Orange Peel Waste Research Articles

The influence of organic pollutant load and external resistance on the performance of a solid phase microbial fuel cell fed orange peel wastes

AbstractThe degradation of organic matter in marine sediments could be taken advantage of to produce electricity by using a sediment microbial fuel cell (SMFC) inspired system. A single solid phase microbial fuel cell (SPMFC) in which orange peel wastes were supplemented as a carbon source mixed to marine sediments produced a power of 0.33 mW and a voltage of 0.7 V. By stacking multiple SPMFCs powers of 2.08 mW were generated for a voltage of 4.6 V. The use of dewatered sludge to inoculate the marine sediment improved the SPMFCs' performance. The removal of organic matter in the SPMFC system under closed circuit conditions was very interesting, removal rates were 19%–40% from readily oxidizable organic matter,15 to 35% for loss on ignition and 22%–55% for total organic carbon, indicating the possibility of using these systems to treat solid organic wastes and produce electricity at the same time.

Application of Zn–Fe layered double hydroxide and its composites with biochar and carbon nanotubes to the adsorption of lead in a batch system: kinetics and isotherms

The adsorption of Pb2+ onto zinc–iron layered double hydroxide (ZnFe–LDH) and its composites coupled with single-walled carbon nanotubes (ZnFe–CNTs) and biochar, which had been obtained from orange peel waste biomass (ZnFe–OPb), was studied in detail. The successful formations of Zn2+- and Fe3+-LDH were investigated by scanning electron microscopy. Moreover, energy-dispersive X-ray spectroscopy revealed that Pb2+ was adsorbed successfully on ZnFe-LDH. Further, both ZnFe-LDH and ZnFe–CNTs exhibited ~ 60% removal efficiencies for Pb2+ at 20 mgL–1 with rapid adsorption at an initial contact time of 30 min, while the equilibrium was achieved at ~ 60 min with a 95% removal efficiency with ZnFe–OPb. Furthermore, the pseudo-second-order kinetics demonstrated the best fit, thus supporting the chemisorption essence of the adsorption mechanism. ZnFe–OPb demonstrated a twofold increase in the adsorption efficiency compared with simple LDH or ZnFe–CNTs, as the initial Pb2+ concentration was enhanced from 10 to 100 mgL–1. The percentage removal and adsorption capacity increased almost linearly as the pH of the solution changed from 2 to 5, suggesting that the optimum pH value was approximately 5 or 6 for all adsorbents. The percentage removal of Pb2+ also increased on increasing the dose. Additionally, the optimum removal efficiency of 99% was obtained with 0.7 g of ZnFe–OPb. The Langmuir model corresponds best with the adsorption data, while the Sips isotherm indicated that ZnFe-LDH exhibited the highest degree of heterogeneity compared with the other adsorbents in this study.

Removal of heavy metals from aqueous solutions using carbonised banana and orange peels

This research demonstrates the feasibility and efficacy of removing heavy metals from aqueous solutions using waste banana and orange peels. The fruit peels are carbonised, without the addition of chemical substances, to enhance their adsorption capacities. The adsorption capacities are studied in aquatic solutions containing individual and combined metal ions of hexavalent chromium (Cr6+), copper (Cu) and zinc (Zn). The selectivity of the adsorbents towards these metal ions is also exhibited. The results show that both fruit peels exhibit a better selectivity towards zinc ions, followed by copper and then hexavalent chromium. The effects of operational conditions, including pH, adsorbent dosage, contact time and concentration of metal ions, on the removal efficiency and uptake capacity of the carbonised fruit peels are investigated. The optimal adsorption for both adsorbents occurs within 30 min of exposure and at an adsorbent dose of 0.5 g. Additionally, the adsorption kinetics and isotherms, including pseudo-second-order, Langmuir and Freundlich, are modelled for the obtained data.

Assessing Green Methods for Pectin Extraction from Waste Orange Peels.

In this work, we assess three different methods for the extraction of pectin from waste orange peels, using water as extracting solvent. “Hot-water”, Rapid Solid Liquid Dynamic (RSLD) and microwave-assisted extractions have been compared and evaluated in terms of amount and quality of extracted pectin, as well as embodied energy. This analysis provides useful guidelines for pectin production from food waste according to green procedures, enabling the identification of acidic “hot-water” as the most sustainable extraction route.

