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[Display omitted] • Synthesis of p-p isotype heterojunction CuO-NiO nanocomposite. • In-depth characterization of the synthesized nanocomposite. • Solar light assisted degradation of cefixime antibiotic. • Scavenging effect on the cefixime degradation. Organic pollutants have emerged as a threat to the environment due to their excessive usage and subsequent continuous release into the aquatic environment. This concern has necessitated the search for effective technologies to deal with the continuous accumulation of active pharmaceutical ingredients (APIs) as pollutants in the environment. Advanced oxidation processes (AOPs), including photocatalysis, have gained special attention for the removal of APIs and other organic pollutants in water. In order to achieve this goal, CuO-NiO nanocomposite photocatalyst with a p-p isotype heterojunction was prepared using the low-cost and facile method of co-precipitation. The composite catalyst was characterized by field emission scanning electron microscopy (FESEM), Thermogravimetric Analysis (TGA), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) which indicated the crystalline and mesoporous structure of the nanocomposite. The photocatalytic activity of the nanocomposite catalyst was studied using the degradation of cefixime as the model antibiotic under sunlight. The nanocomposite photocatalyst demonstrated effective catalytic activity against the degradation (90 %) of cefixime following first-order kinetics with a rate constant (k) of 7.4 × 10−3 min−1. The degradation of cefixime was greatly enhanced with catalyst dosage and at lower pH. A radical trapping study indicated hydroxyl radicals and superoxide radicals are responsible for degradation reactions. [ABSTRACT FROM AUTHOR]

The purpose of this study is to explore the relationship between energy production, energy consumption, and gross domestic product (GDP) growth in China for the period 1981–2016 (at the disaggregate level). The results of the Hatemi-J cointegration and structural-break tests supported long-term co-integration in the consumption and production of coal, oil, and natural gas. Based on the three models (coal, oil, and natural gas) of energy production and consumption, the fully-modified least square (FMOLS) method results confirmed the presence of long-term positive impact of the consumption and production of coal, oil, and natural gas on GDP growth. The CCR model estimations for robustness were found to be consistent with the FMLOS estimations. The vector error correction mechanism (VECM) based Granger-causality tests identified a one-way causality run from coal production and coal consumption to GDP growth; from GDP growth to gas consumption (supporting conservation hypothesis); from natural gas production to natural gas consumption; and from oil production and oil consumption to GDP growth. The paper draws important policy implications for theory, research and practice. • Energy production, energy consumption and economic growth were examined in China. • The Hatemi-J and FMOLS tests supported long term co-integration among variables. • Both energy consumption and production positively affect economic growth. • A one-way Granger causality observed from coal and oil to economic growth. • A one-way Granger causality observed from economic growth to gas consumption. [ABSTRACT FROM AUTHOR]

• The enhanced SOx-NOx interaction in pressurized oxy-combustion is studied. • A nine-step reduced chemistry is developed to estimate SO 3 and NO 2 formation. • The SOx-NOx interaction at elevated pressures significantly accelerates SO 3 formation. • A group of strong cycle reactions is found dominant for SO 3 formation at elevated pressures. Pressurized oxy-combustion is emerging to be one of the best technologies for significantly decreasing the energy penalty for CO 2 capture in coal-fired power plants. However, the higher pressure boosts the formation of acid gases, including SO 3 and NO 2 , which could increase the risk of corrosion. The synergistic promotion of SO 3 and NO 2 formation in pressurized oxy-combustion is kinetically evaluated under representative conditions (1 ~ 30 atm, 600 ~ 1200 °C, NO/SO 2 = 0.1 ~ 5). We begin with a comprehensive mechanism (72 species and 428 reactions), covering nitrogen and sulfur chemistry, relying on GRI-Mech 3.0. This analysis shows that the interaction of SO X and NO X enhances the conversion rates of SO 2 → SO 3 , and this effect is more apparent at elevated pressures and lower temperatures. Mechanism analyses indicate that at elevated pressures, the formation pathways of SO 3 through HOSO 2 + O 2 = SO 3 + HO 2 , and NO 2 through HO 2 + NO = NO 2 + OH, are promoted due to the strong interaction between SO X and NO X. The intermediate between these two reactions is SO 2 + OH + M = HOSO 2 + M, resulting in a strong cycle, that can be expressed by the global reaction NO + SO 2 + O 2 = NO 2 + SO 3. Finally, a nine-step reduced chemistry is developed and validated to accurately predict the formation of SO 3 in the post-flame region at elevated pressures. [ABSTRACT FROM AUTHOR]

