Abstract In this work, a series of coal-based active carbon (CAC) catalysts loaded by Al2O3 were prepared by sol-gel method and used for the simultaneous catalytic hydrolysis of carbonyl sulfide (COS) and carbon disulfide (CS2) at relatively low temperatures of 30–70 °C. The influences of calcinations temperatures and operation conditions such as: reaction temperature, O2 concentration, gas hourly space velocity (GHSV) and relative humidity (RH) were also discussed respectively. The results showed that catalysts with 5.0 wt% Al2O3 calcined at 300 °C had superior activity for the simultaneous catalytic hydrolysis of COS and CS2. When the reaction temperature was above 50 °C, catalytic hydrolysis activity of COS could be enhanced but that of CS2 was inhibited. Too high RH could make the catalytic hydrolysis activities of COS and CS2 decrease. A small amount of O2 introduction could enhance the simultaneous catalytic hydrolysis activities of COS and CS2.

In this work, a series of coal-based active carbon (CAC) catalysts loaded by Al2O3 were prepared by sol-gel method and used for the simultaneous catalytic hydrolysis of carbonyl sulfide (COS) and carbon disulfide (CS2) at relatively low temperatures of 30–70 °C. The influences of calcinations temperatures and operation conditions such as: reaction temperature, O2 concentration, gas hourly space velocity (GHSV) and relative humidity (RH) were also discussed respectively. The results showed that catalysts with 5.0 wt% Al2O3 calcined at 300 °C had superior activity for the simultaneous catalytic hydrolysis of COS and CS2. When the reaction temperature was above 50 °C, catalytic hydrolysis activity of COS could be enhanced but that of CS2 was inhibited. Too high RH could make the catalytic hydrolysis activities of COS and CS2 decrease. A small amount of O2 introduction could enhance the simultaneous catalytic hydrolysis activities of COS and CS2.

Lipase Novozym 435 was used as catalyst to degrade P(BS-co-DGS), which was a kind of PBS-based copolyester modified with diethylene glycol (DEG), in a THF/toluene mixed solvent system. P(BS-co-DGS) copolyesters were synthesized by copolymerization and characterized by 1H NMR. GPC and TGA were used to investigate average molecular weight and thermal property before and after degradation, respectively. After degraded by N435 for 30 h, the Mn of P(BS-co-DGS)10 (DEG content 10%) decreased from 8.33×104 to 3.52×104 g·mol-1 with some yellow oil droplets of oligomers appearing. And the initial decomposition temperature (the temperature at 5% mass loss) of P(BS-co-DGS)10 changed from 300.6 to 178.9. MALDI-TOF-MS results showed that none of DEG oligomers appeared in P(BS-co-DGS)10 degradation products. However, when the DEG content increased to 20%, there were the DEG circle oligomers as well as linear oligomers in the degradation products.

The blank microwave coal-based activated carbons (MCAC) and blank microwave coconut shell activated carbons (MCSAC) were tested for simultaneous catalytic hydrolysis of carbonyl sulfide (COS) and carbon disulfide (CS2) at relatively low temperature (at 50°C). MCAC and MCSAC loaded by Fe–Cu–Ni metal mixed oxides were prepared by sol–gel method, and also tested for the simultaneous catalytic hydrolysis process. The results showed that Fe–Cu–Ni/MCSAC catalyst had the superior activity for the simultaneous catalytic hydrolysis of COS and CS2. These modified catalysts were characterized by XRD, BET, EDS and XPS, the results of which can help us to understand the reasons of the superior catalytic activity and the reasons of catalyst deactivation. Lower generation of sulfate (K3Na(SO4)2), high specific surface areas and more pore sizes of 0.3–1.2nm and 3.5–4.0nm may be the important role in COS and CS2 catalytic hydrolysis reaction. The XPS results showed that most of products on the exhausted catalysts were S/SO42- species which accumulated on the active carbon’s surface and had a negative effect on the hydrolysis activity, and the contents of S/SO42- species of exhausted Fe–Cu–Ni/MCAC were higher than which of exhausted Fe–Cu–Ni/MCSAC catalysts.

