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[Display omitted] • Office paper waste is processed using physiochemical and enzymatic hydrolysis. • The yeast is isolated from rotten banana for the fermentation process. • Box-Behnken analysis was used to determine optimal conditions for key variables. • A blended membrane was applied for the purification process. • Amicon cell and polymeric membrane dehydrate ethanol–water combinations. One potential replacement for fossil fuels is the generation of biofuel from biomass feedstock. To reach the global sustainability goals, it is also necessary to address a number of issues, such as reducing environmental pollution, climate change, and carbon emissions. This work was aimed to convert the office paper waste as biomass feedstock into bioethanol through a sustainable pathway. The office paper waste was hydrolyzed via physiochemical and enzymatic hydrolysis, the liberated glucose was estimated at 15.72 g/L using the optimum conditions of 15 % HCl and 6 % office paper waste followed by enzymatic hydrolysis. The yeast isolate B2 that was applied for the fermentation process was isolated from rotten banana, identified as Hanseniaspora uvarum (STDF-B2) and submitted to GenBank with accession number (OP800106). The Box-Behnken design was applied to estimate the optimal conditions for the three most significant variables depending on the one variable at a time results. A blended membrane of sulphonated polyvinyl chloride with poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (SPVC-PAMPS) was applied for the purification of both standard ethanol and produced bioethanol via pervaporation technique (PV). The morphology, chemical composition, mechanical properties and permeability of the membrane were all analyzed in various ways. Following purification using a membrane-integrated amicon cell, the total permeate flows of the laboratory-prepared ethanol and generated bioethanol were 289.54 and 253.06 (g/m2 h), respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • A two-phase mass transfer model of paper-based microfluidic fuel cell is proposed. • The coupling characteristics of capillary action and two-phase flow are revealed. • The fluctuation mechanism of cell performance and gas distribution is explored. • Gas removal strategies are summarized, with a maximum gas removal rate of 42.30%. Paper-based microfluidic fuel cell powered by capillary force has the advantages of compactness, low cost, and high sensitivity, presenting broad application prospects in portable electronic devices. However, the gas-liquid mass transfer mechanism within the porous medium remains unclear, with a lack of two-phase flow theories adapted to the unique paper-based system. In this study, a two-dimensional two-phase numerical model of a Y-shaped paper-based microfluidic fuel cell is developed to reveal the two-phase flow characteristics under capillary action and explore gas removal strategies. The reliability of the model is validated by real experimental data. By coupling multiple physical fields, the study elucidates the working principle and gas-liquid flow phenomena within the cell. Then, the effects of contact angle, inlet fuel concentration, and paper type on output performance, gas distribution, parasitic effect, and fuel utilization are discussed. The results indicate that increasing the contact angle and using paper with a larger average pore size and porosity as the channel substrate are ideal for promoting gas discharge. The optimal gas removal rate reached 42.30 %, with a favorable power density of 33.92 mW/cm2. This study provides a theoretical basis for a deeper understanding of the two-phase mass transfer process in paper-based microfluidic fuel cell. [ABSTRACT FROM AUTHOR]

Pyrolysis of paper mill sludge (PMS) was conducted to produce syngas (H 2 and CO) and fabricate magnetic biochar (PMS biochar) for use as an adsorbent for As(V). The enhanced generation of CO was observed in the CO 2 atmosphere due to reactions triggered by CO 2 . Particularly, the generation of syngas from pyrolysis of PMS in CO 2 (9.6 mol% at 720 °C) was superior to the cases of pyrolysis of acid-washed PMS ( i.e. , minerals-eliminated PMS) in CO 2 (2.9 mol% at 720 °C), which evidences catalytic effects attributed by Fe and Ca species contained in PMS. Based on the results of X-ray diffraction (XRD), pyrolysis of PMS in CO 2 led to the conversion of Fe species into magnetite (Fe 3 O 4 ) solid phase that imparted the magnetic property to the biochar (saturation magnetization: 28.4 emu g −1 ). The PMS biochar exhibited high As(V) adsorption capacity of 34.1 mg g −1 in a given condition, which could be attributed to the great adsorption affinity of Fe 3 O 4 /CaCO 3 mixture toward As(V). The integrated approach for the utilization of PMS could satisfy growing demand for renewable energy and environmental sustainability. [ABSTRACT FROM AUTHOR]

Pulp and paper mill effluent (PPME), a rich cellulosic material, was found to have great potential for biohydrogen production through a photofermentation process. However, pretreatments were needed for degrading the complex structure of PPME before biohydrogen production. The aim of this study was to gain further insight into the effect of an ultrasonication process on PPME as a pretreatment method and on photofermentative biohydrogen production using Rhodobacter sphaeroides NCIMB. The ultrasonication amplitudes and times were varied between 30–90% and 15–60 min, respectively, and no dilution or nutrient supplementation was introduced during the biohydrogen production process. A higher biohydrogen yield, rate, light efficiency and COD removal efficiency were attained in conditions using ultrasonicated PPME. Among these different pretreatment conditions, PPME with ultrasonication pretreatment employing an amplitude of 60% and time of 45 min (A60:T45) gave the highest yield and rate of 5.77 mL H 2 /mL medium and 0.077 mL H 2 /mL h, respectively, while the raw PPME without ultrasonication showed a significantly lower yield and rate of 1.10 mL H 2 /mL medium and 0.015 mL H 2 /mL h, respectively. The results of this study demonstrated the potential of using ultrasonication as a pretreatment for PPME because the yield and rate of biohydrogen production were highly enhanced compared to the raw PPME. Economic analysis was also performed in this study, and in comparison with raw PPME, the highest net saving was $0.2132 for A60:T45. [ABSTRACT FROM AUTHOR]

