Application of 1D and 2D MFR reactor technology for the isolation of insecticidal and anti-microbial properties from pyrolysis bio-oils

Valuable chemicals can be separated from agricultural residues by chemical or thermochemical processes. The application of pyrolysis has already been demonstrated as an efficient means to produce a liquid with a high concentration of desired product. The objective of this study was to apply an insect and microorganism bioassay-guided approach to separate and isolate pesticidal compounds from bio-oil produced through biomass pyrolysis. Tobacco leaf (Nicotianata bacum), tomato plant (Solanum lycopersicum), and spent coffee (Coffea arabica) grounds were pyrolyzed at 10°C/min from ambient to 565°C using the mechanically fluidized reactor (MFR). With one-dimensional (1D) MFR pyrolysis, the composition of the product vapors varied as the reactor temperature was raised allowing for the selection of the temperature range that corresponds to vapors with a high concentration of pesticidal properties. Further product separation was performed in a fractional condensation train, or 2D MFR pyrolysis, thus allowing for the separation of vapor components according to their condensation temperature. The 300–400°C tobacco and tomato bio-oil cuts from the 1D MFR showed the highest insecticidal and anti-microbial activity compared to the other bio-oil cuts. The 300–350 and 350–400°C bio-oil cuts produced by 2D MFR had the highest insecticidal activity when the bio-oil was collected from the 210°C condenser. The tobacco and tomato bio-oil had similar insecticidal activity (LC₅₀ of 2.1 and 2.2 mg/mL) when the bio-oil was collected in the 210°C condenser from the 300–350°C reactor temperature gases. The 2D MFR does concentrate the pesticidal products compared to the 1D MFR and thus can reduce the need for further separation steps such as solvent extraction.     

Evaluation of the antifungal effects of bio-oil prepared with lignocellulosic biomass using fast pyrolysis technology

This study was performed to investigate the utility of bio-oil, produced via a fast pyrolysis process, as an antifungal agent against wood-rot fungi. Bio-oil solutions (25-100 wt.%) were prepared by diluting the bio-oil with EtOH. Wood block samples (yellow poplar and pitch pine) were treated with diluted bio-oil solutions and then subjected to a leaching process under hot water (70 °C) for 72 h. After the wood block samples were thoroughly dried, they were subjected to a soil block test using Tyromyces palustris and Trametes versicolor. The antifungal effect of the 75% and 100% bio-oil solutions was the highest for both wood blocks. Scanning electron microscopy analysis indicated that some chemical components in the bio-oil solution could agglomerate together to form clusters in the inner part of the wood during the drying process, which could act as a wood preservative against fungal growth. According to GC/MS analysis, the components of the agglomerate were mainly phenolic compounds derived from lignin polymers.     

Efficacy of biochar in removal of organic pesticide,Bentazone from watershed systems

Abstract

Bentazone is one of the toxic insecticides used to control forest tent caterpillar moths, boll weevils, gypsy moths, and other types of moths in various field crops. We report the efficacy of biochar prepared from the Azardirachta Indica waste biomass as adsorbent for removal of Bentazone. Biochar material was prepared by pyrolysis process under limited oxygen conditions. Biochar material was characterized by proximate and ultimate analysis, SEM analysis, FTIR analysis and TG/DTA analyses. The Bentazone adsorption capacity by biochar from aqueous solutions was assessed. Effect of time, adsorbent dosage, insecticide concentration and pH on the adsorption characteristics of the biochar were evaluated. Adsorption parameters were obtained at equilibrium contact time of 150?min, with biochar dosage of 0.5?g at pH 8. From the optimization studies, desirability of 0.952 was obtained with response (adsorption uptake) of 79.40?mg/g, for initial concentration of insecticide (50?mg/L), adsorbent dosage (0.448?g), time 30.0?min and pH 2. The adsorption isotherm data for the removal of Bentazone fitted well with the Freundlich isotherm. This study indicates that the biochar produced from the bark of Azardirachta Indica biomass could be employed as a potential adsorbent for removal of synthetic organic pollutants from the water streams.     

