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Purpose This paper aims to investigate the potential application of Balanites aegyptiaca bark powder (BABP) for removing a basic textile dye, methylene blue (MB), from aqueous solutions. Design/methodology/approach The biosorbent (BABP) was characterized using Fourier transform infrared spectroscopy (FTIR) and point of zero charge (pHPZC). Batch mode was selected to study the biosorption of MB onto BABP surface at different experimental conditions (shaking speed, contact time, initial solution pH, ionic strength, solution temperature, biosorbent dosage and initial dye concentration). Besides, the reusability of BABP for MB biosorption was also examined. Findings The biosorption results revealed that approximately 96% of MB was removed successfully at the optimized operational conditions. Pseudo-second-order and Langmuir models, respectively, better described the adsorption kinetics and isotherms. The monolayer biosorption capacity (qmax) for MB was about 97.09 mg/g. According to thermodynamics findings, the MB biosorption onto BABP is an exothermic and spontaneous process. The results demonstrate that BABP can be considered as potential eco-friendly, readily available and low-cost biosorbent for hazardous textile dyes removal from water bodies and also provides a promising method for minimization of agricultural solid wastes (e.g. plant barks). Originality/value The utilization of Balanites aegyptiaca bark powder (BABP), solid waste material, as low-cost and eco-friendly biosorbent for the removal of hazardous basic textile dye (methylene blue) from the aquatic environment.

Carbon-free electrosynthesis of ammonia using water (H2 source) and air (N2 source) is promising technology to reduce the global CO2 emission resulting from the industrial ammonia production process (Haber-Bosch). In this study, electrocatalysis activity of non-noble metal perovskite-based catalyst (La0.75Sr0.25Cr0.5Fe0.5O3-δ-Ce0.8Gd0.18Ca0.02O2-δ, LSCrF-CGDC) for ammonia synthesis directly from air and water was explored. Ammonia was successfully from wet air (3%H2O) synthesized in a single-chamber type reactor. The highest ammonia formation rate and Faradaic efficiency of about 1.94×10-11 mol s-1 cm-2 and 2.01% were achieved at 375 oC and 1.2 V, respectively. The observed ammonia formation rate is higher than reported for an expensive noble metal-based catalyst (Ru/MgO). The obtained results indicated that the direct synthesis of ammonia from air and water is a promising technology for green and sustainable ammonia synthesis.

In this study, zinc ferrite magnetic nanoparticles (ZnFe2O4, ZFO MNPs) were employed as a sorbent for the removal of oil spill from water surfaces. ZFO MNPs were synthesized via a sol-gel process and characterized by Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction (XRD). Both the apparent density and magnetic force were determined. ZFO MNPs presented a considerable magnetic force (40.22 mN) and an adequate density (0.5287 g/cm3), which are important for the magnetic separation and flotation. Four oil samples (gasoline engine oil, crude oil, used motor oil and diesel engine oil) were used to investigate the gravimetric oil removal capability of ZFO MNPs. The oil sorption capacities were found to be 23.00-6.13, 27.65-7.42, 22.62-7.01 and 30.54-9.93 g/g for crude, diesel engine, gasoline engine, and used motor oil, respectively. The current findings demonstrate that ZFO MNPs exhibit good properties (e.g., magnetic and density) and can be used as a sorbent for oil spill cleaning-up from water surfaces.

