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Microplastic pollution has emerged as a new environmental concern due to our reliance on plastic. Recent years have seen an upward trend in scholarly interest in the topic of microplastics carrying contaminants; however, the available review studies have largely focused on specific aspects of this issue, such as sorption, transport, and toxicological effects. Consequently, this review synthesizes the state-of-the-art knowledge on these topics by presenting key findings to guide better policy action toward microplastic management. Microplastics have been reported to absorb pollutants such as persistent organic pollutants, heavy metals, and antibiotics, leading to their bioaccumulation in marine and terrestrial ecosystems. Hydrophobic interactions are found to be the predominant sorption mechanism, especially for organic pollutants, although electrostatic forces, van der Waals forces, hydrogen bonding, and pi-pi interactions are also noteworthy. This review reveals that physicochemical properties of microplastics, such as size, structure, and functional groups, and environmental compartment properties, such as pH, temperature, and salinity, influence the sorption of pollutants by microplastic. It has been found that microplastics influence the growth and metabolism of organisms. Inadequate methods for collection and analysis of environmental samples, lack of replication of real-world settings in laboratories, and a lack of understanding of the sorption mechanism and toxicity of microplastics impede current microplastic research. Therefore, future research should focus on filling in these knowledge gaps. [Display omitted] • This review investigates MPs to guide better policy action toward MP management. • MPs absorb pollutants like persistent organic pollutants, heavy metals, and antibiotics. • Hydrophobic interactions are the primary sorption mechanism for organic pollutants. • MPs influence the growth and metabolism of organisms. • Innovative sampling and analytical methods are needed to identify MP sources. [ABSTRACT FROM AUTHOR]

Emerging contaminants (ECs) are increasingly recognized as threats to human health and ecosystems. This review evaluates advanced analytical methods, particularly mass spectrometry, for detecting ECs and understanding their toxicity, transformation pathways, and environmental distribution. Our findings underscore the reliability of current techniques and the potential of upcoming methods. The adverse effects of ECs on aquatic life necessitate both in vitro and in vivo toxicity assessments. Evaluating the distribution and degradation of ECs reveals that they undergo physical, chemical, and biological transformations. Remediation strategies such as advanced oxidation, adsorption, and membrane bioreactors effectively treat EC-contaminated waters, with combinations of these techniques showing the highest efficacy. To minimize the impact of ECs, a proactive approach involving monitoring, regulations, and public education is vital. Future research should prioritize the refining of detection methods and formulation of robust policies for EC management. [Display omitted] • Emerging contaminants (ECs) pose significant risks to aquatic ecosystems and human health. • Advanced analytical techniques are effective in detecting ECs in diverse environments. • A comprehensive strategy is most effective for remediating EC-contaminated water. • Future research must focus on detection, source control, monitoring, and public engagement. [ABSTRACT FROM AUTHOR]

Abstract Household waste generation has become a serious environmental issue in recent years. However, some technologies are available to convert household domestic waste into energy. One of such techniques is the biogas generation using household waste. The biogas generation technique is not a new method of energy generation, but its production efficiency is questionable. Biogas yield from domestic waste are influenced by pH level, temperature, HRT and C/N ratio. Moisture and the temperature levels in the biogas generation systems are very critical to its production efficiency, especially this is highly affected in the colder weather condition. Solar assisted biogas plant may provide better production efficiency compared to the traditionally designed biogas plant. In this paper, the scopes and opportunities of solar assisted biogas generation are reviewed. Possible benefits and challenges associated with the solar assisted biogas generation are highlighted. [ABSTRACT FROM AUTHOR]

Abstract There are numerous different sorts of pre-treatment technique have been utilized with a few impediments regarding supportable natural administration in anaerobic assimilation for improvement of biogas generation. Albeit corrosive and salt pretreatment have a huge impact on the corruption of biomass, these techniques have some negative effects on the condition because of their perilous nature, while the enzymatic pre-treatment is more environmentally friendly. In this investigation is to streamline the biogas generation by enzymatic pre-treatment from Palm Oil Mill Effluent (POME) with assessing the improved biogas creation in a pilot scale bioreactor. It is to concentrate coordinate utilization of protein as enzymatic pre-treatment on POME to the improved generation of biogas. Proficiency of privately manufactured chemical with Up-flow Sludge Blanket (UASB) has not been researched in pilot scale previously. In this examination proficiency of COD expulsion and aggregate methane emanation is explored through pilot scale UASB bioreactor from POME through the application of enzyme and reviewed a study with the discussion. [ABSTRACT FROM AUTHOR]