Preliminary evaluation of bitumen contamination in environmental samples using comprehensive gas chromatography GcxGc – Time of flight mass spectrometry (GCxGC-TOFMS)

Abstract

Bitumen and bitumen impacted soil and water samples were investigated for their relative chemical composition using comprehensive gas chromatography GcxGc – time of flight mass spectrometry (GCxGC-TOFMS). The results reveal the presence of key compounds which could serve as environmental biomarkers for bitumen impacted soils and aquifers. Prominent alkanes such as 3-methylpentane; 2,2,4-trimethylpentane; 1,3,5-trimethyladamantane; 2,6,10-trimethyldodecane; 3-ethyl-2,2-dimethyl pentane were tentatively identified and are likely potent biomarkers in environmental forensic assessment of bitumen contamination while the presence of some aromatic compounds: 1,2-benzenedicarboxylic acid, 1,2-dimethyl-3-propylbenzene; 3,4-bis(methoxycarbonyl)benzoic acid; 1,3-bezenedicarboxylic acid, 1,2-benzenediol; 1,3-dimethylbenzene; 1,2-2-(2-ethylhexoxycarbonyl)benzoic acid; (4-methylpentan-2-yl)benzene; 2,4-dimethyl benzo(H)quinolone will further confirm the bitumen contamination in an area under investigation. A host of additional compounds were tentatively identified, mainly in the bitumen samples. The results obtained in this study provides baseline data for effective monitoring, and source apportionment of oil/oil products spills.     

Influence of preparation method on structural,optical, magnetic,and adsorption properties of nano-NiFe2O4

Nickel ferrite (NiFe₂O₄) nanoparticles are prepared through different routes (microwave, co-precipitation, and pyrolysis) and tested for water purification applications through adsorption removal of an acid red dye B as a model organic pollutant. The characterizations of the prepared samples were done using XRD, FT-IR, SEM, TEM, BET, UV-Vis absorbance, Raman spectrum, and vibrating sample magnetometer (VSM). All samples showed an inverse spinel crystal structure. The obtained results pointed out to the effect of the synthetic route on the morphology, particle size, optical, and magnetic properties of the prepared ferrites. Magnetic measurements showed super-paramagnetic behavior for all samples. The magnetic saturation (M_s) of the sample prepared by pyrolysis, was found to possess the highest saturation value, 34.8 emu/g. Adsorption experiments were performed under the change in several parameters, such as pH, adsorbent dosage, and initial dye concentration. A dye removal percentage of 99% was reached under the optimum state. The isothermal adsorption of the acid red dye was investigated using several models, in which the experimental data could be best described by the Freundlich model. Several kinetic and equilibrium models were inspected by linear regression analysis and showed best fitting for the adsorption data through pseudo-second-order model. The calculated thermodynamic parameters indicated that the adsorption of acid red dye onto all the ferrite samples is a spontaneous and endothermic physical adsorption process.

     

An experimental investigation on waste fishing net as an alternate fuel source for diesel engine

In this experimental study, the feasibility of using the oil obtained from waste fishing net as a substitute for diesel fuel was investigated. Waste fishing net oil (WFNO) was obtained through pyrolysis process on a laboratory scale setup and used as a fuel in diesel engine. The properties of oil obtained from waste fishing net were examined and compared with conventional diesel fuel. Results indicated that the WFNO possesses excellent fuel properties. The calorific value of WFNO is 44,450 kJ/kg, which is higher than diesel by 1.48%. In order to study the possibility of using WFNO and its blends (WFNO 25%, WFNO 50%, WFNO 75% and WFNO 100%) with diesel as a fuel, an experimental investigation was carried out on a single-cylinder, four-stroke diesel engine. Experimental results proved that WFNO works satisfactorily on a diesel engine without any engine modifications. Brake thermal efficiency was decreased and brake-specific fuel consumption was increased while using WFNO and its blends. Moreover, there was a slight increase in engine emissions like CO, UHC, NO with WFNO and its blends.

     

