Decomposition Of Chlorobenzene Research Articles

Nonthermal plasma coupled with liquid-phase UV/Fe–C for chlorobenzene removal

Catalyst poisoning problems limit the application of gas-solid non-thermal plasma (NTP) catalyzed decomposition of chlorinated volatile organic compounds (Cl–VOCs). To mitigate the catalyst deactivation, catalyst iron-loaded activated carbon (Fe–C) was added to the UV-activated liquid phase downstream of the NTP reactor (NTP + UV/Fe–C(L)) for the degradation of chlorobenzene (CB) in this study. The CB removal efficiency and mineralization efficiency (MR) of NTP + UV/Fe–C(L) were up to 94% and 68%, respectively, which were increased by 39% and 30% compared with the single NTP system. Compared with the conventional gas-solid NTP + UV/Fe–C(S) system, the stability of the NTP + UV/Fe–C(L) system was significantly improved due to the dissolved organic intermediates and low residuals on the catalyst surface. Reactive oxygen species ·OH and ·O2− dominated the decomposition of CB in the liquid phase, and with the help of UV, much more ·OH and ·O2− were produced by Fe–C catalytic O3. In addition, Fe–C improved the removal of CB by increasing its absorption mass transfer coefficient from 0.0016 to 0.0157 s−1. The degradation pathway of CB in the NTP + UV/Fe–C(L) system was proposed based on the detected organic intermediates. Overall, this study provides a new tactic to solve the catalyst poisoning problem in the NTP catalytic oxidation of Cl–VOCs.

Rod‐Like MnOx Catalyst Derived from Mn‐MOF‐74 for Chlorobenzene Oxidation at Low Temperature

AbstractIn this study, a series of MnOx catalysts were prepared by pyrolysis of Mn‐MOF‐74 precursors. The calcination temperature had influence on the structure and catalytic performance of MnOx catalysts in the catalytic oxidation of chlorobenzene. Their physicochemical properties were characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption, X‐ray photoelectron spectroscopy (XPS), H2 temperature programmed reduction (H2‐TPR) and Fourier transform infrared (FTIR), respectively. The order of catalytic activity was as follows: rod‐like MnOx‐700 > rod‐like MnOx‐600 > boat‐like MnOx‐800. The MnOx‐700 catalysts exhibited excellent activity for chlorobenzene (CB) decomposition, and the T90 (temperature with CB conversion of 90 %) was 225 °C. The main reason was that MnOx‐700 inherited the advantage of Mn‐MOF‐74 with high specific surface area, and had higher ratio of Mn3+/Mn4+ (2.51) and Osur/Ototal (0.53). Meanwhile, the MnOx‐700 can maintain over 90 % CB conversion at elevated temperature for 100 h. This work can provide an idea for the further development of high efficiency catalysts prepared via MOF‐template in the CB decomposition.

Non-thermal plasma coupled with MOx/γ-Al2O3 (M: Fe, Co, Mn, Ce) for chlorobenzene degradation: Analysis of byproducts and the reaction mechanism

Chlorinated volatile organic compounds (VOCs) such as chlorobenzene pose serious human health and environmental risks, but are resistant to elimination techniques that are traditionally applied to Cl-free VOCs. Non-thermal plasma (NTP) offers a promising technique to decompose chlorobenzene, but its application remains limited owing to low COx selectivity and the generation of toxic byproducts. To address these problems, this study investigated chlorobenzene degradation in NTP coupled with MOx/γ-Al2O3 (M: Fe, Co, Mn, Ce) catalysts. The combination of NTP with MOx/γ-Al2O3 remarkably improved the removal efficiency (RE), mineralization rate (MR), Cl selectivity (SCl) and energy yield (EY) of chlorobenzene abatement, and decreased the production of residual O3. CoOx/γ-Al2O3 exhibited the best performance among these tested catalysts with higher RE, MR, SCl and EY by 26.06%, 25.52%, 33.03% and 2.41 g/kWh, respectively, at 510 J/L, compared with those of the NTP alone system. Several catalyst characterizations were applied to explore the relation between the catalyst characteristics and chlorobenzene abatement efficacy in NTP. The results indicate that the NTP catalytic oxidation of chlorobenzene strongly depends on the reducibility and acidity of the MOx/γ-Al2O3 samples, whereas the textural properties of the catalysts exert a limited influence on chlorobenzene degradation. High-resolution gas chromatography and high-resolution mass spectrometry analyses verified for the first time that PCDD/Fs were generated during chlorobenzene degradation in NTP catalytic reactions. A plausible decomposition mechanism of chlorobenzene in the NTP catalytic system is speculated according to the organic intermediates generated during chlorobenzene decomposition.