Purpose The main purpose of this paper is to investigate the adsorption properties of CoFe1.9Mo0.1O4 magnetic nanoparticles (CFMo MNPs) using, anionic dye “congo red (CR)” as a model of water pollutants. Design/methodology/approach The magnetic nano-adsorbent was synthesized via sol-gel process. Different techniques including; Fourier transform infrared spectroscopy, point of zero charge, scanning electron microscope and X-ray powder diffraction were used to characterize the prepared adsorbent. Adsorption experiments were conducted in batch mode under various conditions (contact time, shaking speed, initial dye concentration, initial solution pH, solution temperature and adsorbent amount) to investigate the adsorption capability of CFMo MNPs for CR. Findings The results showed that, CFMo MNPs could successfully remove more than 90% of CR dye within 20 min. Adsorption kinetics and isotherms were better described using pseudo-second-order (PSO) and Langmuir models, respectively. The maximum adsorbed amount (qmax) of CR dye was 135.14 mg/g. The adsorption process was found to be endothermic and spontaneous in nature as demonstrated by the thermodynamics ( ΔGo, ΔHoand ΔSo). Practical implications This study provided a good example of using an easily separated magnetic nano-adsorbent for fast removal of a very toxic organic pollutant, congo red, from the aquatic environment Originality/value The employment of Mo-doped cobalt ferrite for the first time for removing hazardous anionic dyes such as congo red from their aqueous solutions.

Purpose This paper aims to investigate the electrocatalytic activity of CoFe1.9Mo0.1O4-Ce0.8Gd0.18Ca0.02O2-δ composite (CFMo-CGDC) for the direct synthesis of ammonia from H2O and N2 under atmospheric pressure. Designs CoFe1.9Mo0.1O4 nanoparticles (CFMo NPs) were synthesized via a sol-gel method. CFMo NPs were characterized using X-ray diffraction (XRD), Brunauer–Emmet–Teller (BET) specific surface area measurement and scanning electron microscope (SEM). Double-chamber reactor was used to synthesize ammonia using H2O and N2 as precursors. The factors affecting the ammonia formation rate (applied voltage and temperature) were studied. Findings CoFe1.9Mo0.1O4 nanoparticles (CFMo NPs) were synthesized via a sol-gel method. CFMo NPs were characterized using XRD, Brunauer–Emmet–Teller (BET) specific surface area measurement and SEM. Double-chamber reactor was used to synthesize ammonia using H2O and N2 as precursors. The factors affecting the ammonia formation rate (applied voltage and temperature) were studied. Originality/value The usage of CFMo-CGDC composite as an electrocatalyst for the synthesis of ammonia directly from H2O and N2.

The electrocatalytic ammonia synthesis using water (along with nitrogen) as a hydrogen source is proposed as an alternative green and clean technology to the energy-intensive and CO2-emitting process (Haber-Bosch) for ammonia production. Besides, a selective electrocatalyst for ammonia synthesis versus the competing hydrogen evolution remains elusive. This study aims to investigate the electrocatalytic activity of non-noble metal Co and Fe-free perovskite oxide-based composite cathode (La0.75Sr0.25Cr0.5Mn0.5O3-δ-Ce0.8Gd0.18Ca0.02O2-δ) towards ammonia synthesis from H2O and N2. The electrocatalyst was synthesized via a sol-gel process and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Ammonia was successfully with a maximum formation rate of 2.5 × 10-10mol s-1cm-2and Faradaic efficiency of 0.52% at 400 oC and applied voltage of 1.4 V. The results demonstrated that the proposed non-noble metal-based electrocatalyst is a promising material for the carbon-free ammonia synthesis process.

Surface technology provides an important and valuable insight into the practical and theoretical applications of a manufactured surface. Cutting conditions play an important role in assessment of functional performance for engineering surfaces. Also, there is an important relation between the surfaces geometry and the functional performance of the surface. The geometry of the surface has a large influences of the surface performance. Topography analysis is primarily concerned with describing a surface in terms of its features. Then the knowledge gained about the geometry of the surface is used to control the surface production process to predict the performance of the component in its functional environment. Roughness parameters which characterize machined surfaces affect on both culling conditions and functional performance. Previous researches introduced a relations between roughness parameters and functional performance of machined surfaces. In present study, three of the surface functional performance that are friction ,wear, and lubrication which known as the tribological properties are concerned. A hybrid Artificial Neural Network (ANN) is used for selection of optimal cutting conditions. Experimental study is made to obtain the required parameters for the constructed ANN. The experimental study is made on 65 specimens free cutting steel 37, 40 mm in diameter. The specimens are divided into three groups, one of them is machined by turning operation. The second group is machined by milling operation. The third group is machined by grinding operation. All specimen are machined at various cutting conditions (feed, speed, depth of cut). All specimens are measured using Mitutoyo Surf Test SJ201 that give the surface profile and some of roughness parameters of the measured surface as a result. A developed Matlab programs Sur/Test SJ201P and SRCP, are used to give a full assessment of surface roughness parameters from the resulted surface profile of the Mitutoyo SurfTest-S/201. An introduced neural network is modeled by computer programs written in Matlab®. Also, OSCC program made by Matlab© is developed for selection of optimal cutting conditions. The maximum difference between measured data and data obtained from introduced hybrid ANN is of ±0.25%.

