Preparation of PrFe_(x)Co_(1-x)O_(3)/Mt catalyst and study on degradation of 2-hydroxybenzoic acid wastewater by catalytic wet peroxide oxidation

In this study,the perovskite nanocomposite PrFe_(x)Co_(1-x)O_(3)(Pr(S))was successfully synthesized by the sol-gel method;PrFe_(x)Co_(1-x)O_(3)/Al-pillared montmorillonite(Pr(S)/Mt)catalysts were prepared by impregnation(D)method and solid-melting(G)method,respectively,with Pr(S)as the active component and Al-pillared montmorillonite as the carrier.The catalysts were applied to treat the 2-hydroxybenzoic acid(2-HA)-simulated wastewater by catalytic wet peroxide oxidation(CWPO)technique,and the chemical oxygen demand(COD)removal rate and the 2-HA degradation rate were used as indicators to evaluate the catalytic performance.The results of the experiment indicated that the solid-melting method was more conducive to preparing the catalyst when the Co/Fe molar ratio of 7:3 and the optimal structural properties of the catalysts were achieved.The influence of operating parameters,including reaction temperature,catalyst dosage,H_(2)O_(2)dosage,pH,and initial 2-HA concentration,were optimized for the degradation of 2-HA by CWPO.The results showed that 97.64%of 2-HA degradation and 75.23%of COD removal rate were achieved under more suitable experimental conditions.In addition,after the catalyst was used five times,the degradation rate of 2-HA could still reach 76.93%,which implied the high stability and reusability of the catalyst.The high catalytic activity of the catalyst was due to the doping of Co into PrFeO_(3),which could promote the generation of HO·,and the high stability could be attributed to the loading of Pr(S)onto Al-Mt,which reduced the leaching of reactive metals.The study of reaction mechanism and kinetics showed that the whole degradation process conformed to the pseudo-firstorder kinetic equation,and the Langmuir-Hinshelwood method was applied to demonstrate that catalysis was dominant in the degradation process.

Four-channel catalytic micro-reactor based on alumina hollow fiber membrane for efficient catalytic oxidation of CO

The traditional automotive catalytic converter using commercial ceramic honeycomb carriers has many problems such as high back pressure,low engine efficiency,and high usage of precious metals.This study proposes a four-channel catalytic micro-reactor based on alumina hollow fiber membrane,which uses phase inversion method for structural molding and regulation.Due to the advantages of its carrier,it can achieve lower ignition temperature under low noble metal loading.With Pd/CeO_(2) at a loading rate of 2.3%(mass),the result showed that the reaction ignition temperature is even less than 160℃,which is more than 90℃ lower than the data of commercial ceramic substrates under similar catalyst loading and airspeed conditions.The technology in turn significantly reduces the energy consumption of the reaction.And stability tests were conducted under constant conditions for 1000 h,which proved that this catalytic converter has high catalytic efficiency and stability,providing prospects for the design of innovative catalytic converters in the future.

Solar-assisted two-stage catalytic membrane reactor for coupling CO_(2) splitting with methane oxidation reaction

A two-stage catalytic membrane reactor(CMR)that couples CO_(2) splitting with methane oxidation reactions was constructed based on an oxygen-permeable perovskite asymmetric membrane.The asymmetric membrane comprises a dense SrFe_(0.9)Ta_(0.1)O_(3-σ)(SFT)separation layer and a porous Sr_(0.9)(Fe_(0.9)Ta_(0.1))_(0.9)Cu_(0.1)O_(3-σ)(SFTC)catalytic layer.In thefirst stage reactor,a CO_(2) splitting reaction(CDS:2CO_(2)→2CO+O_(2))occurs at the SFTC catalytic layer.Subsequently,the O_(2) product is selectively extracted through the SFT separation layer to the permeated side for the methane combustion reaction(MCR),which provides an extremely low oxygen partial pressure to enhance the oxygen extraction.In the second stage,a Sr_(0.9)(Fe_(0.9)Ta_(0.1))_(0.9)Ni_(0.1)O_(3-σ)(SFTN)catalyst is employed to reform the products derived from MCR.The two-stage CMR design results in a remarkable 35.4%CO_(2) conversion for CDS at 900℃.The two-stage CMR was extended to a hollowfiber configuration combining with solar irradiation.The solar-assisted two-stage CMR can operate stably for over 50 h with a high hydrogen yield of 18.1 mL min^(-1) cm^(-2).These results provide a novel strategy for reducing CO_(2) emissions,suggesting potential avenues for the design of the high-performance CMRs and catalysts based on perovskite oxides in the future.

