This scientific paper provides an overview of the current state of pyrolysis in Europe, with a focus on mapping the key research areas and technologies employed. This research relied on search equations that centered on the utilization of biomass and plastics as primary feedstocks in pyrolysis, with a particular emphasis on biochar generation and different technologies applied. The results showed that both plastic and biomass pyrolysis can contribute to reducing waste and mitigating greenhouse gas emissions. However, plastic pyrolysis can release harmful pollutants due to the presence of chlorine and other additives in plastics, which requires sophisticated emission control systems to be implemented. The production of biochar from sewage sludge is identified as a promising approach for phosphorus recovery, which can subsequently be utilized as a valuable fertilizer in agricultural applications. The data from this study contribute to exploring future applications at pilot and industrial scales for pyrolysis, with a critical assessment of the use of feedstocks. Moreover, this work provides information about current companies that are already operating on a large scale with pyrolysis and a map of the principal countries in Europe engaged in pyrolysis research, correlating the characteristics of the pyrolysis processes investigated.

The per capita municipal solid waste (MSW) generation per day in Ghana is estimated to be 0.47 kg/person/day, which translates to over 14,000 tonnes of solid waste generation daily. The disposal and management of this amount of solid waste has been challenging worldwide, and in Ghana, this is evident with the creation of unsanitary dumping sites scattered across most communities in the country, especially urban communities. The indiscriminate disposal of solid waste in Ghana is known to cause flooding, the pollution of water bodies, and the spread of diseases. The purpose of this review is to highlight the prospects of waste incineration with energy recovery as a waste-to-energy (WtE) technology which has contributed immensely to the disposal and management of MSW in nations worldwide (especially developed ones). The review indicates that waste incineration with energy recovery is a matured waste-to-energy technology in developed nations, and there are currently about 492 waste incineration plants in operation in the EU, over 77 in operation in about 25 states in the USA, and about 1900 in operation in Japan. Waste incineration with energy recovery is also gradually gaining prominence in developing nations like China, Brazil, Bangladesh, Nigeria, Indonesia, and Pakistan. The adoption of waste incineration with energy technology can reduce Ghana’s overdependence on fossil fuels as primary sources of energy. It is, however, recommended that a techno-economic assessment of proposed waste incineration facilities is performed considering the MSW generated in Ghana. Additionally, it is also recommended that the possibility of incorporating the use of artificial intelligence technology into the management of MSW in Ghana be investigated.

Fluoride is a concern for human health at high concentrations, but it is also a valuable compound with multiple applications. Thus, having a system that gives the opportunity to remove and recover this valuable element from water is highly interesting. Reverse osmosis (RO) is a promising technology in the removal of fluoride from water. Nevertheless, the residual retentate highly concentrated in fluoride is still a concern. The aim of this study was to evaluate the performance of an integrated process consisting of RO and membrane crystallization to remove fluoride from water and to recover it as a pure fluoride salt. Pure water permeability and fluoride rejection of a commercial RO membrane was tested under different conditions. In addition, the performance of an osmotic membrane crystallization setup was evaluated, considering the effect caused by the flow rates and the concentration of both the feed and the osmotic solution on the mass transfer coefficient. The crystallization process allowed the production of pure NaF crystals with octahedral morphology with a face-centered cubic crystal system.

This study aimed to investigate the technical feasibility of replacing cement in mortar production with sludge generated in wastewater treatment plants (WWTPs), prepared using different treatments. The sludge used in the experiments was processed using four different methods to investigate the effect of processing on the mechanical strength of the specimens. The sludge was then mixed with mortar in different proportions, and samples were produced for flexural and compressive strength tests. The results showed that specimens with 7% sludge from the burned treatment exhibited the highest resistance, surpassing the standard. Specimens with sludge from the drying treatments showed similar results. This study found that using sludge in mortar production could lead to energy savings compared to traditional cement production methods. Moreover, the incorporation of sludge resulted in mortars that met the specifications of the EN 998-1:2018 standard, thereby indicating their technical feasibility. Therefore, this study demonstrated the potential of using sludge from WWTPs as a substitute for cement in mortar production, which could contribute to the reduction in the environmental impacts caused by civil construction and the development of sustainable alternatives for the disposal of sludge generated in WWTPs.

Road transportation accounts for about 20% of the total GHG emissions in the EU. Nowadays, the substitution of conventional fossil fuel-based ICEs with electric engines, or their hybridization, operating along with Energy Storage Systems, seems to be the most appropriate measure to achieve reductions in both fuel consumption and GHGs. However, EVs encounter crucial challenges, such as long charging time and limited driving range. Hence, the transition to the mass adoption of EVs requires considerable effort and time. However, significant steps have been taken in the hybridization of road vehicles, with the aid of renewables and energy recovery/saving systems. In this context, this paper presents a comprehensive literature review of modern green technologies for GHG reduction that are applicable to road transportation, such as on-vehicle energy harvesting and recovery (e.g., thermal, kinetic, etc.) systems and the incorporation of RES into EV charging stations. The impact of road vehicles on the environment is discussed in detail, along with the EU roadmap towards the decarbonization of transportation. Next, methods and techniques for fuel consumption and GHG reduction are systematically presented and categorized into on-vehicle and off-vehicle ones. Finally, a future outlook on more environmentally friendly road transportation is presented.