In this study, Zn-substituted cobalt ferrite nanoparticles (CoFe1.9Zn0.1O4, CFZ) were successfully synthesized via a combined EDTA-citrate sol-gel process. The synthesized CoFe1.9Zn0.1O4 nanoparticles were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), point zero charge (pHpzc) and scanning electron microscopy (SEM). The adsorption experiments of methylene blue (MB) onto CFZ surface were conducted in batch mode. The experiments were conducted under different conditions (contact time, adsorbent dosage, initial pH solution, solution temperature and initial dye concentration). The experimental data were better fitted to pseudo-second-order (PSO) kinetic model (R2=0.9990). In addition, Langmuir isotherm (R2=0.9906) was the best model to describe the experimental adsorption data. The maximum adsorbed amount of MB (qmax) per unit mass of adsorbent was about 27.79 mg/g. The adsorption thermodynamics (i.e., ΔG°, ΔH°, ΔS°) revealed that the proposed adsorption process is feasible, spontaneous and exothermic in nature. The obtained results suggest that CFZ is a promising material used as an adsorbent for very toxic pollutants from aqueous solutions.

Crude oil is the main economic supply in many countries. Corrosion has been considered as the first fatal factor destroying the crude oil plants such as crude oil equipment, oil wells, separation vessels, storage tanks, and pipelines. This is the main reason encouraging many companies and researchers to develop new technological methods to manipulate corrosion. In this review, we discuss the types of corrosion, corrosion control methods (chemical and non -chemical methods), corrosion removal methods and corrosion monitoring process (direct and indirect measurement of corrosion). In addition some perspectives on SRB bacteria, types of inhibitors and gases removal methods were provided.

In the present study, Zn-doped cobalt ferrite (CoFe1.9Zn0.1O4) magnetic nanoparticles were successfully synthesized via sol-gel method. The prepared materials were characterized using X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The apparent density and magnetic force of CoFe1.9Zn0.1O4 nanoparticles were determined. The results revealed that the prepared materials display an adequate density and considerable magnetic force. The gravimetric oil removal capability tests were also performed to investigate the oil absorption properties of CoFe1.9Zn0.1O4 nanoparticles using four types of oil samples (crude, diesel, gasoline and hydraulic oil) as water pollutant’s model. The oil removal capabilities of the prepared absorbent were found to be 13.72 ± 0.42-5.50 ± 0.53 g/g, 14.99 ± 0.95-8.86 ± 0.42 g/g, 18.23 ± 1.01-8.06 ± 1.26 g/g and 10.58 ± 0.49-5.24 ± 0.31 g/g for crude, diesel engine, gasoline engine and hydraulic oil, respectively. The results suggest that the prepared magnetic nanoparticles can be used as absorbent materials for removing oil spills from water surface.

Along with water scarcity and the new risks related to climate change, pollution is a major issue affecting this vital resource globally. To face the challenge of treating large volumes of pollutants-loaded municipal wastewaters and industrial effluents, researchers have been investigating the application of different biological, physical, and (electro)chemical water treatment technologies. In this context, the application of adsorption for the removal of toxic or undesirable compounds from (waste)water is widely recognized as a versatile decontamination procedure, which is able to deal with a wide range of pollutants under various process configurations and operating conditions. In this chapter, relevant and recent research investigations conducted in North African countries (Libya, Tunisia, and Morocco) are presented and discussed, including diverse sorbents, adsorption systems, and targeted pollutants. Overall the main objective of this chapter is to showcase the current situation and prospects for the production and utilization of conventional and advanced sorbents for water depollution in North Africa.

