AhMed Ibrahim

The rising amount of waste generated worldwide is inducing issues of pollution, waste management, and recycling, calling for new strategies to improve the waste ecosystem, such as the use of artificial intelligence. Here, we review the application of artificial intelligence in waste-to-energy, smart bins, waste-sorting robots, waste generation models, waste monitoring and tracking, plastic pyrolysis, distinguishing fossil and modern materials, logistics, disposal, illegal dumping, resource recovery, smart cities, process efficiency, cost savings, and improving public health. Using artificial intelligence in waste logistics can reduce transportation distance by up to 36.8%, cost savings by up to 13.35%, and time savings by up to 28.22%. Artificial intelligence allows for identifying and sorting waste with an accuracy ranging from 72.8 to 99.95%. Artificial intelligence combined with chemical analysis improves waste pyrolysis, carbon emission estimation, and energy conversion. We also explain how efficiency can be increased and costs can be reduced by artificial intelligence in waste management systems for smart cities.

Access to drinkable water is becoming more and more challenging due to worldwide pollution and the cost of water treatments. Water and wastewater treatment by adsorption on solid materials is usually cheap and effective in removing contaminants, yet classical adsorbents are not sustainable because they are derived from fossil fuels, and they can induce secondary pollution. Therefore, biological sorbents made of modern biomass are increasingly studied as promising alternatives. Indeed, such biosorbents utilize biological waste that would otherwise pollute water systems, and they promote the circular economy. Here we review biosorbents, magnetic sorbents, and other cost-effective sorbents with emphasis on preparation methods, adsorbents types, adsorption mechanisms, and regeneration of spent adsorbents. Biosorbents are prepared from a wide range of materials, including wood, bacteria, algae, herbaceous materials, agricultural waste, and animal waste. Commonly removed contaminants comprise dyes, heavy metals, radionuclides, pharmaceuticals, and personal care products. Preparation methods include coprecipitation, thermal decomposition, microwave irradiation, chemical reduction, micro-emulsion, and arc discharge. Adsorbents can be classified into activated carbon, biochar, lignocellulosic waste, clays, zeolites, peat, and humic soils. We detail adsorption isotherms and kinetics. Regeneration methods comprise thermal and chemical regeneration and supercritical fluid desorption. We also discuss exhausted adsorbent management and disposal. We found that agro-waste biosorbents can remove up to 68-100% of dyes, while wooden, herbaceous, bacterial, and marinebased biosorbents can remove up to 55-99% of heavy metals. Animal waste-based biosorbents can remove 1-99% of heavy metals. The average removal efficiency of modified biosorbents is around 90-95%, but some treatments, such as cross-linked beads, may negatively affect their efficiency.

The global shift from a fossil fuel-based to an electrical-based society is commonly viewed as an ecological improvement. However, the electrical power industry is a major source of carbon dioxide emissions, and incorporating renewable energy can still negatively impact the environment. Despite rising research in renewable energy, the impact of renewable energy consumption on the environment is poorly known. Here, we review the integration of renewable energies into the electricity sector from social, environmental, and economic perspectives. We found that implementing solar photovoltaic, battery storage, wind, hydropower, and bioenergy can provide 504,000 jobs in 2030 and 4.18 million jobs in 2050. For desalinization, photovoltaic/wind/battery storage systems supported by a diesel generator can reduce the cost of water production by 69% and adverse environmental effects by 90%, compared to full fossil fuel systems. The potential of carbon emission reduction increases with the percentage of renewable energy sources utilized. The photovoltaic/wind/hydroelectric system is the most effective in addressing climate change, producing a 2.11-5.46% increase in power generation and a 3.74-71.61% guarantee in share ratios. Compared to single energy systems, hybrid energy systems are more reliable and better equipped to withstand the impacts of climate change on the power supply.

Hydrogen is an energy carrier that can be utilized in various applications, including power plants, the synthesis of high-value products, and clean transportation fuels without emissions. Hence, hydrogen is a potential candidate that can replace fossil fuels and reduce environmental pollution. The high demand for plastics is driving the plastics production rate to increase yearly, leading to a great accumulation of plastic waste materials resulting in a severe burden on the environment. Thermo-catalytic conversion of plastic waste materials to hydrogen and other high-value fuels is a promising route that can efficiently provide an ideal long-term solution necessary to overcome this environmental challenge. Developing durable and high-efficiency catalysts that can immerge hydrogen production from plastic wastes on the industrial scale is still a potential challenge for researchers. This study comprehensively summarizes and discusses the recently published literature for hydrogen production from plastic waste materials using different thermo-catalytic processes, including pyrolysis, pyrolysisair gasification, pyrolysis-steam reforming, pyrolysis-(CO 2) dry reforming, and pyrolysis-plasma catalysis. The scope of this review is to focus on the influence of catalysts and supports, catalysts synthesis method on the production yield of hydrogen, and the impact of several crucial reaction parameters like pyrolysis temperature, catalytic temperature, a catalyst to plastic, and steam to plastic ratios is inclusive in this review as well. The conclusions of this review study will be extremely valuable for researchers interested in the sustainable generation of H 2 from plastic waste materials.

