Order Of Toluene Research Articles

Preparation of CPVC-based activated carbon spheres and insight into the adsorption-desorption performance for typical volatile organic compounds

Chlorinated polyvinyl chloride (CPVC)-based activated carbon spheres with smooth surfaces, good sphericity, interconnected hierarchical porous structure and high porosity have been synthesized by non-solvent induced phase separation method, followed by successive treatments of stabilization, carbonization at 450 °C in N2 atmosphere, and activation with CO2 as an agent at 900–1000 °C. The effect of activation temperatures on the textural properties of activated carbon spheres and their adsorption potential for volatile organic compounds (VOCs) under dynamic conditions is investigated. CO2 activation improves the hierarchy in the microporous range by stimulating the formation of supermicropores and significantly expands the specific surface area and pore volume of activated carbon spheres. The textural properties of adsorbents play a vital role in the adsorption performance of different VOCs. The adsorption capacity of VOC molecules can be greatly promoted by elevating specific surface area and pore volume. Due to the compatibility difference between the VOC molecules and the pore structure of adsorbents, the adsorption capacity follows the order of toluene > m-xylene > n-hexane. The adsorption isotherm of toluene on CPVC-AC1000 can be generally expressed by the Langmuir model. The adsorbents with larger average pore diameters possess a lower activation energy of desorption, which is beneficial for desorption. The carbon sphere activated at 1000 °C is a high-performance adsorbent with good reusability. Thus, the present study provides a synthesis process to produce the activated carbon spheres with high porosity from low-cost CPVC for its application in VOC adsorption.

Adsorption Characteristics and Influencing Factors of Chlorinated and Aromatic Hydrocarbons on Aquifer Medium

To determine the competitive adsorption characteristics and influencing factors of chlorinated and aromatic hydrocarbons on the aquifer medium, toluene, benzene, 1,2−dichloropropane, and 1,2,3−trichloropropane (TCP) were selected as typical pollutants for adsorption tests. The results showed that the adsorption process of pollutants on the aquifer medium conformed to the first−order kinetic and Henry linear model equation, and the adsorption capacity decreased in the order of toluene, benzene, 1,2−dichloropropane, and TCP. Benzene promoted the adsorption of toluene on the aquifer medium, while toluene reduced the adsorption of benzene conversely. 1,2−dichloropropane restrained the adsorption of TCP, and TCP had no significant effect on the adsorption of 1,2−dichloropropane. The adsorption capacity of TCP on the aquifer increased with the concentration of toluene. TCP acted as a stimulus for the adsorption of toluene when the initial concentration of toluene was lower than 2 mg/L. In contrast, TCP served as an inhibitor for the adsorption of toluene on the aquifer medium. Furthermore, the adsorption of all pollutants increased with decreasing medium size. The promotion rates for aromatic and chlorinated hydrocarbons were 7.2~41.1% and 2.7~27.1%, suggesting that the promotion effect on aromatic hydrocarbons was stronger than that on chlorinated hydrocarbons. Natural organic matter (NOM) inhibited the adsorption of pollutants on the aquifer medium (especially for high concentrations of chlorinated hydrocarbons), and the adsorption rate increased by more than 60% when OM decreased from 0.25% to 0.08%. Clay minerals improved the adsorption of organic pollutants in different compound pollution systems, and montmorillonite exhibited a stronger promoting effect than kaolin.

Förster and Dexter energy transfer boosted and weakened respectively by host−guest complexations between cyano-containing perylene diimide and BODIPY/diiodo-BODIPY functionalized pillar[5]arenes