A La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3−δ -Ce 0.8 Gd 0.18 Ca 0.02 O 2−δ composite cathode was used to investigate the electrochemical synthesis of ammonia from wet nitrogen. Wet nitrogen was flown through a dual chamber reactor under atmospheric pressure leading to the successful synthesis of ammonia. Ammonia was synthesised at a rate of 1.5 × 10 −10 mol s −1 cm −2 at 400 °C when applying a dc voltage of 1.4 V, which is the highest reported to date. This rate is twice that of the observed ammonia formation rate (7 × 10 −11 mol s −1 cm −2 ) when Co-free cathode, La 0.6 Sr 0.4 FeO 3−δ -Ce 0.8 Gd 0.18 Ca 0.02 O 2−δ was used as the cathode catalyst. A higher catalytic activity for ammonia synthesis may be obtained when using a catalyst with high oxygen vacancies, with the introduction of oxygen vacancies at the cathode being a good strategy to improve the catalytic activity of ammonia synthesis.

In this study, the adsorption properties of spinel ferrite-based adsorbent, CoFe1.9Mo0.1O4 (CFMo), for removal of methylene blue (MB) from aqueous solution have been investigated. Sol-gel process was successfully employed to prepare CoFe1.9Mo0.1O4 magnetic nanoparticles. The synthesized adsorbent was characterized by Fourier transform infrared (FTIR), scanning electron microscope (SEM) and X-ray diffraction (XRD). The adsorption experiments were carried out at various operational conditions (solution pH, initial dye concentration, contact time, adsorbent dosage and temperature) to evaluate the potential adsorption property of CFMo magnetic nanoparticles. The results showed that, under the optimum adsorption parameters, approximately 95 % of MB dye can be removed. The adsorption data were better described by Langmuir isotherm model and the maximum amount of MB adsorbed was about 20.45 mg/g. Several adsorption kinetic models and thermodynamic parameters (∆Go, ∆Ho, ∆So) were used to fit the adsorption experimental data. The adsorption kinetics followed the pseudo-second-order model (PSO), while the thermodynamic parameters indicate that the proposed adsorption process was endothermic and spontaneous in nature. The obtained results suggest that CFMo is promising adsorbent material for removal of very toxic dyes from aqueous solutions.

Ammonia was directly synthesised from wet air at 400 °C at atmospheric pressure. A new perovskite Sm0.6Ba0.4Fe0.8Cu0.2O3−δ was used as the electrocatalyst for electrochemical synthesis of ammonia. Ammonia formation rates of 9.19 × 10−7 mol s−1 m−2 and 1.53 × 10−6 mol s−1 m−2 were obtained at 400 °C when wet air and wet N2 were introduced into a simple single chamber reactor, respectively. The perovskite catalyst is low cost compared to the previously reported Ru/MgO and Pt/C catalysts. This experiment indicates that ammonia can be directly synthesised from wet air, a very promising simple technology for sustainable synthesis of ammonia in the future.