Effect of Fractionation and Pyrolysis on Fuel Properties of Poultry Litter

Abstract

Raw poultry litter has certain drawbacks for energy production such as high ash and moisture content, a corrosive nature, and low heating values. A combined solution to utilization of raw poultry litter may involve fractionation and pyrolysis. Fractionation divides poultry litter into a fine, nutrient-rich fraction and a coarse, carbon-dense fraction. Pyrolysis of the coarse fraction would remove the corrosive volatiles as bio-oil, leaving clean char. This paper presents the effect of fractionation and pyrolysis process parameters on the calorific value of char and on the characterization of bio-oil. Poultry litter samples collected from three commercial poultry farms were divided into 10 treatments that included 2 controls (raw poultry litter and its coarse fraction having particle size greater than 0.85 mm) and 8 other treatments that were combinations of three factors: type (raw poultry litter or its coarse fraction), heating rate (30 or 10 °C/min), and pyrolysis temperature (300 or 500 °C). After the screening process, the poultry litter samples were dried and pyrolyzed in a batch reactor under nitrogen atmosphere and char and condensate yields were recorded. The condensate was separated into three fractions on the basis of their density: heavy, medium, and light phase. Calorific value and proximate and nutrient analysis were performed for char, condensate, and feedstock. Results show that the char with the highest calorific value (17.39 ± 1.37 MJ/kg) was made from the coarse fraction at 300 °C, which captured 68.71 ± 9.37% of the feedstock energy. The char produced at 300 °C had 42 ± 11 mg/kg arsenic content but no mercury. Almost all of the Al, Ca, Fe, K, Mg, Na, and P remained in the char. The pyrolysis process reduced ammoniacal-nitrogen (NH₄-N) in char by 99.14 ± 0.47% and nitrate-nitrogen (NO₃-N) by 95.79 ± 5.45% at 500 °C.     

A Characterization of Solution Gas Flaring in Alberta

ABSTRACT

Information reported here is the result of a detailed analysis of data on flared and vented solution gas in the Province of Alberta in 1999. A goal of characterizing these flares was to aid in the improved management of solution gas flaring. In total, 4499 oil and bitumen batteries reported flaring or venting with a combined gas volume of 1.42 billion m³. There was significant site-to-site variation in volumes of gas flared or vented, gas composition, and flare design.

Approximately 5% of physical batteries generate 35.7% of the gas flared and vented from oil and bitumen batteries. Therefore, if one were to attempt to mitigate flaring, significant progress could be made by starting with only the largest sites. The monthly variability of gas volumes was considered because high variability could affect implementation of alternative technologies. It was found that slightly more than 40% of the sites were reasonably steady and had monthly deviations of 100% or less from the average flared volume. The variability in monthly volumes was less for the larger batteries. Data from individual well sites show significant variability in the relative concentrations of each of the major species contained in solution gas.     

The Autothermal Pyrolysis of Waste Tires

Abstract

The growing amount of rubber waste, such as that from tires and cables, has resulted in serious environmental problems. Since rubber waste is not easily biodegradable even after a long period of landfill treatment, material and energy recovery is the preferable alternative to disposal. The potential offered by waste tire pyrolysis for solving both energy and waste treatment problems is widely recognized. Pyrolysis is one method of inducing thermal decomposition without using any oxidizing agent, or using such a limited supply of the agent that oxidization does not proceed to an appreciable extent. The latter may be described as autothermal pyrolysis and will be studied in the present work.

The main objective of this research was to study the operating parameters of autothermal pyrolysis of scrap tires in a laboratory-scale fluidized bed reactor with a 100-cm bed height (10 cm I.D.) and a 100-cm freeboard (25 cm I.D.). Scrap tires were pyrolyzed in a limited oxygen supply, so that the heat for pyrolysis of the scrap tires was provided by combustion of some portion of the scrap tires. The operating parameters evaluated included the effect on the pyrolysis oil products and their relative proportions of (1) the air factor (O.O7–O35); (2) the pyrolysis temperature (370–570 °C); and (3) the catalyst added (zeolite and calcium carbonate). The results show that: (1) the composition of the liquid hydrocarbon obtained is affected significantly by the air factor; (2) the higher operating temperature caused a higher yield of gasoline and diesel; (3) the yield of gasoline increased due to the catalyst zeolite added, and the yield of diesel increased due to the addition of the catalyst calcium carbonate; (4) the principal constituents of gasoline included dipentene and diprene.     

Effects of modified biochar on rhizosphere microecology of rice (Oryza sativa L.) grown in As-contaminated soil

Biochar was carbon-rich and generated by high-temperature pyrolysis of biomass under oxygen-limited conditions. Due to the limitations of surface functional groups and the weakness of surface activity in the field of environmental remediation, the raw biochar frequently was chemically modified to improve its properties with a new performance. In this study, a kind of high-efficiency and low-cost amino biochar modified by nano zero-valent iron (ABC/NZVI) was synthesized and applied to paddy soil contaminated with arsenic (As). Dynamic changes of soil properties, arsenic speciations and rhizosphere microbial communities have been investigated over the whole growth period of rice plants. Pot experiments revealed that the ABC/NZVI could decrease the arsenic concentration in rice straw by 47.9% and increase the content of nitrogen in rice straw by 47.2%. Proportion of Geobacter in soil with ABC/NZVI treatment increased by 175% in tillering period; while Nitrososphaera decreased by 61 and 20% in tillering and maturity, respectively, compared to that of control. ABC/NZVI promotes arsenic immobilization in rhizosphere soil and precipitation on root surface and reduces arsenic accumulation in rice. At the same time, ABC/NZVI would inhibit Nitrososphaera which is related to ammonia oxidation process, and it would have a promising potential as soil amendment to reduce nitrogen loss probably.