How the intensities of host−guest interactions influence on FRET/TTET processes based on fluorophore-functionalized pillararenes is a key scientific issue to be resolved for designing novel FRET/TTET-based supramolecular fluorescent materials and devices by using fluorophore-functionalized pillararenes. Herein, 1,3,5,7-tetramethyl-8-phenyl-4,4-difluoroboradiazaindacene (BODIPY)-functionalized pillar[5]arene (EtP5-BDP), diiodo-BODIPY-functionalized pillar[5]arene (EtP5-DIBDP), and cyano-containing perylene diimide (PBI-CN) were prepared respectively. With the increasing of solvents’ polarities and the reducing of their molecular sizes (toluene→CHCl3→acetone→CH3CN), the host−guest interactions between EtP5 moieties and the solvents became stronger, which induced the host−guest interactions between EtP5-BDP⊃PBI-CN and EtP5-DIBDP⊃PBI-CN became weaker so that more free hosts and guests could neither be kept in the effective ranges (1–10 nm), nor diffuse to these effective ranges for FRET owing to the extremely short fluorescence lifetimes of them (only a few nanoseconds), which induced Stern–Volmer fluorescence quenching constants, FRET rate constants and efficiencies of FRET decreased. Meanwhile, in the order of toluene, CHCl3, acetone and CH3CN, the weakening of host−guest interactions between EtP5-DIBDP and PBI-CN enabled more free EtP5-DIBDP and PBI-CN to diffuse for colliding and completing a TTET process more efficiently as a result of the long-enough triplet lifetimes of EtP5-DIBDP in various solvents (>100 μs). Conversely, in the formed stable host−guest complexes of EtP5-DIBDP⊃PBI-CN in low-polar and large molecular size solvents, the steric hindrance of EtP5 moiety in EtP5-DIBDP⊃PBI-CN could not make more free molecules diffuse for colliding and completing an efficient TTET process, therefore, Stern–Volmer triplet quenching constants, TTET rate constants and efficiencies of TTET were all boosted.

Sol–gel reaction of titanium phosphonate alkoxide cluster

AbstractThe synthesis and properties of titanium phosphonate cluster molecules have been investigated; however, nothing has been done to study not only the catalytic ability of a hydrolyzed cluster but also a behavior of hydrolysis–polycondensation by solvents. The sol–gel reaction of [Ti4(μ3‐O)(OiPr)5(μ‐OiPr)3(O3PPh)3]·thf (Ti4P3Ph) was performed in tetrahydrofuran (THF), toluene, and acetone. The hydrolysis–polycondensation of Ti4P3Ph proceeded in THF and toluene, while Ti4P3Ph in acetone proceeded in two paths (hydrolysis–polycondensation and nonhydrolysis–polycondensation). The hydrolyzed Ti4P3Ph retained its cluster structure, while the calcined Ti4P3Ph at 300°C contained a collapsed cluster structure. The specific surface areas of the hydrolyzed Ti4P3Ph in THF, toluene, and acetone were 154, 302, and 7 m2 g−1, respectively. The photodegradation ability of the hydrolyzed Ti4P3Ph for methylene blue was confirmed by ultraviolet irradiation at 365 nm; however, that of the calcined Ti4P3Ph was not. It was considered that the calcined Ti4P3Ph did not retain its cluster structure. The photocatalytic ability of the hydrolyzed Ti4P3Ph was high in the order of toluene > THF > pristine > acetone. The gels retained cluster structure have higher photocatalytic ability than pristine cluster; however, the gel contained a collapsed cluster structure was found no catalytic ability.

Extraction separation of aromatic homologues from n-decane using DMSO: Influence of the alky side chain length

In this study, the liquid-liquid equilibrium of DMSO-aromatic homologues-n-decane systems were measured at 303.15 K under 101.3 kPa at first, followed by Other-Tobias equation data reliability verification and NRTL/UNIQUAC activity coefficient model correlation. Moreover, intermolecular interaction energies and molecular polarity indexes were calculated to interpret the extraction results. Finally, a set of wave function analyses were accomplished to elaborate the physical nature of the interaction concerning alky side chain length in DMSO extraction process.These investigations show that: (1) Both aromatics extraction and alkane entrainment are in the order of toluene > ethylbenzene > isopropylbenzene (cumene). (2) Intermolecular interaction energy and molecular polarity index can characterize the interaction intensity between the stationary dimer. (3) The interactions between aromatics and DMSO are weak hydrogen bonding and van der Waals interaction. The attractive part mainly involves dispersion (50.54 ∼ 53.30%) and electrostatic (35.49 ∼ 37.67%) effect. (4) The interaction between aromatics and n-decane are van der Waals interaction, dominated by attractive dispersion (70.41 ∼ 70.86%) and repulsive exchange effect. With the extension of the alky side chain, the electrostatic contribution decreases, while the dispersion contribution increases.