Abstract The oil from waste coffee possesses the potential as a feedstock for biodiesel production. In this study, waste coffee grounds were collected from Turkey. Then the oil was extracted from waste coffee grounds using N-hexane. The two-step acid-base catalyst transesterification process was used to produce biodiesel as the acid value of the crude oil was found higher (15.4 mgKOH/g).This was followed by an investigation of some physical and chemical properties. It was found that the properties of waste coffee biodiesel fell within the limit of ASTM standards. So the studied physicochemical properties of the waste coffee biodiesel suggest that this fuel can be used as a fuel in diesel engines. [ABSTRACT FROM AUTHOR]

Abstract Presently, the crisis of energy has become a growing concern all over the world and a serious barrier for the developing nations. Conversely, the resources of fossil fuels are limited and depleting due to the exploration and higher production activities around the glove. The impact of fossil fuels exploration has become a serious threat for naturalism and creates environmental hazardous accidents. However, the demand for energy in Bangladesh is increasing day by day and fossil fuel reserves continue the countries demand almost only 50 years. So, it is the high time to utilize its natural biomass resources to fulfill energy demand. The climate condition and waste generation rate of Bangladesh is key factors for biomass energy production. Nowadays the Bangladeshi government has made an agenda "waste to electricity" thus the utilization of biomass resources has become a blessing for the static economic growth in the nation. Recently Bangladeshi government has made an extra effort for the commercialization and marketable of biomass energy engendering and production in the country. This paper explored the potential of biomass energy as a sustainable energy source and their future implementation challenges in Bangladesh. [ABSTRACT FROM AUTHOR]

Abstract Global energy demand has risen sharply over the years with developing countries recording the greatest share in this trend. Biomass as an energy resource is mostly available locally and can easily be converted into secondary energy without huge capital investments. Nowadays, Bangladesh shares a percentage of renewable energy only 3% of total energy ratio, Bangladesh has already taken a master plan in the renewable energy sector. Whereas installed electricity generation installed capacity of Bangladesh rapidly increased to 13265 MW with captive generation capacity which is insufficient for fulfilling the demand of electricity of the nations. One-third of the power production of Bangladesh depends on expensive imported fossil fuel energy resources and 65% of power generation depends on a natural gas reserve of the country, though one day the reserve of current gas will be diminished. Moreover, inadequate electricity production leads the country in a un-industrialization. The present and future crucial energy crisis situation adapted by installing renewable power into electricity production. The current renewable energy agenda of Bangladeshi government force the specialization of renewable energy generation budget by decreasing global pollution with saving movement of biomass, solar, hydro, wind, and tidal power sector. This paper presents the currents national energy scenario of Bangladesh. According to this, the greater potentiality of renewable energy resources is also reviewed and presented in this paper. [ABSTRACT FROM AUTHOR]

Abstract This paper studied the production of waste cooking biodiesel as an alternative fuel for diesel engine. The biodiesel was produced through conventional transesterification process using the base catalyst (KOH). A multi-cylinder diesel engine was used to evaluate the emission of 20% (B20) waste cooking biodiesel fuel at different engine speeds and full load condition. It was found that the characteristics of biodiesel are within the limit of specified standards (American Society for Testing and Materials, ASTM D6751) and comparable to diesel fuel. Engine emission results indicated that waste cooking biodiesel fuel sample reduces the average carbon monoxide (CO) and particulate matter (PM) emissions except nitrogen oxides (NO x) than diesel fuel. Finally, it can be concluded that 20% of waste cooking biodiesel can significantly contribute to lower the harmful emission of an unmodified stationary diesel engine to the environment. [ABSTRACT FROM AUTHOR]

Abstract Increasing global energy demand at a rate faster than the population growth has led the researcher to look for alternative fuel. Amongst the options, biodiesel is an environmentally sustainable substitute of diesel fuel being renewable, biodegradable and have similar properties of fossil diesel. Among the biodiesel sources, microalgae is a potential third generation biodiesel feedstock which can be produced throughout the year and its oil yield is higher than any other crops. This paper reviews recent development in microalgae biodiesel in terms of its oil extraction technics, challenges of oil extraction, production of biodiesel from microalgae oil and its fuel properties. Finally, the paper discusses the performance and combustion analysis of diesel engine fuelled with microalgae biodiesel. This paper provides a clear understanding of the potential use of microalgae biodiesel as an alternative source to fossil diesel for diesel engines. [ABSTRACT FROM AUTHOR]