Pyrolysis is a promising technology for the production of marketable energy products from waste mixtures, as it decomposes heterogeneous material into homogenous fuel products. This research assessed the ability of slow pyrolysis to convert three waste streams, composed of fibre residues contaminated with different plastic mixtures, into char and tarry phase products at three different temperatures (300, 425 and 550 °C). The products were characterised in terms of mass yield, higher heating value (HHV) and gross energy conversion (EC). Significant amounts of hydrocarbon plastics in the feed materials increased the calorific values of the char (up to 32.9 MJ/kg) and tarry phase (up to 42.8 MJ/kg) products, comparable to high volatile bituminous A coal and diesel respectively. For all three waste streams converted at 300 °C, the majority of the energy in the feedstock was recovered in the char product (>80%), while deoxygenation of fibre component resulted in char with increased calorific value (up to 31.6 MJ/kg) being produced. Pyrolysis at 425 °C for two of the waste streams containing significant amounts of plastic produced both a valuable char and tarry phase, which resulted in an EC greater than 74%. Full conversion of plastic at 550 °C increased the tarry phase yield but dramatically decreased the char HHV. The influence of temperature on product yield and HHV was discussed based on the pyrolysis mechanisms and in relation to the plastic composition of the waste streams. [ABSTRACT FROM AUTHOR]

This paper investigates the possibility of combining different forest industries (a pulp and paper mill, its supply chain, and a wood-pellet plant) into an integrated industrial site in which they share a common heat and power utility. Advanced process integration and optimization techniques are used to study the site from both material and energy viewpoints. An existing pulp and paper mill is used as the site core plant and its pulp and paper production rates are kept fixed as they are in reality, while the other material flow links among the plants are based on the current industrial situation in Sweden. Different scenarios are evaluated in order to reflect the two main objectives that can be pursued (increased electricity production or biomass resource saving) and the two technologies that can be considered for the shared CHP system (boilers and product gas fired gas turbines). The corresponding non-integrated (standalone) configurations are compared to these scenarios to quantify the potential benefits of the integration. Investment opportunity is also calculated for the considered scenarios as an indicator of the economic convenience. [ABSTRACT FROM AUTHOR]

• Efforts to enhance PMFC performance are reviewed. • Both exciting advancements and current limitations are discussed. • An innovative strategy of multi-scale simultaneous optimization is proposed. Paper-based microfluidic fuel cell (PMFC) has attracted great attention in the microfluidic fuel cell field in recent years. It utilizes the spontaneous capillary flow of reactant solutions in paper-based porous substrate to achieve passive transportations of fuel and oxidant, solving the fluid driving issue encountered in traditional microfluidic fuel cells and thus having broad application prospects in medical detection, wearable devices, micro sensors, environmental monitoring, and many other fields. However, the commercialization of this technology is impeded by the low output performance caused by the limited mass and energy transfer in PMFCs. To enhance the mass and energy transfer in PMFCs, numerous research studies have been conducted via experimental optimization of the cell materials and structures. Numerical analyses focusing on the structure–activity relationship of PMFCs were also performed recently. To provide a comprehensive and thorough review about the efforts devoted to improving performance of PMFC, research papers relevant to PMFC since its invention in 2014 have been extracted in this work and significant works were filtered to highlight the exciting advancements. The experimental studies were classified and discussed based on the key components involved in the PMFC system, followed by a critical review of the limited computational models. Potential directions for future research were also provided, aimed at overcoming the current technological challenges in PMFCs. Importantly, an innovative strategy of multi-scale simultaneous optimization of the cell properties is proposed considering the typical multi-scale feature of the PMFC system, which could inspire the designing of advanced cell materials with optimal multi-scale structures for applications of PMFCs. [ABSTRACT FROM AUTHOR]

A large amount of sheep dung (SD) produced on farms in China is a potential feedstock for production of clean energy in the form of biogas. Similarly, waste paper can be a notable energy source that is worth exploiting. In this study, we assessed the feasibility of co-digesting nitrogen-rich SD with the carbon-rich corrugated board (CB) or waste office paper (OP) in varying volatile solids (VS) ratios, to produce methane. Synergistic effect of co-digesting SD with CB and SD with OP on methane production was found in this study. The highest methane yields of 151.62 and 198.85 mL/g-VS were obtained during the co-digestions of SD with CB at 4:1 ratio (SDCB) and SD with OP at 2:3 ratio (SDOP), respectively. High-throughput 16 S rRNA gene sequencing demonstrated that the microbial diversity and richness in SDCB and SDOP co-digests were higher than in SD and OP mono-digests, respectively. Characteristic bacteria and archaea in the digests were strongly substrate-related and might contribute to methane production. The validated results indicated that methane production through anaerobic co-digestion of SD and waste paper can be an efficient way that could not only reduce environmental pollution but also contribute to methane production. [ABSTRACT FROM AUTHOR]

Pulp and paper industry is a water-intensive industry. This industry commonly produces considerable amount of effluent, especially from virgin raw materials processing. The effluent, namely pulp and paper mill effluent has the potential to adversely affect the receiving watercourses. However, the nutrients in the pulp and paper mill effluent could be reused as a substrate in biohydrogen production. In this study, photofermentative biohydrogen production was investigated using Rhodobacter sphaeroides and pulp and paper mill effluent as a substrate. An application of low power ultrasound on R. sphaeroides was predicted to increase photofermentative biohydrogen production but excessive ultrasound effects might inhibit the production due to possible cell disruption. Hence, various ultrasonication duration (5, 10 and 15 min) and amplitude (15%, 30% and 45%) were applied on the bacteria to determine the recommended ultrasonication conditions for improving biohydrogen production. The recommended conditions were operated at ultrasonication amplitude and duration of 30% and 10 min, respectively. A maximum biohydrogen yield of 9.62 mL bioH 2 /mL medium was obtained under this condition, which was 66.7% higher than the result obtained using R. sphaeroides without undergoing ultrasonication (control). The light efficiency and cell concentration were increased by 67% and 150%, respectively, using ultrasonication amplitude and duration of 30% and 10 min, respectively as compared to the control. The present results demonstrated that moderate power of ultrasonication applied on R. sphaeroides was an effective method for enhancing photofermentative biohydrogen production using raw pulp and paper mill effluent as a bioresource. [ABSTRACT FROM AUTHOR]