     

Effects of carbofuran on growth,biomass allocation,and intraspecific competition in Bouteloua gracilis

Abstract

Growth, biomass allocation and competition between blue grama plants were examined with and without application of carbofuran, a pesticide which has been used to study insect and nematode effects on primary production. Carbofuran had no apparent effect on total plant growth, biomass allocation, or competition between neighboring plants.     

The conversion of chicken manure to bio-oil by fast pyrolysis. III. Analyses of chicken manure, bio-oils and char by Py-FIMS and Py-FDMS

Fast pyrolysis of chicken manure produced the following three fractions: bio-oil Fraction I, bio-oil Fraction II, and a char. In a previous investigation we analyzed each of the four materials by curie-point pyrolysis-gas chromatography/mass spectrometry (CpPy-FDMS). The objective of this article is to report on the analyses of the same chicken manure and the three fractions derived from it by fast pyrolysis. We now used pyrolysis-field ionization mass spectrometry (Py-FIMS) to characterize the three fractions. In addition, the two bio-oil materials were analyzed by pyrolysis-field desorption mass spectrometry (Py-FDMS). The use of both Py-FIMS and Py-FDMS produced signals over significantly wider mass ranges than did CpPy-GC/MS, and so allowed us to identify considerably larger numbers of constituents in each material. Individual compounds identified in the mass spectra were classified into the following twelve compound classes: (a) low molecular weight compounds (< m/z 62); (b) carbohydrates; (c) phenols + lignin monomers; (d) lignin dimers; (e) n-alkylbenzenes; (f) N-heterocyclics; (g) n-fatty acids; (h) n-alkanes; (i) alkenes; (j) sterols; (k) n-diols and (l) high molecular weight compounds (> m/z 562). Of special interest were the high abundances of low-molecular weight compounds in the two bio-oils which constituted close to one half of the two bio-oils. Prominent among these compounds were water, ammonia, acetic acid, acetamide, propyl radical, formamide and hydrogen cyanide. The main quantitative differences between the two bio-oils was that bio-oil Fraction I, as analyzed by the two mass spectrometric methods, contained lower concentrations of low-molecular weight compounds, carbohydrates, and N-heterocyclics than bio-oil Fraction II but was richer in lignin dimers, n-alkylbenzenes and aliphatics (n-fatty acids, n-alkanes, alkenes, and n-diols). Of special interest were the N-heterocyclics in the two bio-oils such as pyrazole, pyrazoline, substituted pyrroles, pyridine and substituted pyridines, substituted methoxazole, substituted pyrazines, indole and substituted indoles. Fatty acids in all four materials ranged from n-C(9) to n-C(33), alkanes from n-C(9) to n-C(40), alkenes from C(10:1) to C(40:1) and diols from n-C(7) to n-C(29). The chicken manure, bio-oil Fraction I, and char each contained about 4% sterols with cholesterol, ethylcholestriene, ergosterol, ethylcholestene, ethylcholesterol and beta -sitosterol as major components. Semi-quantitative estimates of the total materials identified by Py-FIMS were: chicken manure: 61.1%; bio-oil Fraction I: 81.3%; bio-oil Fraction II: 78.6%; char: 61.3%; and by Py-FDMS were: bio-oil Fraction I: 65.4%; bio-oil Fraction II: 70.0%.     

Effectiveness and mechanisms of hydrogen sulfide adsorption by camphor-derived biochar

The characteristics and mechanisms of hydrogen sulfide (H₂S) adsorption on a biochar through pyrolysis at various temperatures (100 to 500°C) were investigated. The biochar used in the current study was derived from the camphor tree (Cinnamomum camphora). The samples were ground and sieved to produce particle sizes of 0.4 mm to 1.25 mm, 0.3 mm to 0.4 mm, and <0.3 mm. The H₂S breakthrough capacity was measured using a laboratory-designed test. The surface properties of the biochar were characterized using pH and Fourier-transform infrared spectroscopy (FTIR) analysis. The results obtained demonstrate that all camphor-derived biochars were effective in H₂S sorption. Certain threshold ranges of the pyrolysis temperature and surface pH were observed, which, when exceeded, have dramatic effects on the H₂S adsorption capacity. The sorption capacity ranged from 1.2 mg/g to 121.4 mg/g. The biochar with 0.3 mm to 0.4 mm particle size possesses a maximum sorption capacity at 400°C. The pH and FTIR analysis results showed that carboxylic and hydroxide radical groups were responsible for H₂S sorption. These observations will be helpful in designing biochar as engineered sorbents for the removal of H₂S.

