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Water resources are of crucial significance to mutually ecosystem and human developments. Growing ecological toxic waste from industry like metallic ion presents in metal coating, mining, tanneries, etc. These are non-biodegradable and tend to accrue in living creatures triggering disorders. Numerous production units as dye, textile, paper, and plastics utilize dyes to shade their products and utilize significant quantities of water. Therefore, they produce a substantial quantity of effluent. The existence of little quantity of dyes (less than 1 ppm) is extremely noticeable. Consequently, to deal with the poisonous effluents before being expelled into the waterbodies, numerous physico-chemical techniques like coagulation/flocculation are accessible for eradication. Foremost disadvantages of these techniques are high sludge creation, processing and removal difficulties, high cost, etc. Additionally, cost-efficient and ecologically perfect management for effluents is needed. Adsorption is one of the most effective and economical approaches to handle effluents. Adsorbents are presently employed which are by-products from agriculture and industries, which comprise seaweeds, bacteria, crab shells, and agricultural products such as wool, rice, straw, coconut husks, and waste tea leaves. Sorption/biosorption using low-cost sorbents could be techno-economically feasible for the treatment of effluents. Low-cost sorbents are nothing but materials that are plentiful in the environment or are by-products or waste material from another industry. Due to effectiveness of sorption, various adsorbents have been developed and categorized as conventional and non-conventional adsorbents. To investigate the effectiveness of both categories, this review will be aided because it shows the comparative study of the removal efficiency, adsorption capacity, and techno-economical aspects of both sorbent classes. [ABSTRACT FROM AUTHOR]

The growing global concern regarding plastic waste pollution and its detrimental environmental impact has prompted significant research and innovation in waste management and energy generation. This comprehensive review explores the current state of handling plastic waste for energy generation, encompassing various technologies and approaches. It also identifies and addresses the imminent challenges facing pursuing sustainable and efficient plastic waste-to-energy solutions. The review discusses the alarming rise in plastic waste production, emphasizing the critical need for sustainable waste management strategies. It provides an overview of the existing methods for handling plastic waste, including mechanical recycling, chemical recycling, and landfill disposal. Special attention is given to emerging technologies such as pyrolysis, gasification, and waste-to-energy incineration, which offer promising avenues for converting plastic waste into valuable energy resources. This comprehensive review provides a valuable overview of the current state of handling plastic waste for energy generation. It underscores the significance of sustainable waste management practices and outlines the potential benefits and challenges associated with various plastic-to-energy technologies. By addressing these challenges and embracing a holistic approach, society can move closer to a sustainable future where plastic waste is managed effectively and contributes to generating clean and renewable energy. [ABSTRACT FROM AUTHOR]

The presence of emerging pollutants in water bodies has become a significant concern due to their potential adverse effects on human health and the environment. In recent years, bio-sorbents have emerged as promising alternatives for the removal of emerging pollutants due to their eco-friendly nature, cost-effectiveness, and high adsorption capacities. However, primary biochar has some drawbacks like the least adsorption capacity and small sorption limits. However, biochar must be improved in order to be used in the treatment of emulsifiable concentrate water. Number of attempt has been made on the confiscation of ECs from effluents by modified biochar (mBC) are currently available. Functionalizing biochar involves modifying its surface properties to enhance its performance in different applications. These modifications can be achieved through various techniques, leading to biochars with different physicochemical properties. The impacts, behaviors, and adsorption processes of customized biochar on various Environmental Pollutants (EPs) depend on these variations. It is vital to evaluate and assimilate information regarding EC adsorption in a systematic manner. Concerning modified biochar. The first method for removing EC from charcoal is discussed in this review paper. The performance and adsorption mechanism of mBC on conventional EPs are examined. Ultimately, the leading study trends and developments, along with ideas and recommendations for impending progress, are discussed. [ABSTRACT FROM AUTHOR]