[Display omitted] • SO 3 formation catalyzed by hematite were explored in a pressurized fixed bed. • Density functional study was employed to elucidate the catalysis mechanism. • The catalytic effect of hematite weakens at high pressure. • Changing the environment from N 2 to CO 2 has little impact on SO 3 formation. • The inclusion of NO could enhance SO 3 catalytic formation. Pressurized oxy-combustion is one of the most promising carbon capture technologies which could reduce global CO 2 emission. SO 3 is one of the main conventional pollutants and might be produced in large concentration in pressurized oxy-combustion than air combustion, posing risks to the environment and safe operation of boiler. However, no research has been conducted on SO 3 catalytic formation in pressurized oxy-combustion, despite the fact that SO 3 heterogeneous formation accelerated by hematite is more significant than homogeneous formation. Consequently, it is critical to understand SO 3 catalytic formation in pressurized oxy-combustion. In this study, SO 3 homogeneous and heterogeneous formation catalyzed by hematite were explored at 1 bar and 4 bar in a pressured fixed bed reactor. Temperature, pressure, and the addition of NO were discussed in this study. Density functional study method was employed to further elucidate the hematite catalysis mechanism. The findings show that hematite can catalyze the SO 3 formation, but the catalytic effect weakens at high pressure. The inclusion of NO could enhance SO 3 catalytic formation. Density functional study indicated that changing the main gas from N 2 to CO 2 has little impact on SO 2 and O 2 adsorption and subsequent SO 3 production. SO 3 adsorption becomes more stable with increasing O atom coverage, making SO 3 desorption more difficult. Since NO has a lower adsorption energy than SO 2 and O 2 , it has less effect on catalysis, however, NO 2 formation could act as a strong catalyst and can enhance SO 3 formation. This study could provide a better understanding of how the atmosphere and pressure influence SO 3 heterogenous formation in pressured oxy-combustion. [ABSTRACT FROM AUTHOR]

• Water washing can remove about 80% of Na and Cl and some of the organic matter in SEH coal. • Water washing can slightly change the SEH coal chemical structure. • The combustion properties of SEH raw coal can be improved by pretreatment with water. • When the temperature is above 815 °C, almost all of Na and Cl in raw coal can be released. ShaErHu (SEH) coal in Xinjiang province of China, with a reserve of 90 billion tons, is one of the most representative high-chlorine-alkaline coal. The chlorine content in raw coal generally exceeds 1%, which leads to severer corrosion during its combustion in the furnaces. Water washing pretreatment technology is proposed to remove chlorine effectively, and affects the fuel properties. This paper aims to study the effect of water washing pretreatment on the leachate characteristics with inorganic elements and organic matter from SEH coal. Furthermore, the characteristics of coal combustion and ash migration between raw coal and washed coal were compared. Results show that water washing removes approximately 80% of Na and Cl elements as well as some organic matter. The extracted organic matters are primarily aromatic compounds, accounting for more than 75% of the total organic matter. In raw coal, Cl is mostly existed in the inorganic components, accounting for 82.82% of the total, whereas in washed coal, it is mostly present in the organic components, accounting for 70.98% of the total. The alkane structure and -OH group are more prominent in washed coal than in raw coal. The combustion properties of SEH raw coal can be improved by pretreatment with water. When the temperature of the muffle furnace rises above 815 °C, the Na and Cl of SEH raw coal release 99.7% and 92.8 %, respectively, whereas washed coal cannot release nearly all the inorganic elements. [ABSTRACT FROM AUTHOR]

