscopy in the pressure range of 10–10 mbar to several tens of mbar at room temperature, we demonstrate the restructuring of nanostructured KBr surfaces assisted by the presence of water, methanol, and ethanol vapors and the formation of solvation islands. On a flat KBr surface, the two-dimensional solvation islands start nucleating at the step edges and grow with time and with increasing relative pressure. Solvation islands of water wet the terraces; however, solvation islands of methanol and ethanol are localized around the step edges and do not wet the terraces. Two processes are observed on nanostructured KBr surfaces: the movement of the atomic steps and the formation of solvation islands. The first process takes place at comparatively lower pressures at around 1% relative pressure, whereas the second process starts at higher pressures at around 25% relative pressure and above. Furthermore, the second process takes place only after the complete relocation of the step edges and thereby formation of a nearly flat surface. This implies that there is a competition between the restructuring of the atomic steps and solvation layer formation, as both processes require solvated ions. Unlike in the case of a flat surface, solvation islands of alcohols wet the restructured surface due to a higher density of low-coordination sites.

Methanol cookstove a potential alternative to LPG cookstove: Usability, safety and sustainability studies

In the present study, the performance of methanol cookstove as a possible substitute for Liquefied Petroleum Gas (LPG) cookstoves in terms of usability (fuel convenience, cooking performance, operability, maintenance and comfort) and safety (temperature of touchable parts and mechanical stability) are presented. To introduce methanol as an alternative cooking fuel, thermal and emission performances of methanol cookstoves are evaluated. It was found that methanol cookstove yielded a maximum thermal efficiency of 63.2 % at firepower of 1.5 kW and a lesser CO/CO2 ratio of 0.0047 as compared to the prescribed limit (0.02) of IS 11760:1986. The measurement of methanol vapour concentration with burn cycle of 4 h was revealed that the methanol vapour in the confined space was less than 5 ppm which is 97.5 % lesser than the prescribed exposure limit. Also, the methanol cookstove secures a similar score of LPG in terms of maintenance, comfort and mechanical stability. Further, the fuel sustainability analysis revealed that with a 10 % methanol penetration rate in India, 3.69 MMT of LPG import could be reduced by 2030. Safety instructions are also prepared for methanol cookstove which assists in formulating a policy and planned actions that encourages the use of methanol as a safer and cleaner alternative to the LPG.

Laser-induced generation of hydrogen from methanol vapor

A laser-induced generation of hydrogen (LIGH) from methanol vapor by irradiation of graphene aerogel (GA) as the target with focused beam of continuous wave (CW) laser diode is reported. It was found that among the produced gases H2, CO and CH4 were main components. The generation of gas products was observed when light emission from graphene aerogel occurred upon irradiation with laser beam. The efficiency of hydrogen generation increased with excitation power of applied laser and concentration of methanol in vapor. This process is potentially attractive for the H2 - rich and O2 - free syngas for fuel cells.

Improved Current Density and Fill Factor of Non‐Fullerene Organic Solar Cells Prepared under Solvent Vapor Atmosphere

With the continuously increasing power conversion efficiency (PCE) in recent years, organic solar cells (OSCs) have attracted extensive attention as a new clean energy. Further improving PCE is an inevitable requirement for the OSC for commercialization. Herein, PM6: Y6‐based non‐fullerene organic solar cells are prepared by spin‐coating active layer under methanol vapor atmosphere, methanol vapor regulates the active layer morphology and optimizes the molecular arrangement during the active layer film‐forming process, and enriches the acceptor material Y6 on the active layer surface, improving the contact interface between active layer and cathode buffer layer. The improved active layer morphology and interface contact facilitates charge transport and extraction, boosts short‐circuit current density and fill factor, and results in a better PCE of 17.59%, while the PCE of the control device without methanol vapor atmosphere is 16.37%. The results suggest that preparing an active layer under a solvent vapor atmosphere is a simple and efficient method to optimize the active layer morphology and improve the performance of organic solar cells, and this method is convenient to be extended to prepare large‐area and high‐efficiency organic photovoltaic devices.

Fabrication of Polyaniline Thin Film Using Electrodeposition Method as Alcohol Sensor

The use of aliphatic alcohols such as methanol as an alternative renewable fuel in high-density engines can harm both the environment and human health. Polyaniline (PANi), a conductive polymer, has emerged as a solution to this problem because of its benefits as a sensor with relatively high conductivity. In this study, PANi was synthesized using a potentiostat electrodeposition method at a constant potential of -0.4 to +1.0 V at a scan rate of 100 mV/s, resulting in a thin film of PANi on the ITO surface. The formed PANi samples were used to determine the sensitivity level of the sensor to methanol at different concentrations. Morphological results of PANi deposited on the ITO surface were observed using SEM showing the shape of nanoparticles with an interconnected-sponge structure and a porous shape with a diameter of 35.3 nm. The PANI sample can be applied as a sensor material for detecting alcohol vapour in indoor air (at room temperature). The sensing measurement results show that the PANi-based sensor can detect methanol vapour at low concentrations up to 5 ppm. The higher the methanol concentration used, the higher the sensor sensitivity.