The reactivation of CoNiAl calcined hydrotalcite-like compounds for the hydrolysis of carbonyl sulfide was studied. The catalytic activity could be recovered after immersing Na2CO3 and calcining catalyst under air flow at 350 degrees C. The fresh, deactivated, and reactivated catalysts were characterized by various techniques. The presence of sodium introduced in the reactivation was the main source of basicity. It combined with the active center NiO to recover the catalytic activity.

The catalytic performance of COS hydrolysis over calcined CoNiAl hydrotalcite-like compounds (HTLCs) modified by cerium was investigated. All catalysts were prepared by thermal decomposition of hydrotalcite-like precursors synthesized by co-precipitation method and characterized by various technologies. Among all catalysts studied, catalyst CoNiAl-50 exhibited excellent COS conversion. The changes of structural properties, oxidative properties of catalysts and increase of surface defect sites mainly accounted for the enhancements of the catalytic activities with addition of cerium. Element sulfur and the sulfate species accumulated on the surface which might contribute to catalyst poisoning and Ce could affect the formation and content of element sulfur and sulfate.

The adsorption of methane and carbon dioxide on two microwave-activated carbon samples at different temperatures from 298K to 323K, and the thermodynamics of adsorption have been investigated using a vacuum adsorption apparatus. Henry’s law constant and adsorption equilibrium selectivity of CO2 and CH4 on the two samples were calculated via Virial equation. The results showed that the activated carbon modified by potassium carbonate sample has the higher equilibrium selectivity for CO2 over CH4. The adsorption equilibrium data of CO2 and CH4 at various temperatures were fitted to Langmuir and Langmuir–Freundlich isotherm models. It was found the Langmuir model was better for fitting the adsorption of CH4 than CO2 and the Langmuir–Freundlich model was more suitable for description of the two gases adsorption process than Langmuir model through calculating average absolute relative error. The fitted results showed that the adsorption of CH4 was monolayer and CO2 was multilayer adsorption on the surface of two adsorbents. The isosteric enthalpies of adsorption for both adsorbates on microwave-activated carbon (MAC) and microwave-activated carbon modified with potassium carbonate (K2CO3/MAC) were calculated using the Clausius–Clapeyron equations. The isosteric heat of adsorption decreased with an increase of the surface loading on adsorbents, which means that both of MAC and K2CO3/MAC had an energetically heterogeneous surface.

In this work a series of coal-based active carbon (AC) catalysts, combined with metal oxides, were prepared by sol–gel method for carbon disulfide (CS2) hydrolysis and their performances for CS2 hydrolysis were investigated. The influences of preparing the conditions for catalytic activities were studied, namely, the kinds and amount of metal oxide, the calcination temperature, plus the types and content of alkalis. The results show that the optimum preparation conditions for the catalyst occurred with the addition of 5% ferric oxide (Fe2O3), iron (Fe): copper (Cu) (mole ratio) 5:1, and calcination temperature at 400°C. It also indicated that the catalytic hydrolysis activity increased with the intensity of bases in the order of potassium hydroxide (KOH)—5% being the best amount, potassium carbonate (K2CO3), sodium carbonate (Na2CO3). Structure and surface properties were investigated by different methods. The XRD results reveal that calcination temperature controls the crystalline phase and the generation of Fe2O3. The BET results indicate that pores (1.5–3.0nm) played an important role in the CS2 hydrolysis reaction. The XPS results show that most of CS2 hydrolysis products were sulfate ion (SO42-) species, which accumulated on the active carbon surface and had a negative effect on hydrolysis activity.