Implications: This paper studies the potential of biochar derived by camphor to adsorb hydrogen sulfide at environmentally sustainable temperatures. The different sizes of the biochars and the different temperatures of pyrolysis for the camphor particle have a great impact on adsorption of hydrogen sulfide.     

Cellular alterations and modulation of protein expression in bitumen-challenged human osteoblast cells

Purpose

There are many arguments on the carcinogenic potential of bitumen extract. The mechanism of bitumen-induced damage is not well understood at the molecular level. Therefore, in the present study, cell-transforming and tumor-inducing potential of bitumen extract was studied using in vitro [human osteosarcoma (HOS) cells] and in vivo [nude and severe combined immunodeficiency (SCID) mice] models.

Methods

Gas chromatography/mass spectrometry (GC/MS) analysis was carried out to find out the existence of carcinogenic compounds in the bitumen extract. Cell transformation test, anchorage independence assay, karyotyping assay, tumorigenicity assay, and 2-DE analysis were used to find out the effect of bitumen using the in vitro and in vivo models.

Results

GC/MS analysis showed the existence of carcinogenic compounds in the bitumen extract. HOS cells were treated with different concentrations (25, 50, and 100???l/ml) of bitumen extract. Compared to the parental HOS cells, bitumen transformants (HOS T1 and HOS T2) showed the characteristics of anchorage independency, chromosomal anomaly, and cellular transformation. Interestingly, bitumen transformants were not able to form tumor in nude/SCID mice. Proteomic analysis revealed the existence of 19 differentially expressed proteins involved in progression of cancer, angiogenesis, cell adhesion, etc.

Conclusions

Exposure of bitumen extract to HOS cells results in the cellular transformation similar to cancer cells and can modulate proteins involved in the progression of cancer. We state that the non-tumorogenic potential of bitumen transformant in nude/SCID mice can be attributed to the downregulation of galectin-1, chromodomain helicase DNA-binding protein 1-like gene, and membrane-associated guanylate kinase 2 protein.     

A Maximum Entropy Approach to Estimating Emissions

ABSTRACT

A maximum information entropy method of calculating probabilistic estimates of volatile organic compound (VOC) emissions by the wood furniture and fixture coating industry is presented. The maximum entropy approach is used to produce minimally biased probability distributions for number of firms, coating use, and coating emission factors from existing summary statistics. These distributions are combined to estimate VOC emissions. The maximum entropy emissions estimate provides information to support probabilistic modeling of regional air quality, probabilistic assessment of emission reduction strategies, and risk assessments. Accurate estimation of emission distributions produces more informed regulatory decisionmaking, risk comparisons, and regulatory and scientific priority setting.     

Prediction of Traffic Noise: A Screening Technique

Abstract

Traffic noise is ubiquitous in many communities and is an important environmental concern, especially for persons located near major roadways. Several different methods are available to estimate noise levels resulting from roadway traffic. These include computational, graphical, and computer modeling techniques.

The prediction methodology presented here is a simplified technique that can be used for estimating noise resulting from traffic and for screening traffic noise impacts. This Traffic Noise Screening (TNS) approach consists of a series of traffic noise level prediction graphs developed for different roadway configurations. The graphs are based on the results from using the Federal Highway Administration (FHWA) STAMINA2.0 computerized noise prediction model for various scenarios. Data inputs to the TNS approach include roadway geometries, traffic volumes, vehicle travel speed, and centerline distance to the receptors.

The TNS graphs allow easy estimation of traffic noise levels for use in predicting traffic-related noise impacts. This TNS approach is not intended as a substitute for detailed modeling, such as with STAMINA2.0, but as a screening tool to aid in determining when detailed modeling may be necessary. If screening results indicate that noise estimates are significant, or if the scenario is rather complex, then additional, more detailed modeling can be performed.     