Methanol Decomposition on Copper Surfaces under Ambient Conditions: Mechanism, Surface Kinetics, and Structure Sensitivity

Here, we study the adsorption of methanol vapor under ambient pressure and temperature conditions on low-index Cu surfaces using surface-sensitive infrared (IR) and X-ray spectroscopy techniques. The first step of methanol decomposition, i.e., breaking of the O–H bond to form surface-bound methoxy, readily occurs under ambient conditions. Time-lapse IR spectra clearly indicate a gradually decreasing methoxy coverage, which does not obey well-established kinetic models. We rationalize the initial temperature-independent, high, nonequilibrium coverage of methoxy by a H-bonded methanol assembly in the precursor state. A temperature-dependent equilibrium coverage is achieved as the excess methoxy is eliminated gradually via further dehydrogenation to CO that desorbs to the gas phase. The kinetics of this process displays a significant structure sensitivity with considerably faster kinetics on the Cu(110) surface compared to Cu(111) and Cu(100) surfaces.

Layer by Layer Optimization of Langmuir–Blodgett Films for Surface Acoustic Wave (SAW) Based Sensors for Volatile Organic Compounds (VOC) Detection

Rayleigh surface acoustic wave (RSAW)-based resonant sensors, functionalized with single and multiple monomolecular layers of Langmuir–Blodgett (LB) films, were thickness and density optimized for the detection of volatile organic compounds (VOC), which could impose a serious threat on the environment and human health. Single layers of a phospholipid (SLP), hexane dissolved arachidic acid (HDAA), and chloroform dissolved arachidic acid (CDAA) were used for the LB film preparation. Several layers of these compounds were deposited on top of each other onto the active surface of high-Q 434 MHz two-port RSAW resonators in a LB trough to prepare a highly sensitive vapor detection quartz surface microbalance (QSM). Frequency shift was measured with a vector network analyzer (VNA). These devices were probed with saturated vapors of hexane, chloroform, methanol, acetone, ethanol, and water after each deposited layer to test the behavior of the QSM’s insertion loss, loaded Q, vapor sensitivity, and to find the optimum trade-off between these parameters for the best real-life sensor performance. With 2200 ppm and 3700 ppm sensitivity to chloroform, HDAA and CDAA coated QSM devices reached the optimum sensor performance at 15 and 11–15 monolayers, respectively. Surface pressure optimized single monolayers of phospholipid LB films were found to provide up to 530 ppm sensitivity to chloroform vapors with a negligible reduction in loss and loaded Q. This vapor sensitivity is higher than the mass of the sensing layer itself, making SLP films an excellent choice for QSM functionalization.

Evaluation of Physical and Chemical Properties of Residue from Gasification of Biomass Wastes

Thermochemical conversion of biomass waste is a high potential option for increasing usage of renewable energy sources and transferring wastes into the circular economy. This work focuses on the evaluation of the energetic and adsorption properties of solid residue (char) of the gasification process. Gasification experiments of biomass wastes (wheat straw, hay and pine sawdust) were carried out in a vertical fixed bed reactor, under a CO2 atmosphere and at various temperatures (800, 900 and 1000 °C). The analysis of the energy properties of the obtained chars included elemental and thermogravimetric (TGA) analysis. TGA results indicated that the chars have properties similar to those of coal; subjected data were used to calculate key combustion parameters. As part of the analysis of adsorption properties, BET, SEM, FTIR and dynamic methanol vapor sorption tests were conducted. The specific surface area has risen from 0.42–1.91 m2/g (biomass) to 419–891 m2/g (char). FTIR spectroscopy confirmed the influence of gasification on the decomposition of characteristic chemical compounds for biomass. Methanol sorption has revealed for the 900 °C chars of pine sawdust the highest sorption capacity and its mass change was 24.15% at P/P0 = 90%. Selected chars might be an appropriate material for volatile organic compounds sorption.

Reversible and Stepwise Single-Crystal-to-Single-Crystal Transformation of a Platinum(II) Complex with Vapochromic Luminescence.