Removal of chlorobenzene over LaMnO3 and OMS-2 catalysts in a dielectric barrier discharge reactor

Plasma-catalytic removal of chlorobenzene (CB) was conducted in a dielectric barrier discharge (DBD) reactor over two manganese-based catalysts, LaMnO3 and cryptomelane-type octahedral molecular sieve (OMS-2). The physicochemical properties of two catalysts were characterized by XRD, SEM, TEM, BET, XPS and H2-TPR. It was shown that OMS-2 catalyst had larger surface area, smaller particle size, better redox properties, higher ratio of Mn4+/Mn3+ and higher content of surface-adsorbed oxygen (Oads). The introduction of manganese-based catalysts enhanced CB removal, increased the CO2 selectivity, and inhibited ozone (O3) and NOx formation. OMS-2 exhibited a better degradation, mineralization and energy yield, with 89.5% of CB degradation, 57.6% of CO2 selectivity and 0.54 g kWh−1 at discharge voltage of 6 kV, than LaMnO3 in the NTP-catalytic reactor and this was ascribed to more active sites, more Oads, higher redox property and better O3 decomposition ability on OMS catalyst surface. The two manganese-based catalysts were stable in the NTP-catalysis system although some intermediate byproducts were deposited on the catalyst surface during the 24-h activity cycling tests. Moreover, the intermediate byproducts were analyzed by GC/MS, and then the possible degradation pathways of CB decomposition in the plasma-catalysis system were suggested.

Decomposition of gaseous chlorobenzene using a DBD combined CuO/α-Fe2O3 catalysis system

ABSTRACT Copper oxide and hematite (CuO/α-Fe2O3) composite catalysts were prepared by using goethite as precursor adopted impregnation way and applied to the dielectric barrier discharge (DBD) catalytic decomposition of gaseous chlorobenzene. The CuO/α-Fe2O3 composite was characterised by X-ray diffraction, Brunauer–Emmett–Teller method, scanning electron microscopy and X-ray photoelectron spectrometer technique. The decomposition efficiency and energy yield of gaseous chlorobenzene in DBD catalysis system were studied by a function of gas flow rate, initial concentration and input voltage. The results showed that the CuO/α-Fe2O3 composite catalyst exhibited remarkable performance on chlorobenzene decomposition when the molar ratio was 0.4 and calcination temperature was 450°C. When the chlorobenzene initial concentration was 230 mg m−3, the chlorobenzene decomposition efficiency and mineralisation rate on the DBD catalysis system reached 73.33% and 63.37%, respectively, its decomposition and mineralisation efficiency were enhanced about 20.5% and 16.61%, respectively, compared with the bare DBD system, and it also benefited to significantly reduce the ozone and NO2 by-products. The possible pathway of chlorobenzene decomposition in the DBD catalytic hybrid system was proposed based on the products analysis.

Catalytic Oxidation of Chlorobenzene over Pd-TiO2 /Pd-Ce/TiO2 Catalysts

A series of Pd-TiO2/Pd-Ce/TiO2 catalysts were prepared by an equal volume impregnation method. The effects of different Pd loadings on the catalytic activity of chlorobenzene (CB) were investigated, and the results showed that the activity of the 0.2%-0.3% Pd/TiO2 catalyst was optimal. The effect of Ce doping enhanced the catalytic activity of the 0.2% Pd-0.5% Ce/TiO2 catalyst. The characterization of the catalysts using BET, TEM, H2-TPR, and O2-TPD showed that the oxidation capacity was enhanced, and the catalytic oxidation efficiency was improved due to the addition of Ce. Ion chromatography and Gas Chromatography-Mass Spectrometer results showed that small amounts of dichlorobenzene (DCB) and trichlorobenzene (TCB) were formed during the decomposition of CB. The results also indicated that the calcination temperature greatly influenced the catalyst activity and a calcination temperature of 550 °C was the best. The concentration of CB affected its decomposition, but gas hourly space velocity had little effect. H2-TPR indicated strong metal–support interactions and increased dispersion of PdO in the presence of Ce. HRTEM data showed PdO with a characteristic spacing of 0.26 nm in both 0.2% Pd /TiO2 and 0.2% Pd-0.5% Ce/TiO2 catalysts. The average sizes of PdO nanoparticles in the 0.2% Pd/TiO2 and 0.2% Pd-0.5% Ce/TiO2 samples were 5.8 and 4.7 nm, respectively. The PdO particles were also deposited on the support and they were separated from each other in both catalysts.