Uncatalyzed and acid-aided microwave hydrothermal carbonization of orange peel waste

Orange, one of the most important fruit categories to be consumed across the world, when processed produces 50% of its weight as waste. Current waste management options for orange peel waste are inadequate to use the waste in wholesome and its disposal might lead to other environmental concerns. Here, we present microwave hydrothermal carbonization as an alternative to utilize the orange peel waste. Further, using citric acid to catalyze the microwave hydrothermal carbonization resulted in 30% higher maximal yield of hydrochar, and the hydrochar produced had better elemental, proximate and energy properties than hydrochar made during uncatalyzed microwave hydrothermal carbonization. Further, structural analysis revealed that citric acid promoted the formation of nanospheres during microwave hydrothermal carbonization. Taken together, microwave hydrothermal carbonization of orange peel waste using citric acid as a catalyst might not only help address the waste management concerns for orange peel waste, but also can produce end products of potential commercial value.

Characterization of Orange Peel Waste and Valorization to Obtain Reducing Sugars.

Annually, millions of tons of foods are generated with the purpose to feed the growing world population. One particular eatable is orange, the production of which in 2018 was 75.54 Mt. One way to valorize the orange residue is to produce bioethanol by fermenting the reducing sugars generated from orange peel. Hence, the objective of the present work was to determine the experimental conditions to obtain the maximum yield of reducing sugars from orange peel using a diluted acid hydrolysis process. A proximate and chemical analysis of the orange peel were conducted. For the hydrolysis, two factorial designs were prepared to measure the glucose and fructose concentration with the 3,5-DNS acid method and UV-Visible spectroscopy. The factors were acid concentration, temperature and hydrolysis time. After the hydrolysis, the orange peel samples were subjected to an elemental SEM-EDS analysis. The results for the orange peel were 73.530% of moisture, 99.261% of volatiles, 0.052% of ash, 0.687% of fixed carbon, 19.801% of lignin, 69.096% of cellulose and 9.015% of hemicellulose. The highest concentration of glucose and fructose were 24.585 and 9.709 g/L, respectively. The results highlight that sugar production is increased by decreasing the acid concentration.

Carbon dots: Discovery, structure, fluorescent properties, and applications

Abstract Nanotechnology has become one of the most important topics since the beginning of the twenty-first century in numerous fields including drug synthesis and delivery, environmental protection, electronics manufacture, and astronomy due to their nanoscale particles and their properties. The traditional semi-quantum dots are replaced by a new category of fluorescent carbon nanomaterials. Carbon dots (CDs) have been explored in the last few years for their simple synthetic accession, good bio-consonance, and several revelation applications. This review explains the fluorescent properties of CDs in brief, giving also a background on CDs discovery, structure, and composition, as well as on nanocomposites, green synthesis, and their applications. Resources conservation can be achieved by using recycled substances for sustainable development which lead to a new technology. Fluorescent CDs synthesized from food wastes like bananas, orange peel waste, sugarcane bagasse, Trapa bispinosa peels, bread, and jaggery have several applications such as sensing, drug delivery, gene transfer, biological imaging, and food safety. In this study, we concentrate on CDs greener methods to prepare effective and biocompatible CDs.

Semi-Pilot scale extraction of pectin from orange peel waste and evaluating its quantitative and qualitative features