The improvement of batch photofermentative biohydrogen production was investigated using ultrasonication pre-treatment on a combined effluent of palm oil and pulp and paper mills. The effects of the amplitude (30–90%) and ultrasonication duration (5–60 min) were investigated in terms of their influences on the biohydrogen yield and chemical oxygen demand (COD) removal. The recommended ultrasonication parameters were found at the higher ranges of amplitude and duration (A70T45). Using A70T45 ultrasonication, the production of biohydrogen at 30 °C could be enhanced up to 8.72 mL H 2 /mL medium , with a total COD removal of 36.9%. During pre-treatment at A70T45, an energy input of 775 J/mL was supplied to disintegrate complex compounds into simpler structures. As a result, an increase in the soluble organic matter concentration was achieved, which led to enhanced biohydrogen production. On the other hand, the lowest biohydrogen yield (4.67 mL H 2 /mL medium ) and total COD removal (28.8%) were obtained in the control without pre-treatment. The enthalpy of the photofermentation process was estimated to be 141.1 kJ/mol with a threshold temperature of 30.9 °C based on a modified Arrhenius approach. [ABSTRACT FROM AUTHOR]

The performance of vacuum, slow and fast pyrolysis processes to transfer energy from the paper waste sludge (PWS) to liquid and solid products was compared. Paper waste sludges with low and high ash content (8.5 and 46.7 wt.%) were converted under optimised conditions for temperature and pellet size to maximise both product yields and energy content. Comparison of the gross energy conversions, as a combination of the bio-oil/tarry phase and char (EC sum ), revealed that the fast pyrolysis performance was between 18.5% and 20.1% higher for the low ash PWS, and 18.4% and 36.5% higher for high ash PWS, when compared to the slow and vacuum pyrolysis processes respectively. For both PWSs, this finding was mainly attributed to higher production of condensable organic compounds and lower water yields during FP. The low ash PWS chars, fast pyrolysis bio-oils and vacuum pyrolysis tarry phase products had high calorific values (∼18–23 MJ kg −1 ) making them promising for energy applications. Considering the low calorific values of the chars from alternative pyrolysis processes (∼4–7 MJ kg −1 ), the high ash PWS should rather be converted to fast pyrolysis bio-oil to maximise the recovery of usable energy products. [ABSTRACT FROM AUTHOR]

Highlights: [•] 9–12h adsorption of CO2 in the 1st cycle increases cyclic CO2 adsorption of APMW. [•] Repeated prolonged adsorptions in cycles are feasible to capture CO2 using APMW. [•] Prolonged adsorption increases pores in 10–100nm of APMW after desorption of CO2. [Copyright &y& Elsevier]

[Display omitted] • Various carbon nanotube-based devices are developed for solar energy utilization. • The water evaporation system can generate freshwater (1.28 kg m−2h−1). • The solar-thermoelectric system can output a voltage and charge a cellphone. • The supercapacitor performs an areal specific capacitance of 19.6 mF cm−2. • The hybrid energy system can produce freshwater, generate and store electric power. Nowadays, multi-functional systems driven by solar energy have been explored to alleviate the crisis of energy and freshwater scarcity. However, it remains a great challenge to integrate multi-functions into one hybrid system with a monolithic material, which can harvest, convert and store solar energy synergistically. Here, we firstly propose a multi-functional carbon nanotube paper, which starts from a material level to solve these problems. The carbon nanotube paper is fabricated by vacuum filtration. It exhibits high efficiency of solar-thermal conversion. Secondly, three types of energy conversion/storage systems (e.g., solar-thermal evaporation system, solar-thermoelectric generation system, and supercapacitor) are constructed based on the carbon nanotube paper, which extend the research to a device level. The solar-thermal evaporation system shows an evaporation rate of 1.28 kg m-2h−1 under simulated sunlight irradiation of 1 kW m−2. The solar-thermoelectric generation system demonstrates a stable electric power generation with an output voltage of 100 mV under light irradiation of 1 kW m−2. The supercapacitors perform the energy storage function with an areal specific capacitance of 19.6 mF cm−2. These devices and systems can be used in freshwater generation (0.84 kg m-2h−1, sunlight irradiation of 1 kW m−2), water purification/desalination (inorganic ions rejection larger than 99.9%) and portable solar charging system (maximum output voltage of 5 V). Finally, a hybrid energy system is innovatively proposed from the system level to simultaneously produce freshwater, generate and store electric power. Through the synergetic coupling of solar conversion and storage technologies, the hybrid energy system can supply sustainable freshwater and electricity for remote areas in daily life, highlighting the superiority of multi-energy (thermal energy, electrical energy, and electrochemical energy) complementary. [ABSTRACT FROM AUTHOR]

Pyrolysis process of coffee paper cup samples was investigated in a flow stream of nitrogen at different heating rates (10, 20, 30 and 40°Cmin−1), using thermo-analytical techniques. It was found that second pyrolysis stage can be described by Šesták-Berggren (SB) autocatalytic model, with mechanism function f(α)=α0.011(1−α)1.459. Based on analysis of SB kinetic exponents (designated by M and N), it was found that second pyrolysis stage is mainly controlled by chemical process, involving reactions with reaction-order (n) higher than unity. Applying specific statistical analysis, in order to obtain precise distribution of reactivity, the discrete (binomial) distribution has shown that there are two important areas of current distribution for corresponding energy outcomes, within the apparent activation energy as random variable. The first "concentration" area of energy outcomes corresponds to start of chain end depolymerization reaction forming levoglucosan at high enough temperature region, while second "concentration" area of energy outcomes includes occurrence of macro-radicals in liquid phase propagate with radical addition on unsaturated C-C bonds, with cross-linking and formation of small chemical species. It was found that further elevating of temperature (above 340°C), will leads to fact that rate of tar-forming reactions increases and formation of char decreases. [ABSTRACT FROM AUTHOR]