This paper offers a comprehensive analysis of algal-based membrane bioreactors (AMBRs) and their potential for removing hazardous and toxic contaminants from wastewater. Through an identification of contaminant types and sources, as well as an explanation of AMBR operating principles, this study sheds light on the promising capabilities of AMBRs in eliminating pollutants like nitrogen, phosphorus, and organic matter, while generating valuable biomass and energy. However, challenges and limitations, such as the need for process optimization and the risk of algal-bacterial imbalance, have been identified. To overcome these obstacles, strategies like mixed cultures and bioaugmentation techniques have been proposed. Furthermore, this study explores the wider applications of AMBRs beyond wastewater treatment, including the production of value-added products and the removal of emerging contaminants. The findings underscore the significance of factors such as appropriate algal-bacterial consortia selection, hydraulic and organic loading rate optimization, and environmental factor control for the success of AMBRs. A comprehensive understanding of these challenges and opportunities can pave the way for more efficient and effective wastewater treatment processes, which are crucial for safeguarding public health and the environment. [Display omitted] • Algal-based MBRs effectively remove hazardous contaminants. • Challenges remain in biomass accumulation, nutrient limitation, and toxicity. • Mitigation strategies include system optimization and use of renewable energy. • Potential applications beyond wastewater treatment include biofuel and bioproduct production. [ABSTRACT FROM AUTHOR]

This paper examines the performance and emission characteristics of biodiesel produced from edible oil source (palm) and non-edible oil source (Jatropha) and compared that with fossil diesel fuel. Only 20% palm and 20% Jatropha biodiesel (described by PB20 and JB20 respectively) were examined because it has been suggested by the commercial company that up to 20% biodiesel can be used in a diesel engine without any engine modification. The physical and chemical properties of PB20 & JB20 are also presented and compared with diesel fuel (B0). The performance of these fuels and their emissions were measured in a multi-cylinder diesel engine at different engine speeds and at full load condition. The test results indicated that both PB20 and JB20 fuels produces slightly lower brake powers and higher brake specific fuel consumption compared to diesel fuel. Engine emission results indicated that the PB20 and JB20 fuel reduces the average emissions of carbon monoxide (CO) and hydrocarbons (HC). However, the PB20 and JB20 fuels slightly increases nitric oxides (NO) emissions compared to diesel fuel. Although PB20 have slightly better emission performance than JB20 biodiesel, JB20 biodiesel should be used in unmodified diesel engines to meet the global energy demand and to reduce emissions into the atmosphere because it does not create food versus fuel conflict. [ABSTRACT FROM AUTHOR]

Vehicles are the main sources for environmental pollution especially those associated with diesel engines. It causes a number of health diseases and harm to the ecosystem. It is very urgent to find alternative fuel for vehicles. Biofuel is an alternative for vehicles which have potential to reduce engine emissions and maintain the air quality better. In recent years, worldwide biofuel production and use raised drastically. Some developed countries have put their target and mandate to use biofuel. The aim of this review is to discuss the impact of biofuel on diesel engines emission. From this review it is found that biofuel significantly reduces engine emissions and it has potential to reduce more than 80% of GHG emission. Finally, biofuel can be a viable alternative to be used as a transportation fuel. [ABSTRACT FROM AUTHOR]

In this study, the oil extraction process from Australian native beauty leaf seed has been optimised in terms of seed preparation and cracking, seed kernel treatment, moisture content and oil extraction methods. Two methods: mechanical oil extraction using an electric powered screw press and chemical oil extraction using n-hexane as an oil solvent have been applied to extract oil from the seed kernel. Both whole and grated kernels have been used for mechanical oil extraction process. The study indicated that treatment of seed kernel has a significant impact on oil yields for both techniques. It has been observed that kernels prepared to 15% moisture content provided the highest oil yields for both extraction methods. Mechanical extraction using the screw press could produce oil from the prepared kernels at a low cost. In addition, it has been obtained that oil yields by using grated kernels were relatively higher than the whole kernels. However, oil extraction by using this technique is ineffective due to relatively lower oil yields compared to chemical extraction. On the other hand, chemical extraction was found to be a very effective method for oil extraction because of its consistence performance and high oil yield, but cost of production was relatively higher due to high cost of solvent. The outcomes of this study are expected to serve as the basis on which industrial scale oil extraction can be made from beauty leaf seed. [ABSTRACT FROM AUTHOR]

