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Herein, we synthesized a bi-function hybrid material and investigated the dynamic nature of synergy between the individual components of the hybrid and its application aspects in detail. The diverse nature of 2D-ternary hybrid could be exploited as a photocatalyst as well as an electrochemical sensor. Plate-like Bi2WO6 was hybridized with mesh-like g-C3N4 structure and subsequently rGO being loaded into it via simple hydrothermal route. Based on room temperature EPR spectra, we could interpret the inactivity of Bi2WO6 and significant activity of 2D-ternary hybrid. The hybrids were evaluated based on the photocatalytic degradation of antibiotic ciprofloxacin (CIP). Bi2WO6/g-C3N4/rGO hybrid yielded 90% degradation in 110 min while CIP photolysis only yield 4.3%. Mechanism of photocatalytic degradation was investigated via scavenger experiments which gave away the reactive radicals responsible. To investigate the effect of carrier lifetime on photocatalytic ability, time resolved fluorescence life (TRFL) experiments were performed. The relationship between reducibility and enhanced photocatalytic ability of the materials was studied via hydrogen temperature-programmed reduction (H2-TPR) measurement. Furthermore, for elaborating application of the synthesized 2D structured ternary hybrid, its electrochemical ability towards 4-nitrophenol (4-NP) sensing was also studied. An electrochemical sensitive electrode was fabricated to evaluate sensing properties towards 4-NP. To study the electrode kinetics on 4-NP solution, varying scan rate was used via the cyclic voltammetry (CV) analysis. The fabricated BCN-200/rGO electrode delivered promising sensing properties with excellent sensitivity of 12.86 μA.μM−1.cm−2 in range of 0.2–100 μM. Hence, the synthesized 2D-ternary hybrid possesses great potential applications in the field of photocatalysis as well as electrochemical sensor.

Metal-organic frameworks (MOFs) are evolving as emerging materials for application in supercapacitors on account of their inherent porous characteristics, which can be suitably controlled with molecular engineering. This allows suitable attributes to MOFs such as multiple dimensionalities, high surface area and additional aspect ratio compared to traditional materials. Secondary building units (SBUs) are the milestones that allow immense structural diversity, thermodynamic stability, and mechanical/architectural stability to demonstrate materials on-demand with predetermined topologies in the synthesis of MOFs through stronger bonding between the constituent metals and organic linkers. Despite these advancements, the usage of pristine MOFs is lagging in the area of supercapacitor, majorly due to their insulating nature. As smart avenues, hybridization of MOFs or using MOFs as templates for deriving metal oxide, carbon or hydroxides etc., are being proved as hugely successful. This review is directed towards the utilization of MOFs, specifically three-dimensional MOFs as a platform for utilization in supercapacitor. Extensive discussion is developed on divergent methods related to the synthesis of MOFs, their performance in supercapacitor application and various strategies adopted to enhance their functionality. Finally, the future prospective and possible research proceedings in this field are described briefly.

Fabrication of an efficient, stable, and versatile photocatalysts for the energy and environment remediation applications is an urgent task for the current researchers. In this work, we have successfully synthesized a versatile hybrid photocatalysts, i.e.; CdMoO4/g-C3N4 (CMO/CN) by a facile and simple one-pot in-situ hydrothermal method. Here CdMoO4 (CMO) microspheres were deposited on the g-C3N4 (CN) sheets. Fabricated CN, CMO, and CMO/CN composite photocatalysts were analyzed with various characterization techniques like UV–visible diffuse reflectance spectra (UV–Vis DRS), photoluminescence spectroscopy (PL), time-resolved fluorescence lifetime (TRFL), electrochemical impedance spectroscopy (EIS), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy–energy-dispersive X-ray analysis (SEM-EDX), transmission electron microscope (TEM), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller (BET). The results reveal that the formation of a strong heterojunction between two semiconductors leads to the formation of active photocatalyst. Furthermore, as-synthesized materials were tested for the photoelectrocatalytic (PEC) oxygen evolution reactions (OERs) in acidic medium, and photocatalytic (PC) degradation of methylene blue (MB) under light irradiation. Among all tested samples, CMO/CN-10 has shown the highest current density 52.74 mA cm−2 at 1.95 V with lowest over potential of 0.70 mV on glassy carbon electrode for OER in acidic medium under the light irradiation. The PC degradation rate constant of CMO/CN-10 composite in MB solution is k = 2.0 × 10−2 min−1, whereas for the pure CMO and CN degradation rate constant is k = 5.7 × 10−3 min−1 and k = 1.2 × 10−2 min−1, respectively. This enhancement in PEC and PC properties is due to the fast migration of photo-induced electrons in the case of CMO/CN-10 nanocomposite. Trapping experiment results reveal the major reactive species for PC degradation of MB is •OH (hydroxyl radicals) and h+ (holes), respectively, and suitable PC reaction mechanism also proposed for CMO/CN-10 composites. Based on the above remarkable results, it would be a potential nanocomposite for the PEC oxygen evolution and PC degradation of MB under light illumination.

The development of perovskite-based materials with a narrow bandgap for oxygen evolution reactions (OER) and wastewater treatment have much attention in recent years. Herein, a narrow bandgap of Ca-doped BiFeO3 (BCFO) is synthesized by a simple auto combustion method. To create oxygen vacancies by doping Ca2+ the place of Bi3+, the amount of Fe3+ valence state is changed as well. 0.15% of Ca doped BiFeO3 (BCFO-15) indicate a high content of Fe4+ state with a conduction band and valence band located at 0.615 V and 2.46 V vs. NHE, respectively. The electrochemical OER of BCFO-15 observed a lower onset potential of 2.13 V vs. RHE, in acidic with a current density of 25.64 mA cm−2. In alkaline electrolyte, onset potential was observed at 2.10 V vs. RHE, with a current density of 65.87 mA cm−2. Furthermore, the photocatalytic performance of the perovskites in aqueous solution was demonstrated through photocatalytic reduction of Cr(VI) as a model pollutant, resulting in an 89.92% reduction of 50 ppm of Cr(VI) in 210 min under the irradiation of a 35 W Xe arc lamp. These findings suggest that simple divalent doping of Ca into pure BiFeO3 results in excellent photocatalytic and electrocatalytic perovskites.