In this work, we designed novel-based catalysts composed of metals and tungstophosphoric acid supported mesoporous clay through wetness impregnation and reduction methods for getting good activity and selectivity of menthols from catalytic hydrogenations of citral and citronellal. Clay was treated with 4 M HCl and then doped with 12-tungstophosphoric acid and Pd/Ni metals through wetness impregnation method. These catalysts were activated through hydrogen reduction method and applied in high-pressure hydrogenation reactions at optimum reaction conditions. Nickel-doped catalysts showed a good catalytic activity in liquid-phase citral hydrogenation and produced 56% menthols (e.g., selectivity). Similarly, Ni-doped and Pd-doped catalysts could produce 98% and 82% menthols yield/selectivity from citronellal hydrogenation with excellent catalytic activity (e.g., fast conversion), respectively. The catalytic activity and selectivity were connected with balanced metal–acid sites ratio (strong Lewis and medium Bronsted acid-sites) and the presence of mesopores. This multistage reaction was possible in the presence of strong Lewis and medium Brønsted acid sites along with metal active sites. [ABSTRACT FROM AUTHOR]

Microbial fuel cell is considered one of the tremendous technologies as this possesses a potential to utilize waste for energy as well as for wastewater treatment-related environmental pollution. In present work, wet chemical method was adopted to synthesize Ni/G nanocomposite. Scanning electron microscope (SEM) was employed for studying the morphology, phase, and elemental analysis which were done using X-ray diffraction (XRD) and EDS, respectively. Malvern zeta particle sizer was used to determine the particle size of synthesized powder, and by using electrochemical station application, studies were carried out, i.e., cyclic voltammetry and chronocoulometry, and compared with previous studies. In addition, newly developed anode material was used for microbial fuel cell. Saccharomyces cerevisiae sp. was utilized as biocatalyst while 180 μmol l−1 of methylene blue as a mediator in anode and 350 μmol l−1 potassium ferricyanide was used as an oxidizing agent in cathode chamber for treatment of spent wash. All experiments were carried out through balancing the volume of 1 l for power generation from spent wash in MFC under an optimized parameter of 10% agarose, pH 8, aeration rate 200 ml/min, and 50% substrate concentration. The maximum current and a power density obtained at an optimized concentration are approximately 54.21 mA/m2 and 71.12 mW/m2, respectively. The maximum voltage of (1130 mv) was obtained per liter of processed spent wash. [ABSTRACT FROM AUTHOR]

Sulfur emission creates many health as well as environmental problem after release of sulfur compounds. Many approaches have been applied for the treatment of sulfur compounds via physical, chemical, and biological approaches; these techniques have some advantages as well disadvantages. But for as effective treatment of sulfur compounds biological approach put termendeous impact on environment as well as on human health. Different reseracher work on different methods available in the scope of biological approach current review emphasis on Bio-electrochemcial System. In this review study cover the application of Microbial Fuel Cell (MFC) for treating sulfur present in fossil fuel as well as waste stream couple with the changes in ecosystem. One of the latest approaches for sustainable way for treating wastewater stream is the use of MFCs. With this technique, the current work focuses on the mitigation of sulfur compounds in MFC. In addition, there are challenges and perspectives of using MFCs for sulfur removal. [ABSTRACT FROM AUTHOR]

Heavy metal contamination is severely affecting human health and environment. These metals are known to exist naturally but the anthropogenic activities have contributed towards increasing their concentrations beyond permissible limits, which in turn have proved to be hazardous for the human health as well as environment. Various industries release the untreated wastewater containing heavy metals into the open streams, thereby creating a contaminated source affecting negatively on consumers. In order to deal with this, several materials have been researched and proposed as adsorbents to remove these contaminants. Amongst them are carbon-based materials, that have shown to be effective, efficient, and environment-friendly option for heavy metal adsorption from aqueous solutions. The present review thoroughly summarizes the recent developments of carbon-based materials, specifically in terms of their application in heavy metal removal from aqueous solutions. Moreover, it elaborates the adsorption mechanism and compares it with other technologies available for metallic removal. Similarly, various parameters affecting the adsorption using carbon-based materials and their recent regenerative strategies are presented. In the end, numerous shortcomings and discrepancies associated with carbon-based materials are given along with their future prospects that need to be addressed in the upcoming research. [ABSTRACT FROM AUTHOR]