An ultrasonication technique was applied intermittently onto photofermentation broth during the first six hours of photofermentation to improve biohydrogen production by using Rhodobacter sphaeroides NCIMB8253. In this research, photofermentation broth consisted of a combination of palm oil (25%, v/v), pulp and paper (75%, v/v) mill effluents as well as liquid inoculum. The effects of amplitude (10, 20 and 30%, A) and ultrasonication duration (5, 10 and 15 min, T) were investigated in terms of their influences on photofermentative biohydrogen yield and total chemical oxygen demand (COD total ) removal. The recommended ultrasonication parameters were found at the middle range of amplitude and duration (A20T10). Using A20T10 intermittent treatment, the production of biohydrogen could be maximized up to 14.438 mL H 2 /mL medium with a COD total removal and light efficiency of 52.2% and 7.412%, respectively. By comparing the treatment without intermittent ultrasonication, an increase of biohydrogen yield by 44.6% was achieved in A20T10 treatment. A total energy input of 306.1 J/mL (A20T10 treatment) was supplied to improve substrate consumption and light distribution during the photofermentation, which led to the increase of biohydrogen yield. [ABSTRACT FROM AUTHOR]

The thermal characteristics and kinetics of paper mill sludge (PMS), municipal solid waste (MSW) and their blends in the combustion process were investigated in this study. The mass percentages of PMS in the blends were 10%, 30%, 50%, 70% and 90%, respectively. The experiments were carried out at different heating rates (10 °C/min, 20 °C/min and 30 °C/min) and the temperature ranged from room temperature to 1000 °C in a thermogravimetric simultaneous thermal analyzer. The results suggested that the ignition temperature and burnout temperature of MSW were lower than that of PMS, and the mass loss rate of MSW was larger especially at low temperatures. There were only two mass loss peaks in the differential thermogravimetry (DTG) curve, while three mass loss peaks were observed when the blending ratios of PMS were 30%, 50%, 70%. The value of the comprehensive combustion characteristic index of the blends indicated a good combustibility when the percentage of PMS (PPMS) in the blends was less than 30%. There existed certain interaction between the combustion process of PMS and MSW, especially at high temperature stage. Activation energy ( E ) value obtained by the Ozawa–Flynn–Wall (OFW) method and the Starink method were very consistent. When the mass percentage of PMS in the blends was 80%, the E average value attained the minimum. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel method to estimate total technical potential for improving energy efficiency. • Bottom-up sector energy model used to characterize energy demands and opportunities. • Technology-explicit analysis framework used to estimate integrated energy savings. • Application to Canada's pulp & paper sector indicates major savings are possible. • Technical potential to reduce natural gas use by 95% and net electricity by 54% Industrial energy efficiency has long been recognized as a critical tool for energy management and emissions reduction and is increasingly considered to be an energy resource in its own right. However, the complexity of most industrial sectors creates barriers for modellers, companies, and policymakers in understanding and achieving the overall potential for efficiency-driven energy savings. To address this gap, we have developed a novel method that combines disaggregated bottom-up sector energy modelling with analysis of a comprehensive set of technology-explicit energy efficiency measures. This approach overcomes the deficiencies of top-down analyses and better represents the complexities of multi-measure efficiency investments compared to piecewise studies of individual measures. In this study, we demonstrated application of our method to the case of the Canadian pulp and paper sector. Our analysis shows that the sector can reduce its natural gas and electricity use by 95% and 41%, respectively, by adopting economical efficiency measures. This equates to 71 PJ of natural gas and 44 PJ of electricity saved annually and would result in cost savings of $81 per tonne of output sector-wide. Notably, we find that efficiency and fuel switching have the technical potential to reduce natural gas consumption by 98% across the sector. Taken together, the results provide quantitative evidence that energy efficiency is an underestimated resource for cost-effective energy savings in the Canadian pulp and paper sector. Our analysis framework can be applied to any industrial sector in any region to provide insights regarding energy conservation strategies and policy design. [ABSTRACT FROM AUTHOR]

In this work, the types of products and their proportions, the evolution characteristics of the functional groups and gases products, the pollutants emission of combustible solid waste (CSW), paper mill sludge (PMS) and their blends were investigated by Py-GC/MS and TG-FTIR. For the blends, the proportions of PMS were 10%, 30% and 50%. The percentage of pyrolysis products (acid, hydrocarbon, aldehyde, alcohol, benzene, furan, phenol, ester and ketone) was pointed out. Among these, the content of acid was the maximum. Blended with 10% PMS, the percentage of alcohol reached the greatest. Both single sample and blends could be divided into two decomposition phases. The residue mass of blends increased from 17.74% to 30.47% with the PMS ratio increased. O H, C H, C O, C O, SO 2 , NO, HCl, CO, CH 4 and CO 2 were the main functional groups and gases products surveyed from the FTIR spectrums during co-pyrolysis. Adding PMS into CSW could reduce the emission of the pollutants and the lowest yield of pollutants (SO 2 , NO, HCl, CO and CO 2 ) would be obtained covered with 50% PMS. [ABSTRACT FROM AUTHOR]

In the present study, the extraction of polyester like polyhydroxyalkanoates (PHAs) from enzymes extracted sludge was investigated by varying extraction time and chloroform – sodium hypochlorite dosage. Maximum of 874 mg/g of PHAs was achieved at an optimum extraction time of 120 min and chloroform – sodium hypochlorite dosage of 30% v/v. The characteristics of derived PHAs were examined using Fourier transform infrared (FTIR) spectroscopy and Nuclear magnetic resonance ( 1 H NMR) spectroscopy. Then, the effect of derived PHAs dosage on biomethane production from pulp and paper mill secondary clarifier (PPSC) sludge was studied. Higher amount of biomethane production was observed to be 174 L/(kg VS) at 35 mg of PHAs dosage when compared to other dosage. To further enhance biomethane production, disperser pretreatment method was carried out by optimization of specific energy. At optimum specific energy of 8547 kJ/kg TS, the maximum solubilization rate and suspended solids (SS) reduction were found respectively to be 19% and 15.8%. Then, biomethane assay was conducted on disperser pretreated sludge, disperser pretreated sludge with optimized PHAs dosage (35 mg) and control sludge. Among these, disperser mediated PHAs method exhibited maximal biomethane production and was observed to be 267 L/(kg VS). Hence, PHAs based sludge treatment method can be implemented in sludge management studies by retrieval of value added product and PHAs canbe used to enhance biomethane production sustainably. [ABSTRACT FROM AUTHOR]