The purpose of this project is investigate the oxidation reaction of 2,3,6-Trimethylphenol (TMP) green chemistry process design for magnetic nano-catalysts by microwave-induced combustion process. Design chemical syntheses to prevent waste, in order to reduce the raw materials cost, to improve the performance for 2,4,6-Trimethylbenzoquinone(TMBQ) production, and by the way to solve the environmental pollution problem from the scraps. The whole project will be completed that, Preparation of magnetic Cu–Zn ferrite nano-catalysts (Cu1-XZnXFe2O4) by microwave-induced combustion process, the characterized of catalysts and micro-structure was carried out. The kinetics and mechanism of two phase medium are also studied in Cu–Zn ferrite/TiO2 magnetic nano-catalysts.

The doped lanthanum chromite (La 0.8 Ca 0.2 )(Cr 0.9− x Co 0.1 Mn x )O 3 ( x =0.03, 0.06, 0.09 and 0.12) were synthesized by solid state reaction technique. The samples have been characterized by X-ray diffraction for structural and charge density analysis. XRD data show that the grown samples are orthorhombic in structure with single phase. The spatial charge density distribution in the unit cell for the synthesized samples has been studied using maximum entropy method. Further, the samples were analyzed by UV–visible spectrometry for optical properties and scanning electron microscopy for surface morphology. From the optical data, it was found that the direct band gap of the samples range from 2.27 to 2.46 eV. The samples were also investigated by vibrating sample magnetometry for magnetic properties. From VSM data, it is inferred that all the samples in this series are found to be predominantly antiferromagnetic in nature. Since the doped lanthanum chromites have good mechanical properties and electrical conductivity at high temperature, these materials are used in solid oxide fuel cells (SOFC).

The effects of Sr doping on the Ba-site of SmBaCo2O5+δ in term of structure characteristics, thermal expansion coefficients (TECs), electrical properties and electrochemical performance have been investigated as cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The TECs of SBSC-based cathodes are calculated from 19.8 − 20.5 × 10−6 K−1 in the temperature range of 100–800 °C, and the TEC values decrease with increasing Sr content. The oxygen content and the average oxidation state of cobalt increase with increasing Sr content determined by the X-ray photoelectron spectroscopy (XPS) and Thermogravimetry analysis (TGA) results. At a given temperature, the electrical conductivity values are in the order as follows: SBSC55 > SBSC73 > SBSC91. This behavior might be due to the increase in electronic hole. The electrical conductivities of SBSC55 at 600 °C are distributed in the range of 660 S/cm of p(O2) = 0.01 atm to 1168 S/cm of p(O2) = 0.21 atm, indicating that the cathode can endure reducing atmosphere. SBSC55 with high electrical conductivity in p(O2) = 0.01 atm is ascribed to SBSC55 with stable double-perovskite structure at such low oxygen partial pressure. The SBSC55 cathode showed the highest power density of 304 mW/cm2 at operating temperature of 700 °C. Based on the electrochemical properties, SBSC55 is a potential cathode for IT-SOFCs.

Transition metal-doped lanthanum chromites (La0.8Ca0.2)(Cr0.9−x Co0.1Fe x )O3 (x = 0.03, 0.06, 0.09, 0.12) have been synthesized by solid state reaction method. The synthesized samples were characterized for their structural properties using powder x-ray diffraction analysis, which shows that the grown samples are orthorhombic in structure with single phase. The nature of bonding and the charge distribution of the grown samples have been analyzed by maximum entropy method. Further, the samples were characterized for their optical and magnetic properties using ultraviolet–visible spectra and vibrating sample magnetometry. The microstructural studies were carried by scanning electron microscopy/electron dispersive x-ray spectroscopy techniques. From the optical absorption spectra, it was found that the energy band gap of the samples ranges from 2.135 eV to 2.405 eV. From vibrating sample magnetometer measurements, ferromagnetic like behaviour with large coercive field was observed for Fe doping concentration of x = 0.12. Since the doped lanthanum chromites have good mechanical properties and electrical conductivity at high temperature, these materials are used in solid oxide fuel cells.

The purpose of the research was to determine the photocatalytic degradation efficiency of acid orange 7 (AO7) using 2 mol% Fe-doped TiO2 as photocatalysts under UV irradiation. Fe-doped TiO2 powder synthesized by solid-reaction technique reveals the average particle size of 0.91 μm, BET surface area of 11.6 m2/g, a wide pore-size distribution with the average pore diameter of 3.2 nm and pore volume of 0.035 cm3/g. Within the experiment, AO7 was prepared as a synthetic textile wastewater at the initial concentration of 34 mg/L along with using various doses of Fe-doped TiO2 photocatalysts. The results indicated that Fe-doped TiO2 with dose of 0.100 g in 100 mL of AO7 reached the highest removal efficiency about 88.7%.

Heterostructured nanomaterials can paid more significant attention in environmental safety for the detection and degradation/removal of hazardous toxic chemicals over a decay. Here, we report the preparation of hierarchically nanostructured shuriken like bismuth vanadate (BiVO4) as a bifunctional catalyst for photocatalytic degradation and electrochemical detection of highly toxic hexavalent chromium (Cr(VI)) using the green deep eutectic solvent reline, which allows morphology control in one of the less energy-intensive routes. The SEM results showed a good dispersion of BiVO4 catalyst and the HR-TEM revealed an average particle size of ca. 5–10 nm. As a result, the BiVO4 exhibited good photocatalytic activity under UV-light about 95% reduction of Cr(VI) to Cr(III) was observed in 160 min. The recyclability of BiVO4 catalyst exhibited an appreciable reusability and stability of the catalyst towards the photocatalytic reduction of Cr(VI). Also, the BiVO4-modified screen printed carbon electrode (BiVO4/SPCE) displayed an excellent electrochemical performance towards the electrochemical detection of Cr(VI). Besides, the BiVO4/SPCE demonstrated tremendous electrocatalytic activity, lower linear range (0.01–264.5 μM), detection limit (0.0035 μM) and good storage stability towards the detection of Cr(VI). Importantly, the BiVO4 modified electrode was also found to be a good recovery in water samples for practical applications.