The aim of this paper is to study the physical and chemical properties of Moringa oleifera biodiesel and its blends of 10%-90% by volume with petro-diesel according to the American society for testing and materials (ASTM D6751) standards and European standards (EN 14214). It was found that when Moringa biodiesel is blended with diesel fuel, all its fuel properties such as kinematic viscosity (KV), density (D), calorific value (CV), flash point (FP), cloud point (CP), pour point (PP), and cold filter plugging point (CFPP). For example, B10 reduce the viscosity of B100 from 5.05 mm 2 /s to 3.54 mm 2 /s (1.4:1). Then developed empirical models of properties are show high regression value (R 2 ) between properties and MOME-diesel blend. It is believed that the results obtained and empirical model proposed in this study will help the researchers to predict the properties of biodiesel-diesel blend which are important parameters to design the fuel system of biodiesel engine. [ABSTRACT FROM AUTHOR]

Ever increasing drift of energy consumption due to growth of population, transportation and luxurious lifestyle has motivated researchers to carry out research on biofuel as a sustainable alternative fuel for diesel engine. Biofuel such as biodiesel and ethanol, produced from renewable feedstocks, are the most appropriate alternative of petroleum fuels. However, direct using of ethanol in diesel fuel face some technical problem especially in cold weather, due to low cetane number, lower flash point and poor solubility. Biodiesel can be blended with both ethanol and diesel fuel and biodiesel–alcohol–diesel blends can be used in diesel engines. The aim of this review paper is to discuss the effect of mixed blends of biodiesel alcohol and diesel on engine performance and emission parameters of a diesel engine. Most of the researchers reported that adding ethanol into biodiesel-diesel blend in diesel engines significantly reduce HC, PM, NOx and smoke emissions but slightly increase fuel consumption. The study concluded that biodiesel-diesel-ethanol blend can be used as a substitute of petro-diesel fuel to reduce dependency on fossil fuel as well as the exhaust emissions of the engine. [ABSTRACT FROM AUTHOR]

Abstract: As a promising alternative energy source, biofuel imparts a remarkable role for the sustainability and security in energy sector. Strategies, including policy recommendations have been set to put forward the development and implementation of biofuel by different countries. Recent exploitation of Asian biofuels policy is one step towards destination. These types of activity behind the biofuels would be the catalyst for the productiveness of policy set by individual territory like Malaysia, Thailand, Vietnam, etc. This is the high time to standardize, policy recommendation and implementation of biofuels taking into consideration on the feedstock, geographical location, and availability. Pertinent comparison with well-established ASTM and European standards are highly recommended. Sector wise (viz. transportation, industrial) bio fuel policy is now crucial as well. Factors, which would be taking into account, prior to recommend a policy includes feed-stocks available, biofuel infrastructure of the country, compatibility with present automotive materials and performance and emission behaviour. This study sought to explore the investigation of several policies with regards to biofuel and advocates some key factors which could be helpful for diminution of biofuels inferiorities. [Copyright &y& Elsevier]

The utilization of microalgae in treating wastewater has been an emerging topic focussed on finding an economically sustainable and environmentally friendly approach to treating wastewater. Over the last several years, different types of con microalgae and bacteria consortia have been experimented with to explore their potential in effectively treating wastewater from different sources. The basic features considered while determining efficiency is their capacity to remove nutrients including nitrogen (N) and phosphorus (P) and heavy metals like arsenic (As), lead (Pb), and copper (Cu). This paper reviews the efficiency of microalgae as an approach to treating wastewater from different sources and compares conventional and microalgae-based treatment systems. The paper also discusses the characteristics of wastewater, conventional methods of wastewater treatment that have been used so far, and the technological mechanisms for removing nutrients and heavy metals from contaminated water. Microalgae can successfully eliminate the suspended nutrients and have been reported to successfully remove N, P, and heavy metals by up to 99.6 %, 100 %, and 13%–100 % from different types of wastewater. However, although a microalgae-based wastewater treatment system offers some benefits, it also presents some challenges as outlined in the last section of this paper. Performance in eliminating nutrients from wastewater is affected by different parameters such as temperature, biomass productivity, osmotic ability, pH, O 2 concentration. Therefore, the conducting of pilot-scale studies and exploration of the complexities of contaminants under complex environmental conditions is recommended. • Utilization of Microalgae is an environment-friendly method to treat the wastewater. • Microalgae removes the suspended nutrients and polluting compounds from wastewater. • The efficiency of microalgae-based wastewater treatment technology is presented. • Challenges of using microalgae in wastewater treatment is discussed. [ABSTRACT FROM AUTHOR]