Dense La0.5Sr0.5Fe0.8Cu0.2O3−δ–(Li,Na)2CO3 and La0.5Sr0.5Fe0.8Cu0.2O3−δ–(Li,Na)2CO3–LiAlO2 composite membranes were prepared for CO2 separation. The La0.5Sr0.5Fe0.8Cu0.2O3−δ (LSFCu) was prepared via the combined EDTA–citrate complex sol–gel process according to a previous study and then used in the synthesis of the dual phase membrane. XRD characterisation of the La0.5Sr0.5Fe0.8Cu0.2O3−δ sample showed it is orthorhombic structure with space group P n m a ( 62 ) , a=5.4784(5) A, b=7.7456(7) A, c=5.5014(5) A, and V=233.44(4) A3. Dense composite membrane was obtained after carbonate treatment. Mixed CO2/N2, CO2/O2 and CO2/air gases were used for CO2 permeation experiments. At 750 °C, high CO2 permeation rate of 1.55 ml cm−2 min−1 was observed for the LSFCu–(Li,Na)2CO3–LiAlO2 composite membrane when 20% CO2/80% O2 mixture was used as the feed gas. Introduction of ~10 wt% LiAlO2 in the oxide–carbonate composite results in increased CO2 permeation rates which is likely due to the enhancement in surface reaction. The dominant pathway for CO2 permeation in the LSFCu–(Li,Na)2CO3–LiAlO2 composite membrane was believed through the coherent interaction between O2− and CO 3 2 − ions. Increased oxygen partial pressure in the feed gas can facilitate CO2 permeation. Due to the low O2 concentration in real flue gases, potentially the LSFCu–(Li,Na)2CO3–LiAlO2 dual phase membrane will separate CO2 only which provides an alternative technology for CO2 separation.

Electrochemical synthesis of ammonia from water vapour and nitrogen was investigated using an electrolytic cell based on CoFe2O 4-Ce0.8Gd0.18Ca0.02O 2-δ (CFO-CGDC), CGDC-ternary carbonate composite and Sm 0.5Sr0.5CoO3-δ-Ce0.8Gd 0.18Ca0.02O2-δ (SSCo-CGDC) as cathode, electrolyte and anode respectively. CoFe2O4, CGDC and SCCo were prepared via a combined EDTA-citrate complexing sol-gel and characterised by X-ray diffraction (XRD). The AC ionic conductivities of the CGDC-carbonate composite were investigated under three different atmospheres (air, dry O 2 and wet 5% H2-Ar). A tri-layer electrolytic cell was fabricated by a cost-effective one-step dry-pressing and co-firing process. Ammonia was successfully synthesised from water vapour and nitrogen under atmospheric pressure and the maximum rate of ammonia production was found to be 6.5 × 10-11 mol s-1 cm-2 at 400 C and 1.6 V which is two orders of magnitude higher than that of previous report when ammonia was synthesised from N2 and H2O at 650 C.

Single phase perovskite oxide La0.8Cs0.2Fe 0.8Ni0.2O3-δ was synthesised to be used as electrocatalyst for electrochemical synthesis of ammonia directly from wet air. It exhibits an orthorhombic structure with space group Pnma(62); a = 5.5493(5) A, b = 7.8352(10) A, c = 5. 5295(5) A, V = 240.42(4) A3. Composite made of Ce0.8Gd0.2O 2-δ (CGO) and (Li,Na,K)2CO3 was used as electrolyte. An ammonia formation rate of 9.21 × 10-7 mol s-1 m-2 was obtained at 400 C when applied a voltage of 1.4 V, while wet air (3 mol% H2O) was introduced to the single chamber reactor. This is just slightly lower than the value of 1.23 × 10-6 mol s-1 m-2 when wet N2 (3 mol% H2O) was fed under the same experimental conditions. These values are more than two orders of magnitude higher than the reported ammonia formation rates when synthesised from N2 and H2O at ∼ 600°C. The perovskite catalyst is also low cost compared to the Ru/MgO and Pt/C catalysts in previous reports. This experiment indicates that ammonia can be directly synthesised from wet air using low-cost catalysts. This is a very promising simple technology for sustainable synthesis of ammonia in the future.

Electrochemical synthesis of ammonia from wet nitrogen in an electrolytic cell using a La0.6Sr0.4FeO3−δ–Ce0.8Gd0.18Ca0.02O2−δ composite cathode and an oxide–carbonate composite electrolyte has been investigated. La0.6Sr0.4FeO3−δ was prepared via a combined EDTA–citrate complexing sol–gel process, characterised by X-ray diffraction and SEM. A tri-layer electrolytic cell was fabricated by a one-step dry-pressing and co-firing process. Ammonia was successfully synthesised from wet nitrogen under atmospheric pressure. Ammonia formation was observed at 375, 400, 425 and 450 °C and the maximum ammonia formation rate of 7 × 10−11 mol s−1 cm−2 was observed at 400 °C when a voltage of 1.4 V was applied. This ammonia formation rate corresponds to a Faradaic efficiency of ∼0.14% at a current density of 14.25 mA cm−2.