A study on thiophene removals from model oils with different molecular compositions using an inexpensive N-methylpyrrolidone-FeCl3 ionic liquid

Extraction desulfurization technology (EDS) has been widely concerned because of its mild process conditions and low loss of octane number. At present, most of researches on EDS reported in literature mainly adopt single chain alkane as model oil. However, the chemical composition of fluid catalytic crack (FCC) gasoline is quite different from that of single chain alkane. Therefore, in this paper, the removal of thiophene from model oils containing different molecular compositions, such as n-octane, cyclohexane, 1-octene, cyclohexene and toluene, was systematically studied, using NMP + nFeCl3 (n = 0, 5 wt%, 10 wt%, 20 wt%) as extractants. The effects of different molecular compositions on desulfurization rate and the selectivity of extractants were systematically investigated, and their interaction mechanisms were discussed. The experimental results showed that the effects of different molecular compositions on desulfurization rate and selectivity were quite different, with the order of toluene > cyclohexene >1-octene > cyclohexane > n-octane. The higher the π electron cloud densities of the investigated molecular compositions or the more similar their chemical structures to extractants, the lower the desulfurization rates and selectivities. Moreover, the CH⋯π interaction between the investigated molecular composition and the extractant had a greater influence on desulfurization rate and selectivity than ring structure. The desulfurization results of simulated FCC gasoline showed that the selectivity and desulfurization rate of simulated gasoline containing olefins and aromatics were far lower than those of n-octane reported in the literature. The desulfurization results of real gasoline showed that the desulfurization rate and selectivity of real gasoline were also significantly lower than those of n-octane model oil.

Zeolite catalyst containing metals.

Adsorption desulfurization is one of the most promising ways to reduce the sulfur content of gasoline at deeper level. In this work, thiophene (TP) adsorption capacity in cyclohexane onto [Cu3(BTC)2(H2O)3] (HKUST-1) was measured by batch method, and the effect of cyclohexene and toluene on sulfur capacity was investigated. Adsorption isotherms of TP, cyclohexene, and toluene in cyclohexane onto HKUST-1 were conducted at 298.15–313.15 K to explicate the different extent of influence by cyclohexene or toluene addition. The results showed that, compared with cyclohexene, the addition of toluene in model gasoline led to a moderate decline in sulfur capacity of HKUST-1. The isotherm data of TP adsorption were well-correlated using Langmuir equation, while those of cyclohexene or toluene adsorption fitted Freundlich model, indicating different adsorption mechanisms between TP and competitors. The adsorption capacities followed the order of toluene < cyclohexene ≪TP at the same equilibrium concentrations, implying the order of the adsorption affinities, which is in good agreement with the different extent of influence by cyclohexene and toluene. The excellent regeneration performance of HKUST-1 in TP adsorption benefits from the physical adsorption mechanism, which was hinted by the enthalpy of TP adsorption (−37.31 ± 2.04 kJ mol−1) and no detection of new sulfur species.

Revealing Molecular Mechanisms in Hierarchical Nanoporous Carbon via Nuclear Magnetic Resonance

Author(s): Mao, H; Tang, J; Xu, J; Peng, Y; Chen, J; Wu, B; Jiang, Y; Hou, K; Chen, S; Wang, J; Lee, HR; Halat, DM; Zhang, B; Chen, W; Plantz, AZ; Lu, Z; Cui, Y; Reimer, JA | Abstract: Hierarchical nanoporous carbons combining pore sizes of different length scales are highly important for separation processes. However, critical questions remain regarding the hierarchical structure regulation and the molecular mechanisms of gaseous adsorbate uptake and interactions within the hierarchical nanoporous carbons. These materials present characterization challenges in that there are no experimental techniques that can elucidate the molecular mechanisms of the organic compounds and CO within the materials. We deployed multidimensional solid-state nuclear magnetic resonance (NMR) to generate maps of guest-framework interactions as a function of adsorbate concentrations and adsorption times. The NMR spectra provide insight toward the design of effective hierarchical pore structures. Our materials show a high volatile organic compounds/CO physisorption capacity, which reveals promising application to carbon-capture strategies to mitigate global warming. 2 2