A comparative study of the catalytic oxidation of chlorobenzene and toluene over Ce-Mn oxides

The morphology effects on the activity and stability of Ce-Mn oxide catalysts for chlorobenzene (CB) and toluene oxidation were compared and investigated in this work. Ce-Mn nano-sheets (CMS), nano-particles (CMP) and nano-rods (CMR) were firstly prepared. The obvious morphology effects on the reactions were observed: the activity for toluene oxidation followed the order of CMS > CMP > CMR. In contrast, the activity for CB oxidation followed the order of CMR > CMP > CMS. For toluene oxidation, toluene adsorption and the CH bond dissociation occurred at lower temperatures on the CMS catalyst. The experimental results demonstrated that the higher content of surface adsorbed oxygen species and oxygen vacancies, as well as the enhanced Olatt species mobility of the CMS catalyst were responsible for its highest catalytic activity. For CB oxidation, inactive planar CB adsorption on the 2D surface of CMS catalyst and the strongly adsorbed Cl species from the CB decomposition resulted in serious deactivation of the catalyst. On the other hand, CB adsorption and the C-Cl bond dissociation occurred at lower temperatures on the CMR catalyst, Cl-contained species can be easily removed during the Deacon Reaction and gas phase oxygen can be adsorbed on the CMR surface to replenish the consumed oxygen, resulting in the improved activity and stability. These results showed that the catalytic performance of Ce-Mn oxides for CB and toluene oxidation was greatly affected by their morphologies.

Manganese-Doped CeO₂ Nanocubes for Catalytic Combustion of Chlorobenzene: An Experimental and Density Functional Theory Study.

Manganese oxide (MnOx) supported on CeO2 nanocubes (MnOx/CeO2) were synthesized and tested for the catalytic combustion of chlorobenzene (CB), which was taken as a model compound of chlorinated volatile organic compounds (CVOCs). The catalytic activity tests demonstrated that MnOx/CeO2 nanocube catalysts exhibited a catalytic activity significantly better than that of bare CeO2 nanocubes, indicating MnOx plays a significant role for CB oxidation. To illustrate the effect of MnOx on the CeO2 nanocubes, experimental and theoretical methods such as density functional theory (DFT) calculations were carried out. Experimental characterization testified that the introduction of MnOx to CeO2 nanocubes brought the facile reduction of cerium species, larger amount of Oα species and oxygen vacancies, which lead to the enhanced catalytic performance of MnOx/CeO2 nanocube. Furthermore, DFT calculations clearly validated that MnOx/CeO2 (100) models could form the oxygen vacancies more easily, and CB molecules were preferentially adsorbed on the MnOx/CeO2 (100) models than on the CeO2 (100) models, which facilitated the easier formation of C-O* bond; this facile bond formation enabled faster CB decomposition into COx, thereby a higher CB conversion on the MnOx/CeO2 (100) could be found. Therefore, the vital role of MnOx can be successfully elucidated by both experimental and theoretical methods. Hence, this finding can be utilized for enhanced catalytic performance of CeO2 nanocube catalysts for the CVOCs elimination.

Non-thermal plasma catalysis for chlorobenzene removal over CoMn/TiO2 and CeMn/TiO2: Synergistic effect of chemical catalysis and dielectric constant

The decomposition of chlorobenzene (CB) in a non-thermal plasma (NTP) catalysis combined reactor was investigated. CoMn/TiO2 and CeMn/TiO2 were prepared using a deposition–precipitation method. CB decomposition, carbon balance, selectivity of CO2, and the byproducts of NOx and O3 were investigated. NTP catalysis provided significantly better CB removal efficiency and CO2 selectivity than did the plasma alone. CoMn/TiO2 exhibited better removal efficiency than CeMn/TiO2 in the NTP-catalysis reactor, but the performance of the catalysts during the thermal catalytic oxidation was reversed without the NTP. To reveal the activity difference with CB decomposition in the NTP-catalysis hybrid system, the dielectric constant and the physicochemical properties of CoMn/TiO2 and CeMn/TiO2 were analyzed. The plasma, which was affected by the dielectric constant, played a dominant role in this hybrid system. The reducibility of the catalysts promoted the CO2 selectivity and O3 decomposition. The CoMn/TiO2 was remarkably stable in the NTP-catalysis hybrid system during extended testing.