Abstract: Alternative fuels have received much attention due to the depletion of world petroleum reserves and increased environmental concerns. Thus processed form of vegetable oil (Biodiesel) offers attractive alternative fuels to compression ignition engines. The present work investigates the engine performance parameters and emissions characteristics for direct injection diesel engine using coconut biodiesel blends without any engine modifications. A total of three fuel samples, such as DF (100% diesel fuel), CB5 (5% coconut biodiesel and 95% DF), and CB15 (15% CB and 85% DF) respectively are used. Engine performance test has been carried out at 100% load, keeping throttle 100% wide open with variable speeds of 1500 to 2400rpm at an interval of 100rpm. Whereas, engine emission tests have been carried out at 2200rpm at 100% and 80% throttle position. As results of investigations, there has been a decrease in torque and brake power, while increase in specific fuel consumption has been observed for biodiesel blended fuels over the entire speed range compared to net diesel fuel. In case of engine exhaust gas emissions, lower HC, CO and, higher CO2 and NOx emissions have been found for biodiesel blended fuels compared to diesel fuel. Moreover, reduction in sound level for both biodiesel blended fuels has been observed when compared to diesel fuel. Therefore, it can be concluded that CB5 and CB15 can be used in diesel engines without any engine modifications and have beneficial effects both in terms of emission reductions and alternative petroleum diesel fuel. [Copyright &y& Elsevier]

Abstract: The results of an experimental work carried out to evaluate the effect of palm oil methyl esters, also known as palm oil diesel (POD) and its emulsions as alternative fuel on unmodified indirect injection diesel engine''s wear and lube oil performance are presented in this paper. Half throttle engine with constant 2500 rpm setting was maintained throughout the wear debris and lube oil analysis such as for a period of twenty hours for each fuel system. The sample of lube oil was collected through a one - way valve connected to the crankcase sump at the interval of four hours. When the engine warmed up, first sample has collected immediately. The same conventional lubricating oil SAE 30 was used for each fuel system. To measure wear metal debris and lubricating oil additives depletion of used lubricating oil, Multi element oil analyzer (MOA) was used. To measure the viscosity of lub oil an ISL automatic houillon viscometer (ASTM D445) has been used. Very satisfactory results have been obtained by comparing the lub oil analysis results of Ordinary Diesel and Palm Oil Diesel and their emulsions with 10 percent water by volume. In crankcase oil samples, accumulation of wear metal debris was lower with Palm Oil Diesel and emulsified fuels compare to baseline Ordinary Diesel fuel. Both Ordinary Diesel and Palm Oil Diesel emulsions with 10 per cent water by volume showed promising trends for resisting wear. [Copyright &y& Elsevier]

Abstract: Among the alternative fuels the Bio diesel is one the most common and familiar to all. It''s biodegradable, environment friendly as well as suitable source, to meet the future energy crises. The main concern of this experimental analysis is to reach a tentative goal, how this fuel can be utilised with maximum effective way. To find this,an experiment data analysis of different parameter such as break power, break specific fuel consumption, emission characteristic(NOx, HC,CO. etc) and exhaust temperature, is done through bio diesel fuel and also compared with ordinary diesel which is also known as petro diesel. This investigation is carried out through eddy current dynamometer and load cell arrangement which is controlled by a computer in case of finding the break power and BSFC respectively. And the emission characteristics are observed using Bosch and Bacharach exhaust analyzers. And finally the result is compared with diesel engine which is run by ordinary diesel. The final result implied that the bio diesel with some additives (B20+1%) shows best performance and reduce the exhaust emission including NOx.Thus the decision may be taken,20% blended bio diesel with 1% additive as a best alternative fuel considering all the view aspects and alternatives. [Copyright &y& Elsevier]

Abstract: Experimental study has been carried out to analyze engine performance and emissions characteristics for diesel ngine using different blend fuels without any engine modifications. A total of four fuel samples, such as DF (100% iesel fuel), JB5 (5% jatropha biodiesel and 95% DF), JB10 (10% JB and 90% DF) and J5W5 (5% JB, 5% waste ooking oil and 90% DF) respectively were used in this study. Engine performance test was carried out at 100% load eeping throttle 100% wide open with variable speeds of 1500 to 2400rpm at an interval of 100rpm. Whereas, mission tests were carried out at 2300rpm at 100% and 80% throttle position. As results of investigations, the erage torque reduction compared to DF for JB5, JB10 and J5W5 was found as 0.63%, 1.63% and 1.44% and verage power reduction was found as 0.67%, 1.66% and 1.54% respectively. Average increase in bsfc compared to F was observed as 0.54%, 1.0% JB10 and 1.14% for JB5, JB10 and J5W5 respectively. In case of engine exhaust as emissions, compared to DF average reduction in HC for JB5, JB10 and J5W5 at 2300rpm and 100% throttle osition found as 8.96%, 11.25% and 12.50%, whereas, at 2300 and 80% throttle position, reduction was as 16.28%, 0.23% and 31.98% respectively. Average reduction in CO at 2300rpm and 100% throttle position for JB5, JB10 and 5W5 was found as 17.26%, 25.92% and 26.87%, whereas, at 80% throttle position, reduction was observed as 0.70%, 33.24% and 35.57%. Similarly, the reduction in CO2 compared to DF for JB5, JB10 and J5W5 at 2300rpm nd 100% throttle position was as 12.10%, 20.51% and 24.91%, whereas, at 80% throttle position, reductions was bserved as 5.98%, 10.38% and 18.49% respectively. However, some NOx emissions were increased for all blend els compared to DF. In case of noise emission, sound level for all blend fuels was reduced compared to DF. It can e concluded that JB5, JB10 and J5W5 can be used in diesel engines without any engine modifications However, 5B5 produced some better results when compared to JB10. [Copyright &y& Elsevier]