During the last few years, electric and hydrogen vehicles have become an alternative to cars that use internal combustion engines. The number of electric and hydrogen vehicles sold has increased due to support from local governments and because car manufacturers will stop the production of internal combustion engines in the near future. The emissions of these vehicles while being driven are zero, but they still have an impact on the environment due to their fuel. In this article, an analysis of carbon dioxide (CO2) emissions for two types of vehicles: battery electric vehicles (BEVs) powered by electricity and fuel cell electric vehicles (FCEVs) powered by hydrogen, is presented. The analysis considers different values for the mix of power generation and hydrogen production options in comparison to other studies. The CO2 emissions were calculated and compared for the two types of vehicles. The results show that the CO2 emissions of BEVs are lower when compared to FCEVs if the hydrogen is obtained from pollutant sources and is higher if the hydrogen is obtained from nuclear power and renewable energy sources. When compared to conventional combustion engine vehicles, BEVs have lower CO2 emissions, while the emissions of FCEVs are dependent on the hydrogen production method.

Air conditioning and refrigeration have become necessary in modern life, accounting for more than 7.8% of greenhouse gases (GHG) emitted globally. Reducing the environmental impact of these systems is crucial for meeting the global GHG emission targets. Two principal directions must be considered to reduce the environmental impact of air conditioning systems. Firstly, reducing the direct effect by looking at less harmful refrigerants and secondly, reducing the indirect effect by searching for options to improve the system efficiency. This study presents the latest developments in the vapor compression cycle and natural refrigerants, focusing on water as a refrigerant. Natural refrigerants, and especially water, could be the ultimate solution for the environmental problems associated with the operation of vapor compression cycle (VCC) cooling systems, including ozone depletion (OD) and global warming (GW). Reducing the environmental impact of building cooling systems is essential, and the recent system improvements made to enhance the system coefficient of performance (COP) are thoroughly discussed in this paper. Though the cycle improvements discussed in this work are essential and could increase the system efficiency, they still need to solve the direct environmental impact of refrigerants. Accordingly, this paper suggests that natural refrigerants, including water, are the most suitable strategic choice to replace the current refrigerants in the refrigeration and air conditioning industry. Finally, this study reviews the latest VCC system improvements and natural refrigerants in order to guide interested researchers with solutions that may reduce the environmental impact of VCC systems and suggest future research areas.

Carbon dioxide (CO2) adsorption on decorated graphene (GR) sheets with transition metals (TMs) including iron, nickel and zinc was investigated for removing this hazardous gas from the environment. TM-doped GR results in higher activity toward gas detecting than pristine graphene nanosheets. TM embedding restrains hydrogen evolution on the C sites, leaving more available sites for a CO2 decrease. The Langmuir adsorption model with ONIOM using CAM-B3LYP functional and LANL2DZ and 6-31+G (d,p) basis sets due to Gaussian 16 revision C.01 program on the complexes of CO2→(Fe, Ni, Zn) embedded on the GR was accomplished. The changes of charge density illustrated a more considerable charge transfer for Zn-embedded GR. The thermodynamic results from IR spectroscopy indicated that ΔGads,CO2→Zn@C−GRo has the notable gap of Gibbs free energy adsorption with a dipole moment which defines the alterations between the Gibbs free energy of the initial compounds (ΔGCO2 o and ΔGZn@C−GRo) and product compound (ΔGCO2→Zn@C−GRo) through polarizability. Frontier molecular orbital and band energy gaps accompanying some chemical reactivity parameters represented the behavior of molecular electrical transport of the (Fe, Ni, Zn) embedding of GR for the adsorption of CO2 gas molecules. Our results have provided a favorable understanding of the interaction between TM-embedded graphene nanosheets and CO2.

The valorization of bio-waste as a resource for green energy production will be beneficial at a social, economic, and environmental level in different regions. The scope of this research is to develop the energetic valorization of the bio-waste fraction from municipal solid waste, to produce biogas from the anaerobic digestion process and electricity in a biogas CHP process, to increase the penetration of renewables in the electricity production system, with an application of these technologies on islands instead of these waste fractions being transported to other regions. The methodologies developed included: 1. Identification and mapping of resources; 2. State-of-the-art of bio-waste parameters and process solutions; 3. Pilot initiative for separation, collection, and analysis of food waste fractions; 4. Development of process solutions according to resources and needs; 5. Determination of investment, production costs, and revenues of the solution created. The case study selected was Porto Santo Island, with the potential to reduce maritime transportation costs of these undifferentiated waste fractions to Madeira Island and contribute to developing an innovative solution for the energetic valorization of bio-waste, including the participation of the local community. The results demonstrated a production of 272,221 m3 of biogas for use as fuel in a cogeneration unit to transform chemical energy into electrical and thermal energies. Furthermore, the self-consumption of the cogeneration unit is 25% of the total electricity produced and 29% of the total thermal energy produced. In conclusion, this research and solution is in compliance with PNEC, the EU Green Deal, and the European Directive 2018/851, which will make mandatory from 2024: the selective collection of bio-waste, 60% by weight of urban waste to be recycled by 2030, and only 10% of waste to be landfilled by 2035.

With the widespread use of lithium-ion batteries in a wide range of consumer electronics products, the CE industry has undergone a dramatic shift. The Li-ion battery has emerged as the heart of electric cars, and the focus has now shifted to the automotive sector. Liquid crystal displays have evolved over time to meet the demands of automobiles. International research groups and the performance of production electric vehicles are used to discuss and inform vehicle-driven battery targets. There is still a lot of room for improvement in terms of energy, life expectancy, cost, safety, and fast-charging capabilities for LIBs suited for the automotive sector. In this study, a review of lithium-ion battery applications in electric vehicles is presented.