Pomelo Peel Research Articles

Effects of high‐pressure pretreatment on acid extraction of pectin from pomelo peel

SummaryTo explore the effects of high‐pressure processing (HPP) pretreatment on pectin extraction from pomelo albedo, the extraction yield, and characteristics of pectin were compared with those obtained via traditional acid (A‐pectin) extraction. Three different pressures (300, 450, and 600 MPa) and holding times (0, 5, and 10 min) were applied to the fresh albedo, followed by acid extraction. The yield, degree of esterification (DE), galacturonic acid (GalA) content, Fourier transform‐infrared (FT‐IR) spectra, and rheological properties of pectin were investigated. By comparison with A‐pectin, the yield increased by more than two and four times at 300 MPa at holding times of 5 and 10 min, respectively. All extracted pectins were high methoxyl pectins (DE of 76.30–87.83%) with high GalA content (62.3–86.60%); however, there were significant decreases in DE and GalA content when pressure was increased to 600 MPa in comparison with A‐pectin. The pressure level and holding time significantly influenced the viscosity of pectin, and HPP‐pectin 300‐5, 450‐10, and 600‐0 exhibited a much higher viscosity than A‐pectin. Consequently, this study demonstrated that HPP pretreatment of fresh albedo can increase extraction yield and/or alter pectin characteristics for further industrial applications.

Utilization of Pomelo (Citrus maxima) Peel Waste into Bioactive Essential Oils: Chemical Composition and Insecticidal Properties.

The wastes generated during the post-harvest handling of various agricultural commodities is rather under-utlilized. The peels of citrus fruits are often discarded as waste. Citrus peels are rich in essential oils and exhibit toxicity towards various insect species. The essential oils are also an eco-friendly option for insect pest management. The Citrus maxima peel essential oil (CMEO), a waste product, characterized it, and evaluated its potential for insect pest management. The major terpenoids present in CMEO are Limonene and α-Pinene. The CMEO displayed potentials in controlling the insect pests via contact and fumigant toxicity. Moreover, CMEO showed significant larvicidal activities against Culex tritaeniorhynchus and Aedes aegypti species of mosquitoes; however, Armigeres subalbatus was more resistant. The biological safety of the essential oil was also tested against the stored seeds, where no significant inhibition of seed germination was noticed compared to the control. Utilizing a waste product such as citrus peel for pest management can achieve the dual objective of waste utilization and eco-friendly pest management. Overall, the CMEO is therefore found to be a bioactive essential oil extracted from the wastes of pomelo (C. maxima).

Direct Construction of K-Fe3C@C Nanohybrids Utilizing Waste Biomass of Pomelo Peel as High-Performance Fischer–Tropsch Catalysts

As the only renewable organic carbon source, abundant biomass has long been established and developed to mass-produce functionalized carbon materials. Herein, an extremely facile and green strategy was executed for the first time to in situ construct K-Fe3C@C nanohybrids directly by one-pot carbonizing the pomelo peel impregnated with Fe(NO3)3 solutions. The pyrolytically self-assembled nanohybrids were successfully applied in Fischer–Tropsch synthesis (FTS) and demonstrated high catalytic performance. Accordingly, the optimized K-Fe3C@C catalysts revealed excellent FTS activity (92.6% CO conversion) with highlighted C5+ hydrocarbon selectivity of 61.3% and light olefin (C2-4=) selectivity of 26.0% (olefin/paraffin (O/P) ratio of 6.2). Characterization results further manifest that the high performance was correlated with the in situ formation of the core-shell nanostructure consisting of Fe3C nanoparticles enwrapped by graphitized carbon shells and the intrinsic potassium promoter originated in pomelo peel during high-temperature carbonization. This work provided a facile approach for the low-cost mass-fabrication of high-performance FTS catalysts directly utilizing waste biomass without any chemical pre-treatment or purification.

Bioinspired, Simulation‐Guided Design of Polyhedron Metamaterial for Simultaneously Efficient Heat Dissipation and Energy Absorption

AbstractLight‐weight, high‐strength metamaterials with excellent heat dissipation and energy absorption capabilities are of great interest to aerospace and automobile applications. Particularly, innovative structure design and its successful realization are paramount but often challenging due to the vast design space and associated complex manufacturing. Herein, in this study, inspired by pomelo peel's superior shielding protection to the pulp, bionic polyhedron metamaterials (BPMs) that imitate the pomelo peel are designed and realized by metal 3D printing to achieve not only superior heat dissipation but also high energy absorption. Guided by experiments and numerical simulations, the BPM with circular struts possesses the highest Nusselt number, lowest pressure drop, and friction factor at Re = 7000–30000. Above results integrated lead to that the BPM with circular struts exhibit a higher thermal efficiency index that exceeds 1 at 0.92 porosity. Furthermore, the BPM with circular struts possesses moderate specific energy absorption in existing mechanical metamaterials for their corresponding density, which has potential for gas turbines and some cooling structures. The above findings will guide the design of metamaterials with high heat dissipation and energy absorption.