• The products and contents of DMF pyrolysis and fuel-lean combustion and the characteristics of SNCR for DMF combustion products were studied. • The products of largest concentration in DMF pyrolysis are H 2 , CO, HCN and CH 4. • HCN, N 2 O and NO are generated as the mainly N-containing species in DMF's fuel-lean combustion, and NO concentration increases with the increase of temperature or equivalence ratio. • With a lower temperature of 850 °C and high NSR ratio, SNCR has obvious effect on NO removal of the products from DMF combustion, while N 2 O removal rate is low. An experimental investigation was conducted on N,N-dimethylformamide (DMF) pyrolysis at medium-temperature followed by extremely fuel-lean combustion. Furthermore, the NH 3 -SNCR (Selective non-catalytic reduction) method was studied to control NO x produced in DMF oxidation. Jet-stirred reactors (JSRs) were used in experimental investigation, because the uniform gas-phase mixing state formed by high-speed turbulence in JSR makes the validation of detailed models easier. The major gaseous species produced by pyrolysis, oxidation, and SNCR, namely H 2 , N 2 , CO, CO 2 , NO x , N 2 O, HCN, and C x H y , are quantified because the mechanism of NO x reduction will be elaborated using these species. The results show that the main nitrogen-containing pyrolysis products are HCN and N 2 , taking up 65% and 25% of DMF nitrogen, while carbon-containing pyrolysis products are mostly CO, CH 4 and HCN. The HCN concentration increases significantly by 42.13% as pyrolysis time increases from 1.5 to 7 s. In oxidation, HCN and N 2 O concentration peaks are at 650 °C and 750 °C respectively, and NO concentration increases as temperature enhances when it is over 800 °C. A higher ratio of NO/N 2 O concentration was shown in oxidation of the higher equivalence ratio. The de-NO x efficiency of NH 3 -SNCR on oxidation flue gas peaked in range 825–875 °C, and as the NH 3 /NO ratio increased to more than 2.5, NO removal rate tended to reach the maximum of about 50%. The N 2 O removal rate rose significantly as temperature exceeded 900 °C in SNCR. The results shows the feasibility of NO emission control with DMF containing VOCs incineration in current industrial applications·NH 3 -SNCR at 825–875 °C shows significant de-NO x effect, but not a proper solution to limit N 2 O emission at the same time. This study could provide guidance for designing and optimizing the incinerator parameters and its de-NO x system, as well as provide validation data for future chemical kinetic model capable of predicting DMF combustion. [ABSTRACT FROM AUTHOR]

• An improved preheating combustion technology was proposed. • Analyzing the basic effects of HTC parameters on NO emissions. • In terms of NO emission and burnout, HTC and RTC are quite different. • Char and CO play an important role in reducing NO under fuel-rich conditions. In order to avoid the formation of NO from the nitrogen-containing pyrolysis components in the main combustion zone under preheating combustion technology, an improved preheating combustion technology was proposed. A two-stage drop-tube furnace was built to study the NO emission and combustion characteristics of high-temperature char (HTC) under the improved preheating combustion technology. The char was first heated to the initial pyrolysis temperature(600℃,800℃ and 1000℃) in the upper furnace under the atmosphere of nitrogen, before being burned in the second furnace. The influence of important operating parameters such as HTC temperature(600℃,800℃ and 1000℃), combustion temperature (1200℃,1300℃ and 1400℃)and excess air ratio (0.6 ∼ 1.4)were analyzed. The results show that raising the HTC temperature helps to reduce NO emissions. The maximum NO reduction efficiency is 21.1 % when the excess air ratio(α) = 1.0, which differs from the reported literature results of room-temperature char (RTC). In HTC, there is no absolute correlation observed between the BET area and NO reduction. The release of C and N is altered by pre-ignition of char at HTC; additionally, the evolution of nitrogen functional groups during the pyrolysis process is more key influencing factors. The stoichiometric ratio has a considerable influence on the effects of combustion temperature on NO emission. When there is a lack of oxygen, NO x emissions decrease as the temperature rises, whereas under oxygen-rich situations the converse is true. With the increase in HTC temperature from 600 °C to 1000 °C, the critical excess air ratio steadily increases from 0.75 to 0.85. The carbon concentration of fly ash can be reduced by increasing both the HTC and the combustion temperature. The largest reduction in carbon content in fly ash is 28.6 % at α = 1.0. [ABSTRACT FROM AUTHOR]

