Decomposition Of Organic Compounds Research Articles

Bi2WO6‐based Z-scheme photocatalysts: Principles, mechanisms and photocatalytic applications

The development of novel photocatalysts for efficient utilization of solar energy is highly essential for the most critical humanitarian challenges, i.e., energy and water crises as well as environmental pollution. Bismuth tungstate (Bi2WO6), an outstanding Aurivillius phase perovskite, has attracted intensive attention as a visible-light-responsive photocatalyst because of its non-toxicity, low cost, and outstanding physicochemical characteristics, i.e., nonlinear dielectric susceptibility, ferroelectric piezoelectricity, pyroelectricity, catalytic behavior, modifiable morphology, strong oxidation power, and good photochemical stability. However, the photocatalytic activity of bare Bi2WO6 is restricted because of the inherent drawbacks such as poor light-harvesting efficiency, weak reduction potential, relatively low specific surface area, the fast recombination rate of photoinduced charge carriers, and thus poor quantum yields of photocatalytic reactions. Moreover, the impossibility of simultaneous strong redox ability (demanding wide bandgap) and high light-harvesting efficiency (requiring narrow bandgap) is considered as a big challenge for the practical application of Bi2WO6. Undeniably, the construction of Z-scheme photocatalytic systems is recommended strategy to overcome the above-mentioned disadvantages because of the efficient spatial separation of photogenerated charge carriers and the boosting the redox performance. This review summarizes the principles and recent developments on Z-scheme photocatalytic systems with special emphasis on the Bi2WO6-based photocatalysts, including the types, photocatalytic mechanisms and practical applications. Moreover, major differences between type-II heterojunction and Z-scheme photocatalyst have also been discussed. Additionally, the significant role of unique structures (e.g., core-shell and 2D/2D) for the improvement of photocatalytic activity of Z-scheme photocatalyst has been presented. Indeed, Bi2WO6-based Z-scheme photocatalysts have exhibited superior photocatalytic activity for various applications. For example, they show high photocatalytic activity towards water/wastewater treatment (removal of organic and inorganic pollutants, as well as microorganisms), air purification (decomposition of volatile organic compounds and inorganic matters), “green” energy conversion (e.g., generation of H2 and CH4 fuels under solar irradiation), and organic synthesis. It is thought that this remarkable activity of Bi2WO6-based Z-scheme photocatalysts might be attributed to the efficient solar light harvesting, separation and further transfer of charge carriers and strong redox ability. To the best of our knowledge, the present paper is the first attempt to summarize the Bi2WO6-based Z-scheme photocatalytic reactions, providing important insights and up-to-date information for the scientific community to fully explore the potential of Bi2WO6-based photocatalysts for renewable environmental remediation, energy conversion, and chemical synthesis.

Dual confinement strategy based on metal-organic frameworks to synthesize MnOx@ZrO2 catalysts for toluene catalytic oxidation

Active sites confinement is a promising way to enhance the activities of catalysts for volatile organic compounds decomposition (VOCs). However, the rational control of the active sites over composite catalysts raised challenges due to inevitably active sites’ aggregation into larger bulk particles during the pyrolysis. Here, we propose a dual-confinement strategy using metal–organic frameworks (MOFs) to fabricate well-dispersed MnOx@ZrO2 composite catalysts. These products have a distorted three-dimensional (3D) octahedral morphology with both Mn and Zr elements uniformly dispersed. Moreover, the agglomeration of Mn can be reduced through dual confinement. The crystal size of MnOx@ZrO2-NA is 17.65 nm, smaller than 1.17 μm of MnOx-ZrO2-cp and 125.73 nm of MnOx@ZrO2-A. Such MnOx@ZrO2-NA product exhibits a better catalytic ability of T50 = 248 °C than those of MnOx-ZrO2-cp (T50 = 295 °C) and MnOx@ZrO2-A (T50 = 280 °C). The increased Mn (III/Total) ratio, sufficient amount of adsorbed oxygen and good oxygen mobility from c-ZrO2 support play significant roles in the reaction mechanism. Further, a variety of MOx@ZrO2 (M = Co/Cu/Ce) composites with a similar nanostructure has been demonstrated. Therefore, this work can realize the high dispersion of active sites via the dual confinement, and provide a convenient route to synthesize potential catalysts for other pollutants control.