Inhibition of Melanosis and Quality Changes on Indian White Prawn Treated with Lemon and Pomelo Peel Extracts Conjugated with Copper Sulfide Nanoparticles during Chilled Storage

ABSTRACT The study was aimed at the assessment of lemon peel extract (LPE) and pomelo peel extract (PPE) conjugated with copper sulfide nanoparticles (CuSNPs) influence on melanosis formation and improving the quality of chilled stored Indian white shrimp (Fenneropenaeus indicus) after 15 days. Biochemical indices, microbial count, and sensory analysis was performed at 3 day intervals. The trimethylamine, total volatile base nitrogen, free fatty acid, and peroxide value of control was 18.01 ± 0.79 mgN/100 g, 45.08 ± 1.1 mgN/100 g, 0.14 ± 0.01% of oleic acid, and 16.42 ± 0.612 milliequivalents/kg, whereas LPE+PPE+CuSNPs was 10.94 ± 1.04 mgN/100 g, 17.51 ± 1.1 mgN/100 g, 0.091 ± 0.01% of oleic acid, and 7.57 ± 0.38 milliequivalents/kg, respectively, at the 15th day of storage. The biochemical indices, microbial count, and sensory score of the treated sample was significantly lower (P < .05) than the untreated sample at day 15. This study aimed to determine the effectiveness of this biopreservation technique, which could provide a new alternative in preservation techniques, as well as impact shelf life and product safety.

Facile Preparation of Porous Carbon Derived from Pomelo Peel for Efficient Adsorption of Methylene Blue.

Pomelo peel waste-derived porous carbon (PPPC) was prepared by a facile one-step ZnCl2 activation method. The preparation parameters of PPPC were the mass ratio of ZnCl2 to pomelo peel of 2:1, carbonization temperature of 500 °C, and carbonization time of 1 h. This obtained PPPC possessed abundant macro-,meso-, and micro-porous structures, and a large specific surface area of 939.4 m2 g−1. Surprisingly, it had excellent adsorption ability for methylene blue, including a high adsorption capacity of 602.4 mg g−1 and good reusability. The adsorption isotherm and kinetic fitted with Langmuir and pseudo-second order kinetic models. This work provides a novel strategy for pomelo peel waste utilization and a potential adsorbent for treating dye wastewater.

Pomelo Peel Essential Oil Ameliorates Cerebral Ischemia-Reperfusion Injury through Regulating Redox Homeostasis in Rats and SH-SY5Y Cells.

Background In cardiac accident/cardiopulmonary resuscitation (CA/CPR) rat model, oxidative stress occurs during cerebral ischemia/reperfusion injury (CIRI), and antioxidative treatment has a neuroprotective effect. The antioxidant capabilities of pomelo peel essential oil (PPEO) have mostly been investigated in vitro, with little convincing data in vivo, particularly whether PPEO has a neuroprotective role against CIRI. Methods In this investigation, a CA/CPR SD rat model and an oxygen-glucose deprivation/reperfusion (OGD/R) SH-SY5Y cell model were used to imitate the CIRI, and the neuroprotective role of PPEO was discovered in both. The morphological changes of neurons after PPEO treatment were observed using Nissl staining and transmission electron microscopy, while biochemical markers such as MDA, GSH, and Fe2+ were evaluated. Furthermore, western blot, immunofluorescence, and immunohistochemistry were used to examine the proteins GPX4, SLC7A11, ACSL4, and Nrf2. Results Significant morphological alterations were identified during the pathological progression of CIRI. The neurologic deficit scores improved after PPEO therapy, and the expression of GPX4 and SLC7A11 increased, while the levels of intracellular Fe2+, ROS, and ACSL4 declined. PPEO also prevented CIRI caused by erastin (a specific inhibitor of SLC7A11) or RSL3 (inhibitor of GPX4). Furthermore, PPEO-induced increases in SLC7A11 and GPX4 may be related to Nrf2 translocation to the nucleus. Conclusions In vitro and in vivo, we verified and investigated the neuroprotective effects of PPEO on CIRI. The underlying process may be connected to redox homeostasis regulation, which enhances antioxidative capacity through upmodulation of SLC7A11 and GPX4. It implies that PPEO will be considered as a source of potential adjuvant therapeutic agents for improving CIRI outcomes.