Barium doping effect on the activity and stability of nickel-based catalysts, supported on yttria-stabilized zirconia (Ni-YZr), was investigated in dry reforming of methane. Catalysts were characterized by several techniques (nitrogen sorption, X-ray diffraction [XRD], scanning electron microscopy with energy dispersive X-ray, transmission electron microscopy [TEM], thermogravimetric analysis [TGA], temperature programmed oxidation, CO 2-TPD, H 2-TPR) and were tested in a fixed-bed reactor at 800°C and 42,000 mL/h g cat. Barium played a crucial role in enhancing catalyst reducibility and CO 2 adsorption at high temperatures, as indicated by the activity and stability of the Ni-YZr catalyst. The addition of 4.0 wt% of barium appeared to be the optimal loading, allowing for CH 4 conversion of 82%, which remained constant for 7 h of reaction, compared with 72% of bariumunpromoted Ni-YZr at 800°C. TEM images of the spent catalysts revealed the formation of multiwalled carbon nanotubes on all samples. The TGA analysis showed, however, that an increase in baria loading significantly reduced the coke formation amount, indicating the inhibition of coke formation and the enhancement of the catalytic activity. Such improvement in activity and stability was attributed to the incorporation of barium into

The extensive use of petroleum-based synthetic and non-biodegradable materials for packaging applications has caused severe environmental damage. The rising demand for sustainable packaging materials has encouraged scientists to explore abundant unconventional materials. For instance, cellulose, extracted from lignocellulosic biomass, has gained attention owing to its ecological and biodegradable nature. This article reviews the extraction of cellulose nanoparticles from conventional and non-conventional lignocellulosic biomass, and the preparation of cellulosic nanocomposites for food packaging. Cellulosic nanocomposites exhibit exceptional mechanical, biodegradation, optical and barrier properties, which are attributed to the nanoscale structure and the high specific surface area, of 533 m2 g−1, of cellulose. The mechanical properties of composites improve with the content of cellulose nanoparticles, yet an excessive amount induces agglomeration and, in turn, poor mechanical prope...

Global industrialization and excessive dependence on nonrenewable energy sources have led to an increase in solid waste and climate change, calling for strategies to implement a circular economy in all sectors to reduce carbon emissions by 45% by 2030, and to achieve carbon neutrality by 2050. Here we review circular economy strategies with focus on waste management, climate change, energy, air and water quality, land use, industry, food production, life cycle assessment, and cost-effective routes. We observed that increasing the use of bio-based materials is a challenge in terms of land use and land cover. Carbon removal technologies are actually prohibitively expensive, ranging from 100 to 1200 dollars per ton of carbon dioxide. Politically, only few companies worldwide have set climate change goals. While circular economy strategies can be implemented in various sectors such as industry, waste, energy, buildings, and transportation, life cycle assessment is required to optimize n...

In the context of climate change and the circular economy, biochar has recently found many applications in various sectors as a versatile and recycled material. Here, we review application of biochar-based for carbon sink, covering agronomy, animal farming, anaerobic digestion, composting, environmental remediation, construction, and energy storage. The ultimate storage reservoirs for biochar are soils, civil infrastructure, and landfills. Biochar-based fertilisers, which combine traditional fertilisers with biochar as a nutrient carrier, are promising in agronomy. The use of biochar as a feed additive for animals shows benefits in terms of animal growth, gut microbiota, reduced enteric methane production, egg yield, and endo-toxicant mitigation. Biochar enhances anaerobic digestion operations, primarily for biogas generation and upgrading, performance and sustainability, and the mitigation of inhibitory impurities. In composts, biochar controls the release of greenhouse gases and e...

The utilization of Mg−O−F prepared from Mg(OH) 2 mixed with different wt % of F in the form of (NH 4 F•HF), calcined at 400 and 500°C, for efficient capture of CO 2 is studied herein in a dynamic mode. Two different temperatures were applied using a slow rate of 20 mL•min −1 (100%) of CO 2 passing through each sample for only 1 h. Using the thermogravimetry (TG)-temperature-programed desorption (TPD) technique, the captured amounts of CO 2 at 5°C were determined to be in the range of (39.6−103.9) and (28.9−82.1) mg COd 2 •g −1 for samples of Mg(OH) 2 mixed with 20−50% F and calcined at 400 and 500°C, respectively, whereas, at 30°C, the capacity of CO 2 captured is slightly decreased to be in the range of (32.2−89.4) and (20.9− 55.5) mg COd 2 •g −1 , respectively. The thermal decomposition of all prepared mixtures herein was examined by TG analysis. The obtained samples calcined at 400 and 500°C were characterized by X-ray diffraction and surface area and porosity measurements. The total number of surface basic sites and their distribution over all samples was demonstrated using TG-and differential scanning calorimetry-TPD techniques using pyrrole as a probe molecule. Values of (ΔH) enthalpy changes corresponding to the desorption steps of CO 2 were calculated for the most active adsorbent in this study, that is, Mg(OH) 2 + 20% F, at 400 and 500°C. This study's findings will inspire the simple preparation and economical design of nanocomposite CO 2 sorbents for climate change mitigation under ambient conditions.