Review of component designs for post-COVID-19 HVAC systems: possibilities and challenges

The globally occurring recurrent waves of the COVID-19 pandemic, primarily caused by the transmission of aerosolized droplets from an infected person to a healthy person in the indoor environment, has led to the urgency of designing new modes of indoor ventilation. To prevent cross-contaminations due to airborne viruses, bacteria, and other pollutants in indoor environments, heating ventilation and air-conditioning (HVAC) systems need to be redesigned with anti-pandemic components. The three vital anti-pandemic components for the post-COVID-19 HVAC systems, as identified by the authors, are: a biological contaminant inactivation unit, a volatile organic compound decomposition unit, and an advanced air filtration unit. The purpose of the current article is to provide an overview of the latest research outcomes toward designing these anti-pandemic components and pointing out the future promises and challenges. In addition, the role of personalized ventilation in minimizing the risk of indoor cross-contamination by employing various air terminal devices is discussed. The authors believe that this article will encourage HVAC designers to develop effective anti-pandemic components to minimize the indoor airborne transmission.

Investigation of C–ZnO/V2O5 nanocomposite for organic compound decomposition under visible light

Investigation of C–ZnO/V2O5 nanocomposite for organic compound decomposition under visible light

EFFECT OF «MICROORGANIC» ORGANIC FERTILIZER ON WINTER WHEAT PRODUCTIVITY

The results of researches of technological process, chemical-biological indicators of organic fertilizer "Microorganic", obtained as a result of processing of secondary raw materials by the method of accelerated biological fermentation, are given. On the basis of experimental and industrial researches it is established that technological process of aerobic fermentation on open sites should be maintained within the following limits: humidity - the optimal level of 50-60% (permissible - 45-70%); temperature 50-55oC (permissible 40-60oC); oxygen concentration - more than 10% (permissible not less than 5%); density - 650 kg / m2 (550-750 kg / m2 is admissible). The obtained organic fertilizers "Microorganic" contained 1.5-2.3% nitrogen, 0.8-1.4% phosphorus, 1.2-1.8% potassium, the pH was 6.5-7.5. They are environmentally friendly, do not contain similar weed seeds, pathogens. The positive effect of fertilizer on agrophysical, agrochemical and microbiological properties of soil has been established. With the introduction of "Microorganic" increased microbiological activity of the soil as a test indicator of the positive effect of fertilizer, on average by 30% compared to the control (unfertilized soil with this type of organic fertilizer). At the same time, the content of soil copyitrophs (ammonifiers, microorganisms that decompose nitrogen - free compounds and the enzymatic, biochemical activity of the soil, the process of humus formation and the tendency to accumulate it in the soil increased especially). . A characteristic indicator of the activation of the microflora under the influence of these organic fertilizers is the increase in CO2 emissions, which is the result of accelerated accelerated decomposition of soil organic compounds (including humus). The average content of nutrients in the soil increased on average: for mineral nitrogen - by 10-15%, mobile phosphorus - by 10-30%, metabolic potassium - by 5-20%. The microbial potential of the organic fertilizer "Microorganic" contributed to the increase of biological activity of the soil, which led to increased access of biophilic elements to the root systems of plants, ensuring the formation of high yields. The highest yield of winter wheat variety "Tsentilivka", on average for three years, was on the option where organic fertilizers "Microorganic" were applied at a dose of 5 t / ha + N50P50K50 and was 8.81 t / ha, which is 4.75 t / ha more compared to the control Economic analysis obtained. The results of the study showed in this case and the highest economic indicators of cultivation with a level of profitability of 151.7%

Copyrolysis of rice husk and plastic bags waste from low-density polyethylene (LDPE) for improving pyrolysis liquid product