Catalytic effects of Cu-Co~* on the thermal decomposition of AN and AN/KDN based green oxidizer and propellant samples

This paper presents the catalytic effects of Cu-Co~* catalyst on the decomposition of AN and AN/KDN based oxidizer and propellant samples. Ozawa-Flynn-Wall(OFW) iso-conversional method was used for the kinetic studies and to compute the activation energy(Ea) values for various decomposition steps of the prepared oxidizer and propellant samples in the temperature range of 50 e500C. TG-DTG experiments were carried out for both oxidizer and propellant samples at the heating rates of 3, 5, and 10C/min. AN/KDN based oxidizer samples were prepared by an evaporative co-crystallization method. Citric acid sol-gel method was used for the synthesis of Cu-Co~* catalyst. The propellant sample contains HTPB as the fuel binder along with other ingredients such as TDI, DOA, and Glycerol. The Cu-Co~* catalyst was used as 2% by weight to the total weight of catalyzed oxidizer and propellant samples. It was observed from the present study that, Cu-Co~* catalyst helps in reducing the Ea values for AN and AN based propellant samples. However, with the percentage increment of KDN in the AN crystals, Ea value increases.Further, it was observed that Cu-Co~* catalyst stabilizes the initial partial decomposition of KDN.

A highly hydrothermal stable copper-based catalyst for catalytic wet air oxidation of m-cresol in coal chemical wastewater

Catalytic wet air oxidation(CWAO) can degrade some refractory pollutants at a low cost to improve the biodegradability of wastewater. However, in the presence of high temperature and high pressure and strong oxidizing free radicals, the stability of catalysts is often insufficient, which has become a bottleneck in the application of CWAO. In this paper, a copper-based catalyst with excellent hydrothermal stability was designed and prepared. TiO_(2) with excellent stability was used as the carrier to ensure the longterm anchoring of copper and reduce the leaching of the catalyst. The one pot sol–gel method was used to ensure the super dispersion and uniform distribution of copper nanoparticles on the carrier, so as to ensure that more active centers could be retained in a longer period. Experiments show that the catalyst prepared by this method has good stability and catalytic activity, and the catalytic effect is not significantly reduced after 10 cycles of use. The oxidation degradation experiment of m-cresol with the strongest biological toxicity and the most difficult to degrade in coal chemical wastewater was carried out with this catalyst. The results showed that under the conditions of 140℃, 2 MPa and 2 h, m-cresol with a concentration of up to 1000 mg·L^(-1) could be completely degraded, and the COD removal rate could reach 79.15%. The biological toxicity of wastewater was significantly reduced. The development of the catalyst system has greatly improved the feasibility of CWAO in the treatment of refractory wastewater such as coal chemical wastewater.

Life cycle assessment of high concentration organic wastewater treatment by catalytic wet air oxidation

There have been many studies on life cycle assessment in sewage treatment,but there are scarce few studies on the treatment of industrial wastewater in combination with advanced oxidation technology,especially in catalytic wet air oxidation(CWAO).There are no cases of using actual industrialized data onto life cycle assessment.This paper uses Simapro 9.0 software to establish a life cycle assessment model for the treatment of high-concentration organic wastewater by CWAO,and comprehensively explains the impact on the environment from three aspects:the construction phase,the operation phase and the demolition phase.In addition,sensitivity analysis and uncertainty analysis were performed.The results showed that the key factors affecting the environment were marine ecotoxicity,mineral resource consumption and global warming,the operation stage had the greatest impact on the environment,which was related to high power consumption during operation and emissions from the treatment process.Sensitivity analysis showed that electricity consumption has the greatest impact on abiotic depletion and freshwater aquatic ecotoxicity,and it also proved that global warming is mainly caused by pollutant emissions during operation phase.Monte Carlo simulations found slightly higher uncertainty for abiotic depletion and toxicity-related impact categories.