[Display omitted] • A methodical approach for understanding the paper-based microfluidic fuel cells. • Fabrication strategies of various paper-based microfluidic fuel cell has been reviewed. • Paper-based microfluidic fuel cells with different types of fuels are summarized and compared. • Stacking efficiency is compared among different paper-based microfluidic fuel cell stacks. • Applications, challenges and prospects have been discussed. Since they firstly appeared in 2014, paper-based microfluidic fuel cells (PMFC) have received great attention in the past few years, mainly being used for sensors, wearable devices, point-of-care testing and diagnostics. This fuel cell technology exploits the intrinsic characteristics of paper substrate and microfluidic flows of reactant streams eliminating the need for external pumps and conventional membranes. PMFCs operate in a co-laminar flow configuration, and the absence of convective mixing across the liquid–liquid interface of two streams forms a distinct diffusive mixing region, which acts as a pseudo–membrane. The hydrophilicity and porosity of paper substrate allows reactants to flow by capillarity with the assistance of an absorbent pad. Ions can be transported across the channel through the mixing region to reach the other side of the channel and complete ionic conduction. To date, several fuels have been utilised in PMFCs, such as formate, hydrogen, formic acid, hydrogen peroxide, hydrocarbons, borohydride, hydrazine, and biofuels, each of which has specific advantages and disadvantages. This review article summarises the growth of PMFC technology, from its invention in 2014 until the present, with emphasis on fundamentals, fabrication methods, unit cell performance with various fuels, performance achievements, design considerations, and scale-up options. The applications and main challenges associated with the current status of the technology are provided along with future perspectives. Investigations in recent years have shown that PMFCs developed with different fuels enhance power density from several µWcm−2 to several mWcm−2 and that stacking multiple individual cells increases the working voltage. Moreover, enzymatic and microbial PMFCs show great potential to be used as wearable devices, sensors and in lab-on-chip devices. [ABSTRACT FROM AUTHOR]

The pyrolysis characteristics of municipal solid waste (MSW), paper sludge (PS) and their blends were studied through a thermogravimetric simultaneous thermal analyzer from room temperature to 1000 °C. Meanwhile their kinetics were studied by Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods. The mass proportions of PS in the blends were 10%, 30%, 50%, 70%, 90%, respectively and the experiments were carried out at different heating rates (30, 40 and 50 °C/min). The initial temperature of MSW was lower than that of PS and the terminated temperature was higher than PS. The comprehensive characteristic index decreased progressively along with the decrease of the MSW proportion. The values of average activation energies calculated by FWO and KAS methods were highly consistent. The average activation energy reached the minimum number, 96.7 kJ/mol by KAS and 11.56 kJ/mol by FWO, with the proportion of PS was 50%. [ABSTRACT FROM AUTHOR]

Abstract: The purpose of this study was to evaluate the performances of cellulosic pads made out of Kraft and NSSC corrugated papers in three flute sizes, experimentally. A number of experiments have been done in a wind tunnel in order to evaluate the cooling efficiency and water consumption as a function of air velocity. The tests were carried out at three levels of air velocity (1.8, 2.25, and 2.67ms−1) for three flute sizes of Kraft and NSSC corrugated papers (2.5, 3.5, and 4.5mm). Analysis of the results indicated that cooling efficiency improves with decrease of air velocity and flute size of corrugated papers; however, water consumption increases with the increase of air velocity. The results were compared with each other and it was shown that the cellulosic pad made out of Kraft paper with 2.5mm flute size has the highest performance (92%) at 1.8ms−1 air velocity in comparison with the other cellulosic pads. [Copyright &y& Elsevier]

Heat and mass transfer processes in a cross flow liquid desiccant dehumidifier, in which wet durable honeycomb paper constitutes the packing material, is investigated in this paper. The device is expected to be used in hot and humid areas to control the indoor humidity environment. A mathematical model, able to determine the heat and mass transfer between the air and the falling film of liquid desiccant, is developed, and the analysis on Nusselt and Sherwood numbers at the liquid–air interface is performed considering the solution of 40% H2O/CaCl2. Also obtained is the theoretical Nusselt number under assumed conditions and the relevant analysis, as well as the comparison between the two results. [Copyright &y& Elsevier]

Abstract: In a recent paper published in this journal, Gabitto and Tsouris presented a mechanistic model analysis of the rise motion of liquid CO2 drops rising in seawater [Gabitto J, Tsouris C. Dissolution mechanisms of CO2 droplets in deep seawaters. Energy Convers Manage 2006;47(5):494]. By comparing the analysis to the data of a field test of releasing CO2 drops in the ocean [Brewer PG, Peltzer ET, Friederich G, Rehder G. Experimental determination of the fate of rising CO2 droplets in seawater. Environ Sci Technol 2002;36(24):5441], Gabitto and Tsouris estimated the thicknesses of hydrate films encapsulating the drops to vary from ∼130μm to ∼10μm with time (up to ∼2000s) during their rise. This estimation was presumably distorted by a primitive error in Gabitto and Tsouris’ model formulation and also by improper evaluation of some of the relevant physical properties. The model, rectified and combined with the proper property evaluation, predicts that the hydrate film thickness on each CO2 drop decreases from ∼350μm to, though physically impossible, below zero with the time lapse of ∼1000s. Various defects of the model as a tool for predicting the hydrate film thickness are presented, leading to the conclusion that the hydrate film thickness values predicted by this model are highly questionable and should not be used as the basis of considering the mechanism for the interphase CO2 transfer across hydrate films. [Copyright &y& Elsevier]