Biomass‐Derived Carbon Quantum Dots‐Induced Self‐Assembly of 3D Networks of Nickel‐Cobalt Double Hydroxide Nanorods as High‐Performance Electrode Materials for Supercapacitors

AbstractThe nickel‐cobalt double hydroxide hybrid materials induced by biomass‐derived carbon quantum dots (CQDs) have a three‐dimensional network structure of cross‐linked nanorods. The results demonstrate that the functional groups on the CQDs derived from pomelo peel promoted the nucleation and confined the growth of nickel‐cobalt double hydroxide. The as‐synthesized NiCo‐LDH‐CQDs‐20 exhibits the high specific capacitance of 1814 F g−1 at 1 A g−1. When the current density is increased to 15 A g−1, the specific capacitance value remains 75.5 % of the initial one, which indicates that NiCo‐LDH‐CQDs‐20 has an extremely high‐rate performance. Furthermore, the asymmetric supercapacitor NiCo‐LDH‐CQDs‐20//AC provides a high energy density of 46.47 Wh kg−1 in 2 M KOH solution with a power density of 800 W kg−1 and maintains an initial specific capacitance of 82.7 % after 2000 cycles. Therefore, this study provides a promising approach for the development of anode active materials in supercapacitor energy storage devices.

Pomelo-inspired sandwich composites: manufacturing and cushioning property

Inspired by pomelo peel, this study designs an effective cushioning composite with a novel sandwich structure using a columnar lattice mold and two-step foaming technique. This sandwich composite consists of a polyamide nonwoven fabric (i.e. nonwoven surface) as the surface reinforcement layer and a double-layered spacer fabric as the bottom layer for energy absorbing. The static-compression resistance and dynamic cushioning efficacy of composites are investigated, examining the influences of three parameters (i.e. the areal density of the nonwoven surface and laminating angle and the mesh size of the double-layered spacer fabric). The experimental results show that the static-compression resistance and dynamic cushioning efficacy of the composites decrease when increasing the laminating angle of the spacer fabric and the areal density of the polyamide nonwoven fabric. By contrast, with an increment in mesh size, the compression resistance and cushioning efficacy of the composites first decrease and then increase. N200PUH/L(S5) consists of a 200 g/m2 nonwoven surface and a 0° laminated angle, 5 mm mesh size double-layered spacer fabric, which exhibits a higher cushioning efficacy than the pomelo peel. The acceleration of N200PUH/L (S5) was 39 g at 15 ms, and the acceleration of pomelo peel was 72 g at 7 ms, which were 60.7% and 28.5% lower than that of the blank group, respectively. The sandwich-structured composites are proven to have promising applications for low-velocity cushioning behavior, and this study combines the textile structure and foam technique, offering a perspective of designing cushioning composite sandwiches for future studies.

Processing of Ready-to-Brewed Drink from Pomelo, Baby Orange, and Lemon Peel Combination

Indonesia memiliki potensi produksi dan jumlah konsumsi jeruk yang tinggi. Kulit jeruk adalah limbah buah yang potensial untuk diolah menjadi produk pangan, salah satunya adalah minuman siap seduh. Minuman siap seduh merupakan salah satu minuman yang mudah dijumpai, digemari dan populer di Indonesia. Penelitian ini bertujuan untuk mengetahui karakteristik kimia dan sensoris minuman siap seduh dari kombinasi kulit jeruk berbagai varietas seperti pomelo, jeruk baby, dan lemon. Produk dibuat melalui pemisahan kulit, pemotongan, blanching, perendaman dalam air es, dan pengeringan. Hasil penelitian menunjukkan bahwa kadar air teh kulit jeruk telah sesuai dengan standar SNI yaitu dibawah 8,00%. Minuman seduhan dari kulit jeruk memiliki pH dengan kisaran 6,77 -6,84. Nilai warna yang dihasilkan menunjukkan adanya perbedaan yang nyata pada masing-masing formulasi. Secara sensoris, formulasi terbaik yaitu F3 dengan tingkat kesukaan secara keseluruhan tertinggi yaitu 3,73.&#x0D;

Grapefruit and pomelo peel extracts as natural antioxidants for improved storage stability of Turkey patties during refrigerated storage.