Emerging pollutants (EPs) are a group of toxins with low concentrations but substantial toxicity. In recent years, the environment has gained a lot of attention. These trace contaminants can accumulate in different sources and eventually make their way into human bodies, creating a public health risk. Biochar adsorbents are being applied to treat wastewater for removal of emerging contaminants (ECs) as a low-cost and effective adsorbent. However, biochar adsorbents needs improvement for the treat of emulsifiable concentrated water. Several attempts have been made to confiscate ECs from effluents by modified biochar (mBC) which are currently available. Various techniques of functionalizing biochar with different physicochemical properties have been investigated, resulting in different impacts, behaviors, and adsorption processes of customized biochar on various EPs. It is vital to evaluate and assimilate information regarding EC adsorption systematically. Concerning modified biochar, the first method for removing ECs from charcoal is discussed in this paper. The performance and adsorption mechanism of mBC on conventional EPs is examined. Furthermore, the leading trends, developments, ideas and recommendations for impending progress, are discussed. [ABSTRACT FROM AUTHOR]

Agricultural and lignocellulose residues are a large number of available biomass substrates and important sources for the fermentation of biofuels. Gasification and enzymatic hydrolysis are the main technologies for converting lignocellulose biomass into products for the production of biofuels as a sustainable energy source for fuel transportation. Bio-fuel production is getting interest due to the depletion of crude oil reserves. Biofuel production is an economical alternative source for transport and energy sectors since it offers the utilization of cheap lignocellulose biomass for generating valued bio-fuels and chemicals. However, most of the processes are still in development phase due to techno-economic challenges and diversity in composition of lignocellulose biomass. Optimizations have been made over the years to make these processes developed enough to be employed on the industrial scale. This review accounts the sources and compositions of different lignocellulosic biomasses along with several thermo-chemical, catalytic, and integrated strategies for their conversion to produce bio-fuels and other valuable chemicals. [ABSTRACT FROM AUTHOR]

To check the feasibility of the steam glycerol reformation process, thermodynamic analysis of steam glycerol reformation plays vital role. The aim of this work is to carry out thermodynamic analysis, equilibrium calculations of steam reforming of glycerol for hydrogen production. Production of hydrogen is affected by parameters including temperature, pressure, water/glycerol ratio, and byproducts. The thermodynamic analysis has been done by calculating mole fractions as a function of x and mole fraction as a function of ε for single reaction. The effect of temperature, pressure, and water/glycerol ratio is observed on single and multiple reactions. The thermodynamic analysis is carried out on variable ranges of temperature 573.15–1073.15 K, pressure 1–5 atm, and water/glycerol ratio 1:1 to 6:1.The results show that by changing temperature from 573.15 to 1073.15 K, reducing pressure from 5 to 1 atm and rising water/glycerol ratio from 1:1 to 6:1 hydrogen production is improved; glycerol and water are converted to products. [ABSTRACT FROM AUTHOR]

Microbial fuel cell (MFC) has been utilized for energy generation and wastewater treatment since many decades. Due to the better performance of MFC concerning energy generation and wastewater treatment, the current study was conducted. The aim of current study is to utilize spent wash as anode feed along with impact of various parameters on treatment as well as energy production. Saccharomyces cerevisiae sp. was utilized as biocatalyst while 180 μmol l−1 of methylene blue as a mediator in anode and 350 μmol l−1 potassium ferricyanide was used as an oxidizing agent in cathode chamber for treatment of spent wash. All experiments were carried out through balancing the volume of 1 l for power generation from spent wash in MFC under an optimized parameter of 10% agarose, pH 8, aeration rate 200 ml/min, and 50% substrate concentration. The maximum current and a power density obtained at an optimized concentration are approximately 54.21 mA/m2 and 71.12 mW/m2, respectively. The maximum voltage of 830mV (3.3 mA) was obtained per liter of processed spent wash. The removal of COD and BOD from effluent MFC was 94% remarkably. These results demonstrate that MFC can simultaneously generate electricity and remove COD effectively from spent wash. [ABSTRACT FROM AUTHOR]