Abstract: Earlier work has shown that capturing the CO2 from flue gases in the recovery boiler at a pulp mill can be a cost-effective way of reducing mill CO2 emissions. However, the CO2 capture cost is very dependent on the fuel price. In this paper, the potential for reducing the need for external fuel and thereby the possibility to reduce the cost for capturing the CO2 are investigated. The reduction is achieved by using thermal process integration. In alternative 1, the mill processes are integrated and a steam surplus made available for CO2 capture, but still there is a need for external fuel. In alternative 2, the integration is taken one step further, the reboiler is fed with MP steam, and the heat of absorption from the absorption unit is used for generation of LP steam needed at the mill. The avoidance costs are in both cases lower than before the process integration. The avoidance cost in alternative 1 varies between 25.4 and 30.7EUR/tonne CO2 depending on the energy market parameters. For alternative 2, the cost varies between 22.5 and 27.2EUR/tonne CO2. With tough CO2 reduction targets and correspondingly high CO2 emission costs, the annual earnings can be substantial, 18.6MEUR with alternative 1 and 21.2MEUR with alternative 2. [Copyright &y& Elsevier]

Biomass from waste newspaper (WP) was first co-pyrolyzed with high-density polyethylene (HDPE) in order to enhance the oil yield and its fuel properties. The synergistic effects during co-pyrolysis were investigated in terms of entire pyrolysis process, products yield and properties of liquid products (aqueous phase and oil phase) using thermogravimetric analysis coupled with infrared spectroscopy (TG-FTIR), physical properties analysis, elemental analysis, Fourier transform infrared spectroscopy (FT-IR), and gas chromatography/mass spectrometry (GC/MS). The results showed that synergistic effect occurred at 400–500 °C resulting in an obviously increase in oil phase by 31.59% as compared to theoretical data. Positive synergistic effects on fuel properties of co-pyrolysis oil were observed, especially demonstrating dramatically decrease in viscosity and total acid number by 75.96% and 216.04% in comparison to theoretical data. WP pyrolyzed alone gives mainly oxygenated compounds in its derived oil, while HDPE give hydrocarbons. No cross reaction products appeared in co-pyrolysis oil, implying that the synergistic effects were determined by altering its compounds content rather than generating cross reaction products. Unfortunately, aqueous phase and oil phase exhibit similar composition. [ABSTRACT FROM AUTHOR]

Abstract: The economic assessment of an energy enhancement program envisaged for a Kraft wood pulping mill has been performed. The retrofit projects which have been analysed include reduction of the process steam demand, steam exportation to a district heating network and cogeneration. An automated MILP optimisation model has been developed to quantify the economic benefit of the projects independently and in combinations. Three cogeneration systems were considered: single back-pressure steam turbine, single steam condensing turbine and, a two-turbine system. A sensitivity analysis has been conducted for two modalities of key cost parameters (steam demand reduction level, fuel and power purchase costs, steam and power sales price) to determine the impact of those parameters on the economics of co-generation options. Results show that the configuration with the single back-pressure steam turbine has the shortest payback time, but the combination of two turbines produces more power and gives higher benefits in the long term. [Copyright &y& Elsevier]

• Different configurations of TEM were tested in this research. • 6-Jointed TEM provided around 100% higher COP in the same power input. • A comprehensive sensitivity analysis was carried out for 6-jointed mode. • Perforation technique was employed to further enhance the COP. • Spring wire was used to further improve the COP of the cooler. Although individual commercial thermoelectric module has been widely investigated and its cooling behavior is clear, jointed thermoelectric modules show completely different cooling behavior and higher coefficient of performance (without the change of input electrical power) which requires further study. At the first step of this research, cooling characteristics of 2-jointed, 4-jointed and 6-jointed thermoelectric modules are experimentally evaluated and discussed under the same range of input electrical power. In the same total input electrical power, 6-jointed TEM (thermoelectric module) provided around 100% higher COP (coefficient of performance) than the 2-jointed TEM which was significant. Cooling behavior of different-number jointed TEM (in the same input power) are analyzed and discussed in this paper. In the second step of this research, the COP of 6-jointed TEM cooler (selected from the first step) has been increased again by proposition of two new techniques based on the modification of the popular rectangular-fin heat sink. Attempts are made to further enhance the COP of the system by two methods including "perforating technique" and "spring wire technique" through a Peltier air cooler which have not been proposed before. In the same electrical power input, perforating technique enhanced the thermal performance of the Peltier air cooler around 50% (totally 150% compared to the 2-jointed TEM with simple heat-sink) and the use of spring-wire between the fins of heat-sink improved the COP around 130% (totally 230% compared to the 2-jointed TEM with simple heat-sink). Exact explanation of the quality/quantity and improvement reasons of each technique are described in this paper for different working conditions of the cooler. [ABSTRACT FROM AUTHOR]

Abstract: In the present work, thermal performance of two types of cellulosic pads (5090 and 7090) which were made from corrugated papers has been studied experimentally. Samples were tested in a sub sonic wind tunnel made from polyethylene. The pads areas are 0.5×0.5m2 with 75, 100 and 150mm thicknesses. Pressure drop, humidity variation, evaporated water and effectiveness have been investigated for several inlet air velocities. The results show that overall pressure drop and amount of evaporated water increase by increasing the inlet air velocity and thickness in both types of pads. On the other hand, effectiveness and humidity variation decrease by increasing inlet air velocity. [Copyright &y& Elsevier]

The economic evaluation of hybrid transmission is a complicated numerical calculation problem in the finite time domain. Currently, employing traditional dynamic programming methods to evaluate a single design scheme consumes a lot of time, making it arduous to effectively compare performance disparities across various design schemes. This paper introduces a dynamic programming method based on matrix operations, enabling the determination of maximum energy-saving potential in hybrid transmission while reducing the evaluation time for a single design scheme from hours to less than 10 s. It unifies the design variables, constraints, and optimization objectives for multi-gear and multi-mode series–parallel hybrid transmissions (MGMM-SPHTs) during economic evaluation. By solving the performance of tens of thousands of design schemes, it is found that increasing the number of engine direct drive gears from 1 to 2 enhances the economy and power performance of series–parallel hybrid transmissions. For the optimal design scheme of Type-B vehicles, this enhancement results in a 1.712% increase in energy-saving efficiency and a 30.5% increment in power performance. Furthermore, this paper elucidates the adaptive relationship between MGMM-SPHTs and different vehicle types, revealing the energy-saving mechanisms under varied design schemes. This paper holds the promise of offering theoretical underpinnings and methodological instruments for selecting technical routes and optimizing design parameters for MGMM-SPHTs. [Display omitted] • A dynamic programming method utilizing matrix operations is proposed. • A comprehensive performance evaluation framework for MGMM-SPHTs is designed. • Swift economic evaluations of MGMM-SPHTs across extensive design variations are achieved. • The energy-saving mechanism inherent in MGMM-SPHTs is uncovered. [ABSTRACT FROM AUTHOR]