Rice husk is an agricultural waste from the rice milling process that results in environmental problems during its handling. Biomass (such as rice husk) can be transformed into biofuel via pyrolysis. Pyrolysis is a thermal decomposition of organic compounds in biomass at high temperatures in the absence of oxygen. The main difference of pyrolysis liquid compared to fossil fuel is the significant amount of oxygen (O) content instead of its carbon (C) and hydrogen (H). Thus, making pyrolysis liquid has a lower heating value and inferior properties limiting its direct fuel application. On the other hand, plastic bag waste from low-density polyethylene (LDPE) contains a high C and H with almost no O content. This study conducted co-pyrolysis of rice husk and LDPE at a different percentage (%weight) of LDPE (0, 5, 15, 25, 50, and 75). The pyrolysis temperature was measured using a comparison of thermogravimetric analysis (TGA) curves of rice husk powder and LDPE. The pyrolysis liquid resulted was collected and analyzed. The results show that the increase of LDPE content caused the yield of the organic phase (desired as fuel) of pyrolysis liquid to increase. The properties in the term of heating value also increased while the viscosity and density of pyrolysis liquid decreased. These properties were almost similar to diesel fuel with a slightly lower heating value. However, at 50 % LDPE composition, the wax was formed. Therefore, the optimum composition was 25% of LDPE, resulting in 41.69 MJ/kg of heating value.

Online analysis of chemical composition and size distribution of fresh cigarette smoke emitted from a heated tobacco product

Online analysis of chemical composition of cigarette smoke of a heated tobacco product (HTP) was performed by using a home-made vacuum ultraviolet (VUV) lamp-based photoionization time-of-flight (TOF) mass spectrometer. A capillary inlet and an aerodynamic lens were utilized to sample the gas- and particulate-phase of the HTP smoke, without dilution and pretreatment, which can be switched from each other within minutes. A thermal desorption unit was installed to vaporize the particulate-phase into gas and its vaporization temperature was determined, based on an equilibrium between the evaporation efficiency and the thermal decomposition of organic compounds. Then these species were softly ionized by VUV photons and their ions were measured by a reflectron TOF mass analyzer. Meanwhile, the puff-by-puff resolved size distributions of the HTP smoke were probed with a commercial scanning mobility particle sizers (SMPS). The mean diameters of particles firstly increase with the puff number, mainly located in the range of 200 – 300 nm, and then approached a steady state. This method was validated to measure the physical-chemical characteristics of the HTP cigarette smoke.•A capillary inlet and an aerodynamic lens were utilized to sample the gas- and particulate-phase of the HTP smoke.•Chemical composition of the HTP smoke was measured by using a compact VUV photoionization mass spectrometer.•The particle size distribution of the HTP smoke without dilution was measured online.

Tuning the local electronic structure of SrTiO3 catalysts to boost plasma-catalytic interfacial synergy

Boosting plasma-catalyst synergy to enhance volatile organic compounds (VOCs) decomposition remains a challenge. Herein, rich oxygen vacancies (VO) were engineered into the SrTiO3 catalysts through a facile nitrogen incorporation strategy for the plasma-catalytic decomposition of toluene and ethyl acetate. 100% toluene conversion with 81% CO2 selectivity at a competitive energy efficiency was achieved under ambient conditions. The characterization results and theoretical calculations evidenced that the partial substitution of oxygen by nitrogen triggered the electronic reconstruction and local disorder, thus modulating the electronic properties and coordination structures contributed to the formation of VO-Ti3+ pairs. Quasi in-situ EPR, operando OES, and operando DRIFTS originally demonstrated that the VO-Ti3+ pairs as active sites promoted the plasma-catalytic synergy instead of isolated VO. Importantly, the VO-Ti3+ pairs with favorable electron transfer characteristics energetically preferred to capture and utilize vibrationally excited oxygen species. And the lattice oxygen supplied by the VO-Ti3+ pairs were more vigorously activated by the plasma to participate in the surface/interface reaction. This work advances our understanding of the real active sites in plasma-catalytic interfacial synergy and thus paving the way for the rational design of efficiently heterogeneous catalysts.