Effect of samarium on the N_(2) selectivity of Sm_(x)Mn_(0.3-x)Ti catalysts during selective catalytic reduction of NO_(x) with NH_(3)

This work aims to study the improvement effect of Sm on Mn-based catalysts for selective catalytic reduction (SCR) of NO with NH3.A series of Sm_(x)Mn_(0.3-x)-xTi catalysts (x=0,0.1,0.15,0.2,and 0.3) were prepared by co-precipitation.Activity tests indicated that the Sm_(0.15)Mn_(0.15)Ti catalyst showed superior performances,with a NO conversion of 100%and N_(2)selectivity above 87%at 180–300℃.The characterizations showed that Sm doping suppressed the crystallization of TiO_(2)and Mn2O3phases and increased the specific surface area and acidity.In particular,the surface area increased from 152.2 m^(2)·g^(-1)for Mn0.3Ti to 241.7 m^(2)·g^(-1)for Sm_(0.15)Mn_(0.15)Ti.These effects contributed to the high catalytic activity.The X-ray photoelectron spectroscopy (XPS) results indicated that the relative atomic ratios of Sm^(3+)/Sm and Oβ/O of Sm_(0.15)Mn_(0.15)Ti were 76.77at%and 44.11at%,respectively.The presence of Sm contributed to an increase in surface-absorbed oxygen (Oβ) and a decrease in Mn^(4+)surface concentration,which improved the catalytic activity.In the results of hydrogen temperature-programmed reduction(H_(2)-TPR),the presence of Sm induced a higher reduction temperature and lower H_(2)consumption (0.3 mmol·g^(-1)) for the Sm_(0.15)Mn_(0.15)Ti catalyst compared to the Mn0.3Ti catalyst.The decrease in Mn^(4+)weakened the redox property of the catalysts and increased the N_(2)selectivity by suppressing N_(2)O formation from NH3oxidation and the nonselective catalytic reduction reaction.The in situ diffuse reflectance infrared Fourier transform spectra (DRIFTs) revealed that NH3-SCR of NO over the Sm_(0.15)Mn_(0.15)Ti catalyst mainly followed the Eley–Rideal mechanism.Sm doping increased surface-absorbed oxygen and weakened the redox property to improve the NO conversion and N_(2)selectivity of the Sm_(0.15)Mn_(0.15)Ti catalyst.

Fabrication of highly dispersed carbon doped Cu-based oxides as superior selective catalytic oxidation of ammonia catalysts via employing citric acid-modified carbon nanotubes doping CuAl-LDHs

In this work,the CuAl-LDO/c-CNTs catalyst was fabricated via in situ oriented assembly of layered-double hydroxides(LDHs)and citric acid-modified carbon nanotubes(c-CNTs)followed by annealing treatment,and evaluated in the selective catalytic oxidation(SCO)of NH_(3)to N_(2).The CuAl-LDO/c-CNTs catalyst presented better catalytic performance(98%NH_(3)conversion with nearly 90%N_(2)selectivity at 513 K)than other catalysts,such as CuAlO_(x)/CNTs,CuAlO_(x)/c-CNTs and CuAl-LDO/CNTs.Multiple characterizations were utilized to analyze the difference of physicochemical properties among four catalysts.XRD,TEM and XPS analyses manifested that CuO and Cu_(2)O nanoparticles dispersed well on the surface of the Cu Al-LDO/c-CNTs catalyst.Compared with other catalysts,larger specific surface area and better dispersion of CuAl-LDO/c-CNTs catalyst were conducive to the exposure of more active sites,thus improving the redox capacity of the active site and NH_(3)adsorption capacity.In-situ DRIFTS results revealed that the internal selective catalytic reduction(iSCR)mechanism was found over CuAl-LDO/c-CNTs catalyst.