• A novel MITM cyber-attack strategy targeting grid-interactive BAS is proposed. • Energy impacts of MITM attack on smart buildings and power grids are unveiled. • The performance variations of HVAC systems subjected to MITM attack are analyzed. • MPC is adopted to manipulate building power demand intelligently and dynamically. • APAR is incorporated as MPC constraints to evade fault detection alarms. Grid-interactive smart buildings integrated with building automation systems (BAS) have gained increasing attention in recent years because of their ability to enable timely data communication that links physical and cyber-based control systems. However, the increasing integration has made both buildings and power grids more vulnerable to cyber-attacks. This study highlights the critical importance of cyber security considering negative energy impacts on grid-interactive buildings, which can severely jeopardize the safety and stability of power grids. This paper first proposes a novel man-in-the-middle (MITM) cyber-attack with specific malicious intent to manipulate the building power demand from the heating, ventilation, and air conditioning (HVAC) systems. The model predictive control (MPC) strategy is implemented to maximize power consumption or load ramp rate while simultaneously ensuring optimal building thermal comfort and evading detection by building occupants. Furthermore, the expert rules, i.e., air handling unit performance assessment rules (APAR), are incorporated as critical constraints in the MPC algorithm to bypass the fault detection alarms. The results demonstrate the capabilities of the proposed MITM cyber-attack scenarios in achieving predetermined objectives without triggering any fault detection alarms. In attack Scenario 1, the total power consumption is increased by up to 55%, and in attack Scenario 2, the load ramp rate is increased by 19 times compared with the fault-free BAS. The comparison between DoS (denial of service), FDI (false data injection), and the proposed cyber-attack, which focuses on their impact on the power grid and concealment analysis, is conducted to raise awareness of the severity and stealthiness of the proposed cyber-attacks. This paper is among the first few developing comprehensive MITM cyber-attacks to intelligently manipulate building power consumption exploiting real-time BAS data. It unveils the important risks associated with BAS and provides valuable insights for further assessment of cyber security of grid-interactive smart buildings. [ABSTRACT FROM AUTHOR]

• Technology of ammonia-coal co-firing is used to optimize carbon emission of the system. • The study utilize the waste heat from Power-to-Ammonia process for heating purposes. • A two-stage robust optimization scheduling model is developed for integrated energy systems. • Simulation tests are conducted on a real integrated energy system in North China. To balance the stability and economic benefits of integrated energy systems (IES) during low-carbon optimization, this paper proposes a two-stage robust optimization scheduling method that considers ammonia energy and waste heat utilization. Firstly, this paper analyzes the Power-to-Ammonia (P2A) operational mechanism and the energy input–output transformation relationship and establishes a Power-to-Ammonia equipment model incorporating waste heat utilization. Subsequently, the low-carbon operational characteristics of the integrated energy system with cooperative operation between Power-to-Ammonia and coal-fired units are explored by integrating Power-to-Ammonia with ammonia-coal co-firing technology. Then, the paper uses an adjustable uncertainty set to describe the variability of renewable generation (RG) and constructs a max–min structured integrated energy system with a two-stage robust optimization scheduling model to minimize the worst-case scenario system operating costs. Finally, the Column-and-Constraint Generation (C&CG) algorithm decomposes the two-stage robust optimization issue into a master problem and sub-problems for the iterative solution. Furthermore, the proposed method is simulated in an actual integrated energy system in northern China. Simulation results indicate that with the intervention of renewable generation uncertainty, the model developed in this study reduces operating costs and carbon emissions by 13.98 % and 20.95 %, respectively, effectively enhancing the capability for low-carbon economic operation. This study provides crucial theoretical support for advancing the low-carbon energy conversion of integrated energy systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Different photothermal-assisted hydrogen production are summarized. • Photothermal effect enhances carrier migration rate. • Photothermal inhibition of hydrogen–oxygen recombination. • Photothermal reduction of interfacial transport resistance. • Photothermal accelerated water oxidation kinetics. Hydrogen energy is widely regarded as one of the most promising clean energy sources to address contemporary energy and environmental challenges. Hydrogen production via solar energy facilitates the decoupling of energy supply and demand, thereby mitigating the intermittency and instability inherent in solar energy utilization. In the process of solar-driven hydrogen production, a substantial portion of solar energy is inevitably dissipated as heat due to material and system limitations. Therefore, the utilization of solar thermal energy to construct photothermal-assisted solar hydrogen production systems is of paramount importance for enhancing solar energy utilization efficiency. This paper provides a comprehensive review of the latest advancements in photothermal-assisted solar hydrogen production systems, with a focus on the application of photothermal effects in diverse solar hydrogen production systems. It offers an in-depth analysis of the mechanisms by which photothermal effects enhance the process, including photothermal excitation of pyroelectric effects, suppression of hydrogen–oxygen recombination, and enhancement of polaron transport. Additionally, the paper reviews strategies for the integration of solar thermal energy into solar-coupled hydrogen production systems. Subsequently, evaluation metrics for photothermal-assisted solar hydrogen production are proposed, accompanied by a comparative analysis of various photothermal-assisted solar hydrogen production systems. Finally, the prospects and challenges of photothermal-assisted solar hydrogen production are discussed, providing a comprehensive outlook to guide future research in this field. [ABSTRACT FROM AUTHOR]