Ion-Exchange of Cu2+ Promoted Layered Perovskite K2La2Ti3O10 for Photocatalytic Degradation Chlorobenzene under Simulated Solar Light Irradiation

The layered perovskite, K2La2Ti3O10 was prepared by sol-gel method. Ion-exchange of Cu2+ was prepared to improve the photocatalytic activity of K2La2Ti3O10 for chlorobenzene degradation under simulated solar light irradiation. The original K2La2Ti3O10 and Cu2+/K2La2Ti3O10 were characterized by power X-ray diffraction, UV-visible diffuse reflectance spectroscopy, and specific surface area measurement. The XRD analysis shows that Cu2+ ions is incorporated in place of K+ ions and the grain growth is inhibited by ion-exchange. With the rise of calcination temperature, more interlayer Cu2+ was converted into new crystal phase CuO. The degradation ratio reaches 51.1% on Cu2+/K2La2Ti3O10 calcined at 500 °C in air, which is higher 16.9% than the original K2La2Ti3O10. It should be ascribed to the narrow interlayer distance, the formation of CuO, smaller grain size, and the high visible light absorption on the surface of Cu2+/K2La2Ti3O10 calcined at 500 °C. It is found that the exposure of CO2 could promote the photocatalytic activity of Cu2+/K2La2Ti3O10. It also suggests that CO2 is involved in the reduction to form benzaldehyde during decomposition of chlorobenzene.

Activation of sodium percarbonate with ferrous ions for degradation of chlorobenzene in aqueous solution: mechanism, pathway and comparison with hydrogen peroxide

Environmental contextIt is practicable to remediate chlorobenzene-contaminated groundwater by in situ chemical oxidation. This study shows highly efficient degradation of chlorobenzene by an Fe-based process in a wide range of pH values. The technology is feasible for the removal of chlorobenzene from aqueous solutions and is appropriate for remediation of groundwater. AbstractSodium percarbonate (SPC) could be applied as a strong oxidant to degrade organic compounds activated by transition metals. In this study, the degradation performance of chlorobenzene (CB) in the Fe2+-catalysed SPC system was investigated at different Fe2+ and SPC concentrations and pH conditions. Fe2+/Fe3+ conversion was also studied, and the SPC system was compared with the H2O2 and H2O2/Na2CO3 systems. Free radicals were identified through scavenging tests and electron paramagnetic resonance (EPR) experiments, and the reaction intermediates and by-products were determined as well. The results show that CB was completely removed when the molar concentration ratio of Fe2+/SPC/CB was 8 : 8 : 1 and that the decomposition of CB increased as the initial Fe2+/SPC dosage increased. The optimal molar concentration of Fe2+/SPC/CB was 2 : 1 : 1, and the degradation rate was inhibited when increasing or decreasing Fe2+ or SPC. CB degradation was not significantly affected by variation of initial pH, and the variation of pH during the degradation process corresponded well with the degree of Fe2+ to Fe3+ conversion and the formation of •OH. It was confirmed that •OH, O2•− and 1O2 participate in the degradation process. Moreover, not all the •OH takes part in the degradation process, as some transforms into O2•− and 1O2. The same degradation efficiency was obtained when replacing SPC by equal stoichiometric amounts of H2O2, compared with inhibition with the addition of Na2CO3. Further, a likely degradation pathway for CB is proposed based on the identified products. These results show that the Fe2+/SPC system can form the basis of a promising technology for the remediation of CB-contaminated groundwater.

Decomposition of trace chlorobenzene over V<SUB align="right">2O<SUB align="right">5-WO<SUB align="right">3/TiO<SUB align="right">2-based catalysts in simulated flue gas

Commercial and laboratory-prepared V2O5-WO3/TiO2-based catalysts with different compositions were tested for catalytic decomposition of chlorobenzene (ClBz) in simulated waste combustion flue gas. Resonance enhanced multiphoton ionisation-time of flight mass spectrometry (REMPI-TOFMS) was employed to measure real-time trace concentrations of ClBz contained in the flue gas before and after use of the catalyst. The results showed that the ClBz decomposition efficiency was significantly enhanced when nano-TiO2 instead of conventional TiO2 was used as the catalyst support. No promotion effects were found in the ClBz decomposition process when the catalysts were wet-impregnated with CuO and CeO2. A comparison between ClBz and benzene decomposition on the V2O5-WO3/TiO2-based catalyst showed that different active sites were likely involved in the decomposition mechanism, and the V=O and V-O-Ti groups may only work to catalyse the degradation of the phenyl group and the benzene ring rather than the C-Cl bond.