The orthogonal experiment design was employed to investigate the parameters of mixed oxides catalysts derived from a series of hydrotalcite-like compounds preparation through the coprecipitation method.The effects of metal combination,pH value,M2+/M3+,the ratio of divalent metal,calcination temperature,temperature of hydrothermal treatment on capacity of sulfur though hydrolysis COS were investigated.The results indicated that metal combination,the ratio of divalent metal and calcination temperature had notable effect on catalytic activity(p=99%),and temperature of hydrothermal treatment had effect on catalytic activity(p=95%),while pH value and M2+/M3+ had no notable effect(p=90%).The catalysts prepared under following conditions exhibited superior catalytic activity: metal combination Co-Ni-Al,pH value of 9,M2+/M3+ of 3,divalent metal ratio of 1,calcination temperature of 350℃,hydrothermal treatment temperature of 50℃.Moreover,the catalyst under the optimized conditions of preparation was characterized by repetitive experiment and XRD.The results indicated that the sulphur capacity of the catalyst reached 7.10 g sulfur/g catalyst and the Co3O4 may be active center.

A series of microwave coal based active carbon catalysts loaded by metal oxides were prepared by a sol gel method and tested for the simultaneous catalytic hydrolysis of carbonyl sulfide (COS) and carbon disulfide (CS2) at relatively low temperatures of 50-70 degrees C. The influences of preparation conditions on catalytic activity were studied, which were the kinds and amount of additive, calcination temperatures, and types and content of alkali. The results show that catalysts with 5.0% Fe2O3 after calcining at 300 degrees C have superior activity for the simultaneous catalytic hydrolysis of COS and CS2. It also indicated that the catalytic hydrolysis activity increased with the basic intensity, following the order of KOH > K2CO3 > Na2CO3 > NaHCO3, and the optimum amount of KOH was 13%. The structure and surface properties were characterized by Xray diffractometry (XRD), Brunauer-Emmett-Teller measurements (BET), Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS). The XRD and BET results revealed that the calcination temperature controlled the crystalline phase and generation of Fe2O3 and affected the properties of specific surface area and pore structure. The XPS results showed that most of COS and CS2 hydrolysis products were sulfate ion (SO42-) species, which accumulated on the active carbon's surface and had a negative effect on the hydrolysis activity.

A novel catalyst for low temperature hydrolysis of carbonyl sulfide (COS) was prepared by thermal decomposition of Zn–Ni–Al hydrotalcite-like compounds (HTLCs). As the key factors of catalyst activity, effects of calcination temperature have been studied. The samples were carefully characterized by XRD, FTIR, SEM, CO2-TPD and N2 adsorption/desorption. Results showed that HTLCs calcined at 350°C exhibited excellent activity due to the production of more M–O pairs which are active sites of the hydrolysis of COS. However, calcination at 500°C led to the destruction of pore structure and reduction of active sites, ultimately led to a lower COS conversion.

Catalytic hydrolysis technology of carbon disulfide(CS2) at low temperature was reviewed,including the development in hydrolysis catalyst,reaction kinetics and deactivation mechanism.It was indicated that improving the alkaline of catalysts to pepare highly activated hydrolysis catalysts and removing CS2in one step at low temperature would be the research focus in the future.

Catalytic hydrolysis of COS over calcined CoNiAl hydrotalcite-like compounds (HTLCs) modified with slight amount of lanthanum was studied. All catalysts were characterized by X-ray diffractions (XRD), Thermogravimetric analysis (TGA), Brunauer-Emmett-Teller method (BET) and Scanning electron microscope (SEM). The catalytic activities results showed that addition of La could enhance the activity of COS hydrolysis and exhibit higher sulphur capacity. Analysis data showed the catalysts could be considered mesoporous and the surface area could be decreased with La added. La could affect the crystalline phases of NiO, Co3O4 and CoO, which may be the active components for catalytic hydrolysis of COS.

The present status of iron and steel industry of China and Yunnan were given in this work. Base on the analysis of iron and steel industry of Yunnan, we choose two steel plants (marked plant A and plant B) as the typical factories to confirm the emission factor of SO(2). The emission factor of SO(2) was achieved by mass balance method. In steel plant A, the emission factor is 9.684 (kg-SO(2)/t-steel), after flue gas desulfurization, the factor dropped to 1.476 (kg-SO(2)/t-steel). It indicates that desulfuration of sinter flue gas is important to reduce SO(2) emission. In steel plant B, the emission factor is 5.4(kg-SO(2)/t-steel) without desulfurization. However, according to Discharge Coefficients of Industrial Pollutants in the First National General Survey of Pollution Sources(Survey Handbook), the SO(2) emission factor of plant B is 4.15(kg-SO(2)/t-steel). We can see the differences exist between Yunnan's discharges of pollutants with national Survey Handbook. Because the national Survey Handbook represents the national average level and manufacturing technique and raw materials of various factories vary greatly within the country. So it's necessary to confirm the emission factor for Yunnan province.