Friedel–Crafts benzylation of toluene catalyzed by ZnCl2/SiO2 heterogeneous catalyst to para- and ortho-mono-benzylated toluene

A series of catalysts was prepared for the liquid-phase Friedel–Crafts benzylation of toluene with benzyl chloride (BC) by impregnating rice husk ash silica with ZnCl2 (3 wt%, 6 wt%, 9 wt%, and 12 wt%) via a wet impregnation method. The XRD analysis indicates that the catalysts were amorphous with ill-defined pore systems. The XPS analysis detected the coexistence of ZnO nanoparticles together with ZnCl2 on the catalyst surface, whereas the 29Si NMR analysis indicates the formation of Si–O–Zn bond. Quantitative conversion of benzyl chloride (100%) was achieved within 3 h at 353 K when a catalyst with 9 wt% ZnCl2 was used due to its narrow pore size and high surface area (635 m2 g−1). Para- and ortho-mono-benzylated toluene was obtained as the products. The reaction is proposed to take place via weak attraction between benzyl chloride and the Zn through its chlorine atom. The catalyst was recycled four times with minimum loss (8%) in activity. The benzylation of benzene, toluene, p-xylene, and anisole followed the classical mechanism of Friedel–Craft-type acid-catalyzed benzylation reaction. The BC conversion increased in the order of toluene = p-xylene > anisole > benzene. The catalyst was also screened to be active in the benzoylation of toluene with benzoyl chloride (BOC). The conversion of BOC was 45% with selectivity toward 2-methylbenzophenone (50%) and 3-methylbenzophenone (50%).

KOH-activated hydrochar with engineered porosity as sustainable adsorbent for volatile organic compounds

The pore structure of materials plays a key role in adsorption, and it is of great significance to regulate the porosity of adsorbent for specific adsorbate. Herein, porous carbons (PCs) with engineered porosity were synthesized as adsorbents for volatile organic compounds (VOCs), which employed sucrose-based hydrochar via KOH activation. Surface area of 2604 m2/g together with pore volume of 1.685 cm3/g could be reached when KOH/hydrochar ratio was 3. The adsorption capacities of three typical VOCs were in the order of toluene > acetic ether > acetone, with the vapor pressure had greatest effect on adsorption among the properties of adsorbates. Influence of carbon porosity was further investigated, showing that micropores in the range of 1–3 times of the VOC diameter were crucial to the adsorption process. In addition, more than 90 % of the initial adsorption capacity could be reached after four regeneration cycles. Considering economic and environmental aspects, we demonstrated porous carbons derived from hydrothermal carbonized sucrose could be promising materials in adsorption. This work could also provide guidance for the porosity regulation of adsorbents for different VOCs.

Photolytic Transformation Products of Decabromodiphenyl Ethane (DBDPE).

The photolytic transformation of decabromodiphenyl ethane-a current-use brominated flame retardant and major substitute of the structurally related decabromodiphenyl ether-was investigated in different solvents (toluene, dichloromethane, chlorobenzene, and benzyl alcohol). The transformation rate followed pseudo first order kinetics, with increasing half-life ( t1/2) in the order of toluene ( t1/2 = 4.6 min), chlorobenzene ( t1/2 = 14.0 min), dichloromethane ( t1/2 = 27.9 min), and benzyl alcohol ( t1/2 ≈ 60 min). Formation and amount of transformation products varied depending on the solvent used. A detailed study of the hydrodebromination products allowed us to tentatively assign all three possible nonaBDPEs (BDPE 207, 208, and in benzyl alcohol only BDPE 206) and three predominant octaBDPE congeners (BDPE 197, 201, and 202). Next to the reported BDPEs, formation of several oxygen containing transformation products (OxyTPs), dominated by octabrominated OxyTP, was verified by GC-Orbitrap-HRMS analysis. Use of HPLC and Florisil column enabled the separation of OxyTPs and BDPEs, and the polybrominated OxyTPs were most likely tricyclic compounds with almost planar structure.