The role of toxicology in the evaluation of new agrochemicals

Abstract

The use of agrochemicals like crop protecting agents, veterinary disinfectants, and wood preservatives may result in (un)intentional exposure of the environment, animals and man. This paper deals with current testing strategies to assess the potential health risks for humans exposed to these chemicals during production or application or via consumption of foods containing pesticide residues.

Principles and procedures for safety assessment of pesticide residues in food as developed by WHO/FAO are described. Different types of toxicity studies in mammalian test animal species are discussed and a strategy is outlined in order to characterize the toxicity profile of a compound and the relationship between applied doses and adverse effects. Safety testing of agrochemicals should be carried out in relation to its intended use, and in particular attention will be paid to toxicity testing of residues of pesticides in food. Extrapolation of results from animal studies to humans and the use of safety factors is discussed.

Besides the use of animal protocol studies for safety testing of agrochemicals, the potential use of in‐vitro models derived from organs and tissues of animals is discussed. Data on the in‐vitro metabolism of thiabendazole, aldicarb and alachlor are discussed in order to demonstrate that such data may complement or partly substitute whole animal experimentation.

Principles and procedures for safety testing of residues of agrochemicals in food as applied during the last three decades, constitute a ‘safety‐first’ approach, providing sufficient safety margins for the consumer of foods which may contain low levels of residues of agrochemicals.     

Effect of the Mn oxidation state and lattice oxygen in Mn-based TiO2 catalysts on the low-temperature selective catalytic reduction of NO by NH3

TiO₂-supported manganese oxide catalysts formed using different calcination temperatures were prepared by using the wet-impregnation method and were investigated for their activity in the low-temperature selective catalytic reduction (SCR) of NO by NH₃ with respect to the Mn valence and lattice oxygen behavior. The surface and bulk properties of these catalysts were examined using Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), temperature-programmed reduction (TPR), and temperature-programmed desorption (TPD). Catalysts prepared using lower calcination temperatures, which contained Mn⁴⁺, displayed high SCR activity at low temperatures and possessed several acid sites and active oxygen. The TPD analysis determined that the Brönsted and Lewis acid sites in the Mn/TiO₂ catalysts were important for the low-temperature SCR at 80～160 and 200～350 °C, respectively. In addition, the available lattice oxygen was important for attaining high NO to NO₂ oxidation at low temperatures.

Implications: Recently, various Mn catalysts have been evaluated as SCR catalysts. However, there have been no studies on the relationship of adsorption and desorption properties and behavior of lattice oxygen according to the valence state for manganese oxides (MnO_x). Therefore, in this study, the catalysts were prepared by the wet-impregnation method at different calcination temperatures in order to show the difference of manganese oxidation state. These catalysts were then characterized using various physicochemical techniques, including BET, XRD, TPR, and TPD, to understand the structure, oxidation state, redox properties, and adsorption and desorption properties of the Mn/TiO₂ catalysts.     

Comparison of Different Packing Materials for the Biofiltration of Air Toxics

Abstract

Four different biofilter packing materials (two porous ceramics, perlite, and open pore polyurethane foam) were compared for the removal of toluene vapors. The focus was on evaluating performance at relatively short gas retention time (13.5 and 27 sec). The reactors were initially operated as biotrickling filters with continuous feeding and trickling of a nutrient solution. After significant plugging of the biotrickling filter beds with biomass was observed, the operation mode was switched to biofiltration with only periodic supply of mineral nutrients. This resulted in stable conditions, which allowed detailed investigations over >6 months. The reactor packed with cattle bone Porcelite (CBP), a ceramic material containing some macronutrients and micronutrients, exhibited the highest performance. The critical load (i.e., load at which 95% removal occurred) was 29 g m^?3 hr^?1 at a gas retention time of 13.5 sec and 66 g m^?3 hr^?1 at a gas retention time of 27 sec. After the long-term experiment, the packing materials were taken from the reactors and examined. The reactors were divided into three sections, top, middle, and bottom, to determine whether spatial differentiation of biomass occurred. The assays included a double-staining technique to count total and live microorganisms and determination of moisture, protein, and dry weight contents. Microbial community analysis was also conducted by denaturing gradient gel electrophoresis. The results showed that most reactors had a significant fraction of inactive biomass. Comparatively, the CBP biofilter held significantly higher densities of active biomass, which may be the reason for the higher toluene removal performance. The analyses suggest that favorable material properties and the nutrients slowly released by the CBP provided better environmental conditions for the process culture.