Search Results (60)

This paper presents the results of a study on the effect of a biochar additive produced via pyrolysis at 400 °C and 500 °C from waste biomass, i.e., walnut shells, on the tribological and rheological properties of vegetable lubricating compositions. Sunflower oil and amorphous silica, used as a thickener, were used to prepare the lubricants. To the base lubricant prepared in this way, 1 and 5% biochar additive were introduced, and for comparison, we took the same amounts of graphite. Tests were carried out on the anti-wear properties, coefficient of friction, and changes in dynamic viscosity during the tribological test, as well as on the anti-scuffing properties for the tested lubricant compositions. The effect of the applied modifying additive on the lubricating and rheological properties of the prepared lubricating greases was evaluated. On the basis of the study of vegetable greases, it was found that the addition of 5% biochar from walnut shells produced during pyrolysis in 500 °C had the most favorable effect on the anti-wear properties of the tested greases, while the 5% biochar from walnuts shell prepared via pyrolysis at 400 °C had the best anti-scuffing protection. The use of the biochar additive in vegetable greases resulted in a reduction in the dynamic viscosity of the tested greases, particularly for greases modified with 5% walnut shell biochar produced at 500 °C, which is particularly important with respect to the work of steel friction nodes, as well as in central lubrication systems. Full article

This work aimed at replacing per- or poly-fluoroalkyl substance (PFAS)-based food-serving containers with wood-based, oil- and grease-resistant food-serving containers. A novel container was developed by laminating wet cellulose nanofibril (CNF) films to both sides of yellow birch wood veneer using a food-grade polyamide–epichlorohydrin additive (PAE) as an adhesive. CNFs significantly improved the wood veneer container’s mechanical strength and barrier properties. The container’s mechanical testing results showed significant increases in flexural strength and modulus of elasticity (MOE) values in both parallel and perpendicular directions to the grain. All formulations of the container showed excellent oil and grease resistance properties by passing “kit” number 12 based on the TAPPI T 559 cm-12 standard. The water absorption tendency of the formulation treated at higher temperature, pressure, and longer press time showed similar performance to commercial paper plates containing PFASs. The developed composite demonstrates superior flexural strength and barrier properties, presenting a sustainable alternative to PFASs in food-serving containers. Both wood and CNFs stand out for their remarkable eco-friendliness, as they are biodegradable and naturally compostable. This unique characteristic not only helps minimize waste but also promotes a healthier environment. If scaled up, these novel containers may present a solution to the oil/grease resistance of bio-based food containers. Full article

In this study, five distinct industrial waste streams, encompassing bakery processing and kitchen waste (BP plus KW) mixture, fat, oil, and grease (FOG), ultrafiltered milk permeate (UFMP), powder whey (PW), and pulp and paper (PP) compost, underwent mesophilic biochemical methane potential (BMP) assays at F/M ratios of 1, 2, 4, and 6 g COD/g VSS. An F/M ratio of 1 g COD/g VSS showed the highest methane yield across the investigated feedstocks. In the case of UFMP and PW, an F/M ratio of 2 produced identical results to an F/M ratio of 1 despite their relatively high carbohydrate content which is easily acidified to VFAs. Increasing the F/M ratio to 2 decreased the biodegradability of both BP plus KW and FOG by 63%. Increasing the F/M ratio of the PP did not show as much of a significant impact on biodegradability compared to the other feedstocks as methane yields decreased from 135 to 92 mL CH₄/g COD, a decrease of 32%. Full article

Following the concept of “waste into resources”, a mild and controllable light grafting technique was used to immobilize pancreatic lipase (PPL) in situ on modified organic, chromium-free tanned leather scraps to catalyze the hydrolysis of waste oil. The experimental results showed that immobilized PPL significantly improved the catalytic activity, operational stability, reusability, and storage stability compared to free PPL. Furthermore, the study evaluated the environmental compatibility of the system through biological risk assessment of soil extracts after degradation, indicating that the system has good environmental compatibility. The experiment is simple to operate, uses mild conditions, and the immobilized material is obtained from leather-making solid waste. The use of this immobilization system to treat waste oil in the leather-making process is of great significance for achieving clean and sustainable production in the leather industry. Full article

