Enhancing sustainability in phosphate ore processing:Performance of frying oil as alternative flotation collector for carbonate removal

Recycling waste frying oils for the synthesis of flotation reagents presents a promising avenue for sustainable waste management.Moreover,it offers a cost-effective solution for crafting a specialized collector designed to efficiently remove carbonates and enhance phosphate enrichment in froth flotation processes.This study focuses on the synthesis of an anionic collector using the saponification reaction of a frying oil sample,subsequently applied to the flotation of calcite and dolomite.To elucidate the adsorption mechanisms of the frying oil collector(FrOC)and sodium oleate,a reference collector,on fluorapatite,calcite,dolomite,and quartz surfaces,comprehensive experiments were conducted,including zeta potential measurements and Fourier transform infrared spectroscopy.Results revealed diverse adsorption affinities of the molecules towards these minerals.To assess the practical performance of the collector,flotation tests were conducted using a natural phosphate ore mixture,employing a BoxBehnken experimental design.Notably,under optimized conditions(pH 9,1000 g/t of FrOC,3.5 min of conditioning,and 6 min of flotation),FrOC exhibited excellent performance,with calcite and dolomite recoveries exceeding 80%,while apatite recovery in the concentrate fraction remained below 10%.This work exemplifies both circular economy practices and the distinctive approach to sustainable mineral processing.

Plant phenolic extracts for the quality protection of frying oil during deep frying:Sources,effects,and mechanisms

Protection of frying oil from deterioration by adding plant phenolic extracts to guarantee the quality of fried foods becomes the primary approach to promote the sustainable development of deep frying.Therefore,sources,antioxidant effects,and mechanisms of plant phenolic extracts recently applied in the quality protection of frying oil as well as challenges for the actual use of these extracts are comprehensively reviewed in this study.Spices,herbs,berries,tea leaves,and fruit and vegetable wastes are common sources for preparing phenolic extracts showing comparative antioxidant capacity referring to the synthetic antioxidants.The general effect of using these natural antioxidants is the improvement of thermal stability to extend the shelf life of frying oil and thus the modification of edible quality of fried foods.Specifically,the increases in common quality attributes and amount of hazardous products and the oxidative reduction of unsaturated triacylglycerols without negatively influencing the sensory quality are inhibited when suitable plant extracts are applied.The incorporation of plant phenolic extracts other than synthetic counterparts in frying oil has been demonstrated as a potential method to improve the frying performance of oils.However,challenges for the scale application of plant phenolic extracts,such as the purity,thermal stability,and antioxidant timing,are still needed to be further investigated.

Combined Effect of a Catalytic Reduction Device with Waste Frying Oil-Based Biodiesel on NOx Emissions of Diesel Engines

Internal combustion engines with application in automobiles and other relevant industries constitute significant environmental pollution via the release of toxic exhaust gasses like carbon monoxide (CO), hydrocarbons (HC), particulate matter (PM), and nitrogen oxide (NOx). Engine researchers and manufacturers are challenged to develop external and internal measures to ensure environmentally friendly solutions to accommodate and conform to the growing list of emission standards. Therefore, this work presents an experimental investigation of the NOx emission profile of a diesel engine that is fuelled and fitted with waste frying oil-based biodiesel and catalytic converter. Using a single-cylinder, four-stroke air-cooled CI engine at a constant speed of 1900 rpm and different loadings of 25%, 50%, 75%, and 100%;fitted with a catalytic converter at the exhaust outlet of the engine and linked to a dynamometer and a gas analyser, an experiment was conducted at biodiesel/diesel volume blends of B0 (0/10), B5 (5/95), B20 (20/80), B30 (30/70), B70 (70/30), B100 (100/0);and 30% concentration (v/v), 0.5 litre/hr flow rate of aqueous urea from the catalytic converter. The results show an increasing NOx emission as the biodiesel component increased in the blend. The catalytic converter showed a downward NOx reduction with a significant 68% reduction in efficiency at high exhaust gas temperatures. It is concluded that the combined utilisation of waste frying oil-based biodiesel and the catalytic converter yields substantial NOx emission reduction.