Integrating electrochemical oxidation and flow-electrode capacitive deionization for enhanced organic degradation and perchlorate removal in high salinity waters

This study aimed to assess the application of an electrochemical oxidation (ECO) and flow-electrode capacitive deionization (FCDI) sequential hybrid process for the treatment of high-concentration ions, organic pollutants (i.e., humic acid, alginate, benzoic acid, phenol, and 4-chlorophenol), and marine algae. The ECO system led to the rapid generation of reactive chlorine species (RCS) via anodic oxidation of the boron-doped diamond (BDD) electrode under optimum current in the NaCl-based feed solution, which caused the reduction of total organic carbon (TOC) and the degradation of algae cells. However, the formation of undesirable by-products (i.e., toxic perchlorate) was triggered by direct electrolysis. Concurrently, the optimal operational conditions of the FCDI system were evaluated based on the monitoring of process performance according to various parameters (i.e., applied voltage, electrode mass loading, electrolyte concentration in the flow electrode, feed solution concentration, and adsorption/desorption phase operation). Finally, the superiority of the ECO–FCDI hybrid process was confirmed and clearly demonstrated via the effective decomposition of organic compounds and the complete removal of toxic perchlorate by-product together with the effect of deionization. To the best of our knowledge, this work is the first to develop and apply the ECO–FCDI integrated process for the removal of a broad spectrum of pollutants (including both organics and ions) and to attain successful desalination.

Influences of ZnO Nanorod Arrays on Photocatalytic Activity of n-ZnO Nanorods/p-Si Heterostructure

Zinc oxide is known as an excellent material for biosensors, solar cells, semiconductors and photocatalysts. In this work, n-ZnO nanorods/p-Si heterostructures were successfully fabricated by a hydrothermal method at different baking temperatures. The n-ZnO nanorods/p-Si heterostructures show good photocatalytic ability at high baking temperature. The concentration of Rhodamine B can be decreased up to 97% after 150 min treated by the n-ZnO nanorods/p-Si heterostructures grown at 80 oC. This result indicates that the n-ZnO nanorods/p-Si heterostructures are capable of being used in the decomposition of organic compounds.

Enhanced photocatalytic performance of visible-light-driven CuOx/TiO2-x for degradation of gaseous formaldehyde: Roles of oxygen vacancies and nano copper oxides

Photocatalysis is an effective method for the removal of formaldehyde (HCHO), and high-efficiency visible-light-driven photocatalysts were urgently required. Herein, oxygen vacancies (OVs) and nano copper oxides (CuOx) synergistically modified TiO2 (CuOx/TiO2-x) photocatalysts were synthesized by one-step hydrothermal followed by impregnation method. The photocatalytic decomposition of HCHO reached 100% at initial concentration of 180 ppm under relative humidity (RH) = 60% by 0.1g CuOx/TiO2-x in 150 min visible light irradiation. Characterization results explored the complementary effect of OVs and CuOx systematically. The OVs increased the separation efficiency of photogenerated charge carriers and act as adsorption/active sites in HCHO photocatalytic oxidation. The moisture and O2 were adsorbed and actived by OVs to generate reactive oxygen species (ROS). After doped CuOx on the surface of TiO2-x, the photoexcited electrons in Cu2O could transfer to the conduction band (CB) of TiO2-x and the photoexcited electrons of TiO2-x could be captured by Cu nanoparticles. Therefore, more ROS were generated due to the synergistic effect of OVs and CuOx. The In-situ Fourier transform infrared (in-situ FTIR) measurements show the hydroxyl radical (•OH) was the dominant radical in HCHO photocatalytic oxidation, while •O2− could also upgrade the photodegradation efficiency of HCHO. Furthermore, the stability tests showed the degradation efficiency of HCHO still reached 90% after five recycles, indicating that CuOx/TiO2-x nanocomposites displayed a stable and high photoactivity in volatile organic compounds (VOCs) decomposition.