The COVID-19 pandemic has exerted great shocks and challenges to the environment, society and economy. Simultaneously, an intractable issue appeared: a considerable number of hazardous medical wastes have been generated from the hospitals, clinics, and other health care facilities, constituting a serious threat to public health and environmental sustainability without proper management. Traditional disposal methods like incineration, landfill and autoclaving are unable to reduce environmental burden due to the issues such as toxic gas release, large land occupation, and unsustainability. While the application of clean and safe pyrolysis technology on the medical wastes treatment to produce high-grade bioproducts has the potential to alleviate the situation. Besides, medical wastes are excellent and ideal raw materials, which possess high hydrogen, carbon content and heating value. Consequently, pyrolysis of medical wastes can deal with wastes and generate valuable products like bio-oil and biochar. Consequently, this paper presents a critical and comprehensive review of the pyrolysis of medical wastes. It demonstrates the feasibility of pyrolysis, which mainly includes pyrolysis characteristics, product properties, related problems, the prospects and future challenges of pyrolysis of medical wastes. [Display omitted] • Medical wastes are highly potential environmental hazards on public health risks. • Pyrolysis of medical waste together with associated problems were reviewed. • Prospects and future challenges of medical waste pyrolysis were discussed. • Pyrolysis of medical wastes presents great environmental and economic benefits. Before the COVID-19 pandemic, medical wastes were often mixed with municipal solid waste and disposed of in waste landfills or improper treatment facilities. Many reviews have been devoted to the pyrolysis of plastics and other solid wastes. However, a review on the pyrolysis potential of medical wastes has not been reported previously, prompting its publication during this pandemic. Pyrolysis of medical wastes can deal with wastes and generate valuable products like bio-oil and biochar. [ABSTRACT FROM AUTHOR]

Biodiesel is a fuel that has numerous benefits over traditional petrodiesel. The transesterification process is the most popular method for biodiesel production from various sources, categorized as first, second and third generation biodiesel depending on the source. The transesterification process is subject to a variety of factors that can be taken into account to improve biodiesel yield. One of the factors is catalyst type and concentration, which plays a significant role in the transesterification of biodiesel sources. At present, chemical and biological catalysts are being investigated and each catalyst has its advantages and disadvantages. Recently, nanocatalysts have drawn researchers' attention to the efficient production of biodiesel. This article discusses recent work on the role of several nanocatalysts in the transesterification reaction of various sources in the development of biodiesel. A large number of literature from highly rated journals in scientific indexes is reviewed, including the most recent publications. Most of the authors reported that nanocatalysts show an important influence regarding activity and selectivity. This study highlights that in contrast to conventional catalysts, the highly variable surface area of nanostructure materials favours interaction between catalysts and substrates that efficiently boost the performance of products. Finally, this analysis provides useful information to researchers in developing and processing cost-effective biodiesel. Image 1 • Transesterification is the most efficient catalytic mechanism for biodiesel production. • Nanocatalysts show the important influence in selectivity in transesterification. • Nanocatalysts can be used at a lower temperature and speed up the reaction process. • Comparative benefits and challenges of nanocatalysts are discussed. [ABSTRACT FROM AUTHOR]