Catalytic systems based on mixed oxides catalysts derived from a series of hydrotalcite-like compounds through the coprecipitation method were investigated for hydrolysis of carbonyl sulfide (COS) in a fixed-bed reactor. The effects of pH, temperature of synthesis and hydrothermal treatment on catalytic activity were studied. Furthermore, the samples were characterized by pH titration, X-ray diffraction (XRD) and Brunauer–Emmett–Teller method (BET). The results showed that the catalysts could be prepared by precipitating solution of (Co + Ni)/Al at pH 9.0, synthetic temperature at 25 °C, and then hydrothermal treatment at 50 °C for 12 h. The XRD patterns showed the precursors had typical hydrotalcite structure and the catalysts were mixed oxides. All catalysts could be considered mesoporous.

A series of CoNiAl composite oxide catalysts were prepared by calcining the CoNiAl hydrotalcite-like precursor at various temperatures and used in the catalytic hydrolysis of carbonyl sulfide (COS). The raw CoNiAl precursor and calcined products were characterized by various technologies. The catalyst calcined at 350 °C showed excellent activity and stability for COS hydrolysis at 50 °C and GHSV of 2000 h–1 with temperature of water saturator of 25 °C. The CoNiAl precursor was decomposed at 350 °C to form NiO accompanying spinel phase and hydroxyl groups (OH–), which were active sites of the hydrolysis of COS. With lower calcination temperature, the precursor is incompletely decomposed to form mixed oxides, thereby decreasing the catalyst activity. Increasing the calcination temperature above 350 °C led to severe sintering of NiO and other active components, causing decrease in the number of active sites. The deactivation of catalysts was also investigated.

A new type electrochemical reactor was designed for electrochemical promotion catalytic oxidation of NO, which was a flat-plate fixed-bed reactor. The experimental results showed that the process of NO catalytic oxidation could be promoted though this electrochemical reactor with Mn/TiO2and Mn-Fe, which were two kinds of selected catalysts for NO oxidation. Approximately 70% NO could be converted to NO2at 50 °C when the input voltage of electrochemical reactor was 0.5v. Moreover, the reaction rates can be adjusted with the input voltage varying.

A series of coal-based active carbon(AC) catalysts loaded by Fe-Cu,Fe-Cu-Ce and Fe-Cu-La were prepared by the sol-gel method for carbon disulfide(CS2) hydrolysis and their performances for CS2 hydrolysis in a fixed-bed reactor were investigated in this work.The results showed that the kind of rare earth oxide and its content had obvious effect on hydrolysis removal of CS2.The effects of temperature,space velocity,CS2 concentration and O2 concentration were also discussed respectively.Furthermore,the suitable operating conditions were obtained.It was found that the poisoning of hydrolysis active sites could result in the formation of sulfuric acid on the catalyst surface.

In order to investigate the effect of Ce-doping on the catalysts derived from hydrotalcite-like precursors for carbonyl sulfide(COS) hydrolysis,a series of Zn-Ni-Al-Ce hydrotalcite-like compounds were prepared by co-precipitation method and the catalytic activity of their derived composite oxides were studied at 50 oC.The effect on the structural properties caused by Ce doping was studied by the X-ray diffractometer(XRD),scanning electron microscopy(SEM) and energy dispersive spectrometer(EDS).The catalytic activities results showed that addition of Ce enhanced the catalytic activities significantly,but excessive Ce-doping had a negative effect on COS hydrolysis.XRD,SEM and EDS results illustrated that,compared with the Ce-free sample,the particle size of oxide solids decreased and the degree of dispersion increased due to Ce doping.