The development and recycling of biomass production can partly solve issues of energy, climate change, population growth, food and feed shortages, and environmental pollution. For instance, the use of seaweeds as feedstocks can reduce our reliance on fossil fuel resources, ensure the synthesis of cost-effective and eco-friendly products and biofuels, and develop sustainable biorefinery processes. Nonetheless, seaweeds use in several biorefineries is still in the infancy stage compared to terrestrial plants-based lignocellulosic biomass. Therefore, here we review seaweed biorefineries with focus on seaweed production, economical benefits, and seaweed use as feedstock for anaerobic digestion, biochar, bioplastics, crop health, food, livestock feed, pharmaceuticals and cosmetics. Globally, seaweeds could sequester between 61 and 268 megatonnes of carbon per year, with an average of 173 megatonnes. Nearly 90% of carbon is sequestered by exporting biomass to deep water, while the remaining 10% is buried in coastal sediments. 500 gigatonnes of seaweeds could replace nearly 40% of the current soy protein production. Seaweeds contain valuable bioactive molecules that could be applied as antimicrobial, antioxidant, antiviral, antifungal, anticancer, contraceptive, anti-inflammatory, anti-coagulants, and in other cosmetics and skincare products.

Climate change and the unsustainability of fossil fuels are calling for cleaner energies such as methanol as a fuel. Methanol is one of the simplest molecules for energy storage and is utilized to generate a wide range of products. Since methanol can be produced from biomass, numerous countries could produce and utilize biomethanol. Here, we review methanol production processes, techno-economy, and environmental viability. Lignocellulosic biomass with a high cellulose and hemicellulose content is highly suitable for gasification-based biomethanol production. Compared to fossil fuels, the combustion of biomethanol reduces nitrogen oxide emissions by up to 80%, carbon dioxide emissions by up to 95%, and eliminates sulphur oxide emission. The cost and yield of biomethanol largely depend on feedstock characteristics, initial investment, and plant location. The use of biomethanol as complementary fuel with diesel, natural gas, and dimethyl ether is beneficial in terms of fuel economy, thermal efficiency, and reduction in greenhouse gas emissions.

Dihydrogen (H 2), commonly named 'hydrogen', is increasingly recognised as a clean and reliable energy vector for decarbonisation and defossilisation by various sectors. The global hydrogen demand is projected to increase from 70 million tonnes in 2019 to 120 million tonnes by 2024. Hydrogen development should also meet the seventh goal of 'affordable and clean energy' of the United Nations. Here we review hydrogen production and life cycle analysis, hydrogen geological storage and hydrogen utilisation. Hydrogen is produced by water electrolysis, steam methane reforming, methane pyrolysis and coal gasification. We compare the environmental impact of hydrogen production routes by life cycle analysis. Hydrogen is used in power systems, transportation, hydrocarbon and ammonia production, and metallugical industries. Overall, combining electrolysis-generated hydrogen with hydrogen storage in underground porous media such as geological reservoirs and salt caverns is well suited for shifting excess off-peak energy to meet dispatchable on-peak demand.

Rising demand for energy resources alongside climate emergency concerns has attracted the urgent attention of researchers towards the preparation and utilization of biofuels. This review will investigate the different generations of biofuels and more particularly, the developmental and production processes for creating liquid biofuels. Initially, the first-generation biofuel was dependent on edible resources, which has caused controversy and arguments on whether to fulfil the "food or fuel requirement" for civilization. Second-generation biofuels employed inedible resources, however, the cost of production at a commercial scale has restricted its expansion. Recently, third and fourth-generation use microorganisms and genetically modified microorganisms, respectively, to produce biofuels and create an efficient synthetic fuel switch route. Although the last two generations are still in the developmental phase, thorough research is required before commercial-scale production. In conclusion, this review has found that first-and second-generation biofuel production approaches will soon be inadequate to satisfy the exponentially rising demand for biofuels. Therefore, substantial research efforts currently and in the future should focus on the production of third and fourth-generation biofuels, especially on engineered microorganisms. Ultimately, the structure of this review is to outline the current state of the art research regarding biofuels, their production processes and limitations/challenges. This was done through critically reviewing the most up-to-date literature and utilizing bibliometric analysis tools to put forward the guidelines for the future routes of the four generations of biofuels.