Discharging microplastics into the environment with treated wastewater is becoming a major concern around the world. Wastewater treatment plants (WWTPs) release microplastics into terrestrial and aquatic habitats, mostly from textile, laundry, and cosmetic industries. Despite extensive research on microplastics in the environment, their removal, and WWTP management strategies, highlighting their environmental effects, little is known about microplastics' fate and behaviour during various treatment processes. Microplastics interact with treatment technologies differently due to their diverse physical and chemical characteristics, resulting in varying removal efficiency. Microplastics removed from WWTPs may accumulate in soil and harm terrestrial ecosystems. Few studies have examined the cost, energy use, and trade-offs of large-scale implementation of modern treatment methods for the removal of microplastics. To safeguard aquatic and terrestrial habitats from microplastics' contamination, focused and efficient management techniques must bridge these knowledge gaps. This review summarizes microplastic detection, collection, removal and management strategies. A compilation of treatment process studies on microplastics' removal efficiency and their destiny and transit paths shows recent improvement. Bioremediation, membrane bioreactor (MBR), electrocoagulation, sol-gel technique, flotation, enhanced filtering, and AOPs are evaluated for microplastic removal. The fate and behaviour of microplastics in WWTPs suggest they may be secondary suppliers of microplastics to receiving ecosystems. Innovative microplastic removal strategies and technologies such as nanoparticles, microorganism-based remediation, and tertiary treatment raise issues. These new WWTP technologies are examined for feasibility, limitations, and implementation issues. Pretreatment modifies microplastic size, adsorption potential, and surface morphology to remove microplastics from WWTPs. Membrane bioreactors (MBR) can remove 99.9% of microplastics more efficiently than other approaches. MBR systems require membrane cleaning and fouling control, which raises operational and capital costs. To reduce MPs, plastic alternatives and strict controls, including microplastic waste transformation, should be prioritized. Microplastics must be controlled through monitoring policy execution and awareness. [Display omitted] • Discharging microplastics (MPs) via industrial wastewater is a pressing global issue. • MPs harm soil and ecosystems requiring a search for effective removal technologies. • Membrane bioreactor (MBR) showed effectiveness in removing more than 99.9 % of MPs. • Despite being expensive, bioremediation is demonstrated as an effective approach. • Plastic alternatives and stringent control approaches should be prioritized. [ABSTRACT FROM AUTHOR]

Corn stover (CS) is one of the most abundant agricultural wastes and is ubiquitous around the world that is left over after grain harvest and accounts for 47–50% dry mass of the total grain yield. The global CS yield is 1661.25 million tons/year, which is 27.2% of the total agricultural waste. CS consists of about 34.5% stems, 32.3% leaves, 14.3% husks, 12.3% cobs and 6.6% flowers, with up to 45% cellulose, 30% hemicellulose and 20% lignin. Due to its favorable economic and environmental potential, CS is considered an ideal raw material for producing biofuels and biobased chemicals, which can largely be divided into carbohydrate and lignin platforms. However, the techno-economic perspectives of CS-based biorefineries have remained questionable due to the inadequate supply chain logistics, lack of cost-effective conversion technologies, limited scale-up of the product-specific technologies, and lower competitiveness in the market compared to their counterparts, such as sugar and starch-based biorefineries. While CS is converted by thermochemical and biochemical approaches, the latter is considered to be more sustainable for its selective conversion under mild conditions using microorganisms. This review aimed to critically discuss the latest research and developments on the biochemical conversion of CS into biofuels and chemicals. In particular, this paper covers the market potential of biofuels and chemicals to which CS can make a significant contribution, technological developments in the microbial conversion of CS, major biofuels and chemicals produced from CS-derived carbohydrates and lignin, and the technoeconomic perspectives of CS-based biorefinery. [ABSTRACT FROM AUTHOR]