Application of waste frying oils in the biosynthesis of biodemulsifier by a demulsifying strain Alcaligenes sp.S-XJ-1

Exploration of biodemulsifiers has become a new research aspect.Using waste frying oils（WFOs） as carbon source to synthesize biodemulsifiers has a potential prospect to decrease production cost and to improve the application of biodemulsifiers in the oilfield.In this study,a demulsifying strain,Alcaligenes sp.S-XJ-1,was investigated to synthesize a biodemulsifier using waste frying oils as carbon source.It was found that the increase of initial pH of culture medium could increase the biodemulsifier yield but decrease the demulsification ratio compared to that using paraffin as carbon source.In addition,a biodemulsifier produced by waste frying oils and paraffin as mixed carbon source had a lower demulsification capability compared with that produced by paraffin or waste frying oil as sole carbon source.Fed-batch fermentation of biodemulsifier using waste frying oils as supplementary carbon source was found to be a suitable method.Mechanism of waste frying oils utilization was studied by using tripalmitin,olein and tristearin as sole carbon sources to synthesize biodemulsifier.The results showed saturated long-chain fatty acid was diffcult for S-XJ-1 to utilize but could effectively enhance the demulsification ability of the produced biodemulsifier.Moreover,FT-IR result showed that the demulsification capability of biodemulsifiers was associated with the content of C=O group and nitrogen element.

Biodiesel production from waste frying oil in sub- and supercritical methanol on a zeolite Y solid acid catalyst

Waste frying oil （WFO） is a very important feedstock for obtaining biodiesel at low cost and using WFO in transesterification reactions to produce biodiesel helps eliminate local environmental problems. In this study biodiesel was produced from WFO in sub- and super- critical methanol on a zeolite Y solid acid catalyst. The procedure was optimized using a design of experiments by varying the methanol to WFO molar ratio, the reaction temperature, and the amount of catalyst. Typical biodiesel yields varied from 83 to nearly 100% with methyl esters content ranging from 1.41-1.66mol.L-~ and typical dynamic viscosities of 22.1-8.2 cE Gas chromatography was used to determine the molecular composition of the biodiesel. The reaction products contained over 82 wt-% methyl esters, 4.2 wt-% free acids, 13.5 wt-% monoglycer- ides, and 0.3 wt-% diglycerides. The transesterification of WFO with methanol around its critical temperature combined with a zeolite Y as an acid catalyst is an efficient approach for the production of biodiesel with acceptable yields.

Capacitive sensor probe to assess frying oil degradation

The repeated usage of frying oil has been proven hazardous due to the degradation process by chemical reactions that lead to changes in the quality of the oil.Currently,the degree of frying oil degradation is indicated by the percentage of its total polar compounds(TPC).In this study,a capacitive sensor was designed to assess frying oil degradation at several heating time intervals by measuring changes on its electrical capacitance.The sensor was designed using interdigitated electrode structure.A total of 30 samples of 130 ml palm oil were heated at 180℃ up to 30 h.For each one hour interval,one sample was moved out from the laboratory oven.The electrical capacitance,total polar compound(TPC)and viscosity of the samples were measured for analysis.Preliminary results demonstrated significant correlation between oil electrical capacitance with TPC and viscosity with R^2 ranged from 0.83 to 0.90.The designed sensor has good potential for simple and inexpensive way of determining frying oil quality.

Theoretical, Simulation and Experimental Analysis of Microfluidic Droplet Generation and Recovering Process with Applications in Frying Oil Assessments

The research on microfluidic droplet size prediction has been extensive and fruitful, while the droplet deforming process has been seldom studied. In this paper, a frying-oil-assessing microfluidic device was designed to study the droplet deforming and recovering processes, which were dominated by channel geometry, flow rates,sheath flow viscosity and interfacial tension of the two phases. Theoretical expressions of the deforming process and its extreme value were obtained for the first time, supported by simulation and experiments. Theoretical,simulation and experimental results indicated that the steady-state droplet length could be a useful parameter for frying oil assessment.

A novel method for the green utilization of waste fried oil

Waste fried oil was studied to prepare three different types of detergent such as soap,liquid soap and soap powder via saponification process.The preparation conditions of soap base were optimized by orthogonal experiment.The specific preparation processes included waste fried oil treatment,orange peel extract preparation,saponification,demoulding and drying.Results showed that the optimal con-ditions for saponification were as follows:ratio of pure waste fried oil to coconut oil=6∶4,alkali liquor(NaOH)mass fraction 30%,saponification temperature 70℃,orange peel extract concentration 15%.The mature soap was then used to make liquid soap and soap powder by surfactant(sodium dodecylbenzene sulfonate,coconut diethanol amide)addition,followed by grinding.The prepared detergent conforms to the production standard of strong decontamination ability,possesses stable performance,is gentle to skin and non-toxic.