• CH 4 , C 2 H 6 , C 2 H 4 and C 2 H 2 mutual conversion behavior during coal pyrolysis process were well investigated. • Five CH 4 evolution paths, two C 2 H 6 evolution paths were proposed by the mathematic fitting method. • The coal aliphatic chain function group was studied by FTIR analysis. Different hydrocarbon species in coal pyrolysis gases have the NOx reduction potential. To investigate hydrocarbons CxHy mutual conversion in the coal pyrolysis gases, four typical coals were pyrolyzed under slow and fast heating rate conditions below 1200 °C. Results show that the yield of the hydrocarbon species has positive relation to coal volatiles. In fast heating condition CH 4 is the major pyrolysis products. In addition, the alkanes generation behavior is quite different from that of olefins and alkynes. In the range of 600–1200 °C, as the pyrolysis temperature increases, the yield of C 2 H 4 and C 2 H 2 increases while CH 4 and C 2 H 6 decreases. The yield of C 2 H 2 is significant at the temperature above than 1000 °C. Fourier transform infrared (FTIR) analysis show a close relationship between the coal functional group from 2800 to 3000 cm−1 and the alkanes yield. In the slow heating condition, five CH 4 and two C 2 H 6 evolution paths are proposed by the mathematic fitting method. The ethylene in the high temperature produced from the decomposition of C 2 H 6. When the heating rate is low, no C 2 H 2 is detected which illustrates that the formation of acetylene is closely related with the heating rate. [ABSTRACT FROM AUTHOR]

Abstract: Biohydrogen presents tremendous potential as an alternate source of energy. Microalgae are cheaper and sustainable source of biohydrogen production. To produce hydrogen from microalgae, a two-stage method is adopted; stage-1 for carbon fixation and stage-2 for anaerobic digestion and hydrogen production. In-efficient anaerobic digestion, low hydrogen yield, and high cost are the fundamental issues of two-stage process. All these issues are attributed to the lack of understanding in key processes of hydrogen production, such as cultivation, immobilization, sulfur deprivation, and anaerobic digestion. This review gives an insight into the improvement of hydrogen yield by discussing the whole process of hydrogen production. This work also delineates the developments, barriers, and recent trends of biohydrogen production. [Copyright &y& Elsevier]

• Bio-CPD model is used to optimize the two empirical models for biomass pyrolysis. • The optimized parameters of two models are applied in CFD modeling. • Both the two optimized model can be used to predict the wood pyrolysis with good accuracy. Pyrolysis is the key step in biomass thermochemical conversion process. The network model can accurately predict the pyrolysis process but generally cannot incorporate the combustion and gasification sub-models due to its complexity. This paper used the Bio-CPD model to predict the pyrolysis products of softwood and hardwood respectively; based on the predicted results, two empirical-simple forms of pyrolysis models were further optimized. The ultimate kinetic parameters obtained are suitable for biomass pyrolysis at high heating rate. For softwood, after being optimized, the apparent frequency factor and E / R of single rate are 4.3106e + 07 s−1, 10042 K respectively. While for two-competing rates model, the parameters are, α 1 = 0.75, α2 = 0.89, A1 = 7992 s−1, E 1 /R = 7000 K, A2 = 8.3e + 09 s−1, E 2 /R = 14520 K, respectively. The numerical simulation of biomass pyrolysis and combustion process were performed by using CFD code Ansys Fluent. The results reveal that the release of volatile predicted by the default parameters have a delay compared with the actual process and is not appropriate for biomass simulation, while the optimized parameters in two simple models are accurate enough to simulate the biomass pyrolysis at high heating rate (103–105 K/s). [ABSTRACT FROM AUTHOR]