High-performance liquid-phase catalytic purification of phosphine in tail gas using Pd(Ⅱ)/Cu(Ⅱ)composite

Pd/Cu liquid-phase composite was utilized as the catalyst in this study to remove PH_(3) at low temperatures.The anti-heterotoxicity of catalysts in the PH_(3) catalytic oxidation purification process was carefully explored and pioneered.The catalytic performance,thermodynamics,kinetics,and catalytic oxidation mechanism of Pd/Cu liquid-phase catalyst catalytic oxidation of PH_(3) were thoroughly investigated.The results showed that Pd/Cu has a superior catalytic effect on the removal of PH_(3) in the gas mixture under low temperature.With CO as the carrier gas,the removal efficiency of PH_(3) could be maintained at 100%for nearly 450 min,indicating that the Pd/Cu liquid phase catalyst has good resistance to heterotoxicity.According to the thermodynamic,kinetic,and related characterization results of the PH_(3) purification process,the kinetic region of the gas–liquid reaction of PH_(3) absorption by Pd/Cu solution was an interfacial reaction.Pd was the primary catalyst and Cu was the secondary catalyst,and the adsorption of PH_(3)was a primary reaction.PH_(3) was spontaneously oxidized to H_(3)PO_(4) in the Pd/Cu catalytic system during the removal process.Pd was regenerated by O_(2) and Cu,increasing the activity and stability of the Pd/Cu catalyst in the sustain and efficient purification of PH_(3) in tail gas.

A comparison between high temperature catalytic and persulfate oxidation for the determination of total dissolved nitrogen in natural waters

Total dissolved nitrogen(TDN) is an important parameter for assessing the nutrient cycling and status of natural waters.The accurate determination of TDN in natural waters is essential for assessing its contents and distinguishing different forms of nitrogen in the water.The TDN in various systems has been largely documented,and the concentrations of TDN are usually obtained using high-temperature catalytic(HTC) or persulfate oxidation(PO).However,the accuracy of these methods and their suitability for all types of natural waters are still unclear.To explore both methods in-depth,assorted samples were tested,including eight solutions composed of nitrogen-containing compounds(3 dissolved inorganic nitrogen fractions:NO_(3)^(-),NO_(2)^(-)and NH_(4)^(+);5 organic compounds:EDTA-2Na,vitamin B1,vitamin B12,amino acids,and urea) and 105 natural waters which were collected from an open ocean(Northwest Pacific Ocean,28),a marginal sea(Yellow Sea,34),an estuary(Huanghe River mouth,31),rivers(Huanghe River,4;Licun River,4),and precipitations(4 samples).The results showed that heterocycles and molecular dimensions had certain effects on the oxidation efficiency of the PO method but had little effect on HTC.There was no significant difference between the two methods for natural waters,but HTC was more suitable for deep-sea samples with low TDN concentrations(less than 10 μmol/L) and low organic activity.Overall,HTC has a relatively simple measurement process,a high degree of automation,and low error.Therefore,HTC can be recommended to determine the TDN of samples in freshwater and seawater.

Study on the catalytic degradation of sodium lignosulfonate to aromatic aldehydes over nano-CuO:Process optimization and reaction kinetics

As one of the few renewable aromatic resources,the research of depolymerization of lignin into highvalue chemicals has attracted extensive attention in recent years.Catalytic wet aerobic oxidation(CWAO)is an effective technology to convert lignin like sodium lignosulfonate(SL),a lignin derivative,into aromatic aldehydes such as vanillin and syringaldehyde.However,how to improve the yield of aromatic aldehyde and conversion efficiency is still a challenge,and many operating conditions that significantly affect the yield of these aromatic compounds have rarely been investigated systematically.In this work,we adopted the stirred tank reactor(STR)for the CWAO process with nano-CuO as catalyst to achieve the conversion of SL into vanillin and syringaldehyde.The effect of operating conditions including reaction time,oxygen partial pressure,reaction temperature,SL concentration,rotational speed,catalyst amount,and NaOH concentration on the yield of single phenolic compound was systematically investigated.The results revealed that all these operating conditions exhibit a significant effect on the aromatic aldehyde yield.Therefore,they should be regulated in an optimal value to obtain high yield of these aldehydes.More importantly,the reaction kinetics of the lignin oxidation was explored.This work could provide basic data for the optimization and design of industrial operation of lignin oxidation.