Electrochemical synthesis of ammonia was investigated using a cobalt-free La0.6Sr0.4Fe0.8Cu0.2O3-δ-Ce0.8Sm0.2O2-δ (LSFCu-SDC) composite cathode and SDC-ternary carbonate composite electrolyte. La0.6Sr0.4Fe0.8Cu0.2O3-δ and Ce0.8Sm0.2O2-δ were prepared via combined EDTA-citrate complexing sol–gel and glycine nitrate processes, respectively, and characterised by X-ray diffraction (XRD). Ammonia was successfully synthesised from wet hydrogen and dry nitrogen under atmospheric pressure using Ni-SDC, SDC-carbonate and LSFCu-SDC composites as anode, electrolyte and cathode respectively. Ammonia formation was observed at 400, 425, 450 and 475 °C and the maximum rate of ammonia production was found to be 5.39 × 10−9 mol s−1 cm−2 at 450 °C and 0.8 V. The AC impedance measurements were recorded before and after the ammonia synthesis in the range of temperature 400–475 °C. The formation of ammonia at the N2 side together with stable current at 450 °C under constant voltage demonstrates that SDC-(Li/Na/K)2CO3 composite electrolyte exhibits significant proton conduction at a temperature around 450 °C.

Ammonia is one of the most produced chemicals worldwide, and it is not only a major end product but also an important energy storage intermediate. The solid-state electrochemical synthesis of ammonia has the promise to overcome the limitations of the conventional catalytic reactors such as the limited conversion, severe environmental pollution and high energy consumption. Solid-state electrolytes either protonic or oxide ion conductors have been reviewed and particular emphasis is placed on their application to synthesise ammonia. The highest rate of ammonia formation according to the type of electrolyte utilised were in the following order; solid polymers > Ce0.8Gd0.2O2−δ-(Ca3(PO4)2-K3PO4) composites > fluorites > perovskites > pyrochlores although the catalysts in electrodes also play an important role. The highest rate reported so far is found to be 1.13 × 10−8 mol s−1 cm−2 at 80 °C with a potential of 2 V using Nafion membrane, SmFe0.7Cu0.1Ni0.2O3 (SFCN), and Ni-Ce0.8Sm0.2O2−δ as solid electrolyte, cathode and anode, respectively. Synthesising ammonia from steam and N2, by-passing H2 stage offers many advantages such as reduction of device numbers and then the overall costs. The factors affecting the rate of ammonia formation have been discussed as well.

Electrochemical synthesis of ammonia based on carbonate electrolyte is presented in this paper. Spinel oxide CoFe 2 O 4 was synthesised via a co-precipitation method and characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Ammonia was successfully synthesised from hydrogen and nitrogen under atmospheric pressure using CoFe 2 O 4 as catalyst (primary particle size 10–20 nm) together with silver at the cathode, Ag–Pd at the anode and carbonate-LiAlO 2 composite as electrolyte respectively. Ammonia formation was observed at 400, 425 and 450 °C and the maximum rate of ammonia production was found to be 2.32 × 10 −10 mol s −1 cm −2 at 400 °C and 0.8 V. The AC impedance measurements were recorded before and after the ammonia synthesis at 400, 425 and 450 °C. The electrolytic cell during the ammonia synthesis process was more stable at 450 °C and 0.8 V over a period of 2 h. This experiment also indicates that the carbonate-LiAlO 2 composite electrolyte exhibits proton conduction.