The increase in carbon dioxide (CO2) gas emissions in the atmosphere has been contributing to the global warming, leading to climate change. CO2 capture and conversion technologies have received attention for removal of CO2. Several technologies, such as cryogenic separation, absorption, membrane separation, and adsorption, are being researched to encourage CO2 mitigation. Among others, adsorption technology is considered as environmentally friendly and economical. In the recent past, the waste biomass–derived adsorbents have emerged as potential materials for CO2 separation. This review attempts to report and critically analyze the work conducted on the synthesis of biomass-derived adsorbents from various biomasses. Parametric evaluation on the synthesis of adsorbents and their application is an important aspect to fully understand the applicability and limits of these materials. So, in this study, emphasis is given on the parameters, which affect the development and performance of the biomass-derived adsorbents for CO2 separation. Some of the major parameters include biomass feedstocks, methods related to the synthesis of activated carbons, carbonization, and physical as well as chemical activation. The sub-parameters such as gas flow rate, temperature, activating agent, heating rate, and residence time on carbonization and activation parameters have also been reviewed and critically analyzed. Furthermore, the influence of different factors including porosity, initial concentration of adsorbate, particle size distribution, adsorbent dosage, total surface area, temperature, pressure, and pH are reviewed and discussed for the removal of CO2 through adsorption. [ABSTRACT FROM AUTHOR]

Emission of sulfur-based compounds create problem for environment as well as for on human health. To remove sulfur compounds from sulfur-rich fossil fuel, various techniques have been proposed and studied. Based on problem associated with environment as well as for human health, current study focused on DBT removal using novel Rhodococcus spp. (SL-9). Furthermore, study focused on kinetic modeling and simulation of biodesulfurization process for calculating the efficiency of newly isolated bacteria Rhodococcus spp. (SL-9), effect of cell growth, and degradation rate for DBT (dibenzothiophene). Rhodococcus spp. (SL-9) degrade 0.39 mM DBT within 7 days via 4S pathway. The efficiency of Rhodococcus spp. (SL-9) for maximum degradation and conversion of DBT into 2-HBP (2-hydroxybiphenyl) at optimized parameters are 30 °C, 7 pH, and glucose as carbon source. It has been observed through the study that an increase in degradation rate of model DBT compound at 3 mM about 70 hr of incubation period. Rhodococcus sp-SL-9 shows maximum rate of growth about 0.067 h−1 along with biodegradation of DBT rate about 0.89 h−1, which endorses its application in coal desulfurization process. [ABSTRACT FROM AUTHOR]

Recent years have witnessed rise in the production of microbial fermentation of metabolites and proteins for industrial applications. The innovative method aims to improve the conventional batch fermentation and the separation. Furthermore, the idea of downstream processing of the target product enhances the efficiency of the overall process and makes it cost-effective and eco-friendly. Even though being cost-effective and eco-friendly, the process faces challenges in commercial applications. When the concentration of the final product/by-product reaches a certain level, feedback inhibition is a common problem encountered in the fermentation process. Excessive accumulation of end products/by-products in culture also inhibits cell growth and secretion of target metabolites. The fermentation results in the production of antibiotics, fungal metabolites, and amino acids, which come with serious inhibition problems. Hence, to mitigate such problems and enhance fermentation performance, extractive fermentation via in situ ion exchange adsorptive technique can be incorporated. The present review highlights the advances and suggests the strategies to resolve the inhibition problems using extractive fermentation via internal, external, and dispersed resin systems. Furthermore, methods for synthesis of resins are discussed and adsorption mechanism of ion exchanges is also elaborated. [ABSTRACT FROM AUTHOR]

The bulk quantity of poultry manure (PM) and buffalo dung (BD) is generated by the growing poultry industry and buffalos in Pakistan that causes serious environmental issues such as air, water, and land pollution. Nutrient leaching, mainly nitrogen, phosphorus contaminates soil and water bodies, ammonia evaporation results in air quality degradation, and pathogen contamination affects the health of flora and fauna. This research study aims to utilize PM and BD for biogas generation to meet the energy requirement of the people and save the environment that was degraded due to improper disposal of selected waste. The anaerobic co-digestion technique was used for the treatment of poultry manure and buffalo dung. The ratio selected was 3:1, 1:3, and 1:1 in 500-ml glass bottles acting as digesters. The PM and BD were used in a separate digester. All the digesters have a retention time of 63 days and operated at a temperature of 37 °C and 45 °C. The detailed experimental work shows that 1:3 ratio of PM and BD yield 561 Nml/gm.VS. The quality of the biogas generated from 1:3 of PM and BD digester was also maximum among all five digesters; the volumetric composition of biogas obtained was methane 64% and carbon dioxide 32%. From this study, it was observed that the digestion of a single substrate is less productive as compared with co-digestion; co-digested substrate gives more quantity and quality of biogas, higher biodegradability of biomass, and effective volatile solids (VS) removal. [ABSTRACT FROM AUTHOR]