Background and objective: Pectin as a natural polysaccharide possesses a wide spectrum of functional properties. It can act as a thickener, gelling agent, stabilizer, emulsifier, cation-binding agent, etc. These properties make pectin as a biopolymer valuable especially for medicine and food production. All of the pectin needed in food, medicine and cosmetic industries is supplied abroad while there is a good potential for production of this valuable substance from waste of beverage industries. In addition, the production of the pectin is simple and low cost and its added value is high. Pectin production was done only in laboratory scale and has not been industrialized. Therefore, the aim of this research was to optimize the pectin extraction from orange juice waste in the laboratory scale and then, scaling up to semi- pilot extraction. Designing and constructing the production line of Semi-pilot scale extraction of pectin from orange peel was done for the first time in Iran, to can finally, evaluate the possibility of industrialization and localization of the pectin. Materials and methods: In the first, the effect of pH (1.5-3), time of extraction (1-4 h) and S/L ratio (1:10- 1:30 g/mL) were optimized singularly and then, semi-pilot production of pectin at the optimized condition, which was obtained at the laboratory scale, was done. Two filtration methods (filter press and centrifuge) were used to to separate impurities. The yield, DE and galacturonic acid content of the extracted pectins in the semi- pilot scale were compared to the laboratory one. Results: The results indicated that all the parameters had significant effect (p≤0.05) on the yield of the extracted pectin. Increasing the pH from 1.5 to 2 increased the yield and the highest yield was obtained at pH of 2 (14.87 g/100 g d.m.) and by increasing pH from 2 to 3, the yield was decreased (6.65 g/100 g d.m). Increasing the time of extraction up to 3 h, enhaned the yield significantly but then, it was remain constant. By increasing the S/L ratio from 1:10 to 1:15, the yield was increased from 16.55 to 18.84 g/100 g d.m. and after that the yield was decreased. Designing the pectin production line was done and semi- pilot extraction was done at the optimized conditions (pH of 2, S/L ratio of 1:15 and time of 3 h). The yield of extracted pectin in the semi- pilot scale (which filter press employed instead of centrifuge) was more than that obtained at the laboratory scale althogh its galacturonic acid content was lower than that obtained at semi- pilot scale. When centrifuge was employed, the extracted pectin at the semi- pilot scale was comparable with laboratory one, indicating its high purity. Conclusion: Results indicated that the yield and quality properties of the pectin extracted at the semi-pilot extraction, which centrifuge was employed (instead of filter press), were similar to the pectin extracted at the laboratory scale and therefore, producting the pectin with high yield and quality at the semi-pilot scale is possible.

Continuous and pulsed ultrasound pectin extraction from navel orange peels

Pectin is a valuable product (up to 30 $kg−1) that makes-up 20–30% of an orange’s peel. The commercial extraction is lengthy (up to 6h) and energy intensive as it requires heating aqueous solutions (60–100 °C). Ultrasound speeds up the extraction process reducing processing time by macroscopic and microscopic mixing by acoustic cavitation. We adopted an ultrasonic horn to deliver a rated power of 500W at amplitudes of 20%, 40%, and 60% with and without pulsation to extract pectin from waste orange peels. These correspond to power densities of 0.08Wml−1, 0.16Wml−1 and 0.24Wml−1, respectively. The extractions operated at a pH of either 2 or 3. The experimental data agree with the fitted values from the statistical model (R2=95.5%). The model confirms our predictions that yield increases with amplitude/power density and decreasing pH. The highest yield was (11%) at a pH of 2 and with continuous ultrasonic irradiation at a power density of 0.24Wml−1. There is only a 1.3% difference between this datum and pulse ultrasound mode (1 s on/1 s off) at the same conditions — a Student’s t test confirmed that there was no significant difference in yield between continuous and pulse mode. However, pulsing is more efficient in that it consumes less than half the energy of continuous operation (80kJ vs. 190kJ).

A Review on Bioethanol Production from the Orange Peel Waste (OPW) Using Cellulolytic Soil Bacteria

To avoid economic impact and environmental effect of agricultural waste, the reuse of the agricultural waste is needed. For this purpose, the naturally available cheap soil microorganisms with potential application can be used. Many soil microbes have cellulase enzyme which can act on lignocellulosic waste material. The current research on producing bioethanol are aimed to reduce the production cost using low-cost substrates and enzymes. In line with this, in this study the orange peel waste will be used to produce bioethanol using the soil isolated microorganisms in the cost-effective way.

A comprehensive approach for biorefineries design based on experimental data, conceptual and optimization methodologies: The orange peel waste case

The aim of this work was to propose a comprehensive methodological approach integrating two of the most applied approaches to design biorefineries based on experimental data: conceptual design and optimization. The proposed methodology involves three critical aspects i) experimental procedures, ii) simulation approach, and iii) optimization tools. The proposed approach was applied to a specific case as an example. The orange peel waste (OPW) was studied as raw material to feed the biorefinery with the purpose of valorizing the residues produced by the orange juice factories in the Colombian context. After implementing the methodology, the results show how essential oil and biogas were the most profitable and reliable products to be obtained through the processing of OPW.In this case, it is demonstrated also, that the understanding of the biorefinery possibilities is higher when this design methodology is applied.