Comparative effects of oxygenates-gasoline blended fuels on the exhaust emissions in gasoline-powered vehicles

This study aimed to investigate the comparative effects of oxygenates such as ethanol (EA), methyl tertiary-butyl ether (MTBE), and ethyl tertiary butyl ether (ETBE) by fixing the oxygen contents as 0.82 wt% 1.65 wt%, and 2.74 wt% of the fuels on the regulated (CO, NMHC and NOx) and unregulated (formaldehyde, acetaldehyde and BTEX) exhaust emissions in gasoline-powered vehicles. The most widely used type of vehicles (light-duty, medium-duty, heavy-duty) in Korea were tested on a chassis dynamometer under the CVS-75 Cycle. When EA, MTBE and ETBE percentage increased, the CO and NMHC concentration decreased. The NOx emission decreased at 1.65 wt% and 2.74 wt% oxygen content of MTBE and ETBE. The emissions of CO decreased by 0.363 g/km, 0.266 g/km and 0.356 g/km for light-duty vehicle when EA, MTBE and ETBE oxygenates blending ratio increased. Increased EA, MTBE and ETBE oxygenates blending ratio demonstrated no specific reducing effect on CO emissions from low-mileage vehicle, but NMHC emissions decreased by 0.011 g/km (medium-duty), 0.015 g/km (light-duty) and 0.018 g/km (heavy-duty). More CO was emitted from MTBE among three oxygenates at same oxygen content. The emitted concentrations of NMHC from three oxygenates at same oxygen content were almost similar, but reduced NOx emissions from EA (10%) to MTBE (20.4%) and ETBE (23.6%) were observed at 2.74 wt% oxygen content. Reducing effect on CO emissions was order of EA > ETBE > MTBE. Formaldehyde emissions increased up to 54.3% as MTBE ratio increased. When oxygen content of ETBE, EA, and MTBE increased from 0.82 wt% to 2.74 wt%, the acetaldehyde emissions increased up to 177.4%, 39.5% and 31.0%, respectively. There was significant formaldehyde concentration difference between high emission vehicle type (light-duty and medium-duty) and low emission vehicle type (heavy-duty and low-mileage) for three oxygenates. Reduction effect of MTBE and ETBE on BTEX was the order of toluene > benzene > ethylbenzene > xylene, and MTBE showed more reduction effect than ETBE at same oxygen content.

Investigation on laminar burning velocities of benzene, toluene and ethylbenzene up to 20 atm

The laminar flame propagation of benzene, toluene and ethylbenzene was investigated at Tu = 423 K, Pu = 1–20 atm and various equivalence ratios in a high-pressure constant-volume cylindrical combustion vessel. The laminar burning velocities (LBVs) were observed to increase in the order of toluene, ethylbenzene and benzene at both atmospheric and high pressures, and the Markstein lengths were evaluated to be similar among the three aromatic fuels. Three recently developed kinetic models of aromatic fuels were used to simulate the experimental data. Sensitivity analysis was performed to investigate the kinetic effects on LBVs of the three aromatic fuels under various conditions. Different from the cases of alkane LBVs, the reactions of fuel-specific species are important for the LBVs of the three aromatic fuels at 1–20 atm, especially for the LBVs under rich conditions. In particular, the pyrolysis reactions in the sub-mechanism of aromatic fuels play a dominant role in negatively sensitive reactions under rich conditions, indicating prominent inhibition effects of aromatic flame chemistry on the LBVs. The sensitivity variation analysis and normalized sensitivity variation analysis indicate that the importance of most of the small species and fuel-specific species reactions are enhanced with increasing pressure, especially under rich conditions. The pressure effects of the flame chemistry on the aromatic LBVs strongly depend on the reaction circumstance. A series of chain termination reactions and chain propagation reactions producing less active radicals have large negative sensitivity coefficients and are generally more susceptible to the pressure variation than the positively sensitive reactions. The modeling analysis indicates that aromatic flame chemistry inevitably changes to resist the enhanced combustion intensity with increasing pressure.