The vapochromic single-crystal-to-single-crystal (SCSC) transformation of a highly luminescent PtII complex bearing an N-heterocyclic carbene [Pt(CN)2 (tBu-impy)] (tBu-impyH+ =1-tert-butyl-3-(2-pyridyl)-1H-imidazolium) is reported. The trihydrate form of the complex, which exhibits blue 3 MMLCT emission owing to weak Pt⋅⋅⋅Pt interactions, changed its luminescence color from blue to yellowish-green upon the desorption of water molecules while keeping the high emission quantum yield of more than 0.45. Variable-temperature and continuous in-situ tracking of single-crystal X-ray diffraction measurements revealed that the SCSC transformation proceeds reversibly by the release and reabsorption of water molecules, thereby changing the stacked structure slightly. As a result, the dynamics of vapor-induced SCSC transformation were elucidated: that the anhydrous form returned to the original trihydrate form in a two-step process under a water vapor atmosphere. In addition, the PtII complex exhibited a similar SCSC response accompanied by a luminescence color change in the presence of methanol vapor, while being inactive toward ethanol vapor.

Enhanced charge transport of conjugated polymer/reduced graphene oxide composite films by solvent vapor pre-treatment

In this study, a facile approach that could provide a significant enhancement of the charge transport properties of the conjugated polymer/reduced graphene oxide (rGO) composite films using a non-solvent vapor treatment is reported. As the methanol vapors were exposed to the poly(3-hexylthiophene) (P3HT)/rGO composite solution, P3HT chains self-assembled to create nanofibrillar structures via favorable π–π interactions. The π–π staking in P3HT occurred by the non-solvent vapor exposure to minimize unfavorable interactions of P3HT chains with the non-solvent vapor molecules. The self-assembly of P3HT chains was chiefly facilitated by the presence of rGO. This is because the surface of rGO can serve as nucleation sites for the growth of P3HT nanowires. Consequently, P3HT/rGO composite films obtained from the methanol vapor treated corresponding solutions exhibited a high charge carrier mobility (1.3 × 10−1 cm2 V−1 s−1), which is approximately 11-times and 6.5-times higher than those of pristine P3HT (1.2 × 10−2 cm2 V−1 s−1) and P3HT/rGO (2.0 × 10−2 cm2 V−1 s−1) composite films, respectively.

Study of sorption of alcohols vapors by cellulose

In this article, the sorption of vapors of various alcohols by cellulose samples has been studied. Isotherms of vapors sorption of all studied alcohols have a sigmoid shape combining multilayer surface adsorption and absorption with capillary condensation at the final stage. To separate sorption from capillary condensation, the thermodynamic equation was used describing only the sorption process. It was found that sorption of methanol vapor was performed via absorption of alcohol molecules by accessible clusters of amorphous domains of cellulose. In contrast to methanol, the sorption of vapors of higher alcohols such as propanol and butanol by cellulose is carried out by the mechanism of multilayer surface adsorption. Sorption of ethanol vaper by cellulose combined multilayer surface adsorption and very limited absorption by accessible clusters of amorphous domains of cellulose.

Design and qualification of a bench-scale model for municipal waste-to-energy combustion

ABSTRACT This paper reports the design and qualification of the first purpose-built, bench-scale reactor system to model the municipal waste-to-energy combustion of fluorinated polymers. Using the principle of similarity, the gas-phase combustion zone of a typical municipal waste-to-energy plant has been scaled down to the bench with a focus on chemical similarity. Chemical similarity is achieved in large part through the use of methanol as a surrogate for municipal solid waste (MSW). Review of prior research shows that methanol is one of the major volatile products expected during MSW thermal conversion in the fuel bed of waste-to-energy plants. Like full-scale waste-energy plants, the design of the bench-scale model includes a flame zone and a post-flame zone. Maintaining steady methanol vapor flow premixed with air to the model reactor system ensures stable combustion resulting in bench-scale CO emission levels comparable to those of full-scale waste-to-energy plants. Since investigation of fluorinated polymer combustion includes trace analysis of exhaust gas for perfluorooctanoic acid (PFOA), qualification testing focused on PFOA collection efficiency. High PFOA collection efficiency (>90%) demonstrated the capability of the reactor system in transporting and absorbing PFOA that may be generated during high-temperature combustion testing of fluorinated polymers. Overall, the bench-scale system is qualified for its intended use to investigate potential generation of PFOA from combustion of fluorinated polymers under conditions representative of waste-to-energy combustion. Implications: Decision makers depend on environmental researchers to provide reliable predictions of pollutant emissions from waste combustion of polymers at end of product life. Reliable predictions are especially important with regard to questions about potential PFOA emissions from municipal waste combustion of fluorinated polymers. Results from qualification testing confirm that the novel bench-scale model reactor system is capable of representing gas-phase municipal waste combustion behavior upstream of air pollution control and generating representative exhaust gas samples for off-line trace-level analysis of PFOA.