Integral valorization of orange peel waste through optimized ensiling: Lactic acid and bioethanol production

The management of the huge amount of orange peel waste (OPW) is a complex issue although it has a very high potential in terms of biorefining. One of the main problems in the valorisation of OPW is the seasonality of its production with the ensiling method being largely proposed as a possible solution. During the ensiling process, value added chemicals including lactic acid, acetic acid and ethanol are spontaneously produced together with a significant loss of volatile solids (VS) . In this contribution, the stimulation of lactic acid bacteria by either a biological (inoculation with leachate coming from a previous ensiling process) or chemical (MnCl2 supplementation) methods has been tested with the aim to increase the chemicals production preventing, at the same time, the VS loss. The inoculation with the leachate improves both the VS recovery (+7%) and the concentration of lactic acid (+113%) with respect to the uninoculated one (control). The overall yields of the process are noticeable, up to about 55 g·kgTS−1 of lactic acid, 26 g·kgTS−1 of acetic acid and 120 g g·kgTS-1 of ethanol have been produced. On the other hand, the chemical stimulation enhances the production of liquid products together with a significant VS loss. The proposed preservation method, due to its simplicity, can be easily implemented at full-scale allowing the production of added-value chemicals and the concurrent storage of the OPW that can be further valorised (e.g. animal feed, pectin or biomethane production).

Greener synthesis and characterization of cadmium-tellurium quantum dots using aqueous extract of waste orange peel

Cadmium-Tellurium quantum dots are inorganic semiconductor material. In the present study, highly stable Cadmium-Tellurium (CdTe) quantum dots with good optical properties were successfully synthesized by using waste orange peel extract. Fourier-transform infrared spectroscopy (FTIR) identified the presence of hydroxyl, carboxyl and amine groups. Multifunctional X-ray Photoelectron Spectroscopy (XPS) confirmed the presence of cadmium and tellurium. The average size of the quantum dots was found to be 6nm using Transmission Electron Microscopy (TEM). The cubic zinc blende type crystalline structure of quantum dots was confirmed by X-ray powder diffraction (XRD). Thermal stability was studied using thermo-gravimetric analysis (TGA). The influence of temperature with respect to mass change of 8% was observed at 200C. The high luminescence property exhibits at the wavelength of 502 nm were investigated using photoluminescence analysis (PL) and the blue shift is confirmed by UV-Visible spectroscopy.

Sustainable electrode material for high-energy supercapacitor: biomass-derived graphene-like porous carbon with three-dimensional hierarchically ordered ion highways.

Biomass-derived carbonaceous materials have been deemed to be one of the up-and-coming electrode materials for high-performance energy storage systems due to their cost-neutral abundant resources, sustainable nature, easy synthesis methods, and environmentally benign features. In this work, various graphene-like porous carbon networks (GPCs) with three-dimensional (3D) hierarchically ordered "ion highways" have been synthesized by the carbonization/activation of orange-peel wastes for use as an electrode material in high-energy supercapacitors. The porous structures and surface morphologies of the GPCs were rationally fine-tuned as a function of the activation agent ratio. The prepared GPCs offered superior specific surface area in addition to a 3D porous structure with a fine-tuned pore size distribution. The electrochemical behaviors of all the GPCs were evaluated in 6.0 M KOH aqueous electrolyte via a three-electrode electrochemical setup. Owing to their synergistic characteristics, including superior specific surface area (1150 m2 g-1), large pore volume, and fine-tuned 3D porous architecture, GPC-3.0 (synthesized with a KOH : GPC ratio of 3.0, by wt.) exhibited the best capacitive behavior amongst the studied GPCs. The 3D hierarchically ordered architecture acts like well-designed ion highways that boost electron transportation, thereby enhancing electrochemical energy storage. A coin-cell-type symmetrical supercapacitor based on GPC-3.0 was tested in both 1.0 M Na2SO4 (salt-in-water) and 12.0 m NaNO3 (water-in-salt) electrolytes. The supercapacitor cell based on the water-in-salt electrolyte offered a wide operating voltage of 2.3 V. The obtained energy density and power density values were comparable to those of commercial high-performance electrical double-layer capacitors. Such notable findings will shed light on next-generation high-rate electrochemical energy storage systems based on biomass-derived carbonaceous materials.