Thiophene adsorption onto metal–organic framework HKUST-1 in the presence of toluene and cyclohexene

Adsorption desulfurization is one of the most promising ways to reduce the sulfur content of gasoline at deeper level. In this work, thiophene (TP) adsorption capacity in cyclohexane onto [Cu3(BTC)2(H2O)3] (HKUST-1) was measured by batch method, and the effect of cyclohexene and toluene on sulfur capacity was investigated. Adsorption isotherms of TP, cyclohexene, and toluene in cyclohexane onto HKUST-1 were conducted at 298.15–313.15 K to explicate the different extent of influence by cyclohexene or toluene addition. The results showed that, compared with cyclohexene, the addition of toluene in model gasoline led to a moderate decline in sulfur capacity of HKUST-1. The isotherm data of TP adsorption were well-correlated using Langmuir equation, while those of cyclohexene or toluene adsorption fitted Freundlich model, indicating different adsorption mechanisms between TP and competitors. The adsorption capacities followed the order of toluene < cyclohexene ≪TP at the same equilibrium concentrations, implying the order of the adsorption affinities, which is in good agreement with the different extent of influence by cyclohexene and toluene. The excellent regeneration performance of HKUST-1 in TP adsorption benefits from the physical adsorption mechanism, which was hinted by the enthalpy of TP adsorption (−37.31 ± 2.04 kJ mol−1) and no detection of new sulfur species.

Combined removal of a BTEX, TCE, and cis-DCE mixture using Pseudomonas sp. immobilized on scrap tyres.

The simultaneous aerobic removal of a mixture of benzene, toluene, ethylbenzene, and o,m,p-xylene (BTEX); cis-dichloroethylene (cis-DCE); and trichloroethylene (TCE) from the artificially contaminated water using an indigenous bacterial isolate identified as Pseudomonas plecoglossicida immobilized on waste scrap tyres was investigated. Suspended and immobilized conditions were compared for the removal of these volatile organic compounds. For the immobilized system, toluene, benzene, and ethylbenzene were completely removed, while the highest removal efficiencies of 99.0 ± 0.1, 96.8 ± 0.3, 73.6 ± 2.5, and 61.6 ± 0.9% were obtained for o-xylene, m,p-xylene, TCE, and cis-DCE, respectively. The sorption kinetics of contaminants towards tyre surface was also evaluated, and the sorption capacity generally followed the order of toluene > benzene > m,p-xylene > o-xylene > ethylbenzene > TCE > cis-DCE. Scrap tyres showed a good capability for the simultaneous sorption and bioremoval of BTEX/cis-DCE/TCE mixture, implying a promising waste material for the removal of contaminant mixture from industrial wastewater or contaminated groundwater.

Fly ash/polyurethane thin film for the adsorption of volatile organic compounds (VOCs) from air

Polyurethane (PU) films containing different amounts of fly ash particles (FAPs) were prepared by simple solution casting method. The morphological, thermal, and mechanical properties of the composite films were investigated by several characterization methods. Results show that sufficient amounts (up to 40 wt%) of FAPs can be incorporated throughout the film. The presence of FAPs within PU film not only acts as filler to increase the mechanical strength of the film but also increases its volatile organic compounds (VOCs) adsorption capacity. The VOCs adsorption capacity of FAPs/PU composite films were investigated on three different compounds (chloroform, toluene, and benzene). It showed consistent trend in the order of toluene > benzene > chloroform for all the samples. The VOCs adsorption capacity of PU film was found to be increased by two fold when 20 wt% of FA was incorporated through it. The present results suggest the potential use of FAPs as filler materials for PU films with improved VOCs adsorption from outdoor and indoor air.

Modeling the selectivity of indoor pollution gases over N2 on covalent organic frameworks.

The selectivity of indoor pollution gases (including formaldehyde, benzene, and toluene) over N2 on a set of 37 covalent organic frameworks (COFs) was modeled by combining classical grand canonical Monte Carlo (GCMC) methods and periodic density functional theory with dispersion correction (DFT-D2). The pore volume, pore size, and the isosteric heat (Q st) of gases on COFs were investigated to explore the origin of the high selectivity of pollution gases over N2. We found that the size match between the pore of the COFs and the corresponding pollution gases is the key factor for high selectivity. Additionally, the Q st for the investigated four gases follows the order of toluene > benzene > formaldehyde > N2, which is consistent with the order of selectivity. Furthermore, the favorite sites and interaction energies of pollution gases on COFs were calculated by the periodic DFT-D2 method. Our simulation procedure offers an alternative approach with which to evaluate or design the best candidate porous materials in capture pollution gases.

