Valorization of Albedo Orange Peel Waste to Develop Electrode Materials in Supercapacitors for the Electric Industry

This work proposes the use of albedo of orange peel in generation of carbon for applications in supercapacitors. For this, a comparison of compositional and electrochemical properties present in the carbons obtained of albedo, flavedo, and the complete orange peel was carried out. The morphology and composition of carbons obtained were analyzed by Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray (EDX), X-Ray Diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). The synthetized carbons were not subjected to the activation process by chemical compounds to relate only the properties of orange peel parts with their electrochemical behaviour. All samples were tested by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The carbon obtained of albedo presented a superior specific capacitance (210 F/g) of the rest samples. The value of albedo-based carbon capacitance is comparable with works presented in the literature that used a whole orange peel with chemical activators. In this way, it is possible to obtain large capacitances using only a part of orange peel (albedo). Thus, the importance of this study is that the albedo can be proposed as a material applied to electrodes for supercapacitors while the flavedo can be used in food industry or for oil extraction.

Hydrothermal Carbonization as Sustainable Process for the Complete Upgrading of Orange Peel Waste into Value-Added Chemicals and Bio-Carbon Materials

In this study, a simple and green protocol to obtain hydrochar and high-added value products, mainly 5-hydroxymethylfurfural (5-HMF), furfural (FU), levulinic acid (LA) and alkyl levulinates, by using the hydrothermal carbonization (HTC) of orange peel waste (OPW) is presented. Process variables, such as reaction temperature (180–300 °C), reaction time (60–300 min), biomass:water ratio and initial pH were investigated in order to find the optimum conditions that maximize both the yields of solid hydrochar and 5-HMF and levulinates in the bio-oil. Data obtained evidence that the highest yield of hydrochar is obtained at a 210 °C reaction temperature, 180 min residence time, 6/1 w/w orange peel waste to water ratio and a 3.6 initial pH. The bio-products distribution strongly depends on the applied reaction conditions. Overall, 180 °C was found to be the best reaction temperature that maximizes the production of furfural and 5-HMF in the presence of pure water as a reaction medium.

BIOPLASTIC MADE OF ORANGE PEELS

This study uses orange peel waste to create a biopolymer that can be used for different purposes. In order to achieve this, we evaluated various technologies for the production of the biopolymer, and tried to design the most environmentally friendly process possible. One of the reasons why this bioplastic should be manufactured is to participate in the replacement of common environmental hazardous plastic, which has been banned in many places. On the other hand, using orange peel as the main ingredient is an alternative and gives value to an organic waste that has limited use in circular economy solutions. In this research we present a methodology to create a bioplastic of orange peels. As a result, we obtained a biodegradable, flexible and resistant material to be used in the manufacture of containers, utensils, etc. In addition, it is a material that, given the raw materials used, is considered GRAS (Generally Recognized As Save), implying a non-toxic product that is safe for the consumer.

KOH Activation with Microwave Irradiation and its Effect on the Physical Properties of Orange Peel Activated Carbon

Chemical activation with assisted microwave irradiation was used to produced activated carbon from orange peel waste. The activating agent was potassium hydroxide (KOH) with concentrations of 2 M, 3 M, and 4 M. The microwave irradiation was done for 15 minutes with a 630 Watt output power. KOH concentration affected the physical properties of OP-ACxM. With increasing KOH concentration, the interlayer spacing (d002 and d100 ) grew, stack height (Lc ) increased, and stack width (La) dropped. The number of pores on the surface of OP-ACxM increased after the chemical activation process. In OP-ACxM, FTIR analysis reveals the presence of O-H, C-H, C-C, C=O, C=C, and C-O.