This study focuses on addressing the pressing challenge of reusing plastic in an eco-friendly manner. This research aimed to produce synthetic grease through an environmentally friendly pyrolysis technique, utilizing 69% predegraded low-density polyethylene (LDPE) combined with visible-light-working TiO₂ thin film, protein-coated TiO₂ NPs, and Lactobacillus plantarum bacteria in a batch reactor. The optimized conditions of temperature (500 °C) and heating time (2 h) resulted in the creation of 166 gm of partially degraded polyethylene grease 2 (PDPLG2) with National Lubricating Grease Institute (NLGI 2) grade consistency. PDPLG2 grease exhibits a wide-range dropping point of 280 °C and effectively maintains lubrication under high friction and stress loads, thereby preventing wear. Thermal analysis using TG and DSC validated the grease’s stability up to 280 °C, with minimal degradation beyond this point. Taguchi analysis using substance, sliding speed, and load as factors identified the ideal process parameters as aluminum, 1500 rpm, and 150 N, respectively. The present study revealed that sliding speed has the greatest impact, contributing 31.74% to the coefficient of friction (COF) and 11.28% to wear, followed by material and load. Comparative tribological analysis with commercially available grease (NLGI2) demonstrated that PDPLG2 grease outperforms NLGI2 grease. Overall, this innovative eco-friendly approach presents PDPLG2 as a promising alternative lubricant with improved anti-wear and friction properties, while also contributing significantly to plastic waste reduction. Full article

The increasing production of plastics, driven by modern societal development, has resulted in a significant rise in plastic waste, which poses serious environmental concerns due to its lengthy degradation times. The growing issue of single-use plastics (SUPs), such as packaging for food items and disposable utensils, has led to their reduction and potential future prohibition in the European Union. Cellulose, a natural biopolymer sourced from nature, has been proposed as a viable alternative to SUPs because it degrades without toxicity. However, its limited barrier properties against water and grease have restricted its effectiveness as a substitute. This study focuses on developing an environmentally friendly alternative to SUPs by combining cellulose with acetylated starch and incorporating inorganic fillers like kaolin and talc. These fillers enhance the material’s barrier properties and reduce production costs. The results indicate that the addition of kaolin significantly lowers moisture absorption and water vapor permeability, while a mixture of kaolin and talc provides superior grease resistance. Additionally, incorporating D-sorbitol as a plasticizer improves the mechanical properties of the coated sheets, preventing cracking and enhancing strength. Overall, these coatings offer a promising alternative for packaging applications, such as for sugar, candies, or chocolate. Full article

Coffee is one of the most consumed commodities globally, and its harvests generate large quantities of wood waste with low industrial value. This study aimed to explore the potential of residual Coffea arabica wood to produce lignocellulose microfibrils and lignocellulose nanofibrils (LCMF/LCNF) and biodegradable films with possible application in packaging. The fibers were treated with 5% NaOH and fibrillated in an ultrarefiner until they formed a gel. The resulting suspensions were used to create films whose physical, morphological, optical, and mechanical properties were analyzed. The NaOH treatment removed extractives and exposed hemicelluloses, allowing the gel point to be reached with just seven passes through the ultrarefiner, saving energy (~4700 kWh/t). More than 65% of the fibers had diameters of less than 100 nm and little sedimentation after 8 h. The films were flexible, thin (24.5 µm), with a high density (~1100 kg/m³) and good resistance to grease, as well as a water vapor permeability of ~1230 g/m²/day, suitable for packaging bread, fruit, and vegetables. However, the higher wettability of the surface may limit its use in humid environments. The films showed moderate tensile strength (~25 MPa) but low puncture resistance (~7 N mm), making them suitable for biodegradable packaging. Full article

As byproducts generated by commercial and domestic food-related processes, FOGs (fats, oils, and grease) are the leading cause of sewer pipe blockages in the US and around the world. Grease trap waste (GTW) is a subcategory of FOG currently disposed of as waste, resulting in an economic burden for GTW generators and handlers. This presents a global need for both resource conservation and carbon footprint reduction, particularly through increased waste upcycling. Therefore, it is critical to better understand current GTW handling practices in the context of the urban food–energy–water cycle. This can be accomplished with firsthand data collection, such as onsite visits, phone discussions, and targeted questionnaires. GTW disposal methods were found to be regional and correspond to key geographical locations, with landfill operations mostly practiced in the Midwest regions, incineration mainly in the Northeast and Mid-Atlantic regions, and digestion mainly in the West of the US. Select GTW samples were analyzed to evaluate their potential reuse as low-cost feedstocks for biodiesel or renewable diesel, which are alternatives to petroleum diesel fuels. Various GTW lipid extraction technologies have been reviewed, and more studies were found on converting GTW into biodiesel rather than renewable diesel. The challenges for these two pathways are the high sulfur content in biodiesel and the metal contents in renewable diesel, respectively. GTW lipid extraction technologies should overcome these issues while producing minimum-viable products with higher market values. Full article