Adsorption Performance of La(III) and Y(III) on Orange Peel: Impact of Experimental Variables, Isotherms, and Kinetics

To alleviate the environmental problem associated with rare earth wastewater, this research applied waste orange peel (OP) for the adsorption of La(III) and Y(III) from aqueous solution. The adsorption properties of orange peel are characterized using scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), and the participation of hydroxyl and other oxygen-containing groups that promote the physical-chemical interaction is verified. Batch adsorption results suggest that orange peel possesses a satisfactory adsorption performance for La(III) and Y(III). The optimal adsorption conditions were obtained at pH of 6, temperature of 40°C, appropriate dosage of 2 g/L and 3 g/L, contact time of 30 min, and initial ion concentration of 32 mg/L. Under the same condition, adsorption performance of La(III) is better than that of Y(III). The experimental data is well fitted by the Langmuir isotherm model with [Formula: see text] and the minimum standard error values. Equilibrium results show that Langmuir monolayer adsorption capacity of La(III) and Y(III) onto orange peel is up to 37.61 and 31.10 mg/g. The fitting results of kinetics prove that the adsorption process of La(III) and Y(III) follows the pseudosecond-order model. Thus, natural orange peel as a recyclable biosorbent has potential economic and applicative benefits to remove La(III) and Y(III) from aqueous solutions.

A simple procedure to obtain a medium-size oligogalacturonic acids fraction from orange peel and apple pomace wastes

Pectin oligosaccharides, which can be obtained from fruit wastes, have proven their potential as plant immune-system elicitors. Although the precise size of active species is still under investigation, medium size oligosaccharides have been reported as the most active. Three defined oligogalacturonic acid (OGAs) mixtures were produced from commercial pectin, orange peel and apple pomace residues. The methodology developed involves two sequential acid treatments followed by stepwise ethanol precipitation. Without the need of chromatographic separations, three different fractions were obtained. The fractions were analyzed by high performance anion exchange chromatography (HPAEC) and were completely characterized by mass spectrometry, showing that the small size, medium size and large size fractions contained OGAs of degree of polymerization 3 to 9, 6 to 18, and 16 to 55, respectively.

Glycolysis of Poly(Ethylene Terephthalate) Using Biomass-Waste Derived Recyclable Heterogeneous Catalyst.

Plastic production has increased by almost 200-fold annually from 2 million metric tons per year in 1950s to 359 million metric tons in 2018. With this rapidly increasing production, plastic pollution has become one of the most demanding environmental issues and tremendous efforts have been initiated by the research community for its disposal. In this present study, we reported for the first time, a biomass-waste-derived heterogeneous catalyst prepared from waste orange peel for the depolymerisation of poly(ethylene terephthalate) (PET) to its monomer, bis(2-hydroxyethyl terephthalate) (BHET). The prepared orange peel ash (OPA) catalyst was well-characterised using techniques such as IR, inductively coupled plasma (ICP)-OES (Optical Emission Spectrometry), XRD, X-ray fluorescence (XRF), SEM, energy-dispersive X-ray spectroscopy (EDX), TEM, BET (Brunauer-Emmett-Teller) and TGA. The catalyst was found to be composed of basic sites, high surface area, and a notable type-IV N2 adsorption–desorption isotherm indicating the mesoporous nature of the catalyst, which might have eventually enhanced the rate of the reaction as well as the yield of the product. The catalyst completely depolymerises PET within 90 min, producing 79% of recrystallised BHET. The ability of reusing the catalysts for 5 consecutive runs without significant depreciation in the catalytic activity and its eco- and environmental-friendliness endorses this protocol as a greener route for PET recycling.

The impact of pyrolysis conditions on orange peel biochar physicochemical properties for sandy soil.