Ammonia was directly synthesised from wet nitrogen at an intermediate temperature (375–425 °C) based on the oxygen-ion conduction of the Ce0.8Gd0.18Ca0.02O2−δ–((Li/Na/K)2CO3) composite electrolyte. A redox stable perovskite-based catalyst, La0.75Sr0.25Cr0.5Fe0.5O3−δ (LSCrF), was synthesised via a combined EDTA–citrate complexing sol–gel process to be used as a component of the La0.75Sr0.25Cr0.5Fe0.5O3−δ–Ce0.8Gd0.18Ca0.02O2−δ composite cathode for ammonia synthesis. Ammonia formation was studied at 375, 400 and 425 °C and a maximum ammonia formation rate of 4.0 × 10−10 mol s−1 cm−2 with corresponding Faradaic efficiency of 3.87% was observed at 375 °C when the applied voltage was 1.4 V. This is much higher than 7.0 × 10−11 mol s−1 cm−2 at 1.4 V and 400 °C when Cr-free Sr-doped LaFeO3−δ, La0.6Sr0.4FeO3−δ was used as the catalyst for the electrochemical synthesis of ammonia, indicating LSCrF is potentially a better catalyst. Ammonia was successfully synthesised using a redox stable cathode with higher formation rates at reduced temperature. Introduction of Cr3+ ions at the B-site of doped LaFeO3 improves both the chemical stability and catalytic activity for ammonia synthesis.

Pyrolysis capillary gas chromatography has been applied to the study of the co-pyrolysis of polymethyl methacrylate (PMMA) with Slovakian brown coal with the aim of finding pyrolysis conditions yielding a maximum amount of methyl methacrylate (MMA). Effects of pyrolysis temperature and PMMA–coal weight ratios were investigated. Capillary gas chromatography coupled with mass spectrometric detector (cGC-MS) was used for MMA identification. The highest yield of MMA in the pyrolysate was obtained at 750 °C. The optimal PMMA–coal weight ratio for maximum MMA production lies in the interval 0.5 mg PMMA and 0.6–0.8 mg brown coal with an MMA yield of 64%. Coal addition to the sample affects species recombination in gaseous phase, augments MMA production at higher temperatures and eliminates degradation products of PMMA and coal pyrolysis. Different conversion diagrams are characteristic for thermal degradation of single PMMA and in the mixture with coal. Detailed mechanism of synergetic effects arisen during co-pyrolysis are not yet known. It was also found that lower pyrolysis temperatures are more suitable to study degradation mechanism and kinetics while higher temperatures are more applicable for identification purposes. MMA decomposes completely at 900 °C.

Cobalt molybdenum nitride (Co3Mo3N) catalyst was synthesised through ammonolysis of the corresponding precursors by flowing pure ammonia gas. The catalyst was characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Ammonia was successfully synthesised from wet hydrogen and dry nitrogen at atmospheric pressure using Co3Mo3N–Ag composite as cathode, Ag–Pd alloy as anode and LiAlO2–(Li/Na/K)2CO3 composite as an electrolyte. Ammonia formation was investigated at 400, 425 and 450 °C, and the maximum observed ammonia formation rate was 3.27×10−10 mol s−1 cm−2 at 450 °C when applied at 0.8 V. The catalytic activity of Co3Mo3N for electrochemical ammonia synthesis is lower than that of Pd. The successful synthesis of ammonia demonstrates that LiAlO2–(Li/Na/K)2CO3 composite exhibits protonic or/and oxygen ion conduction.

For the first time, ammonia has been directly synthesised from wet air at intermediate temperature. Ce0.8Gd0.2O2−δ (CGO)–(Li,Na,K)2CO3 electrolyte together with a new perovskite oxide Pr0.6Ba0.4Fe0.8Cu0.2O3−δ were used for electrochemical synthesis of ammonia. An ammonia formation rate of 1.07 × 10−6 mol s−1 m−2 was obtained at 400 °C when applied a voltage of 1.4 V, while wet air was introduced to the single chamber reactor. This is just slightly lower than the value of 1.83 × 10−6 mol s−1 m−2 when wet N2 was fed under the same experimental conditions. These values are two to three orders of magnitude higher than the reported ammonia formation rates when synthesised from N2 and H2O at ∼600 °C. The perovskite catalysts are also low cost compared to the Ru/MgO and Pt/C catalysts in previous reports.