Graphene oxide-based composites have been developed as cheap and effective photocatalysts for dye degradation and water splitting applications. Herein, we report reduced graphene oxide (rGO)/Ag/Fe-doped TiO

This paper reviews the related literature reported in 2019 about various types of wastewaters associated with chemical and allied products. The subjects comprise wastewaters produced from various activities in agricultural, chemical, dye, petrochemical, and pharmaceutical. PRACTITIONER POINTS: Bioflocculant chitosan was used for sludge dewatering and the treatment of water and wastewater, and polishing of sanitary landfill leachate. Alkaline lignin-based flocculants were used to achieve excellent color removal for paper mill sludge. Powdered activated coke was used to remove COD (chemical oxygen demand) from chemical industry wastewater effluents.

The microstructure, lattice parameters, and electrical conductivity mechanisms for Fe doping on B-site of (La0.8Ca0.2)(Cr0.9Co0.1)O3−δ were systematically investigated. The oxygen nonstoichiometry was measured by means of thermogravimetry as a function of oxygen partial pressure. In this study, the concept of defect chemistry is used to explain the relationship between the concentration of electron hole with the electrical conductivity. Based on the result of electrical conductivity in air, it is concluded that the concentration of electron hole at high oxygen activity is larger than that at low oxygen activity. This is due to the fact that (La0.8Ca0.2)CrO3−δ-based ceramics are p-type conductors, the electrical conductivity is dominated by the concentration of hole. At higher Fe-doping level, the compensation mechanism at high oxygen activity is significantly dominated by the formation of oxygen vacancy, that is, ionic compensation. The compensation mechanism at low oxygen activity is significantly dominated by the formation of the formation of Cr4+, that is, electrical compensation at lower Fe-doping level. Based on oxygen nonstoichiometry data, it is found that with increasing Fe-doping amount on B-site of (La0.8Ca0.2)(Cr0.9Co0.1)O3−δ specimens, the initial weight-stable temperature shifted to lower temperature which might be highly related with the change in compensation mechanism at the temperature.

The aim of the work is to study the effects of oxygen vacancy and surface hydroxyl group density on the photocatalytic activity of Fe3+-doped TiO2, and to investigate how the titanium dioxide doped with different levels of the Fe3+ influenced their physical and chemical characterizations. The photocatalysts were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), electron spin resonance (ESR), X-ray photoelectron spectroscope (XPS) and Fourier transform infrared (FTIR) spectra. The results revealed that adsorbed hydroxyl group density significantly influenced the photocatalytic activity, and a small amount of Fe3+ can act as a photo-generated hole and a photo-generated electron trap and inhibit the electron–hole recombination. The 0.10%-Fe3+-TiO2 with the highest surface hydroxyl group density revealed the maximum rate constant of 0.716 and the optimal photocatalytic degradation of MB. As Fe3+ doping levels are larger than 0.10%, the cluster of Fe Ti ′ – V ¨ O – Fe Ti ′ generated gradually. This implied that an excessive amount of Fe3+ doped into TiO2 is detrimental to the photocatalytic activity due to the formation of Fe Ti ′ – V ¨ O – Fe Ti ′ clusters and enhances the recombination of photogenerated electrons and holes.

This literature review examines process, design, and cost issues related to using oxidation ponds for wastewater treatment. Many of the topics have applications at either full scale or in isolation for laboratory analysis. Oxidation ponds have many advantages. The oxidation pond treatment process is natural, because it uses microorganisms such as bacteria and algae. This makes the method of treatment cost-effective in terms of its construction, maintenance, and energy requirements. Oxidation ponds are also productive, because it generates effluent that can be used for other applications. Finally, oxidation ponds can be considered a sustainable method for treatment of wastewater.

The chemical stability of potassium substituted for A-site of SrCe 0.95 Y 0.05 O 3 specimens was examined under CO 2 atmosphere treated at 600 °C and further analyzed by X-ray diffractometer to see their CO 2 -resisted capabilities. According to thermodynamic data, the Gibbs free energy of CeO 2 was lower than that of SrCO 3 at the temperature of 600 °C. Thus the formation of CeO 2 might be faster than that of SrCO 3 in SrCeO 3− based materials under CO 2 atmosphere. Unfortunately, the chemical stability of SrCe 0.95 Y 0.05 O 3 materials in CO 2 atmosphere was reduced with increasing potassium-substituted amount. The microstructures of Sr 1− x K x Ce 0.95 Y 0.05 O 3 sintered specimens were identified using field emission scanning electron microscope. The conductivity in moisture H 2 atmosphere (RH 30%) was increased with increasing potassium-substituted concentration. The conductivity reached a maximum of 0.0081 Scm -1 at 900 °C for Sr 0.95 K 0.05 Ce 0.95 Y 0.05 O 3 sintered specimens in moisture H 2 atmosphere (RH 30%). Potassium substituted for A-site of SrCe 0.95 Y 0.05 O 3 could improve the conductivity but not CO 2 -resisted capability.