The widespread occurrence of various types of emerging pollutants (EC) and their adverse effects on the environment and health have become a matter of great concern. In EC, bioactive compounds from drugs, cosmeceuticals, biomedicine, personal care (PPCP), endocrine disruptors (EDC), and flame retardants are the main concerns. The persistence and existence of EC in (aqueous solution) have aroused intense and continuous worldwide attention. This work overviews the current and state-of-the-art critical aspect related to hazardous pollutants at large and ECs in particular by the immobilized oxidoreductase enzyme. In addition, challenges and perspectives of emerging contaminates are also discussed. [ABSTRACT FROM AUTHOR]

The demand for the development of high-performance and eco-friendly nanocomposites is soaring up. This is because of their desired mechanical, thermal, electrical, magnetic, catalytic, and optical properties and their ecofriendly development. The diversity of nanocomposites has introduced them to a wide variety of applications such as drug delivery, biosensors, bone regeneration, solar cells, super capacitors, fuel cells, automobiles etc. The nanocomposites are deemed competing materials for the sustainable development, this is because of their ecofriendly behavior and value addition. This manuscript reviews the status of the silicon enhanced nanocomposites, various classes of nanocomposites such as ceramic based matrix nanocomposites, metal-based matrix nanocomposites, Polymer based matrix nanocomposites, etc. advanced green polymer-based nanocomposites and sustainable nanofillers for nanocomposites. The applications of nanocomposites in various sectors such as energy, automobiles, packaging, biomedical, environment and safety have been critically reviewed. [ABSTRACT FROM AUTHOR]

Compared with traditional battery and super capacitor materials, nanomaterials can significantly improve ion transport and electron conductivity. There are many features to the achievement of nanomaterials in energy storage applications. Nanomaterials development and their related processes can improve the performance based on the energy storage existing system. Current study discuss fruitful approaches and outline a roadmap for using green nanomaterials for advancement in energy storage devise. This review includes the information of the latest research being carried out on green nanomaterials and its sustainability. It also provides an overview of the latest state and proposes the future direction of the use of green nanomaterials for numerous possible applications, which are mainly used in the fields of biotechnology, agriculture, and biomedicine. [ABSTRACT FROM AUTHOR]

Aerogel is a special type of porous material with many outstanding physical and chemical properties, such as low density, high porosity, high surface area, and adjustable surface chemistry. Thanks to the latest advances in the synthesis of different types of aerogels, the feasibility of this porous material in several applications has been widely explored. In a variety of high performance applications, aerogels have received much attention as an adsorption medium that removes a variety of environmental and human health pollutants. Although the performance of aerogels in environmental sanitation is encouraging, some shortcomings of aerogels, such as complex drying process, mechanically fragile structure and processing costs, have also been taken into account and have been taken into account been determined in some studies. Degree of relief. This review article aims to describe the synthesis and processing of aerogels and their latest applications in air purification, such as carbon dioxide capture and VOC removal, as well as applications in the treatment of air, water, including oils and toxic organic compounds and heavy metals ion removal. [ABSTRACT FROM AUTHOR]

Oil spills are a major contributor to water contamination, which sets off a significant impact on the environment, biodiversity, and economy. Efficient removal of oil spills is needed for the protection of marine species as well as the environment. Conventional approaches are not efficient enough for oil-water separation; therefore, effective strategies and efficient removal techniques (and materials) must be developed to restore the contaminated marine to its normal ecology. Several research studies have shown that nanotechnology provides efficient features to clean up these oil spills from the water using magnetic nanomaterials, particularly carbon/polymer-based magnetic nanocomposites. Surface modification of these nanomaterials via different techniques render them with salient innovative features. The present review discusses the advantages and limitations of conventional and advanced techniques for the oil spills removal from wastewater. Furthermore, the synthesis of magnetic nanocomposites, their utilization in oil-water separation, and adsorption mechanisms are discussed. Finally, the advancement and future perspectives of magnetic nanocomposites (particularly of carbon and polymer-based magnetic nanocomposites) in environmental remediation are presented. [ABSTRACT FROM AUTHOR]