Sustainable treatment and nutrient recovery from leafy waste through vermicomposting

The present investigation was carried out to evaluate the vermicomposting potential of two cruciferous vegetables' residual biomasses under laboratory conditions. Cabbage and cauliflower residual biomasses were spiked with 60% cow dung and vermicomposted for 90 days. The results showed a decrease in pH (5.3–9.8%), Total Organic Carbon (36.7–42.8%); increase in Electrical Conductivity (33–99.4%) and ash content (144.7–187.8%) after vermicomposting. Significant reduction in C:N ratio (49.5–76.4%) and C:P ratio (62.8–66.04%), increase in Total Kjeldahl Nitrogen (49.3–85.3%), Total Available Phosphorus (68.2–98.1%), Total Potassium (91.8–120.3%) were observed. FT-IR spectra of the vermicomposts had lesser band heights and peak intensities than raw materials. This evidenced decomposition of organic compounds and vermicompost stability. Germination Index values was calculated to determine the phytotoxicity level. Earthworms' growth and prolificacy was evaluated in terms of biomass gain, cocoons production and worm growth rate. Finally, it was inferred that cruciferous vegetables' biomass can be used for vermicomposting. The cauliflower residual biomass has shown better decomposition efficiency than cabbage residual biomass.

Wet oxidation of aqueous phase from hydrothermal liquefaction of sewage sludge

Hydrothermal liquefaction (HTL) is a thermochemical process for the conversion of biomass into bio-crude oil. However, treatment of post-HTL aqueous by-products is an emerging issue towards the commercialisation of HTL technology. This study investigates the use of non-catalytic wet oxidation (WO) for the reduction of organic compounds and heat production at different temperatures (200–350 °C), residence times (RT) (2–180 min) and excess oxygen. The aqueous phase from HTL of sewage sludge is investigated, and 97.6% of the chemical oxygen demand (COD) and 96.1% of the total organic carbon (TOC) were removed at the highest temperature and retention time. The minimum energy requirement achieved was 9.6 kWh/kg COD removed at 200 °C for 180 min, and the exothermic reactions of the process can generate 28.3% of the required heat. GC-FID and -MS analysis revealed that the degradation of different groups of organic compounds generates acetic acid as an intermediate by-product of WO, being further oxidised at temperatures higher than 300 °C. NH4+and NH3 are generated from the decomposition of nitrogenated organic compounds showing the highest concentration of 704.5 mg NH4+ /L at 350 °C after 180 min.

The Effect of High-frequency Ultrasound on the Photocatalytic Decomposition of Organic Compounds in Water

Access to clean water is necessary for the well-being and economic development of society. Thus, water contamination from human activity such as industry is a serious threat. Recently, the method in which organic contaminants in water are decomposed by photocatalysis has been proposed. However, the rate of decomposition with photocatalysis alone is slow. To enhance the degradation, the authors have developed a process that uses photocatalytic TiO2 in combination with ultraviolet (UV) light and high-frequency ultrasound (US). High-frequency US irradiation generates mist that contains TiO2 to increase the reaction area and to overcome the limited light penetration depth. To clarify the effect, the decomposition rate of phenol, known as a representative organic compound in wastewater, is experimentally evaluated. The results support that the proposed process enhances phenol degradation. This technology may be applied to decompose organic gaseous pollutants in waste gas.

Template-free synthesis of Co-based oxides nanotubes as potential anodes for lithium-ion batteries

Transition metal oxides as anodes for lithium-ion battery have attracted significant attention due to their high theoretical capacity. However, they usually suffer from poor cycling stability. Here, we developed a facile synthetic protocol for the preparation of Co-based oxides nanotubes without the usage of templates. By simply changing metal species, Co3O4 and binary Co-based transition metal oxides including MnCo2O4 and NiCo2O4 nanotubes could be successfully prepared. The crystallization of transition metal oxides and the thermal decomposition of organic compounds during calcination was proved to together prompt the formation of this hollow structure. Benefitted from this favorable hollow structure, the Co3O4 nanotubes showed superior cycling performance and rate capability compared with the solid Co3O4 nanoparticles when used as anodes for lithium-ion batteries.