As the global cumulative installation of solar photovoltaic (PV) devices grows every year, a proportionate number of waste PV modules arises because of their limited lifespan. It is estimated that by 2050, there will be approximately 60−78 million tonnes of PV waste (Farrell, C.; Osman, A. I.; Zhang, X. et al. Sci Rep. 2019, 9, 5267). These modules are bound in a strong encapsulated laminate that is prone to imminent degradation. Subsequently, a form of treatment is required to remove a problematic polymeric material such as the encapsulant poly(ethylene-co-vinyl acetate) (EVA) in order to recycle. Pyrolysis is an ideal option that facilitates clean delamination by removing the polymer fraction, and it does not promote chemical oxidation to any of the constituents left behind after pyrolysis. To date, there are limited studies on the pyrolysis of EVA found in PV modules, resulting in significant gaps in the knowledge of pyrolysis kinetic parameters. This work aims to investigate the pyrolysis reaction kinetics concerning the EVA encapsulant found in end-of-life (EoL) crystalline silicon (c-Si) PV modules. The thermoanalytical technique employed was thermogravimetric analysis, which was carried out at 0.5, 1, 2, 4, and 5°C min −1 to ensure accuracy and high resolution while analyzing the kinetics. The kinetic triplet was determined and reported for the first time using the Advanced Kinetics and Technology Solutions (AKTS) Thermokinetics software. The main kinetic modeling method employed was the Friedman differential isoconversional method. Other conventional kinetic modeling approaches were also used, such as the integral (Ozawa) and ASTM-E698 methods for comparison of apparent activation energy. It was observed that the activation energy values for each method were 167.66−260.00, 259.70, and 167.00−252.65 kJ mol −1 for EVA pyrolysis. Additionally, isothermal, nonisothermal, and step-based predictions were reported for the first time using the thermokinetics package. Furthermore, pyrolysis of EVA can have a triple role in the successful delamination of PV modules, recovery of additional constituents, and aiding of waste management of this problematic polymer.

The global energy demand is projected to rise by almost 28% by 2040 compared to current levels. Biomass is a promising energy source for producing either solid or liquid fuels. Biofuels are alternatives to fossil fuels to reduce anthropogenic greenhouse gas emissions. Nonetheless, policy decisions for biofuels should be based on evidence that biofuels are produced in a sustainable manner. To this end, life cycle assessment (LCA) provides information on environmental impacts associated with biofuel production chains. Here, we review advances in biomass conversion to biofuels and their environmental impact by life cycle assessment. Processes are gasification, combustion, pyrolysis, enzymatic hydrolysis routes and fermentation. Thermochemical processes are classified into low temperature, below 300 °C, and high temperature, higher than 300 °C, i.e. gasification, combustion and pyrolysis. Pyrolysis is promising because it operates at a relatively lower temperature of up to 500 °C, compared to gasification, which operates at 800-1300 °C. We focus on 1) the drawbacks and advantages of the thermochemical and biochemical conversion routes of biomass into various fuels and the possibility of integrating these routes for better process efficiency; 2) methodological approaches and key findings from 40 LCA studies on biomass to biofuel conversion pathways published from 2019 to 2021; and 3) bibliometric trends and knowledge gaps in biomass conversion into biofuels using thermochemical and biochemical routes. The integration of hydrothermal and biochemical routes is promising for the circular economy.

Human activities have led to a massive increase in CO 2 emissions as a primary greenhouse gas that is contributing to climate change with higher than 1 • C global warming than that of the pre-industrial level. We evaluate the three major technologies that are utilised for carbon capture: pre-combustion, post-combustion and oxyfuel combustion. We review the advances in carbon capture, storage and utilisation. We compare carbon uptake technologies with techniques of carbon dioxide separation. Monoethanolamine is the most common carbon sorbent; yet it requires a high regeneration energy of 3.5 GJ per tonne of CO 2. Alternatively, recent advances in sorbent technology reveal novel solvents such as a modulated amine blend with lower regeneration energy of 2.17 GJ per tonne of CO 2. Graphene-type materials show CO 2 adsorption capacity of 0.07 mol/g, which is 10 times higher than that of specific types of activated carbon, zeolites and metal-organic frameworks. CO 2 geosequestration provides an efficient and long-term strategy for storing the captured CO 2 in geological formations with a global storage capacity factor at a Gt-scale within operational timescales. Regarding the utilisation route, currently, the gross global utilisation of CO 2 is lower than 200 million tonnes per year, which is roughly negligible compared with the extent of global anthropogenic CO 2 emissions, which is higher than 32,000 million tonnes per year. Herein, we review different CO 2 utilisation methods such as direct routes, i.e. beverage carbonation, food packaging and oil recovery, chemical industries and fuels. Moreover, we investigated additional CO 2 utilisation for base-load power generation, seasonal energy storage, and district cooling and cryogenic direct air CO 2 capture using geothermal energy. Through bibliometric mapping, we identified the research gap in the literature within this field which requires future investigations, for instance, designing new and stable ionic liquids, pore size and selectivity of metal-organic frameworks and enhancing the adsorption capacity of novel solvents. Moreover, areas such as techno-economic evaluation of novel solvents, process design and dynamic simulation require further effort as well as research and development before pilot-and commercial-scale trials.