Indigenous hematite iron ore was chemically activated as a function of various hydrogen peroxide concentrations (0.5, 1, 1.5, and 2.0 M), activation time, and iron ore size. Adsorption potential was evaluated at various initial arsenic concentrations, contact time, adsorbent dose, and particle size. Maximum 95% removal efficiency was achieved at 600-μm size of iron ore, activated with 0.5 M concentration of hydrogen peroxide at 24 h of activation time. The experimental data were further evaluated through Langmuir and Freundlich isotherms. The maximum 14.46 mg/g of adsorption capacity was observed through Langmuir isotherm. Moreover, adsorption kinetics was evaluated using pseudo-first-order and pseudo-second-order kinetics, and the intra-particle diffusion model. The kinetics of arsenic adsorption was best described by using the pseudo-first-order kinetics with a kinetic rate of 0.621 min−1. The hematite iron ore before and after arsenic adsorption was characterized by XRD, SEM, and EDX. [ABSTRACT FROM AUTHOR]

Petroleum, coal, and natural gas reservoir were depleting continuously due to an increase in industrialization, which enforced study to identify alternative sources. The next option is the renewable resources which are most important for energy purpose coupled with environmental problem reduction. Microbial fuel cells (MFCs) have become a promising approach to generate cleaner and more sustainable electrical energy. The involvement of various disciplines had been contributing to enhancing the performance of the MFCs. This review covers the performance of MFC along with different wastewater as a substrate in terms of treatment efficiencies as well as for energy generation. Apart from this, effect of various parameters and use of different nanomaterials for performance of MFC were also studied. From the current study, it proves that the use of microbial fuel cell along with the use of nanomaterials could be the waste and energy-related problem-solving approach. MFC could be better in performances based on optimized process parameters for handling any wastewater from industrial process. [ABSTRACT FROM AUTHOR]

Combustion of coal create many harmful gases which effect on human health as well as on environment. The sulfur in coal limits its own use, and bio-desulfurization (BDS) shows enormous development potential and the prospects for the application of coal desulfurization. Present study highlights the bioprocess strategies for reduction of sulfur content from coal before combustion. The bioprocess involved the use of Airlift Bioreactor along with Rhodococcus sp. ATCC55309 as biocatalyst. Different nutritional and operational parameters involved to promote sulfur reduction at maximum level. The parameters were investigated are different carbon source, temperature, pH, Agitation speed, and pulp density. The impact of these parameters shows that sulfur removal can be enhanced though optimized conditions. The amount of total sulfur and organic sulfur present in coal were reduced by 33 ± 1.7% and 71 ± 1.5%, respectively, compared to untreated coal at controlled condition of various parameters are 20% (w/v) pulp density, 30 °C, 170 rpm, glucose as carbon source and pH 7. Whereas organic sulfur degrades from coal using Rhodococcus sp. ATCC55309 about 0.36 mM DBT (Di-benzothiophene) within 8 days via 4S-pathway. The maximum conversion of DBT compound into 2-HBP(2-hydroxybiphenyl) by utilizing 30 °C, 170 rpm, 20 pulp density and glucose as carbon source. [ABSTRACT FROM AUTHOR]