Study on the Catalytic Reforming Law of Solid-Phase Carbon and Nitrogen Sources Loaded with MnO_(2)at Low Temperatures in Tahe Heavy Oil

MnO_(2)/Melem composites were synthesized with MnO_(2)nanoparticles loaded onto the Melem using the hydrothermal method.As raw materials for C and N carriers,Melem was prepared from melamine roasted at 354℃,and KMnO_(4)as a raw material for Mn,MnO_(2)nanoparticles were prepared using the hydrothermal synthesis of KMnO_(4).Scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray diffraction(XRD),and a laser particle size analyzer were used for structural characterization,and the catalytic oxidation performance of the heavy oil was investigated at different reaction temperatures(100℃to 180℃)using MnO_(2)/Melem with an oxidant and donor protonic acid.The results showed that the synthesizedβ-MnO_(2)nanoparticles were successfully loaded onto the Melem surface;the oil samples before and after the reaction at different temperatures were subjected to SARA analysis using Fourier transform infrared(FT-IR),elemental analysis,gas chromatography-mass spectrometry(GC-MS)and viscosity tests,respectively.It was determined that the hydrocarbons in the crude oil were converted to heavy mass by oxidation reactions with the oxidant mainly through a low-temperature oxidation process below 140℃in the heavy oil when the temperature exceeds 140℃,in addition to the oxidation reaction with the oxidant,a cleavage reaction in the carbon chain occurs to form hydrocarbon substances with lower molecular weights.

无有机模板法制备Cu-ZSM-5催化剂及其选择性催化氧化苯乙烯

不使用任何有机模板剂,硝酸铜和正硅酸四乙酯(TEOS)经过酸性水解、碱性陈化和水热晶化,制备得到四配位铜修饰ZSM-5沸石(Cu-ZSM-5)。考察凝胶的Si/Al摩尔比、pH值、晶化温度和晶化时间对Cu-ZSM-5的晶型和相对结晶度的影响。采用X射线衍射(XRD)、红外光谱(FT-IR)、紫外漫反射谱和X-射线光电子能谱等手段对Cu-ZSM-5进行分析表征。结果表明:Cu-ZSM-5沸石具有MFI结构,结晶度高,无其他杂晶;铜原子以四配位为主。四配位铜是催化氧化苯乙烯的活性位点;在m(Cu-ZSM-5-50)=0.1 g、n(TBHP)/n(Styrene)=1.5、T=60℃、t=5 h条件下,苯乙烯转化率和苯甲醛选择性分别为76.5%和69.4%,表明Cu-ZSM-5-50具有较高的催化活性和较好的重复利用性。该制备方法不使用有机模板剂,无需高温焙烧,Cu-ZSM-5催化剂的制备成本大大降低。

石墨烯基介孔锰铈氧化物催化剂:制备和低温催化还原NO

锰铈氧化物由于较强的氧化还原活性、优良的低温脱硝性能,已被广泛用于选择性催化还原(SCR)脱硝反应,但是锰铈氧化物存在活性组分易团聚、比表面积较低等问题,限制其催化剂活性的提高。本研究以介孔结构的石墨烯基SiO_(2)(G@SiO_(2))纳米材料为模板,采用水热法制备了系列石墨烯基介孔锰铈氧化物(G@MnO_(x)-CeO_(2))催化剂,并考察了该催化剂在低温下(100~300℃)的SCR脱硝性能。结果表明,与石墨烯基铈氧化物(G@CeO_(2))相比,G@MnO_(x)-CeO_(2)催化剂具有较高脱硝活性。当Mn、Ce与模板G@SiO_(2)质量比分别为0.35、0.90时,G@Mn(0.35)Ce(0.9)催化剂的脱硝活性最佳,220℃下NO转化率达到最高(80%)。添加适量MnO_(x),提高了G@MnO_(x)-CeO_(2)催化剂的比表面积、孔容,降低了催化剂的结晶度;并且MnO_(x)-CeO_(2)以纳米尺度(2~3 nm)较为均匀地分散于石墨烯片层表面。此外,由于MnO_(x)与CeO_(2)之间存在协同作用,Mn原子可以部分替代Ce原子掺杂于CeO_(2)的晶体结构中形成MnO_(x)-CeO_(2)固溶体,使G@Mn(0.35)Ce(0.9)催化剂表面存在较高含量的高价态Mn^(3+)和Mn^(4+)、Ce^(4+)以及较高的化学吸附氧浓度,从而展现出较高的脱硝性能。该工作为MnO_(x)-CeO_(2)基催化剂在低温NH3-SCR中的实际应用提供了基础数据。