The European Union’s energy policy favors increasing the share of renewable energy in total energy production. In this context, the co-digestion of various waste streams seems an interesting option. This study aimed to determine the effect of selected pretreatment methods on the efficiency and kinetics of the co-digestion process of poultry manure with sewage sludge and organic waste. This research was carried out in four stages: (1) the selection of the third component of the co-digestion mixture; (2) the determination of the most favorable inoculum-to-substrate ratio for the co-digestion mixture; (3) the selection of the most favorable pretreatment parameters based on changes in volatile fatty acids, ammonium nitrogen, extracellular polymers substances (EPS) and non-purgeable organic carbon (NPOC); and (4) the evaluation of anaerobic co-digestion based on the result of the BMP tests and kinetic studies. All the pretreatment methods increased the degree of organic matter liquefaction as measured by the NPOC changes. Waste with a high fat content showed the highest methane potential. The addition of grease trap sludge to feedstock increased methane yield from 320 mL/g VS_add to 340 mL/g VS_add. An optimal inoculum-to-substrate ratio was 2. The pretreatment methods, especially the thermochemical one with NaOH, increased the liquefaction of organic matter and the methane yield, which increased from 340 mL/g VS_add to 501 mL/g VS_add (trial with 4.5 g/L NaoH). Full article

Biobased greases are derived from renewable resources, are considered more environmentally friendly, and offer comparable performance to petroleum-based greases. In this study, lubricating greases from frying cooking oils were prepared, thus valorizing waste in order to obtain sustainable and environmentally friendly products. Twelve batches (500 g each) were produced from sunflower and palm frying oils, with 20% by weight calcium/lithium stearate soaps prepared in situ and filled with 15 wt.% cellulose or lignin sulfate. The greases were rheologically characterized. Their consistency was assessed by the penetration test performed before and after working the greases. Dropping point determinations offered information about the stability at higher temperatures, and oil bleeding tests were performed. The average values of the friction coefficient (COF), the contact resistance, and the wear scar diameter were measured through mechanical tests. The greases prove to be comparable to those obtained from mineral oils, with good rheological properties, soft consistency, and good antiwearing behavior, e.g., in open or total-loss lubricating systems, like in open gears and certain food processing machinery; they are thermally stable andprone touse in low-loading working mechanisms. Full article

The purpose of this study was to determine the origin, presence, and fate of the endocrine disruptor di-ethylhexil phthalate (DEHP) during tequila production. For this, three tequila factories (small, medium, and large) were monitored. DEHP concentrations in water, agave, additives, lubricating greases, neoprene seals, and materials of each stage process were analyzed using gas chromatography/mass spectrometry. DEHP mass balances were performed to identify the processes with significant changes in the inputs/outputs. DEHP was detected in agave at up to 0.08 ± 0.03 mg kg⁻¹, water 0.02 ± 0.01 mg kg⁻¹, lubricant greases 131.05 ± 2.80 mg kg⁻¹, and neoprene seals 369.11 ± 22.52 mg kg⁻¹. Whereas, tequila produced in the large, medium, and small factories contained 0.05 ± 0.01, 0.24 ± 0.04, and 1.43 ± 0.48 mg kg⁻¹ DEHP, respectively. Furthermore, in waste materials (vinasses and bagasse) released, 534.26 ± 349.02, 947.18 ± 65.84, and 5222.60 ± 2836.94 mg of DEHP was detected for every 1000 L of tequila produced. The most significant increase in DEHP occurred during the sugar extraction and distillation stages. Results demonstrate that main raw materials, such as agave and water, contain DEHP, but lubricant greases and neoprene seals are the major sources of DEHP contamination. Identification of the contamination sources can help the tequila industry to take actions to reduce it, protect consumer health and the environment, and prevent circular contamination. Full article