This work aims to utilize fly ash from a thermal power station for melanoidin reduction from distillery effluent by adsorption. To accomplish this, coal fly ash was modified through chemical treatment and was then tested for melanoidin adsorption as a function of various melanoidin concentrations, contact time, and pH. The specific novelty of this study is the evaluation of coal fly ash as a low-cost adsorbent for melanoidin removal. Furthermore, the simulation study was carried out using Aspen ADSIM software in order to optimize the commercial usage of the prepared adsorbent. The main results achieved include the maximum removal efficiency of 84% which was reached at initial melanoidin concentration of 1100 mg L−1 (5% dilution), pH 6, and a contact time of 120 min. The Langmuir and Freundlich isotherm models were used to evaluate adsorption isotherms. The maximum adsorption capacity of 281.34 mg/g was observed using the Langmuir isotherm. Furthermore, pseudo-first- and pseudo-second-order and intra-particle diffusion models were used to fit adsorption kinetic data. The pseudo-second-order was best describing the adsorption kinetic with a faster kinetic rate of 0.142 mg g–1 min−1. CFA (coal fly ash) after acidic activation resulted in a slightly higher surface area, average pore volume, and pore size. The maximum breakthrough time and adsorbent saturation time were achieved at initial melanoidin concentration of 1 mol/lit, bed height of 2.5 m, and flow rate of 50 lit/min. [ABSTRACT FROM AUTHOR]

Menthol synthesis is possible through citral and citronellal hydrogenations via following multistage chemical reactions such as hydrogenation and cyclization. This research mainly focuses on a design of selective, active and cost-effective metal-acid (bifunctional) catalysts for menthol production via citral and citronellal hydrogenations. More specifically, Pd and Ni metals were impregnated over acidic support (e.g., hetero-poly acid supported montmorillonite, HPA_MM). The prepared catalysts were characterized by BET, pyridine adsorption and amine titration methods. Some of the most important parameters such as metal type and loading; applied pressure and reaction time have been investigated throughout this work. The obtained results reveals that the 8 wt% Ni-HPA-MM catalyst (Cat-5) has produced 63% menthols (initial reaction rate 0.126 mmol/min) from citral hydrogenation (80 °C, 1.0 MPa) within 24 h. Similarly, during lower applied pressure (0.5 MPa), the production of menthol was significantly improved (approximately 98% of menthol, initial reaction rate ~ 0.138 mmol/min) with the application of 8 wt% Ni-HPA-MM catalyst (Cat-5) in citronellal hydrogenation. Higher menthol selectivity was achieved from both reactions (citral and citronellal hydrogenation) which might be due to the presence of strong Lewis and medium Brønsted acid sites. [ABSTRACT FROM AUTHOR]

Due to the rising demands of cleaner fuels (free from sulfur), most of the oil industries are implementing the process of the desulfurization. In present work, the extractive desulfurization (EDS) efficiency of binary solvents composed as mixtures of bronsted acidic ILs ([Hnmp][HSO4] and [Hnmp][H2PO4]) and nonvolatile organic solvent known as dimethylformamide (DMF), is investigated for the model fuel oil (containing thiophene as S-compounds). The main advantages of using binary solvents are; low viscosity of extractant and reduced cost of the process. Effect of key operating parameters such as temperature, time, multiple steps, initial S-content in oil and oil:binary solvent (w/w) ratio on the S-removal efficiency is examined. Based on the obtained results, optimal 40 °C and 45 min are chosen as operating temperature and extraction time, respectively. Almost 95% of S-removal (decrease from 500 to 22 ppm and 28 ppm) is obtained through five steps extraction for both binary solvents, also these exhibited remarkable extraction performances for different initial S-content of fuel oil. The recyclability and reusability of solvents are investigated, where it is observed that binary solvent has reasonable effectiveness when reused for four times. The solvents can also be regenerated without undergoing any change in the actual structure of ILs. This study shows that EDS based on the binary solvents can be a suitable option to produce the cleaner fuel oils. [ABSTRACT FROM AUTHOR]

Biomass utilization has received much attention for production of high density solid fuels. Utilization of cheap and naturally available precursors through environmentally friendly and effective processes is an attractive and emerging research area. Pyrolysis and hydrothermal carbonization (HTC) are well-known technologies available for production of solid biofuel using conventional or microwave heating. Microwave heating is a simpler and more efficient heating method than conventional heating. This study presents a critical review on microwave pyrolysis and microwave HTC for solid fuel production in terms of yield and quality of products. Moreover, a brief summary of parameters of microwave pyrolysis and microwave HTC are discussed. The fuel, chemical, structural and thermal weight loss characteristics of solid fuels produced from different biomass are discussed and compared. [ABSTRACT FROM AUTHOR]