The extensive use of petroleum-based synthetic and non-biodegradable materials for packaging applications has caused severe environmental damage. The rising demand for sustainable packaging materials has encouraged scientists to explore abundant unconventional materials. For instance, cellulose, extracted from lignocellulosic biomass, has gained attention owing to its ecological and biodegradable nature. This article reviews the extraction of cellulose nanoparticles from conventional and non-conventional lignocellulosic biomass, and the preparation of cellulosic nanocomposites for food packaging. Cellulosic nanocomposites exhibit exceptional mechanical, biodegradation, optical and barrier properties, which are attributed to the nanoscale structure and the high specific surface area, of 533 m 2 g −1 , of cellulose. The mechanical properties of composites improve with the content of cellulose nanoparticles, yet an excessive amount induces agglomeration and, in turn, poor mechanical properties. Addition of cellulose nanoparticles increases tensile properties by about 42%. Barrier properties of the composites are reinforced by cellulose nanoparticles; for instance, the water vapor permeability decreased by 28% in the presence of 5 wt% cellulose nanoparticles. Moreover, 1 wt% addition of filler decreased the oxygen transmission rate by 21%. We also discuss the eco-design process, designing principles and challenges.

Background: Recycling the ever-increasing plastic waste has become an urgent global concern. One of the most convenient methods for plastic recycling is pyrolysis, owing to its environmentally friendly nature and its intrinsic properties. Understanding the pyrolysis process and the degradation mechanism is crucial for scale-up and reactor design. Therefore, we studied kinetic modelling of the pyrolysis process for one of the most common plastics, polyeth-ylene terephthalate (PET). The focus was to better understand and predict PET pyrolysis when transitioning to a low carbon economy and adhering to environmental and governmental legislation. This work aims at presenting for the first time, the kinetic triplet (activation energy, pre-exponential constant, and reaction rate) for PET pyrolysis using the differential iso-conversional method. This is coupled with the in-situ online tracking of the gaseous emissions using mass spectrometry. Results: The differential iso-conversional method showed activation energy (E a) values of 165-195 kJ mol −1 , R 2 = 0.99659. While the ASTM-E698 method showed 165.6 kJ mol −1 and integral methods such as Flynn-Wall and Ozawa (FWO) (166-180 kJ mol −1). The in-situ Mass Spectrometry results showed the gaseous pyrolysis emissions, which are C 1 hydrocarbons and H-O-C=O along with C 2 hydrocarbons, C 5-C 6 hydrocarbons, acetaldehyde, the fragment of O-CH=CH 2 , hydrogen, and water. Conclusions: From the obtained results herein, thermal predictions (isothermal, non-isothermal and step-based heating) were determined based on the kinetic parameters. They can be used at numerous scale with a high level of accuracy compared with the literature.

The generation of synthesis gas (hydrogen and carbon monoxide mixture) from two global warming gases of carbon dioxide and methane via dry reforming is environmentally crucial and for the chemical industry as well. Herein, magnesium-promoted NiO supported on mesoporous zirconia, 5Ni/xMg-ZrO 2 (x = 0, 3, 5, 7 wt%) were prepared by wet impregnation method and then were tested for syngas production via dry reforming of methane. The reaction temperature at 800 °C was found more catalytically active than that at 700 °C due to the endothermic feature of reaction which promotes efficient CH 4 catalytic decomposition over Ni and Ni-Zr interface as confirmed by CH 4-TSPR experiment. NiO-MgO solid solution interacted with ZrO 2 support was found crucial and the reason for high CH 4 and co 2 conversions. The highest catalyst stability of the 5Ni/3Mg-ZrO 2 catalyst was explained by the ability of CO 2 to partially oxidize the carbon deposit over the surface of the catalyst. A mole ratio of hydrogen to carbon monoxide near unity (H 2 /CO ~ 1) was obtained over 5Ni/ZrO 2 and 5Ni/5Mg-ZrO 2 , implying the important role of basic sites. Our approach opens doors for designing cheap and stable dry reforming catalysts from two potent greenhouse gases which could be of great interest for many industrial applications, including syngas production and other value-added chemicals. The production of syngas (a mixture of H 2 and CO) through dry reforming of methane is an excellent strategy to reduce the global warming effects of carbon dioxide (CO 2) and methane (CH 4). Noble metals such as palladium (Pd), platinum (Pt), and ruthenium (Ru) have been used for this purpose, but costly precursors and instability of catalyst, at high reaction temperature around 800 °C, have limited their application 1. On the other hand, cost-effective nickel (Ni) metal, supported on an appropriate supports such as alumina 2 , mesoporous silicates 3-7 , and zirconia 8-10 , has been found to withstand at this reaction temperature (800 °C). In this context, many researchers have followed the surface modification methodology to optimise the catalyst performance because Ni-based catalyst is also prone to deactivation. The first series of modifications were carried out over alumina supports. Due to the extended pore network (from micro to meso) and easy pore tunable synthetic methodology of silicates, silica support is preferable over alumina support 28. Therefore, the second series of modifications were carried out over mesoporous silicates supports with Li alumina nor silica supports can utilize their lattice oxygen during carbon deposit oxidation at the surface, but zirconia support does and is thus are used as oxygen carrier materials. Zirconia support is characterized by its thermal stability, an expanded network, and the ability to utilize its mobile oxygen during the surface reaction 45. The third series of modifications were carried out over open