Thickener, also known as a gelling agent, is a critical component of lubricating greases. The most critical property of thickener, temperature resistance, is determined by the molecular structure of the compounds. Currently, all high-temperature-resistant thickeners are based on 12-hydroxystearic acid, which is exclusively produced from castor oil. Since castor oil is also an important reagent for other processes, finding a sustainable alternative to 12-hydroxystearic acid has significant economic implications. This study synthesises an alternative thickener from abundant agricultural waste, cashew nut shell liquor (CNSL). The synthesis and separation procedure contains three steps: (i) forming and separating calcium anacardate by precipitation, (ii) forming and separating anacardic acid (iii) forming lithium anacardate. The obtained lithium anacardate can be used as a thickener for lubricating grease. It was found that the recovery of anacardic acid was around 80%. The optimal reaction temperature and time conditions for lithium anacardate were 100 °C and 1 h, respectively. The method provides an economical alternative to castor and other vegetable oils. The procedure presents a simple pathway to produce the precursor for the lubricating grease from agricultural waste. The first reaction step can be combined with the existing distillation of cashew nut shell processing. An effective application can promote CNSL to a sustainable feedstock for green chemistry. The process can also be combined with recycled lithium from the spent batteries to improve the sustainability of the battery industry. Full article

The effects of rapid industrialization created an enormous burden on the environment. The quality of the water source is drastically affected by the discharge coming from industry and domestic usage. Nowadays, the treatment of wastewater involves the use of chemicals, and powder-activated carbon made from agricultural waste is commonly used. This study used corn cob wastes activated with sodium chloride in a 1:2.5 ratio and utilized a microwave. The percent adsorption for powder-activated carbon (PAC) from corn cobs with microwave heating reached 93% removal of oil and grease for a 10 g dosage, while 87% was reached for powder-activated carbon without microwave heating. Freundlich and Langmuir isotherms both represent the behavior of PAC, and the breakthrough time decreased as the flow rate of contaminants increased in the continuous flow system. The characteristics of powder-activated corn cobs contained a lot of grooves, crevices, and cracks, and the macropores deep inside the surface were highly developed, which is typical for an activated carbon that facilitates an effective adsorption process. The pore volume was found to be 1.3 cm³/g for PAC with microwave heating and 1.5 cm³/g for that without microwave heating. The pore volume determined the adsorption capacity of PAC from corn cobs. Full article

The established classical method of treating oil refinery effluent is flotation followed by biological treatment. Membrane bioreactors (MBRs) offer more advanced treatment, producing a clarified and potentially reusable treated effluent, but demand robust pretreatment to remove oil and grease (O&G) down to consistent, reliably low levels. An analysis of a full-scale conventional oil refinery ETP (effluent treatment plant) based on flotation alone, coupled with projected performance, energy consumption and costs associated with a downstream MBR, have demonstrated satisfactory performance of flotation-based pretreatment. The flotation processes, comprising an API (American Petroleum Institute) separator followed by dissolved air flotation (DAF), provided ~90% removal of both total suspended solids (TSS) and O&G coupled with 75% COD (chemical oxygen demand) removal. The relative energy consumption and cost of the pretreatment, normalised against both the volume treated and COD removed, was considerably less for the API-DAF sequence compared to the MBR. The combined flotation specific energy consumption in kWh was found to be almost an order of magnitude lower than for the MBR (0.091 vs. 0.86 kWh per m³ effluent treated), and the total cost (in terms of the net present value) around one sixth that of the MBR. However, the nature of the respective waste streams generated and the end disposal of waste solids differ significantly between the pretreatment and MBR stages. Full article

An increase in energy consumption and the extended use of nonrenewable fossil fuels raises the need to develop alternative fuels as an energy supply that can protect the environment from unwanted emissions of pollutants. One alternative renewable fuel is biodiesel. Currently, most biodiesel feed sources are edible oils, but using them leads to the dilution of global food sources. The present study aims to find an effective method of biodiesel production using food industry fatty wastes called brown grease (BG). BG contains fats, mainly linoleic and oleic free fatty acids (FFAs), that can serve as raw materials for biodiesel production using esterification reactions. The esterification and transesterification reactions for biodiesel production were studied using commercial FFAs, commercial glyceryl trilinoleate (trilinolein), soybean oil, and BG. The reactions were carried out under ultrasonic activation using BF₃ and AlCl₃ Lewis acids as catalysts in both free and immobilized forms when immobilization was performed in silica matrices using the sol-gel synthesis route. Biodiesel production was examined in batch and continuous flow reactors. The BF₃ catalyst was more efficient at the initial stages of the continuous operation, reaching a maximum conversion of 90%, with a gradual decrease in efficiency after 15 h of the process. The AlCl₃ catalyst showed better stability, reaching maximum yields of 97% and maintaining efficiency until the end of the experiment. The proposed method offers an efficient and easy way to produce biodiesel from a variety of lipids sources, including fatty wastes (BG). Full article