Mesoporous Ce–Fe–Ni nanocomposites encapsulated in carbon-nanofibers: Synthesis, characterization and catalytic behavior in oxygen evolution reaction

Ceria-iron oxide mesoporous materials with Fe:Ce molar ratio of 5:5 and 9:1 were synthesized by hydrothermal method using CTAB as a template and subsequently modified with NiO (molar ratio Ni:Fe = 1:2) by incipient wetness impregnation technique. In order to increase the electro-capacitive properties and reduce the intrinsic impedance of the metal oxides, the samples were consecutively modified by reduction in hydrogen to obtain highly dispersed Ni–Fe alloys into ceria matrix. By exploiting the high permeability of carbon inside ferrous alloys, the metal phase has been further modified into ferrous carbides and metal alloys encapsulated within carbon nanofibers. For this purpose, a reaction, already widely studied for the production of hydrogen, was used, that is the decomposition of methanol vapors. In fact, this decomposition, in addition to producing syn-gas and methane, changes the catalysts in use through a chemical vapor deposition-carbon coating process. This fact, has been used by us to demonstrate how the newly obtained metal-carbon nanocomposites can be used for electro-catalytic purposes. The modified phases of the two molar ratios of the Fe–Ni–Ce catalysts were tested in the Oxygen Evolution Reaction (OER) in an alkaline environment (1 M KOH), showing a satisfactory and progressive increase in activity and a surprising decrease in the overpotential at 10 mA/cm2 of current density. The morphological, textural and physicochemical properties of the samples were characterized in details by XRD, N2-physisorption, TG-TPO, TEM, EDX, FTIR, XPS, Raman and Moessbauer spectroscopies.

Vapour Sorption on Coal: Influence of Polarity and Rank

The surface properties of coal, interactions with gaseous and vapour media, and knowledge of the pore structure are important in terms of preparation, use, and utilisation of coal. This publication combines new unpublished data with analyses included in earlier publications by the research team to expand and systematise information on the sorption of water vapour, methanol vapour, and the saturated and unsaturated hydrocarbons hexane, 1-hexene, heptane, 1-heptene, octane on coals of different ranks. The study showed that the affinity of coal for water and methanol is related to the content of oxygen in the coal rather than the rank of the coal. Water sorption is a multilayer phenomenon, while methanol sorption is a monolayer phenomenon. The water monolayer is greater than that of methanol for low-rank coal, but for the higher-rank coals it is the opposite. The sorption capacity of the applied hydrocarbons depends on the presence or absence of a double bond and the size of the molecule. It increases in the order: n-octane &lt; n-heptane/n-hexane &lt; 1-heptene &lt; 1-hexene. The effect of a double bond is dominant over the influence of the length and shape of the molecule.

Removal of a mixture of formaldehyde and methanol vapors in biotrickling filters under mesophilic and thermophilic conditions: Potential application in ethanol production

ABSTRACT Ethanol is a significant source of energy as a biofuel; however, its production using corn involves the generation of harmful emissions from both fermentation tanks and dryers. Scrubbers control the emissions from fermentation tanks, while the emissions from the dryers are controlled by regenerative thermal oxidizers. Potential alternatives to these energy- and water-intensive technologies are biotrickling filters (BTFs). In this study, two BTFs were operated in parallel to treat formaldehyde and methanol emissions in a volumetric ratio of 4:1, one at 25°C (mesophilic), and the other at 60°C (thermophilic). The mesophilic BTF simulated emissions from fermentation tanks, while the thermophilic BTF simulated emissions from dryers. Both beds were operated at an empty bed residence time of ~30 s and influent formaldehyde concentrations of 20, 50, and 100 parts per million per volume (ppmv). Formaldehyde polymerization was reduced in this study by adding NaOH to pH levels of 7.0–7.4 and heating the solution to a temperature of 60°C. BTFs have successfully removed formaldehyde at typical ethanol plants emissions ~21 ppmv. The BTF technology have the potential in replacing the conventional air treatment methods used at ethanol plants. Implications: Currently, ethanol plants remove and treat hazardous air pollutants (HAPs) using wet scrubbers from the fermenter off-gasses and using thermal oxidizers to combust off-gasses. The utilization of biotrickling filters (BTFs) for HAP removal generally and formaldehyde particularly has wide implication in the field of renewable energy. Utilizing BTFs in the 200+ ethanol plants in USA will save cost and reduce water and energy needs significantly. BTFs can reduce an ethanol plant’s carbon intensity (CI) by 1 to 3 g CO2/MJ. This can result in roughly $50 million per year in additional revenue in Nebraska for instance.