In this work, the chemical bulk diffusion coefficient ( D chem ) of SmBa 0.6 Sr 0.4 Co 2 O 5+ δ was determined by an electrical conductivity relaxation (ECR) method. The equation of D chem as a function of temperature in the range of 500–700 °C exhibits as follows: D chem = 1.77×10 −5 (−68.039 (kJ mol −1 )/ RT ) (m 2 s −1 ) Electrochemical impedance spectroscopy (EIS) technique was performed over the temperature range of 600–850 °C to determine the cathode polarization resistance ( R p ). The area specific resistances (ASR) of SmBa 0.6 Sr 0.4 Co 2 O 5+ δ -Ce 0.8 Sm 0.2 O 1.9 (70:30 in wt%) composite cathode were 5.16, 0.86 and 0.21 Ω cm 2 at the operating temperatures of 600, 700 and 800 °C respectively. The exchange current densities ( i o ) for oxygen reduction reaction (ORR) were determined from the EIS approach, and low-field and high-field cyclic voltammetry. The activation energies ( E a ) of ORR determined from the slope of Arrhenius plots for EIS, low-field and high-field technique were 148.6, 69.8 and 74.2 kJ mol −1 , respectively. Based on the electrochemical properties, the mixed-ionic-and-electronic conductor (MIEC) of SmBa 0.6 Sr 0.4 Co 2 O 5+ δ is a potential cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs) based on a SDC electrolyte.

The microstructure, lattice parameters, morphology, mechanical properties, and conductivity of BaCe0.9M0.1O2.95 (M=Gd, Nd, Sm, Y) were systematically investigated under different atmospheres (in air and in wet 5%H2–95%Ar). The XRD results indicated that all of the specimens sintered in air have orthorhombic symmetry, whereas BaCeO3 and BaCe0.9Gd0.1O2.95 decomposed into CeO2 and BaCO3 in their specimens. Secondary CeO2 and BaCO3 might adversely affect the conductivity of BaCeO3-based specimens. The maximum conductivity (σtotal,800 °c=6.46×10−3 S/cm) and minimum activation energy (Ea=52.3 kJ/mol) measured in air were observed for BaCe0.9Y0.1O2.95 among the BaCeO3-based specimens, Whereas in wet 5%H2–95%Ar, the maximum conductivity (σtotal,800 °c=9.20×10−3 S/cm) and minimum activation energy (Ea=55.6 kJ/mol) were measured. The difference in conductivity between the air and wet reducing atmosphere can be explained by the chemical stability. The mechanical properties of BaCe0.9M0.1O2.95 significantly depended on the doping element with the rare-earth oxide dopants affecting the structure stability, grain size, conductivity, thermal expansion, and the mechanical properties. Based on a comprehensive evaluation, BaCe0.9Y0.1O2.95 revealed good chemical stability and high conductivity and thus it is a promising candidate for a proton-conducing electrolyte for intermediate temperature solid oxide fuel cells (IT-SOFCs).

In the first part of this study, the characteristics of a La0.5Sr0.5CoO3−δ cathode are described, including its chemical bulk diffusion coefficient (Dchem), and electrical conductivity relaxation experiments are performed to obtain experimental Dchem measurements of this cathode. The second part of this study describes two methods to improve the single-cell performance of solid oxide fuel cells. One method uses a composite cathode, i.e., a mix of 30 wt% electrolyte and 70 wt% cathode; the other method uses an electrolyte-infiltrated cathode, i.e., an active ionic-conductive electrolyte with nano-sized particles is deposited onto a porous cathode surface using the infiltration method. In this work, 0.2M Ce0.8Sm0.2O1.9 (SDC)-infiltrated La0.5Sr0.5CoO3−δ exhibits a maximum peak power density of 1221 mW/cm2 at an operating temperature of 700°C with a thick-film SDC electrolyte (30 μm), a NiO + SDC anode (1 mm) and a La0.5Sr0.5CoO3−δ cathode (10 μm). The enhancement in electrochemical performances using the electrolyte-infiltrated cathode is attributed to the creation of electrolyte/cathode phase boundaries, which considerably increases the number of electrochemical sites available for the oxygen reduction reaction.

A Fe–Cr alloy, used for metallic interconnects, was coated with a protective layer of lanthanum strontium manganite (LSMO) using the aerosol deposition method (AD). The effects of the LSMO protective layer, which was coated on the Fe–Cr interconnects using AD, on the area specific resistance (ASR) during high temperature oxidation and the Cr evaporation behaviors were systematically investigated in this paper. The microstructures, morphologies, and compositions of the oxidized scales that appeared on the LSMO-coated Fe–Cr alloy after annealing at 800 °C for 750 h in air were examined using SEM equipped with EDS. The EPMA mapping of the LSMO-coated Fe–Cr interconnects undergoing long term, high-temperature oxidation was used to explain the formation layers of the oxidized scale, which consists of (Mn,Cr) 3 O 4 and Cr 2 O 3 layers. Moreover, the experimental results revealed that the AD process is a potential method for preparing denser protective layers with highly desirable electrical properties for metallic interconnects.

In this study, ZnO films, prepared by Chemical Bath Deposition (CBD), are applied as the conductive layers for thin film solar cells. Zinc acetate is used as a source of zinc, and different proportions of ammonia solution are added and well mixed. The growth of zinc oxide films in reaction solutions is taken place at 80°C and then heated to 500°C for one hour. In this study, the different ammonia concentrations and deposition times is controlled. The thin film structure is Hexagonal structure, which is determined by X-ray diffraction spectrometer (XRD) analysis. Scanning electron microscopy (SEM) is used as the observation of surface morphology, the bottom of the film is the interface where the heterogeneous nucleation happens. With the increase of deposition time, there were a few attached zinc oxide particles, which is formed by homogeneous nucleation. According to UV / visible light (UV / Vis) absorption spectrometer transmittance measurements and the relationship between/among the incident wavelength, it can be converted to the energy gaps (Eg), which are about 3.0 to 3.2eV, by using fluorescence spectroscopy analysis. The emission of zinc oxide films has two wavelengths which are located on 510nm and 570nm. According to Based on the all analytic results, the ammonia concentration at 0.05M, and the deposition time is 120 minutes, would obtain the conditions of ZnO films which is more suitable for applications of conductive layer material in thin film solar cell.