The study investigated the effect of albedo and flavedo extracts of grapefruit and pomelo on storage stability of turkey patties during refrigerated storage. Five different types of products were developed depending on the addition of extracts viz. control (C), albedo and flavedo extract of grapefruit (GA and GF), and albedo and flavedo extract of pomelo (PA and PF). The products were stored for 10days and evaluated for lipid and protein oxidation, pH, colour and sensory properties. The extracts improved the lipid oxidative stability by decreasing (P < 0.05) the TBARS values of the samples compared to control group. No effect of the extract treatments (P > 0.05) was observed on pH and colour values of the products (a* and b*). The lowest TBARS values were found for the products containing GF (0.78mg MA/kg) on day 4. The treatments showed a significant impact on flavour of the products and the highest scores were obtained for PA containing products.

Functional Anatomy, Impact Behavior and Energy Dissipation of the Peel of Citrus × limon: A Comparison of Citrus × limon and Citrus maxima.

This study analyzes the impact behavior of lemon peel (Citrus × limon) and investigates its functional morphology compared with the anatomy of pomelo peel (Citrus maxima). Both fruit peels consist mainly of parenchyma structured by a density gradient. In order to characterize the lemon peel, both energy dissipation and transmitted force are determined by conducting drop weight tests at different impact strengths (0.15–0.74 J). Fresh and freeze-dried samples were used to investigate the influence on the mechanics of peel tissue’s water content. The samples of lemon peel dissipate significantly more kinetic energy in the freeze-dried state than in the fresh state. Fresh lemon samples experience a higher impulse than freeze-dried samples at the same momentum. Drop weight tests results show that fresh lemon samples have a significantly longer impact duration and lower transmitted force than freeze-dried samples. With higher impact energy (0.74 J) the impact behavior becomes more plastic, and a greater fraction of the kinetic energy is dissipated. Lemon peel has pronounced energy dissipation properties, even though the peel is relatively thin and lemon fruits are comparably light. The cell arrangement of citrus peel tissue can serve as a model for bio-inspired, functional graded materials in technical foams with high energy dissipation.

Functionalization of mesoporous carbons derived from pomelo peel as capacitive electrodes for preferential removal/recovery of copper and lead from contaminated water

• Waste pomelo peel converted into a novel adsorbent for use in CDI. • Removal of Pb and Cu ions strongly enhanced by functionalizing with pyrrolic-N. • Strong selectivity of Pb 2+ from water containing multiple competing ions. • Easy regeneration of adsorbent on no loss in performance over 300 cycles. Water is not only a valuable resource that is needed to sustain life, but also an essential ingredient in many engineering processes, which unavoidably leads to large volumes of water being contaminated. To achieve safe discharge and also recover valuable “pollutants”, better performing sorbents are needed to rapidly and efficiently decontaminate water while generating minimal secondary wastes. Bio-sorbents derived from pomelo peel were functionalized with pyrrolic-N (BNC-5 electrode) and pyridinic-N (BNC-6 electrode) to enhance electroadsorption and selectivity of Pb 2+ and Cu 2+ . The interaction between soft acid ions (Pb 2+ ) and soft base sites (pyrrolic-N) contributed to a strong chemisorption that elevated the electroadsorption capacity to 2.0 mmol g −1 for Pb 2+ at an applied voltage of 1.2 V. With fast removal kinetics (0.077 g mg −1 min −1 of Pb 2+ ), the BNC-5 sorbent performed comparably to other N-doped sorbents prepared using graphene. The large adsorption–desorption hysteresis of BNC-5 in responding to the applied electric voltage confirmed the nature of chemisorption. The results showed only 32.4% of the adsorbed ions being desorbed from the sorbent by reducing the applied voltage to 0 V, but reached almost complete desorption (98.5% of adsorbed ions) at –0.8 V. When operated in adsorption–desorption cycle mode, BNC-5 after ∼ 400 cycles maintained a capacity retention ≥ 80%. After 400 cycles, the electrode capacity was almost fully restored (98.7%) by only mild chemical washing (0.1 M HNO 3 ) of the sorbent and the cycling performance maintained. The study demonstrated the robustness of the sorbent over 1200 cycles and hence the potential to successfully convert waste into high-performance materials for large-scale remediation strategies of contaminated wastewater using CDI.