Phosphogenesis in the Zagros Fold-Thrust Belt, Iran: The link between the Tethyan paleoenvironment and phosphate ore deposition

The Zagros phosphogenic horizon, hosted by the Eocene-Oligocene Pabdeh Formation, is located in the NW-SE-trending Zagros Fold-Thrust Belt (ZFTB), Iran. These phosphorites, which formed along the Tethyan Realm, are the most important and highest-grade phosphatic resources of Iran. This paper discusses the evolution and depositional paleoenvironment of the Zagros phosphogenic horizon. Petrographic studies indicate that the main components of the ZFTB phosphatic horizons are pellet, ooid, intraclasts, and bone fragments and various microfossils, which are common in other Tethyan phosphorites. Post-Archean Australian Shale-normalized patterns of REE in these rocks show HREE enrichment, a negative Ce anomaly in all studied samples and a positive Eu anomaly in the majority of the studied samples. These patterns are interpreted to reflect the original REE signature of the paleo-seawater rather than any significant effect of diagenetic changes on the geochemistry of the Zagros phosphorites. Comparison of measured 87Sr/86Sr values with the Eocene secular seawater curve suggests a Lutetian age (47.8 and 41.2 m.y.) for the Sheykh-Habil deposit and a Priabonian age (37.8 and 33.9 m.y.) for the Kuh-e-Sefid and Kuh-Rish deposits. The Zagros and eastern Mediterranean phosphorites form part of the Tethyan Phosphogenic Province which, over a period of ∼ 50 m.y., developed in a long (∼7000 km) and narrow (<800 km) east–west trending marine channel system. Additionally, the δ18OCarb values from the studied samples indicate minimal weathering, while the obtained δ13CCarb values support an unaltered authigenic origin, as has been proposed for other eastern Mediterranean phosphorites. Our findings suggest that the paleoenvironmental conditions during formation of the Zagros phosphorites varied from oxic-suboxic to anoxic during microbial decomposition of organic compounds and/or bacterial reduction of sulfate. The negative shifts evident in the δ13CCarb data and presence of glauconite are consistent with precipitation of the Zagros phosphorites in a shallow marine environment, most likely a mid- to outer ramp setting at a depth of ∼ 150 m within which the Pabdeh Formation is believed to have been deposited.

Removal of Flotation Collector O-Isopropyl-N-ethylthionocarbamate from Wastewater.

Flotation collector O-isopropyl N-ethylthionocarbamate (IPETC) is widely used for separation of sulfide ores. Its removal from water by several oxidation processes was studied. Photocatalytic oxidation with air in the presence of iron salts, utilizing solar irradiation or artificial UV-A light is very efficient. Oxidation leads through the formation of O-isopropyl N-ethylcarbamate and several other reaction intermediates to total decomposition of organic compound in the final stage in 1 day. Similar results were obtained with a Fenton type oxidation with hydrogen peroxide and iron salts. Treatment with sodium hypochlorite yields mainly O-isopropyl N-ethylcarbamate. The formation of this compound in wastewaters can be of concern, since simple alkyl carbamates are cancer suspect agents.

The effect of KOH activation and Ag nanoparticle incorporation on rice husk-based porous materials for wastewater treatment

Major agricultural solid waste, rice husk (RH)-based mesoporous materials were prepared by potassium hydroxide (KOH) treatment of RH and RH hydrochar (RHH) produced at 180 °C with 20 min reaction time. In this study, RH was treated with three different methods: RH activation by KOH (KOH-RH), RH activation by KOH-aqueous silver (Ag)-shell nanoparticle (AgNP) incorporation followed calcination at 550 °C for 2 h (AgNP–KOH-RH) and hydrothermally carbonized RH activation by KOH (KOH-RHH). The main objective of this study was to determine the effect of KOH activation with different synthesis approaches and compare the characterization results of RH based porous material to identify the potential adsorbent application for wastewater treatment. Therefore, after activation in different methods, all interactive properties such as elemental, chemical, structural, morphological, and thermal analyses were investigated comprehensively for all samples. The crystallinity peak intensity around 22°λ at the angle of diffraction of 2θ confirmed the presence of silica, higher stability of the material, and removal of organic components during the KOH activation. AgNP–KOH-RH and KOH-RHH presented high porosity on the outer surface. The presence of negligible volatile matter in KOH-RHH by TGA demonstrated the decomposition of organic compound. Very high ratio of aromatic carbon and lignin content by FTIR and XPS analysis in both AgNP–KOH-RH and KOH-RHH showed these two samples have improved stability. Very high negative surface charge (zeta potential) in AgNP–KOH-RH (−43.9 mV) and KOH-RHH (−43.1 mV) indicated the enhanced water holding capacity. Surface area for all experimented porous materials has been enhanced after KOH activation, where KOH-RHH demonstrated the maximum surface area value, 27.87 m2/g. However, AgNP–KOH-RH presented maximum pore diameter, 18.16 nm, and pore volume, 0.12 cm3/g. Hence, it can be concluded that both KOH-RHH and AgNP–KOH-RH have the potential to be implemented as wastewater adsorbents.