Ozone-assisted UV254 nm photodegradation of gaseous ethylbenzene and chlorobenzene: Effects of process parameters, degradation pathways, and kinetic analysis

Ultraviolet photodegradation can destroy a wide range of organic compounds and has gained considerable interest for use in reducing environmental pollution. In the present study, ozone-assisted UV photodegradation was developed for the decomposition of gaseous ethylbenzene (EB) and chlorobenzene (CB). The effects of various experimental parameters were investigated, namely initial concentration, initial ozone addition, relative humidity, and reaction time. The results showed that an ozone/EB ratio of 2.5 and an ozone/CB ratio of 1.5 increased the conversion efficiencies 13.0 and 6.3 times, respectively, compared with photolysis alone. The relative humidities of the reaction media affected the target conversions, and also the dominant oxidizer in the conversion process (O3 for EB and hydroxyl radicals for CB). Possible pathways and mechanisms were suggested on the basis of the intermediates identified, some of which were more soluble and biodegradable than the target compounds. Two kinetic models, based on initial concentration and ozone addition, were developed to describe the EB and CB conversion behaviors. The preliminary results indicated that ozone-assisted photodegradation enhanced gaseous EB and CB decomposition, and that this could be a promising technology for the conversion of recalcitrant and insoluble volatile organic compounds.

Decomposition of Chlorobenzene by Thermal Plasma Processing

Decomposition of chlorobenzene as a model molecule of aromatic chlorinated compounds was studied in radiofrequency thermal plasma both in neutral and oxidative conditions. Optical emission spectroscopy was applied for the evaluation of the plasma excitation and molecular rotational-vibrational temperature. Atomic (C, H, O) and molecular (CH, OH, C2) radicals were identified, while the morphology of the formed soot was characterized by electron microscopy. Organic compounds adsorbed on the surface of the soot after plasma processing were comprised of various polycyclic aromatic hydrocarbons (PAH) and chlorinated PAH molecules. Their amount was greatly affected by experimental conditions, especially the oxygen content and plate power. The higher input power reduced the ring number of the PAH molecules. Addition of oxygen significantly reduced the amount of both PAHs chlorinated PAH molecules but enhanced the formation of polychlorinated benzene compounds.

Catalytic combustion of chlorobenzene over Ru-doped ceria catalysts

CeO2 and Ru doped CeO2 nanoparticles with small particle sizes (∼7nm) and high surface area (∼100m2g−1) were prepared by a simple precipitation/coprecipitation method and aqueous NaOH solution (10wt%) as the precipitating agent, and characterized by XRD, N2 adsorption, TEM/HRTEM, Raman, XPS and H2-TPR. The catalytic combustion of chlorobenzene (CB) was investigated for the first time. The results revealed that the Ru doped CeO2 catalysts exhibit an outstanding catalytic activity (T90% below 250°C) and stability (at least 82h at 275°C) for CB decomposition. The better stability of the Ru-CeO2 catalysts can be ascribed to the inorganic chlorine species or dissociative Cl adsorbed on active sites can be removed rapidly via the Deacon process catalysized by RuO2 component with extraordinary stability (limited chlorination and easier Cl2 evolution).

Integrating Fluidized Copper/Iron Bimetal Nanoparticles and Microwave Irradiation for Treating Chlorobenzene in Aqueous Solution

In this research, MW irradiation is combined with copper/iron bimetal (Cu/Fe) nano-scale particles suspended in aqueous chlorobenzene (CB) solution to reduce the CB activation energy for enhancing its decomposition. When the metal particles are fluidized in solution, their surface area to absorb the MW energy will increase so that the heat converted from the absorbed MW energy will be distributed evenly in the solution to enhance CB decomposition. Laboratory results show that when MW energy is applied at 250 W for 300 sec to irradiate 100 mg L-1 of CB solution containing 1 g of fluidized Cu/Fe bimetallic particles, the CB removal rate is improved by 1.3 times (95.0% vs. 76.2%), and the activation energy is lowered by 3.6%. The integrated fluidized copper/iron bimetal nanoparticle and Microwave Irradiation system is effective in treating toxic organic substances as demonstrated in this study.