堇青石负载CuCo整体式催化剂的制备及其催化氧化甲苯性能

以堇青石蜂窝陶瓷为载体,采用浸渍法制备了CuCo整体式催化剂,通过XRD、SEM、XPS和H2-TPR等手段对催化剂进行了表征,考察了Cu^(2+)与Co^(2+)的质量比(Cu/Co质量比)、活性组分负载量、煅烧温度对其催化氧化甲苯性能的影响。结果表明:部分Cu^(2+)取代Co^(2+)进入Co3O4形成Cu_(0.27)Co_(2.73)o_(4)尖晶石;整体式催化剂的最佳制备条件为Cu/Co质量比2∶1、活性组分负载量15%(w)、煅烧温度500℃;在空速为10000 h^(-1)、甲苯质量浓度为2000 mg/m^(3)的条件下,整体式催化剂催化氧化甲苯转化50%和90%时的温度分别为252℃和289℃。

亚麻催化氧化与碱煮一浴脱胶工艺及其性能

使用棉纺系统进行亚麻纺纱前需经过脱胶处理,为解决传统碱脱胶工艺得到的亚麻纤维白度低和氧化脱胶时纤维易氧化受损、木质素残留造成纤维断裂伸长率低的问题,采用N-羟基-3,4,5,6-四苯基邻苯二甲酰亚胺(NHTPPI)催化氧化与碱煮一浴的方法对亚麻落麻进行脱胶,研究了pH值,反应温度以及催化剂NHTPPI、助催化剂9,10-蒽醌、双氧水、氢氧化钠质量浓度等因素对脱胶后亚麻纤维断裂强度以及白度的影响,得到了NHTPPI催化氧化与碱煮一浴亚麻脱胶的最佳工艺:pH值为10.5,反应温度为83.6℃,NHTPPI、9,10-蒽醌、双氧水、氢氧化钠质量浓度分别为0.6、0.5、10.35、5.67 g/L,此优化条件下得到的亚麻纤维断裂强度为4.39 cN/dtex,白度为70.53%。将催化氧化与碱煮一浴脱胶、高碘酸钠氧化脱胶以及传统碱脱胶与双氧水漂白3种工艺进行对比,发现3种工艺得到的纤维主体长度在28 mm左右,白度均在70%以上,但催化氧化与碱煮一浴脱胶得到的亚麻纤维断裂强度最高,处理时间最短。

CuCe-SAPO-34选择性催化丙烯还原柴油车尾气氮氧化物

采用等体积浸渍法制备Cu Ce-SAPO-44分子筛催化剂,用于选择性催化丙烯还原柴油车尾气氮氧化物(C3H_(6)-SCR)。采用X射线衍射(XRD)、N_(2)吸附-脱附、紫外可见光谱(UV-Vis)、H_(2)程序升温还原(H_(2)-TPR)和NH3程序升温脱附(NH3-TPD)等方法对催化剂的物理化学性质进行表征。研究表明,引入的铈与铜物种之间存在相互作用,有利于生成更多的孤立Cu^(2+)物种,提高了分子筛催化剂的低温氧化还原性能,从而提高了Cu CeSAPO-34的低温脱硝活性。同时,双金属分子筛骨架上具有丰富的Lewis酸性位,有助于C3H_(6)和NO_(x)的吸附和活化。当Cu∶Ce=4∶2时,Cu Ce-SAPO-34催化剂具有最佳的脱硝性能,在含有10%O_(2)和5%H_(2)O的柴油车尾气氛围中,在250℃最高能实现90%以上的脱硝效率。