One-pot conversion of industrial hemp residue into fermentable feedstocks using green catalyst and enzyme cocktails generated by solid-state fermentation

This study isolated fascinating novel fungal consortium from pomelo peel (PP) to discover its potential for on-site production of lignocellulose degrading enzymes through solid-state fermentation (SSF). SSF strategy was developed to use low and high recalcitrant substrates including PP and industrial hemp residue (IHR), respectively. The result revealed that SSF using a mixture of these substrates was significantly enhanced as compared with the corresponding individual substrate. IHR was pretreated with autohydrolysis, thermal hydrolysis, and thermochemical hydrolysis. A green and sustainable catalyst, oxalic acid, was employed to further optimize the thermochemical pretreatment of IHR. Pretreatment with 3% (w/v) oxalic acid resulted the highest sugar which is 8.3 and 3.24 folds compared to autohydrolysis and thermal hydrolysis, respectively. Finally, a novel approach dubbed one-pot pretreatment and saccharification was implemented using IHR treated with 2% oxalic acid and enzymes generated by SSF of mixed substrates. This strategy resulted the highest sugar production of 39.49 g/L. The current study can be considered as a proof-of-concept for sustainable and economic production of bio-based products from waste biomass resources.

Low-temperature hydrothermal liquefaction of pomelo peel for production of 5-hydroxymethylfurfural-rich bio-oil using ionic liquid loaded ZSM-5

Ionic liquid loaded ZSM-5 with high stability and catalytic performance was used for hydrothermal liquefaction (HTL) of pomelo peel for the first time. Bio-oil obtained at 200 °C had the highest yield (29.21 wt%) and high heating value (21.41 MJ/kg), with main constituents of 5-hydroxymethylfurfural (5-HMF, 50.10%), 3-Pyridinol (19.8%) and pentanoic acid (5.35%). The higher 5-hydroxymethylfurfural yield obtained using ionic liquid loaded ZSM-5 was further compared to other studies (0–50%). In comparison to high-temperature HTL, catalytic HTL with ionic liquid loaded ZSM-5 led to lower activation energy requirements (31.93 kJ·mol−1) for the conversion of glucose into 5-HMF. Additionally, the catalysts showed excellent recyclability, with 19.68 wt% of bio-oil containing 59.6% of light oil obtained after 5 cycles. Hence, this study presents a novel approach for the catalytic conversion of lignocellulosic biomass into 5-HMF-rich bio-oil for energy and green chemistry applications.

Preparasi Komposit Polimer Alami Berbasis Pektin Kulit Jeruk Bali sebagai Edible Coating pada Tomat

Tomato (Solanum lycopersicum L.) is very susceptible to damage and has a relatively short shelf life. The increased production of tomatoes which are not accompanied by an increase in consumption will cause a large amount of waste. An edible coating (EC) film could increase the durability of tomatoes thus it is needed to improve the quality and shelf life of tomatoes. EC is a thin layer that is safe for consumption and environmentally friendly. In this study, EC was prepared by extracting pectin from pomelo peel combined with one of two ingredients, carboxy methyl cellulose (CMC) and tapioca, and using a plasticizer in the form of glycerol. Measurement of weight loss and organoleptic tests (color and texture) of tomatoes were carried out for 14 days. The best results were obtained by pectin 3% (w/w), CMC 1% (w/w) and tapioca 1% (w/w). The EC was able to increase the shelf life of tomatoes up to day 14 with a weight loss of 0.063%, while tomatoes without coating had been tainted on day 6 with a weight loss of 0.387%.

Improved Method for Preparing Nanospheres from Pomelo Peel to Achieve High Graphitization at a Low Temperature

Biomass waste is a valuable resource that can be recovered, reused, and is renewable. However, converting biomass waste to a high degree of order is a bigger challenge, and graphitization at low temperatures is even more difficult. This paper proposes an improved method (Ni element catalysis) for highly graphitizing pomelo peel at low temperatures (750 –900 °C). In this paper, X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), and high-resolution transmission electron microscopy (HRTEM) were used to study the method and the effect of temperature on structural changes during graphitization. Under the improved method, pomelo peel was transformed into nano-spherical graphitized material. The degree of graphitization reached 80.23% at 900 °C, which was 31.39% higher than that of the traditional method. Furthermore, through HRTEM, the lattice fringe spacing was observed to be 0.337 nm, which is between pure graphite (0.3354 nm) and amorphous graphite (0.3440 nm). In this paper, the improved method can obtain highly graphitized nanospheres at low temperatures, thus reducing energy consumption, reducing environmental pollution, and promoting sustainable development.