The citrus industry is considered one of the main contributors to agricultural waste. Peels are commonly used in the food industry or as feedstock in biorefining. In this study, the potential of waste orange peel biochar for agricultural applications in sandy soil was investigated. This will not only increase the percentage of agricultural waste recycling, but also lead to more sustainable agriculture with environmental benefits such as carbon sequestration. Biochar was produced through slow pyrolysis in the temperature range 300-600°C and at two holding durations (10 min and 60 min). Both factors had a significant impact on the physicochemical characteristics of biochar in the heating region 300-450°C. However, varying the holding time for pyrolysis temperatures beyond 450°C had a diminishing effect on biochar properties compared with the impact of increasing pyrolysis temperature. The study also looked at certain properties that are specific to agricultural application not previously reported for orange peel. Very high cation exchange capacities of 70 cmol kg-1 were achieved at 300°C, whereas water holding capacity was not strongly influenced by pyrolysis conditions. Preliminary planting tests indicate potential for improving agricultural sustainability in sandy soils. The technoeconomic analysis of biochar showed that the pyrolysis process can be profitable with sufficient plant capacity.

Natural deep eutectic solvent as a unique solvent for valorisation of orange peel waste by the integrated biorefinery approach

This research investigates the use of seven natural deep eutectic solvents (NADESs) for valorisation of orange peel waste, with the final goal to propose a unique NADES for integrated biorefinery. Initial screening of NADESs revealed the excellent ability of cholinium-based NADES with ethylene glycol as hydrogen bond donor (ChEg50) to serve as a medium for orange peel-catalysed kinetic resolution (hydrolysis) of (R,S)-1-phenylethyl acetate with high enantioselectivity (ee = 83.2%, X = 35%), as well as it’s stabilizing effect on the hydrolytic enzymes (hydrolytic enzymes within ChEg50 peel extract were stabile during 20 days at 4 °C). The ChEg50 also showed a satisfactory capacity to extract D-limonene (0.5 mg gFW−1), and excellent capacity to extract polyphenols (45.7 mg gFW−1), and proteins (7.7 mg gFW−1) from the peel. Based on the obtained results, the integrated biorefinery of orange peel waste using ChEg50 in a multistep process was performed. Firstly, enantioselective kinetic resolution was performed (step I; ee = 83.2%, X = 35%), followed by isolation of the product 1-phenylethanol (step II; h = 82.2%) and extraction of polyphenols (step III; h = 86.8%) from impoverished medium. Finally, the residual orange peel was analysed for sugar and lignin content, and results revealed the potential of waste peel for the anaerobic co-digestion process. The main bottlenecks and futures perspective of NADES-assisted integrated biorefinery of orange peel waste were outlined through SWOT analysis.

Effects of tray drying, vacuum infrared drying, and vacuum microwave drying techniques on quality characteristics and aroma profile of orange peels

AbstractThis study aimed to dry orange peels using tray drying (TD), vacuum infrared drying (VID), and vacuum microwave drying (VMD) techniques and to investigate the effects of different drying techniques on the drying kinetics, physical, chemical characteristics, and volatile compounds. The VMD raised the drying rate and the effective water diffusivity compared to the TD and the VID. It was detected that the TD, VID, and VMD at 50°C required 300, 106, and 20.67 min, respectively. The VMD showed the highest vitamin C, total phenolic substance, total carotenoid content, whereas the TD indicated the lowest color values. A total of 63 volatile compounds which consist of 16 aldehydes and ketones, 4 esters, 34 terpenes, and 9 other types of compounds were determined in dried orange peels. It was determined that the VID technique caused the least destructing in volatile compounds, whereas the TD technique was the most destructive.Practical ApplicationsDrying is a common preservation method used for the long‐term durability of foods. Drying of orange peel conduces not only to decrease environmental problems but also to provide economic benefits. Dried orange peel is used in herbal teas and food products because it is rich in aromatic flavor and odor components. Orange peel was dried using tray drying, vacuum infrared drying, and vacuum microwave drying. The vacuum microwave drying increased the drying rate and effective water diffusivity to others. The vacuum microwave drying and vacuum infrared drying protected quality characteristics, and volatile compounds of orange peels. This study demonstrated that the waste orange peels could be dried with different drying methods and converted into products with high nutritional components.