We successfully prepared the TiO 2 @Mn-Zn ferrite composite powder for magnetic photocatalyst. The core Mn-Zn ferrite powder was synthesized by using steel pickling liquor and used alkaline batteries as the starting materials. The shell TiO 2 nanocrystal was prepared by sol–gel hydrolysis precipitation of titanium isopropoxide (Ti(OC 3 H 7 ) 4 ) on the Mn-Zn ferrite powder. The thickness of the titania shell was found to be approximately 2 nm. The core of Mn-Zn ferrite is of spherical or elliptical shape and the particle size of the core is in the range of 20–40 nm. The magnetic Mn-Zn ferrite nanopowder is uniformly encapsulated in a titania layer forming the core–shell structure of TiO 2 @Mn-Zn ferrite powder. The magnetic photocatalyst can be successfully used to treat dye waste waters.

This work reports the characteristics of Sm0.5Sr0.5CoO3−δ (SSC) cathode including its chemical bulk diffusion coefficient (Dchem), current density (i0), and single cell performance. In this study, the value of Dchem is measured by an electrical conductivity relaxation (ECR) technique. The equation of Dchem as a function of temperature in the range of 500–700 °C exhibits as follows: D chem = 4.65 × 10 − 5 exp ( − 91.33 ( kJ mol − 1 ) R T ) ( m 2 s − 1 ) To improve the cathode performance, the active ionic-conductive Ce0.8Sm0.2O1.9 (SDC) nanoparticles deposit on a porous SSC cathode surface by infiltration method. The enhancement in electrochemical performances is ascribed to the creation of electrolyte/cathode phase boundaries, which considerably increases the electrochemical sites for oxygen reduction reaction. In this work, the 0.2 M SDC-infiltrated SSC reveals the maximum peak power density of 489 mW cm−2 at operating temperature of 700 °C with a thin film SDC electrolyte (30 μm), a Ni + SDC anode (1 mm) and a SDC-infiltrated SSC cathode (20 μm).

This work divided into two parts. The first part reports the characteristics of a La 0.8 Ca 0.2 CoO 3− δ (LCCO) cathode including its chemical bulk diffusion coefficient ( D chem ) and chemical surface exchange coefficient ( k chem ) measured by an electrical conductivity relaxation (ECR) technique. The second part reports two methods to improve the performance of solid oxide fuel cells (SOFCs). One is the use of composite cathode, i.e., mixture of 30 wt% electrolyte and 70 wt% cathode. The other is the use of electrolyte-infiltrated cathode, i.e., the active ionic-conductive electrolyte with nanosize was infiltrated onto a porous cathode surface. In this work, the 0.2 M Ce 0.8 Sm 0.2 O 1.9 (SDC)-infiltrated La 0.8 Ca 0.2 CoO 3− δ (LCCO) reveals the maximum peak power density of 305 mW cm −2 at operating temperature of 800 °C with a thin film SDC electrolyte (30 μm), a Ni+SDC anode (1 mm) and a SDC-infiltrated LCCO cathode (20 μm). The enhancement in electrochemical performances by using the electrolyte-infiltrated cathode is ascribed to the creation of electrolyte/cathode phase boundaries, which considerably increase the electrochemical sites for oxygen reduction reaction. Therefore, the infiltrated method is a potential way to improve the performance of SOFCs.

This study investigates the microstructure and electrochemical properties of Sm 0.5 Sr 0.5 Co 0.8 Cu 0.2 O 3− δ (SSC-Cu) cathode infiltrated with Ce 0.8 Sm 0.2 O 1.9 (SDC). The newly formed nanosized electrolyte material on the cathode surface, leading the increase in electrochemical performances is mainly attributed to the creation of electrolyte/cathode phase boundaries, which considerably increases the electrochemical sites for oxygen reduction reaction. Based on the experiment results, the 0.4 M SDC infiltration reveals the lowest cathode polarization resistance ( R P ), the cathode polarization resistances ( R p ) are 0.117, 0.033, and 0.011 Ω cm 2 at 650, 750, and 850 °C, and the highest peak power density, are 439, 659, and 532 mW cm −2 at 600, 700, and 800 °C, respectively. The cathode performance in SOFCs can be significantly improved by infiltrating nanoparticles of SDC into an SSC-Cu porous backbone. This study reveals that the infiltration approach may apply in SOFCs to improve their electrochemical properties.

One can describe industries involving dye treatment as the essentials (food, beverage, and textile) simply since they involve application to entities that are used for necessity. Dye wastewater is generated from the intense application within its industry. However, it is more common to find research on the treatment and application of dyes within the textile industry, as it has been highlighted and targeted by federal regulations. Some of the more harmful components from dye wastewater include the presence of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and color, to name a few. Direct discharge from the plant can cause potential harm toward a water body, impacting the lives of human health and the environment. The purpose of this chapter is to provide a survey of various treatment methods and review the literature that has been applied for the purpose of treating wastewater produced by the textile dye industry. In addition, the text will discuss some of the important preceding topics prior to treatment applications such as legislation, and definition and classification of dyes. The aim of this chapter is to be both comprehensive and concise describing some of the major components that are heavily integrated within the dyeing industry.