Climate change is defined as the shift in climate patterns mainly caused by greenhouse gas emissions from natural systems and human activities. So far, anthropogenic activities have caused about 1.0 °C of global warming above the pre-industrial level and this is likely to reach 1.5 °C between 2030 and 2052 if the current emission rates persist. In 2018, the world encountered 315 cases of natural disasters which are mainly related to the climate. Approximately 68.5 million people were affected, and economic losses amounted to $131.7 billion, of which storms, floods, wildfires and droughts accounted for approximately 93%. Economic losses attributed to wildfires in 2018 alone are almost equal to the collective losses from wildfires incurred over the past decade, which is quite alarming. Furthermore, food, water, health, ecosystem, human habitat and infrastructure have been identified as the most vulnerable sectors under climate attack. In 2015, the Paris agreement was introduced with the main objective of limiting global temperature increase to 2 °C by 2100 and pursuing efforts to limit the increase to 1.5 °C. This article reviews the main strategies for climate change abatement, namely conventional mitigation, negative emissions and radiative forcing geoengineering. Conventional mitigation technologies focus on reducing fossil-based CO 2 emissions. Negative emissions technologies are aiming to capture and sequester atmospheric carbon to reduce carbon dioxide levels. Finally, geoengineering techniques of radiative forcing alter the earth's radiative energy budget to stabilize or reduce global temperatures. It is evident that conventional mitigation efforts alone are not sufficient to meet the targets stipulated by the Paris agreement; therefore, the utilization of alternative routes appears inevitable. While various technologies presented may still be at an early stage of development, biogenic-based sequestration techniques are to a certain extent mature and can be deployed immediately.

The ever-increasing world energy demand drives the need for new and sustainable renewable fuel to mitigate problems associated with greenhouse gas emissions such as climate change. This helps in the development toward decarbonisation. Thus, in recent years, hydrogen has been seen as a promising candidate in global renewable energy agendas, where the production of biohydrogen gains more attention compared with fossil-based hydrogen. In this review, biohydrogen production using organic waste materials through fermentation, biophotolysis, microbial electrolysis cell and gasification are discussed and analysed from a technological perspective. The main focus herein is to summarise and criticise through bibliometric analysis and put forward the guidelines for the potential future routes of biohydrogen production from biomass and especially organic waste materials. This research review claims that substantial efforts currently and, in the future, should focus on biohydrogen production from integrated technology of processes of (i) dark and photofermentation, (ii) microbial electrolysis cell (MEC) and (iii) gasification of combined different biowastes. Furthermore, bibliometric mapping shows that hydrogen production from biomethanol and the modelling process are growing areas in the biohydrogen research that lead to zero-carbon energy soon.

There is a growing interest in the utilisation of biomass for a range of applications. Coupled with this is the appeal of improving the circular economy and as such, there is a focus on reusing, recycling and upcycling of many materials, including biomass. This has been driven by society in terms of demand for more sustainable energy and products, but also by a paradigm shift in attitudes of the population to reduce their personal carbon footprint. Herein we have selected a number of types of biomass (woody, herbaceous, etc.) and surveyed the ways in which they are utilised. We have done this in combination with assessing some kinetic modelling approaches which been reported for the evaluation of different processes for the recycling, reuse and upcycling of biomass.

Solid food waste digestate MDF dust Sodium silicate Adsorption Isotherms and kinetics ABSTRACT Anaerobic digestate originating from food waste has been studied herein for two different purposes. Firstly, for combustion, co-granulation of the digestate and medium density fibreboard (MDF) dust with the addition of sodium silicate as the binder was used to produce the granular solid biofuel. It was found that increasing the content of the medium density fibreboard dust could increase the calorific value but had no significant effect on the strength of the final granules. Additionally, a significant reduction of the ash content was also observed. For heavy metal removal, granules made using the digestate and sodium silicate binder were carbonised to produce biochar which was characterised and applied as adsorbent materials. The biochar has a good removal capacity for both lead and cadmium, and the binder concentration had a positive correlation with the removal capacity of the resultant biochar. The maximum lead removal capacity (355.3 mg g −1) of biochar made using 3 wt.% sodium silicate binder, was six times more than the analogous commercial activated carbon. Langmuir model showed better fitting for adsorption data of Pb 2+ , while the Freundlich model showed better fitting of Cd 2+. For both Pb 2+ and Cd 2+ kinetic data, the pseudo-second-order had a better correlation. Our approach helps aid and facilitate the concept of the circular economy by effectively up-cycling and valorising waste lignocellulosic biomass such as food waste digestate into value-added products.