[Display omitted] • Different efficient energy conversions of ammonia are comprehensively reviewed. • Existing work on theoretical and experimental aspects of ammonia hybrid systems for hybrid vehicles is summarized. • The possibility of ammonia hybrid systems for automotive use is recognized. • The future research direction of ammonia new energy hybrid vehicles is pointed out. Ammonia is recognized as a promising and environmentally friendly energy source. This paper provides a comprehensive overview of emerging ammonia hybrid power systems and a detailed examination of the potential applications of this technology in automotive scenarios. Firstly, it summarizes three important ammonia energy conversion technologies in hybrids: ammonia internal combustion engine (A-ICE), direct ammonia fuel cell (DAFC), and ammonia decomposition, analyzing the technical characteristics and future development trends of each. Subsequently, this paper further discusses the architectural features of the new energy hybrid powertrain, highlighting the potential for a highly efficient hybrid powertrain based on the combination of the aforementioned powerplants. Currently, modeling optimization plays a crucial role in advancing research on the architecture of ammonia hybrid powertrains. The paper presents a comprehensive review of current research on energy management strategies (EMS) for hybrid vehicles. It discusses the key elements of model building, optimization objectives, and method selection in detail. Furthermore, the direction of these key elements in ammonia hybrid systems is also indicated. [ABSTRACT FROM AUTHOR]

• Operation and construction of an energy hub based upon the flexibility. • The flexibility index covers maximum system capacity and system response time. • Effect of energy hub flexibility on battery aging. • Consumer participation rate prediction in demand response programs by deep learning. Energy hubs (EHs), hold promise for improving energy efficiency and mitigating carbon emissions. The increasing renewable energy resources, with its inherent uncertainty and variability in power generation, presents challenges for power systems, thereby highlighting the importance of flexibility. This paper proposes a multi-objective framework for enhancing EH flexibility. It is expected that flexibility can induce battery aging which is demonstrated in this paper. The framework leverages a novel flexibility index encompassing both capacity and response time to optimize EH configuration and operation. In this paper employs a data-driven approach to analyze battery degradation under varying flexibility demands. This analysis informs the acceleration of aging associated with increased flexibility. Given the critical role of flexibility, this paper investigates the tripartite relationship between flexibility, time, and battery lifespan. Additionally, considering Demand Response Programs as crucial flexibility resources, the proposed framework utilizes deep learning to forecast consumer participation rates. Utilizing historical data on temperature, price, and participation, various deep learning models are compared. Results indicate a 30% reduction in operating costs associated with a 12% increase in flexibility. However, this flexibility comes at the cost of increased manufacturing expenses and a 20% decrease in battery lifespan due to operational fluctuations. [ABSTRACT FROM AUTHOR]

• Optimize retrofitting strategies by simulation-based multi-objective optimization. • Compare the retrofitting strategy and reconstruction strategy by emergy analysis. • Consider the large domain strategy space of building retrofitting strategy. • NSGA-III algorithm, EnergyPlus software, emergy analysis and LCA are integrated. • The retrofitting strategy is better than the reconstruction strategy. Building renewal has become a promising approach for improving energy efficiency and reaching carbon neutrality targets. Two renewal strategies, namely, the retrofitting of existing buildings and their demolition and reconstruction of a new one, are often explored and compared to determine which strategy is the optimal one. However, the decision is still uncertain due to the large domain space of strategies and the lack of comprehensive methods. This paper, therefore, presents a novel hybrid method to help decision-makers identify the optimal building renewal strategy based on the integration of multi-objective optimization algorithm with emergy analysis. A simulation-based non-dominated sorting genetic algorithm is developed to select the optimal retrofitting strategy, where dynamic simulation model is created in EnergyPlus software and non-dominated sorting genetic algorithm is written in Python. Then, the equivalent reconstruction strategy is projected by the optimal retrofitting strategy while meeting mandatory standards. A comparison between the optimal retrofitting strategy and the equivalent reconstruction strategy can be made by applying emergy analysis considering the whole life cycle phase. A fictional office building was chosen as a case study to illustrate the practical implementation of the proposed method. High-cost building retrofitting strategies were found to consistently yield the highest energy savings and thermal comfort, and the energy use decreased by 4.63 % to 48.25 %. The input emergy of the original building, retrofitting building and reconstruction building are 3.16E + 20 sej , 1.41E + 21 sej , and 1.46E + 21 sej , respectively, and the output emergy are 2.39E + 20 sej , 1.66E + 20 sej , and 4.76E + 19 sej. The results also indicate that the sustainability of the retrofitting strategy is better than that of the reconstruction strategy. This paper provides a guidance method and framework for decision-makers and policy-makers to identify the optimal building renewal strategy for reducing the energy use and achieving carbon peak targets. [ABSTRACT FROM AUTHOR]

Design of hybrid Nano-Grid system (HNGS) necessitates a careful thought to benchmark reliable and cost effective solutions for remote areas. Optimal sizing of HNGS using Honey Badger Algorithm (HBA) for futuristic residential area in Mahendragarh, Haryana, India is presented in this paper. The HNGS comprise combination of solar panels, wind turbines, storage batteries, diesel generator, inverter and residential load components. The primary objective functions considered in this paper are Cost of Electricity (COE) and Net Present Cost (NPC), in continuation these problems are stated as multi objective optimization issues. Numerous permutations of diverse resources were examined to assess parameters such as NPC, COE, battery storage, land utilization, emission and potential employment opportunities. HBA is almost independent of traps in the local minimum, therefore the results obtained are superior as compared with Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Biogeography Basic Optimization (BBO), Improved Artificial Ecosystem Optimization (IAEO) and Grey Wolf Optimization (GWO) as well as HOMER software, in order to determine the quality of solution the proposed HBA algorithm has obtained. HNGS system can be readily and efficiently optimized using the suggested HBA algorithm a detailed sensitivity analysis is done to better understand the system behavior for a wider region use. • A well optimized HNGS design is cost-effective, highly reliable and simple system for remote areas. • An optimization problem is formulated and solved by means of Honey Badger algorithm. • The optimization aim is to find HNGS size in terms of number of individual sources which supplies demand successfully. • Outcomes show that HBA effectively optimizes HNGS by lowering the NPC and CoE, ensuring the electricity supply. • The HBA's results has been compared to GA, PSO, BBO, IAEO, and GWO, as well as HOMER software. • Sensitivity analysis has been used to explore the impact of weather and component parameters on COE and NPC. [ABSTRACT FROM AUTHOR]