Currently, Taiwan's major source of gravel for construction purposes is its river systems; however, over exploitation could potentially deplete this source. To address this problem and reduce dependence on natural aggregate exploitation, this article investigates artificial lightweight aggregates (ALWAs) synthesized from industrial waste such as sewage sludge and sewage-sludge-derived ash. The ALWAs were synthesized from the sewage sludge and ash using Na2CO3. The sodium carbonate helps produce the required viscous glassy phase (needed for ALWA sintering) at a lower co-melting temperature than would otherwise be possible. Water absorption, apparent porosity, bulk density and compressive strength of the ALWAs were tested to assess resource-recycling feasibility. The required dosages of Na2CO3 were 16 and 22 wt % for conditioned sludge and ash, respectively. The dosed sludge sample required preheating at 400°C for 0.5 h, followed by sintering at 900°C for 5 min. The ash sample required sintering only at 900°C for 15 min. The sludge-derived ALWAs gave the following percentages 2.84%, 3.31%, 1.20 g/cm3, and 13.0 MPa for water absorption, apparent porosity, bulk density, and compressive strength, respectively. The corresponding values for ash-derived ALWAs were: 4.85%, 6.55%, 1.41 g/cm3, and 87.3 MPa, respectively. The characteristics of ALWAs derived in this study were then compared to those of commercially available lightweight aggregates—Lytag and Arlita F7. The characteristics mentioned above of the former were superior than those of the latter except that the value ofdensity was an interval value between Lytag and Arlita. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 740–748, 2013

Paper sludge is a major waste by-product of the paper industry. Its disposal creates serious problems, as approximately 30% of treated sludge is not flammable. In this study, artificial lightweight aggregates (ALWAs) were synthesized from paper sludge by co-sintering with H3BO3. H3BO3 acts as a flux to lower the sintering temperature below 900 °C, with co-melting occurring during the procedure. The decomposition gas is sealed within the ALWA during the glassy phase to form a porous structure. Water absorption, apparent porosity, bulk density, compressive strength, and weight loss after rinsing with Na2SO4 were tested to understand the physical properties of the manufactured ALWAs. The optimal method suggested is co-sintering with 18% H3BO3 flux at 890 °C for 30 min. The tested properties mentioned above gave the following results: 4.64 %, 2.77 %, 0.6 g/cm3, 13.2 MPa, and < 0.1 %, respectively. The ALWAs produced in this study have been compared to commercially available lightweight aggregates – Lytag and Arlita – with the examined ALWAs possessing better qualities than Lytag. Water absorption and compressive strength of ALWAs in this study met government requirements of pre-stressed concrete necessary for civil works, and could make useful building material.

Modified perovskite ceramics (La 0.9 Ca 0.1 )(Co 1− x Ni x )O 3− δ ( x = 0–0.3) cathodes for solid oxide fuel cells (SOFCs) were synthesized by solid state reaction. The lattice parameters, electrical conductivity, activation energy, and microstructures of these specimens were investigated systematically in this study. The results exhibited that all specimens are rhombohedron structures and their tolerance factors were greater than 0.97, indicating that the perovskite was not distorted by Ni 2+ cation substitution for the B site of (La 0.9 Ca 0.1 )CoO 3− δ . The microstructures of the (La 0.9 Ca 0.1 )(Co 1− x Ni x )O 3− δ specimens showed good densification, and were well-sintered, with few pores. The electrical conductivity behavior conformed to the nature of a semiconductor, for all specimens. As x = 0.1, the electrical conductivity reached the maximum value of 750.3 S/cm at 800 °C, and the activation energy calculated from the Arrhenius plot of the electrical conductivity versus the reciprocal of temperature is 7.1 kJ/mol. The novelty of this study is its introduction of the concept of defect chemistry to explain the relationship between compensation mechanisms and electrical conductivity. The information gleaned regarding charge compensation mechanisms and defect formation may be valuable for a better understanding of the cathode of (La 0.9 Ca 0.1 )(Co 1− x Ni x )O 3− δ ceramics used for SOFCs. Moreover, the information about oxygen content versus temperature is useful for expressing the relationship between electrical conductivity and composition. Therefore, we also used thermogravimetric analysis combined with the room-temperature oxygen content which was determined by iodometric titration to investigate the oxygen content from room temperature to high temperature, in air. Based on the experimental results, the (La 0.9 Ca 0.1 )(Co 0.9 Ni 0.1 )O 3− δ specimen shows high electrical conductivity. Consequently, it is identified as a promising candidate for cathode SOFC applications.

This study investigates Sm 0.5 Sr 0.5 CoO 3− δ (SSC)–Ce 0.8 Sm 0.2 O 1.9 (SDC) composite cathodes with a gradual change in composition from electrolyte to the cathode in an attempt to discover a potential approach applicable to solid oxide fuel cells (SOFCs). The gradual change in composition from electrolyte to cathode shows the decline in charge transfer resistance ( R 2 ) and gas phase diffusion resistance ( R 3 ). Because the value of R 3 is always larger than R 2 and R 3 significantly dominates the total cathode polarization resistance ( R P ) at temperatures within the range of 750–850 °C, i.e., in this temperature range, the rate-determining step is dominated by the diffusion or dissociative adsorption of oxygen. The functionally gradient cathode with a graded interface between cathode and electrolyte reveals both a higher exchange current density ( i 0 ) and a lower activation energy for oxygen reduction reaction (ORR), which suggests that the ORR kinetics can be improved by using the configuration of a functionally gradient cathode.

The microstructure, lattice parameters, mechanical properties, and electrical conductivity mechanisms for Cu doping on B-site of (La0.8Ca0.2)(Cr0.9Co0.1)O3−δ have been systematically investigated. In this study, the concept of defect chemistry is used to explain the relationship between the concentration of hole with the electrical conductivity. The information of charge compensation mechanisms and defect formation may be valuable for a better understanding of the interconnect of (La0.8Ca0.2)CrO3−δ-based ceramics used for solid oxide fuel cells (SOFCs). The electrical conductivity increases with the increase in temperature in air, whereas the electrical conductivity has a maximum value at a certain temperature in 5% H2–95% Ar. The concentration of hole at high oxygen activity is larger than that at low oxygen activity. Because (La0.8Ca0.2)CrO3−δ-based ceramics are p-type conductors, the electrical conductivity is dominated by the concentration of hole. Obviously, the electrical conductivities of Cu doping on B-site of (La0.8Ca0.2)(Cr0.9Co0.1)O3−δ in air are larger than those in 5% H2–95%. At higher Cu-doping levels, higher temperatures, and high oxygen activity, the compensation mechanism is significantly dominated by the formation of oxygen vacancy, i.e. ionic compensation. On the contrary, the compensation mechanism is significantly dominated by the formation of the formation of Cr4+, i.e. electrical compensation at lower Cu-doping levels, higher temperatures, and lower oxygen activity. Because mechanical properties of SOFCs interconnect materials are very important in reducing atmosphere, the effect of atmospheres on fracture toughness and microhardness for specimens is investigated, which results revealed that when specimens were exposed to 5% H2–95% Ar forming gas, all specimens appeared to have hydrogen-induced cracking (HIC) except for (La0.8Ca0.2)(Cr0.87Co0.1Cu0.03)O3−δ. Although the exact mechanism of HIC is still not clear, it is known from this study that Cu doped in the B-site of (La0.8Ca0.2)(Cr0.9Co0.1)O3−δ enhanced HIC damage and with the increase of Cu-doping level, the degree in HIC is increased.