Adsorption to date is the most effective and utilized technology globally to remove several pollutants in wastewater. In this approach, many adsorbents have been synthesized, tested and used for the elimination and separation of the contaminants such as radionuclides, heavy metals, dyes and pharmaceutical compounds both at lab and industrial scale. However, there are many challenges to adsorption processes such as reducing the high cost, through means of separation of suspending adsorbents to be used again, as well as the ease to synthesize. Two methods that have shown promising results and gained significant interest is that of magnetic nanomaterials and biosorbents due to their effective, safe, eco-friendly, low cost and low-energy intensive material properties. Magnetic nanomaterials act as efficient adsorbents due to their ease of removal of contaminants from wastewater using an applied magnetic field but also their advantageous surface charge and redox activity characteristics. On the other hand, biosorbents have a synergistic effect with their efficient adsorption capacity to remove contaminants, high abundance and participation in waste minimization, helping alleviate ecological and environmental problems. This review highlights, discusses and reports on the state-of-the-art of these two promising routes to adsorp-tion and provides indications as to what are the optimum materials for utilization and insight into their efficiency, reusability and practicality for the removal of pollutants from wastewater streams. Some of the main material focuses are zero-valent iron, iron oxides, spinel ferrites, natural and waste-based biosorbents.

Herein, an in situ DRIFT technique was used to study the reaction mechanism of methanol dehydration to dimethyl ether (DME). Moreover, the effect of silver loading on the catalytic performance of η-Al 2 O 3 was examined in a fixed bed reactor under the reaction conditions where the temperature ranged from 180 to 300 °C with a WHSV = 48.4 h −1. It was observed that the optimum Ag loading was found to be 10% Ag/η-Al 2 O 3 with this novel catalyst also showing a high degree of stability under steady-state conditions, and this is attributed to the enhancement in both the surface Lewis acidity and the hydrophobicity.

Miscanthus species originated in Asia and were imported
into Europe and North America as ornamental plants. They
are perennial rhizomatous grasses with lignified stems and
present very high growth rates, even in more temperate maritime
climates. This potentially abundant biomass offers benefits
to many sectors and is used to an extent in energy generation
applications, however, issues with regards to its physicochemical
combustion characteristics currently hinder this uptake. In
this work, a novel alternative application, namely its direct use
of dry miscanthus (DM) plant as an adsorbent for heavy metals
removal (HMR) from wastewaters, was investigated. The physical,
chemical, and leaching properties of DM were analyzed
using XRD, SBET, TGA, DSC, SEM-EDX, elemental analysis, halogen,
and ICP techniques. Subsequently, the HMR capacity of
miscanthus was studied for lead, copper, and zinc from aqueous
solutions. Results showed a high percentage removal of
66%, 83%, and 88%, respectively, with the majority being
removed during the first hour of the test. Overall the results
show that DM plant can be effectively utilized in wastewater
treatment

Herein, we studied the combustion and pyrolysis for miscanthus × giganteus (Elephant Grass) using TG/DSC techniques. Currently, miscanthus is used to an extent in energy generation applications however; issues with regards to its physicochemical combustion characteristics currently hinder this uptake. In this work, the thermal and kinetic analysis of dry miscanthus and its char were investigated for a better understanding of its physicochemical combustion characteristics and consequently, achieving the highest benefit from the combustion process. Different kinetic modeling has been used to calculate the activation energy and the kinetic parameters during combustion/pyrolysis such as the ASTM-E698, Flynn-Wall and Ozawa (FWO) and differential iso-conversional methods. It was observed that the activation energy values were 22.3, 40-150 and 40-165 kJ mol-1 for miscanthus, respectively. Furthermore, miscanthus species were tested in wastewater treatment and showed a potential for the rapid removal of cadmium heavy metal. In addition, a study of miscanthus ash was performed and indicated that it can be used as a source of potassium in the fertiliser industry.

BACKGROUND: Methanol to dimethyl ether (MTD) is considered one of the main routes for the production of clean bio-fuel. The effect of copper loading on the catalytic performance of different phases of alumina that formed by calcination at two different temperatures was examined for the dehydration of methanol to dimethyl ether (DME).