Efficient recovery of carboxylates from the effluents treated by advanced oxidation processes using flow-electrode capacitive deionization in short-circuited closed-cycle operation

• Acetate and oxalate can be effectively recovered from wastewater using FCDI. • Carbon flow-electrodes of FCDI facilitated the decrease of cell voltage. • FCDI in SCC operation showed high removal efficiency of anions, low energy consumption and stable desalination. • High selective recovery of oxalate could be realized by adjusting influent pH. Advanced oxidation processes (AOPs) are highly efficient novel methods for a wide range of organic substances. However, the decomposition of organic pollutants usually results in the formation of a series of carboxylates that are difficult to be further degraded by oxidants, which not only induces the excessive consumption of chemicals, but also leads to waste of carbon resources. Therefore, the recovery of small molecular carboxylates from effluents is a significant strategy. However, the excessive high voltage in conventional electrochemical technology for recovering small molecule acids can easily lead to organic matter degradation and high energy consumption. In present study, the removal and recovery of refractory acetate and liable oxalate by using FCDI system operated in short-circuited closed-cycle (SCC) operation was investigated. The results showed that Ac − and Ox − could be effectively accumulated in anode chamber from wastewater containing high-strength of Cl − . The significance of carbon flow-electrodes for the recovery performance and operating cost was evidenced. Higher carbon conditions induced an obvious decrease of cell voltage and thus the decomposition of organic compounds and energy consumption were decreased simultaneously. On the premise of the recovery rate, under the optimal conditions (carbon = 5 wt%, j = 5.7 A/m 2 , HRT = 7.45 min, pH i = 7.1 and t = 180 min), more than 80% of acetate and oxalate can be recovered from wastewater with a low energy consumption of 0.45 kWh/m 3 . The calculated average salt recovery rates (ASRR r ) for Ac − and Ox − were 0.186 and 0.45 μmol/(cm 2 ·min), respectively. The findings indicated that FCDI system with carbon particle flow-electrode operating in SCC mode is a promising strategy for continuously recovering aqueous carboxylates. In further research, combining FCDI operation with other techniques such as AOPs is possible to realize simultaneous oxidation and carboxylates recovery, in other words, in-situ product recovery, that if recovered will greatly contribute to the sustainability of the low carbon economy.

Effect of interaction between different CeO2 plane and platinum nanoparticles on catalytic activity of Pt/CeO2 in toluene oxidation

The plane exposure of support vitally affects the catalytic performance of the catalyst. In this work, CeO2 nanorods ((110) plane exposure), nano-octahedrons ((111) plane exposure) and nano-cubes ((100) plane exposure) were prepared as the supports of Pt/CeO2 samples to investigate the effect of CeO2 plane exposure on total toluene oxidation. Characterizations reveal that the (110) plane of CeO2 is more helpful to the dispersion of Pt species, followed by (111) face. The improved dispersion of Pt species can enhance the metal-supports interaction, which promotes the electron transfer of CeO2 carrier to Pt nanoparticles and the adsorption-activation of O2, thereby facilitating the total oxidation of toluene via the Langmuir–Hinshelwood (L-H) mechanism. Therefore, Pt/CeO2-r (nanorods) sample expresses excellent catalytic performance of toluene oxidation. Finally, the procedure of toluene total oxidation was studied by in-situ diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. We expect that this work can contribute to the development of an effective sample for the decomposition of volatile organic compounds (VOCs).