VOCs 연소용 Mn-PC 촉매 특성

In this study, the catalytic activity of Mn-Phthalocyanine (Mn-PC) for VOCs (acetadehyde, propionaldehyde and toluene) combustion was determined. The reaction was carried out in a fixed bed reactor at the temperature range of . We investigated the physicochemical properties of Mn-PC before and after the pretreatment (air, , 1 hr, 60 cc/min) by TGA (Thermogravimetric Analyzer), BET (Brunauer Emmett Teller), EA (Elemental Analyzer), XRD (X-ray Diffractometer) and SEM (Scanning Electronic Microscope). By TGA analysis, 88 wt.% mass loss of Mn-PC was found at . The BET surface area of Mn-PC increased after the pretreatment. The decomposition and combustion of organic components in Mn-PC were observed by EA analysis. We also confirmed that Mn-PC had transformed into a new manganese oxide phase () after the pretreatment by XRD analysis. By SEM analysis, many of the micropores generated during the pretreatment were found. The catalytic activity of Mn-PC with the pretreatment for propionaldehyde combustion was higher than that of and fresh Mn-PC. It showed the catalytic activity of Mn-PC with the pretreatment for VOCs combustion by the order of toluene

Adsorption and degradation of model volatile organic compounds by a combined titania–montmorillonite–silica photocatalyst

A series of adsorptive photocatalysts, combined titania–montmorillonite–silica were synthesized. The resultant photocatalysts consisted of more and more spherically agglomerated TiO 2 particles with increasing of TiO 2 content, and anatase was the only crystalline phase with nano-scale TiO 2 particles. With increasing of the cation exchange capacity to TiO 2 molar ratio, specific surface area and pore volume increased very slightly. In a fluidized bed photocatalytic reactor by choosing toluene, ethyl acetate and ethanethiol as model pollutants, all catalysts had relatively high adsorption capacities and preferred to adsorb higher polarity pollutants. Langmuir isotherm model better described equilibrium data compared to Freundlich model. Competitive adsorptions were observed for the mixed pollutants on the catalysts, leading to decrease adsorption capacity for each pollutant. The combined titania–montmorillonite–silica photocatalyst exhibited excellent photocatalytic removal ability to model pollutants of various components. Almost 100% of degradation efficiency was achieved within 120 min for each pollutant with about 500 ppb initial concentration, though the efficiencies of multi-component compounds slightly decreased. All photocatalytic reactions followed the Langmuir–Hinshelwood model. Degradation rate constants of multi-component systems were lower than those for single systems, following the order of toluene < ethyl acetate < ethanethiol, and increased with the increase of adsorption capacities for different pollutants of various components.

A Study on the Discharge of Volatile Organic Compounds in Indoor Air of Newly-constructed Apartment Houses

Because of the building is made airtight, Indoor Air Quality(IAQ) is go from bad to worse. There are many source of indoor pollution in any home. These include irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. Such immediate effects are usually short-term and treatable. In this study was measured and analyzed VOCs exposure levels and characteristic of Indoor air pollutant from new apartments in Korea. VOCs were measured indoor pre-residential and residential in new apartment and analyzed GC/MS. The concentration levels of indoor respirable TVOC were found to be higher than those of outdoor TVOC for new apartments. Before occupation, the average indoor and outdoor concentrations were 1498.61 ug/m3 and 468.38 ug/m3, respectively. After being occupied, the average indoor and outdoor concentration were 847.04 ug/m3 and 102.84, respectively. The concentrations of TVOC in new apartments before occupation were shown in the order of Toluene(328.12 ug/m3) > m,p-Xylene(163.67 ug/m3) > Ethylbenzene(80.70 ug/m3)>o-XYlene (67.04ug/m3). In addition, the TVOCs concentrations after occupation were also found in the order of Toluene (272.28 ug/m3) > m.p-Xylene(121.79 ug/m3) > Ethylbenzene(53.92 ug/m3)>O-Xylene(24.94 ug/m3). As a result, the concentrations of VOCs in new apartment houses were shown to be affected by indoor environment according activity patterns. So new apartments need to be controled in indoor air quality so that the residents can have more comfortable and healthier living environment.