A novel green preparation route to prepare nano-mesoporous γ-Al 2 O 3 from AlCl 3 .6H 2 O derived from aluminum foil waste and designated as ACFL550 is demonstrated, which showed higher surface area, larger pore volume, stronger acidity and higher surface area compared to γ-Al 2 O 3 that is produced from the commercial AlCl 3 precursor, AC550. The produced crystalline AlCl 3 .6H 2 O and Al(NO 3) 3 .9H 2 O in the first stage of the preparation method were characterized by single-crystal XRD, giving two crystal structures, a trigonal (R-3c) and monoclinic (P2 1 /c) structure, respectively. EDX analysis showed that ACFL550 had half the chlorine content (Cl%) relative to AC550, which makes ACFL550 a promising catalyst in acid-catalysed reactions. Pure and modified ACFL550 and AC550 were applied in acid-catalysed reactions, the dehydration of methanol to dimethyl ether and the total methane oxidation reactions, respectively. It was found that ACFL550 showed higher catalytic activity than AC550. This work opens doors for the preparation of highly active and well-structured nano-mesoporous alumina catalysts/supports from aluminum foil waste and demonstrates its application in acid-catalysed reactions. Aluminum (Al) manufacture and expenditure are considered to be two sides of a coin and both are increasing. Aluminum is mainly produced from bauxite mines worldwide, reaching 270 million metric tonnes (Mt) in 2015 compared to 183 Mt in 2006 1. Conversely, the Al consumption approximately tripled from 2006 to 2015 by 45 to 120 Mt, respectively, with a growth rate of 4% per year. To meet the dramatic increase in the Al consumption, a large amount of bauxite production is needed, which generates significant levels of waste such as tailings, red mud, emissions of perfluorocarbon and CO 2 gases during the production process. Recycling this Al waste is crucial for the environment; in fact, recycling 1 kg of Al saves 8 kg of bauxite, 4 kg of chemical products and 14 kW of electricity 2. Al waste can be recycled to produce various useful products. Li et al. 3 successfully prepared γ-Al 2 O 3 from oil shale ash waste which consists of 10.66 wt% Al 2 O 3 ; however, they used a high calcination temperature at 700–800 °C to remove residual organic compounds and expensive chemicals such as Eu(NO 3) 3 , urea and surfactant. Chotisuwan et al. 4 managed to prepare γ-Al 2 O 3 at low calcination temperature (500 °C) from Al cans, however, they used a costly preparation method by using isopropanol and mercury iodide. Al foil is one of the biggest Al waste sources which is difficult to recycle; thus the end-of-life options are either landfilling or incineration 5. The global Al foil market had a size of 3.4 Mt in 2010. In the UK alone in 2001, 160,000 t of Al waste were sent to landfill 6. Converting the Al foil into useful products is an environmental issue; few efforts were performed in previous publications 7. Recently, Al foil was used in H 2 production by converting it into active Al powder that reacts with water producing H 2 7 or by using Ca(OH) 2 to remove the surface oxide layer and initiate the hydration reaction of Al foil 8. Furthermore, α-Al 2 O 3 was prepared at a low calcination temperature (1100 °C) for the industrial applications such as refractory materials, however, aqua regia was used during the preparation procedures, consequently, the release of NO x emissions is possible during the preparation, which is harmful to the environment 9. Qin et al. 10 demonstrated a facile and a robust method to prepare ordered anodic aluminum oxides with continuously tunable inter-pore distances. Ye et al. 11 studied the catalytic decomposition of formaldehyde

Nickel supported on η-Al2O3 and ZSM-5(80) catalysts with and without the addition of ceria-zirconia, were prepared by co-precipitation and wet impregnation methods and used for the low temperature catalytic partial oxidation of methane (CPOM). The catalysts were tested under reaction temperatures of between 400 and 700 °C with a WHSV of 63,000 mL g−1 h−1. The activity of the catalyst was found to be dependent on the support and preparation method. The optimum catalyst composition of those tested was 10% Ni on 25%CeO2-ZrO2/ZSM-5(80), prepared by co-precipitation, where the reaction reached equilibrium conversion at 400 °C (T50% < 400 °C), which is one of the lowest temperatures reported to date. Further increases in temperature led to improved selectivity to CO reaching 60% at 600 °C. Although the observed kinetics were found to be controlled by strong adsorption of CO at lower temperature, this was an equilibrium limitation with longer time on stream experiments showing no decrease in the catalyst activity over 25 hours at 400 °C.

Dimethyl ether (DME) is amongst one of the most promising alternative, renewable and clean fuels being considered as a future energy carrier. In this study, the comparative catalytic performance of-Al 2 O 3 prepared from two common precursors (aluminum nitrate (AN) and aluminum chloride (AC)) is presented. The impact of calcination temperature was evaluated in order to optimize both the precursor and pre-treatment conditions for the production of DME from methanol in a fixed bed reactor. The catalysts were characterized by TGA, XRD, BET and TPD-pyridine. Under reaction conditions where the temperature ranged from 180 • C to 300 • C with a WHSV = 12.1 h −1 it was found that all the catalysts prepared from AN(-Al 2 O 3) showed higher activity, at all calcination temperatures, than those prepared from AC(-Al 2 O 3). In this study the optimum catalyst was produced from AN and calcined at 550 • C. This catalyst showed a high degree of stability and had double the activity of the commercial-Al 2 O 3 or 87% of the activity of commercial ZSM-5(80) at 250 • C.