Feasibility of pomelo peel dietary fiber as natural functional emulsifier for preparation of Pickering-type emulsion.

The application of Pickering emulsions stabilized by food-derived particles is of great interest, studies have focused on development of natural functional emulsifiers from agricultural byproducts. Dietary fiber (DF) has been recognizing for its excellent physiological functions. Moreover, physicochemical properties of pomelo peel DF (PDF) make it a potential emulsifier. However, pristine PDF is not suitable as emulsifier due to its compact physical structure and high hydrophobicity, which seriously limits its utilization. The objective of the study was to investigate the effects of cellulase on physicochemical properties of PDF and to illustrate the feasibility of cellulase modified PDF (MPDF) as natural functional emulsifier. Cellulase modification significantly improved (P < 0.05) specific surface area, water-holding capacity/oil-holding capacity, viscoelasticity, hydrophobicity, and pore structure while decreased crystallinity index and particle size of PDF. Emulsion could remain stable over 30 days as MPDF concentrations up to 1wt% and oil/water ratio 3:7. The appearance stability of emulsions was not influenced by temperature (4-60 °C), pH (3.0-12.0), and ion concentration (0-200 mmol L-1 ) which was similar to Pickering emulsions. The mechanism of MPDF as an emulsifier was mainly attributed to the combination of Pickering effect and the three-dimensional network. In addition, MPDF showed higher antioxidant capacity in emulsions than other classical emulsifiers. The results illustrated that MPDF has a favorable feasibility for preparation of stable Pickering-type emulsions, which will be a practical support for application of PDF as a natural functional emulsifier and will be helpful to realize the resource utilization of DF in pomelo industries. © 2022 Society of Chemical Industry.

Karakterisasi fisikokimia dan functional properties tepung kulit buah jeruk bali (Citrus maxima) dan tepung kulit buah nangka (Artocarpus heterophyllus)

Jackfruit and pomelo are tropical fruits that are popular among the people of Southeast Asia, including Indonesia because of their nutritional content such as carbohydrates, protein, minerals, and vitamins that are very beneficial for the health of the body. Jackfruit peel and pomelo peel are often just a waste and disposed of as organic waste. This study aims to compare the physical, chemical, and functional characteristics of jackfruit peel flour, pomelo peel flour, and wheat flour. The experimental design used was a completely randomized design with a variety of flour types. Based on the results of the physical test, the three types of flour gave significant differences in the color parameters. The kamba density value of jackfruit rind flour was not significantly different from that of wheat flour, while the kamba density value of pomelo rind flour was significantly different from that of wheat flour and jackfruit rind flour. Based on the results of chemical tests, the three types of flour differed significantly from each other in the content of ash, fat, crude fiber, protein, carbohydrates, pectin, and starch. The water content of pomelo peel flour was not significantly different from that of wheat flour. However, the water content of jackfruit rind flour was significantly different from that of wheat flour. Meanwhile, the ash content of pomelo peel flour and jackfruit peel flour were not significantly different from each other, but both were significantly different from wheat flour. Then for the functional parameters, OHC, swelling power, and solubility of the three flours were significantly different from each other. While the WHC of pomelo peel flour and jackfruit peel flour were not significantly different from each other, but the WHC values were significantly different from that of wheat flour.

Copper supported on activated carbon from hydrochar of pomelo peel for efficient H2S removal at room temperature: Role of copper valance, humidity and oxygen

In this work, the activated carbon prepared from KOH activation of pomelo peel hydrochar was selected as support to synthesize various valance copper adsorbents (maintaining a 20 wt% total content of copper) for H2S adsorption at room temperature, with a focus on the desulfurization performance under moist or oxygen conditions. The results showed that Cu0/activated carbon has a highest H2S breakthrough capacity of 358.3 mg/g under co-presence of steam and oxygen, followed by Cu+ and Cu2+ loaded activated carbon. The H2S removal process consists of catalytic oxidation and reactive adsorption, resulting in the formation of large amount of elemental sulfur and part of sulfate and sulfide. The presence of steam or oxygen mainly enhances the catalytic oxidation of H2S to form elemental sulfur, and the breakthrough sulfur capacity decreases in the order of moist oxygen, moist nitrogen, dry oxygen and dry nitrogen conditions. The evolution of desulfurization product at different reaction times indicate that the sulfate and sulfide are mainly generated at prometaphase stage of desulfurization, while the elemental sulfur could be formed in the whole stage. These findings provide a new route to prepare in-expensive and high efficient copper-based H2S adsorbent from high moisture organic waste.