BiFe1-xSmxO3 composites with different samarium (Sm) concentration (x=5-20%) in BFO3 were fabricated by the solid-state method. Their structure and magnetic property due to the samarium substitution in BFO3 were analyzed by the X-ray diffractometer and vibration sample magnetometer responses, respectively. The complex permeability (μ = μ'-jμ") and shielding effectiveness (SE) of powder-resin composites consisting of magnetic particles (BiFe1-xSmxO3) embedded into a dielectric matrix (PMMA) were studied at the microwave frequencies. The samarium concentration dependence of permeability and SE was measured using the free-space method. We found that the magnetic properties of the Sm-substitute BFO3 mainly lead to the shielding effect for the PMMA/BiFe1-xSmxO3 composites. In this paper, we demonstrate the gradual change of the shielding effect and permeability of the PMMA/BiFe1-xSmxO3 composites in the microwave range.

The electrical conduction behaviors of isovalent and acceptor dopants on B site of (La 0.8 Ca 0.2 )CrO 3− δ perovskites at high and low oxygen activities were investigated systematically. In this study, the concept of defect chemistry is used to explain the relationship between the concentration of electron hole with the electrical conductivity. The information of charge compensation mechanisms and defect formation may be valuable for a better understanding of the interconnect of (La 0.8 Ca 0.2 )CrO 3− δ -based ceramics used for solid oxide fuel cells (SOFCs). Since (La 0.8 Ca 0.2 )CrO 3− δ -based specimens belong to p-type conductors, their conductivities are proportional to the concentration of electron hole. In reducing atmosphere, the oxygen may be lost and ionic compensation may be take place through the formation of oxygen vacancies and the electrical compensation may arise by changing the valence of Cr from tri-valence to tetra-valence in reducing atmosphere. However the formation of oxygen vacancies has no contribution to electrical conductivity, the compensation mechanism is dominated by the electrical compensation, i.e . the take place a transition of Cr 3+ → Cr 4+ rather than that of ionic compensation, i.e. the formation of oxygen vacancies. Based on the defect chemical reactions and the results of electrical conductivity, the concentration of electron hole at high oxygen activity is larger than that at low oxygen activity. Therefore the electrical conductivity of (La 0.8 Ca 0.2 )CrO 3− δ -based ceramics at air is larger than that at 5% H 2 –95% Ar forming gas. The compensation mechanisms contain ionic and electrical compensation and the ratios of electrical to ionic compensation varied with the kind of dopant which significantly effects the electrical conductivity. The results suggest that the (La 0.8 Ca 0.2 )Cr 0.9 Co 0.1 O 3− δ specimen shows high electrical conductivity in air ( σ 850 °C = 59.59 S/cm) and 5% H 2 –95% Ar forming gas ( σ 850 °C = 47.98 S/cm) leading it a promising candidate as an interconnect material for SOFCs applications.

This study focuses on copper recovery from printed circuit board (PCB) sludge. The copper and other metals in the sludge were extracted with sulfuric acid, and the major metals in the leachate were copper and iron. Jarosite process was utilized to remove impurities such as iron and calcium from the leachate. The elimination percentage of iron from the leachate increased when the molar ratio of potassium/iron (K/Fe) increased in the jarosite process. When the molar ratio of K/Fe was 1.4., it was found that 18.91% of iron content was held while 92.97% of copper content remained in the leachate. The filtrate could be purified further with sulfide precipitation and its filtration characteristics were improved. Then copper sulfide was formed through sulfidation precipitation with a molar ratio of sulfide agent/copper at 0.7; the grade of copper in the recovered material was 57.55%. This indicates that the product was pure CuS, and filtration resistance could be reduced to promote improved copper recovery. © 2011 American Institute of Chemical Engineers Environ Prog, 2011

The mixed ionic and electronic conductors (MIEC) of La 0.9 Sr 0.1 Co 0.8 Ni 0.2 O 3−δ (LSCN)–Ce 0.8 Sm 0.2 O 1.9 (SDC) were investigated for potential application as a cathode material for solid oxide fuel cells (SOFCs) based on a SDC electrolyte. Electrochemical impedance spectroscopy (EIS) technique was performed over the temperature range of 600–850 °C to determine the cathode polarization resistance, which is represented by area specific resistance (ASR). This study systematically investigated the exchange current densities ( i 0 ) for oxygen reduction reaction (ORR), determined from the EIS data and high-field cyclic voltammetry. The 70LSCN–30SDC composite cathode revealed a high exchange current density ( i 0 ) value of 297.6 mA/cm 2 at 800 °C determined by high-field technique. This suggested that the triple phase boundary (TPB) may spread over more surface of this composite cathode and revealing a high catalytically active surface area. The activation energies ( E a ) of ORR determined from the slope of Arrhenius plots for EIS and high-field techniques are 96.9 kJ mol −1 and 90.4 kJ mol −1 , respectively.