Membrane technology has rapidly gained popularity in wastewater treatment due to its cost-effectiveness, environmentally friendly tools, and elevated productivity. Although membrane performance in wastewater treatment has been reviewed in several past studies, the key techniques for improving membrane performance, as well as their challenges, and solutions associated with the membrane process, were not sufficiently highlighted in those studies. Also, very few studies have addressed hybrid techniques to improve membrane performance. The present review aims to fill those gaps and achieve public health benefits through safe water processing. Despite its higher cost, membrane performance can result in a 36% reduction in flux degradation. The issue with fouling has been identified as one of the key challenges of membrane technology. Chemical cleaning is quite effective in removing accumulated foulant. Fouling mitigation techniques have also been shown to have a positive effect on membrane photobioreactors that handle wastewater effluent, resulting in a 50% and 60% reduction in fouling rates for backwash and nitrogen bubble scouring techniques. Membrane hybrid approaches such as hybrid forward-reverse osmosis show promise in removing high concentrations of phosphorus, ammonium, and salt from wastewater. The incorporation of the forward osmosis process can reject 99% of phosphorus and 97% of ammonium, and the reverse osmosis approach can achieve a 99% salt rejection rate. The control strategies for membrane fouling have not been successfully optimized yet and more research is needed to achieve a realistic, long-term direct membrane filtering operation. [Display omitted] • Strategies to improve membrane performance in wastewater treatment are reviewed. • Despite its increased cost, membrane performance can reduce flow degradation by 36%. • The fouling issue is identified as one of the key issues of membrane technology. • Mitigation techniques like nitrogen bubble scouring can reduce fouling rates by 60%. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) have garnered significant attention as low-cost thermal energy storage systems that efficiently capture and store solar energy. Recent review works have largely focused only on thermal conductivity enhancement techniques, and/or applications of PCMs, while others have mainly discussed the performance enhancement of either heating, cooling, or clean energy storage systems integrating with PCMs. However, not enough studies recently reviewed all of these techniques/systems comprehensively to provide insights into them. This paper thus comprehensively reviews the integration of PCMs as an enhancement to most types of heating, cooling, and clean energy storage system performance, and the techniques to enhance thermal conductivity. The integration of PCMs with these systems has shown promising performance. For instance, an improvement of 13.5% is found in the efficiency of photovoltaic (PV) system when it is integrated with PCM/Al 2 O 3 nanoparticles. In addition, the solar air heater's daily energy efficiency reaches 17% on its own, but when combined with PCM, it reaches 33%. However, the major drawback of using PCM–TES (thermal energy storage) for cooling is that PCM does not entirely solidify at night. The literature also shows that the issues related to PCMs' low thermal conductivity, phase separation, and subcooling/supercooling, their poor compatibility with other materials, and the environmental hazards they pose hinder their application on a large scale. It is necessary to implement international standards for assessing the thermophysical properties of PCMs and compile data to better facilitate the utilization of PCMs by end-users. [ABSTRACT FROM AUTHOR]

The utilization of renewable lignocellulosic biomasses for bioenergy synthesis is believed to facilitate competitive commercialization and realize affordable clean energy sources in the future. Among the pathways for biomass pretreatment methods that enhance the efficiency of the whole biofuel production process, the combined microwave irradiation and physicochemical approach is found to provide many economic and environmental benefits. Several studies on microwave-based pretreatment technologies for biomass conversion have been conducted in recent years. Although some reviews are available, most did not comprehensively analyze microwave–physicochemical pretreatment techniques for biomass conversion. The study of these techniques is crucial for sustainable biofuel generation. Therefore, the biomass pretreatment process that combines the physicochemical method with microwave-assisted irradiation is reviewed in this paper. The effects of this pretreatment process on lignocellulosic structure and the ratio of achieved components were also discussed in detail. Pretreatment processes for biomass conversion were substantially affected by temperature, irradiation time, initial feedstock components, catalyst loading, and microwave power. Consequently, neoteric technologies utilizing high efficiency-based green and sustainable solutions should receive further focus. In addition, methodologies for quantifying and evaluating effects and relevant trade-offs should be develop to facilitate the take-off of the biofuel industry with clean and sustainable goals. • Fundamental and characteristic of microwave assisted pretreatment were introduced. • Effects of microwave irradiation on the lignocellulosic biomass reviewed. • Combination of microwave physicochemical methods obtained higher efficiency. • Energy and economic aspects of microwave-physicochemical methods evaluated. [ABSTRACT FROM AUTHOR]

Bioresource valorization to obtain valuable phenolic compounds for medicinal, nutraceutical, food, and cosmetic applications are critical for a current and future sustainable and bio-based economy. Renewable, environmentally friendly, and non-toxic choline chloride-based deep eutectic solvents are the newest and utmost environmentally friendly alternatives to conventional organic solvents for the pretreatment and extraction of phenolic compounds. Recently, numerous studies have focused on phenolic compound extraction using choline chloride-based deep eutectic solvents as solvents or catalysts. Process variable optimization has been reported in terms of kinetic modeling and mechanisms involved in phenolic compounds extraction. This paper describes the cutting-edge methods used to extract phenolic compounds from different bio-based sources using choline chloride-based deep eutectic solvents. In addition, the factors affecting, kinetic models, and mechanisms involved in phenolic compound extraction using choline chloride-based deep eutectic solvents are thoroughly summarized. Moreover, future predictions, challenges, and anticipated growth in this field are addressed and can be used for biomass valorization. • Extraction of phenolic compounds using deep eutectic solvents is promising. • Extraction mechanism depends on the nature of the deep eutectic solvent components. • Scaling up should be optimized using experimental and computational approaches. • Recovery of phenolic compound from solvent is difficult due to low vapor pressure. [ABSTRACT FROM AUTHOR]