活性碳负载纳米金属氧化物对AP热分解的催化性能

采用水热法制备了两种纳米金属氧化物(纳米CuO和纳米Fe_(2)O_(3)颗粒),将纳米CuO和纳米Fe_(2)O_(3)负载在活性碳上,制备成CuO@C、Fe_(2)O_(3)@C复合材料,并将其作为催化剂与高氯酸铵(AP)混合制备成混合物样品AP/CuO、AP/CuO@C、AP/Fe_(2)O_(3)、AP/Fe_(2)O_(3)@C;通过扫描电子显微镜(SEM)、差示扫描量热仪(DSC)、热重-微分热重分析(TG-DTG)和热重-红外光谱(TG-FTIR)联用等技术研究了4种催化剂对AP热分解的催化机理及分解动力学特性。结果表明,4种催化剂均将AP的两步分解反应催化为单放热峰,在5 K/min升温速率下,AP的分解峰温较纯AP分别提前90.1、73.4、65.4和69℃;AP/CuO@C分解主要气相产物有HCl、CO_(2)、N_(2)O、HNO_(3)和NO_(2),其中NO_(2)含量最高;AP/Fe_(2)O_(3)@C分解主要气相产物中CO_(2)含量显著提升,NO_(2)含量稍有降低。

Fe-ZSM-5催化S_(2)O_(8)^(2-)脱除烟气中Hg 0的研究

烟气中的零价汞Hg^(0)难以被脱除,是燃煤电厂汞排放的主要形式。过硫酸根可以有效地氧化脱除Hg^(0),但其本身反应效率不佳限制了其在燃煤电厂中氧化脱除Hg^(0)的工业应用。为此,从催化S_(2)O_(8)^(2-)与Hg^(0)的氧化反应入手,以商用H-ZSM-5为原料,通过浸渍法成功制备了不同Fe含量的Fe-ZSM-5催化剂。结合ESEM-EDS、XRD、BET和XPS等分析方法对制备的催化剂进行了表征,发现随着Fe负载量的增大,分子筛表面的分散度越大且Fe均匀分布在表面上,有助于催化反应的进行,同时浸渍的Fe主要以Fe^(2+)和Fe^(3+)形式存在于ZSM-5,Fe负载量的增大也会导致Fe^(2+)占比增大,而Fe^(2+)对氧化反应有极大的促进作用,Fe主要以Fe-Si-O形式存在,ZSM-5被铁改性后仍保持其完整的骨架结构和孔隙形状。实验结果表明,3.0Fe-ZSM-5作催化剂时效果最佳,氧化脱除Hg^(0)效率最高能达到88.31%。

CeO_(2)-Ps-LaCoO_(3)/Al_(2)O_(3)的制备及其对高浓度有机废水的臭氧催化降解研究

为有效降解高浓度造纸废水有机物,通过电化学沉积法分别在磷酸盐中性缓冲溶液和纯水中制得CeO_(2)-Ps-LaCoO_(3)/Al_(2)O_(3)和CeO_(2)-LaCoO_(3)/Al_(2)O_(3)。通过对CeO_(2)-Ps-LaCoO_(3)/Al_(2)O_(3)、CeO_(2)-LaCoO_(3)/Al_(2)O_(3)以及LaCoO_(3)/Al_(2)O_(3)进行XRD、SEM、析氧过电位和电阻抗等物性表征发现,CeO_(2)-Ps-LaCoO_(3)/Al_(2)O_(3)具有更强催化氧化性及稳定性。对高浓度造纸废水臭氧催化氧化降解3 h后,CeO_(2)-Ps-LaCoO_(3)/Al_(2)O_(3)对废水COD的降解率为76.5%,而相同条件下CeO_(2)-LaCoO_(3)/Al_(2)O_(3)和LaCoO_(3)/Al2O_(3)的化学需氧量(COD)降解率分别为68.5%和63.5%。