The microwave dielectric properties of Sm(Mg 0.5 Ti 0.5 )O 3 incorporated with various amount of Bi 2 O 3 and B 2 O 3 additives have been investigated systematically. In this study, both Bi 2 O 3 and B 2 O 3 additives acting as a sintering aid can effectively lower the sintering temperature from 1550 °C to 1300 °C. The ionic radius of Bi 3+ for a coordination number of 6 is 0.103 nm, whereas the ionic radius of B 3+ is 0.027 nm. Clearly, the ionic radius of Bi 3+ is greatly larger than one of B 3+ , which resulted in the specimens incorporated with Bi 2 O 3 having larger lattice parameters and cell volume than those incorporated with B 2 O 3 . The experimental results show that no second phase was observed throughout the entire experiments. Depending on the interfacial tension, the liquid phase may penetrate the grain boundaries completely, in which case the grains will be separated from one another by a thin layer as shown in Sm(Mg 0.5 Ti 0.5 )O 3 ceramics incorporated with Bi 2 O 3 . Whereas, in Sm(Mg 0.5 Ti 0.5 )O 3 ceramics incorporated with B 2 O 3 , the volume fraction of liquid is high, the grains may dissolve into the liquid phase, and rapidly rearrange, in which case contact points between agglomerates will be dissolved due to their higher solubility in the liquid, leading plate-like shape microstructure. A dielectric constant ( ɛ r ) of 29.3, a high Q × f value of 26,335 GHz (at 8.84 GHz), and a τ f of −32.5 ppm/°C can be obtained for Sm(Mg 0.5 Ti 0.5 )O 3 ceramics incorporated with 10 mol% Bi 2 O 3 sintered at 1300 °C. While Sm(Mg 0.5 Ti 0.5 )O 3 ceramics incorporated with 5 mol% B 2 O 3 can effectively lower temperature coefficient of resonant frequency, which value is −21.6 ppm/°C. The Sm(Mg 0.5 Ti 0.5 )O 3 ceramic incorporated with heavily Bi 2 O 3 and B 2 O 3 additives exhibits a substantial reduction in temperature (∼250 °C) and compatible dielectric properties in comparison with that of an un-doped one. This implied that this ceramic is suitable for miniaturization in the application of dielectric resonators and filters by being appropriately incorporated with a sintering aid.

The mixed ionic and electronic conductors of La 0.9 Ca 0.1 Ni 0.5 Co 0.5 O 3 –Ce 0.8 Sm 0.2 O 1.9 (LCNC–SDC) are investigated systematically for potential application as a cathode for solid oxide fuel cells based on a Ce 0.8 Sm 0.2 O 1.9 (SDC) electrolyte. The electrochemical impedance spectroscopy (EIS) measurements are performed in air over the temperature range of 600–850 °C to determine the cathode polarization resistance. The exchange current densities for oxygen reduction reaction (ORR), determined from the low-field cyclic voltammetry, high-field cyclic voltammetry, and EIS data are systematically investigated. The activation energies ( E a ) for ORR determined from the slope of Arrhenius plots are in the range of 102.33–150.73 kJ mol −1 for LCNC–SDC composite cathodes. The experimental results found that LCNC–SDC (70:30) composite cathode has a maximum exchange current density and a minimum polarization resistance of 0.30 Ω cm 2 for 850 °C among LCNC–SDC composite cathodes.

The lattice parameters, electrical conductivity, activation energy, mechanical properties, and microstructure of (La0.8Ca0.2)CrO3−δ-based specimens were investigated systematically in this paper. The tolerance factors for (La0.8Ca0.2)CrO3−δ-based specimens were all greater than 0.9, indicating the perovskite was not distorted with different cations (Al3+, Co3+, Cu2+, Fe3+) substitution for B site of (La0.8Ca0.2)CrO3−δ. (La0.8Ca0.2)Cr0.9Co0.1O3−δ specimen revealed the maximum electrical conductivity, σ850 °C = 59.59 S/cm with minimum activation energy, Ea = 11.2 kJ/mol among (La0.8Ca0.2)CrO3−δ-based specimens. The grain size seemed dependent on doping species and the grain sizes were distributed in the range of 2.4–5.6 μm for (La0.8Ca0.2)CrO3−δ-based specimens. The rate of grain growth was proportional to the boundary mobility Mb, which was related to the diffusion coefficient of doping cation. (La0.8Ca0.2)CrO3−δ-based specimens revealed variety in microhardness, in the range of 4.33–9.85 GPa and the fracture toughness were distributed in the range of 3.52–4.33 MPa m1/2. Based on the results in terms of grain size and mechanical properties, we concluded that the microhardness and fracture toughness were dependent on the dopant ions. The (La0.8Ca0.2)Cr0.9Co0.1O3−δ specimen shows high electrical conductivity and mechanical properties Consequently, it is a promising candidate as an interconnect material for intermediate temperature solid oxide fuel cell (IT-SOFC) applications.

The mixed ionic and electronic conductors (MIECs) of Sm 0.5 Sr 0.5 Co 0.4 Ni 0.6 O 3−δ (SSCN)–Sm 0.2 Ce 0.8 O 1.9 (SDC) were investigated for potential application as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs) based on an SDC electrolyte. Electrochemical impedance spectroscopy (EIS) technique was performed over the temperature range of 600–850 °C to determine the cathode polarization resistance which is represented by area specific resistance (ASR). To investigate the ORR mechanism, the impedance diagram for 70SSCN–30SDC was measured under applied cathodic voltage from E = 0.0 to E = −0.3 V. It indicated that the charge transfer dominated the rate-determining step at the temperature of 600 °C; whereas the diffusion or dissociative adsorption of oxygen dominated the rate-determining step at the temperature of 800 °C. In this study, the exchange current density ( i 0 ) for oxygen reduction reaction (ORR) was determined from the EIS data. The i 0 value of 70SSCN–30SDC/SDC was 187.6 mA cm −2 which is larger than the i 0 value of 160 mA cm −2 for traditional cathode/electrolyte, i.e. LSM/YSZ at 800 °C, indicating that the 70SSCN–30SDC composite cathode with a high catalytically active surface area could provide the oxygen reduction reaction areas not only at the triple-phase boundaries but also in the whole composite cathode.