Catalytic combustion of chlorobenzene over Mn-Ce-La-O mixed oxide catalysts

A series of Mn(x)-CeLa mixed oxide catalysts with different compositions prepared by sol-gel method were tested for the catalytic combustion of chlorobenzene (CB), as a model of chlorinated aromatics. Mn(x)-CeLa catalysts with the ratios of Mn/(Mn + Ce + La) in the range from 0.69 to 0.8 were found to possess high catalytic activity in the catalytic combustion of CB. The stability and deactivation of Mn(x)-CeLa catalysts were studied by other assistant experiments. Mn(x)-CeLa catalysts can deactivate below 330 °C, due to the strong adsorption of Cl species produced during the decomposition of CB. Nevertheless, the increase in oxygen concentration can enhance the resistance to Cl poisoning through the reaction of surface oxygen species with residual chlorine. At 350 °C, high activity, good selectivity and desired stability were observed over Mn(x)-CeLa catalysts.

Degradation of Chlorobenzene by the Hybrid Process of Supercritical Water Oxidation and TiO2 Photocatalysis

A novel hybrid process of hydrothermal or supercritical water oxidation and TiO2 photocatalysis was developed to examine the degradation of chlorobenzene as a model of the oxidative decomposition of organic pollutants. Aqueous solutions of chlorobenzene containing H2O2 as the oxidizing agent and/or colloidal TiO2 nanoparticles as catalyst, were fed into the reactor with the temperature and the pressure controlled to be T = 25–400°C and P = 30 MPa, respectively. Chlorobenzene was considerably decomposed in the presence of H2O2 under hydrothermal conditions for T ≧ 300°C. It appeared that photocatalytic decomposition of chlorobenzene takes place at all temperatures by colloidal TiO2 nanoparticles under irradiation with near-UV light. We have realized the synergic decomposition of chlorobenzene by the coexistence of H2O2 and TiO2 in which maximum conversion is more than 80% under irradiation at T = 200°C.

Combining zero-valent iron nanoparticles with microwave energy to treat chlorobenzene

In this research, MW energy is combined with nanoscale zero-valent iron (ZVI or Fe 0) particles suspended in aqueous chlorobenzene (CB) solution for enhancing the CB decomposition. When MW energy is applied at 250 W for 300 s to irradiate 100 mg/L of CB solution containing 1 g ZVI particles, the CB activation energy is decreased by 8.6 kJ/mol (21.9–13.3 kJ/mol) so that the CB removal efficiency is enhanced 4.6 times (82.8% vs. 18.1%). The reductive dechlorination reaction occurs at the surface of zero-valent iron particles; the organic substance in the bulk of the solution diffuses to the iron particle surface to contact the iron particle for the reductive dechlorination reaction to occur. When MW radiation penetrates the solution to reach the surface of suspended Fe 0 particles, the radiation accelerates the iron oxidization, and increases the surface activity site thus enhancing the CB decomposition rate. Hence the MW-induced zero-valent iron can reduce the CB activation energy that contributes to the enhanced rate of CB removal.

ダイオキシン汚染土壌からのダイオキシン抽出法およびＲｕ・α‐Ｆｅ・Ｆｅ３Ｏ４複合粒子による抽出ダイオキシンの分解

To carry out the decomposition of chlorinated aromatic compounds such as dioxins, which are hard to decompose at room temperature, nanoscale α-Fe · Fe3O4 composite particles were synthesized via α-FeO(OH) obtained by the reaction of ferrous sulfate and sodium carbonate aqueous solutions and contained 0.25 wt% precious metals (Pt, Pd, Rh and Ru). As the result of the decomposition of chlorobenzene (CB) using the composite particles containing precious metals, it was shown that Rh · α-Fe · Fe3O4 and Ru · α-Fe · Fe3O4 composite particles exhibit superior dechlorination function. Ru · α-Fe · Fe3O4 composite particles were selected because of their low price. For the application of dioxin decomposition at room temperature in contaminated soil, an extractive reagent was selected. Successively, the decomposition of dioxins in extracted-reagent- suspended soil using Ru · α-Fe · Fe3O4 composite particles was carried out at room temperature for seven days, and the initial Toxicity Equivalency Quantity (TEQ) values of dioxins in the solvents and soils decreased to 41-63% after the decomposition.