Synthesis of MnFe2O4/activated carbon derived from durian shell waste for removal of indole in water: Optimization, modelling, and mechanism.

While durian shell is often discharged into landfills, this waste can be a potential and zero-cost raw material to synthesize carbon-based adsorbents with purposes of saving costs and minimizing environmental contamination. Indole (IDO) is one of serious organic pollutants that influence aquatic species and human health; hence, the necessity for IDO removal is worth considering. Here, we synthesized a magnetic composite, denoted as MFOAC, based on activated carbon (AC) derived from durian shell waste incorporated with MnFe2O4 (MFO) to adsorb IDO in water. MFOAC showed a microporous structure, along with a high surface area and pore volume, at 518.9 m2/g, and 0.106 cm3/g, respectively. Optimization of factors affecting the IDO removal of MFOAC were implemented by Box-Behnken design and response surface methodology. Adsorption kinetics and isotherms suggested a suitable model for MFOAC to remove IDO. MFOAC was recyclable with 3 cycles. Main interactions involving in the IDO adsorption mechanism onto MFOAC were clarified, including pore filling, n-π interaction, π-π interaction, Yoshida H-bonding, H-bonding.

Exploiting the Waste Biomass of Durian Shell as a Heterogeneous Catalyst for Biodiesel Production at Room Temperature.

Durian shell, a biomass waste, was simply burned and then could serve as a heterogeneous catalyst for the transesterification reaction of palm oil with methanol at room temperature. The chemical composition, structure, and morphology of the catalyst were well-characterized by XRD, BET, SEM, TEM, EDS, TGA, FT-IR, and XPS measurement. With the preparation temperature rising to 350 °C, the maximum yield of the biodiesel could reach 94.1% at room temperature, and the optimum reaction conditions were 8 wt.% catalyst, 8:1 methanol/oil molar ratio, ad 2.5 h reaction time. The characterizations results indicated that K2O and K2CO3 existed on the surface of catalyst, and a moderate amount of carbon, which acts as a carrier, attributed to the activity of the catalyst. After repeating five times, the catalyst prepared at 350 °C showed better stability than other catalysts. This might be because the incomplete combustion of the remaining carbon slowed down the loss of K to some extent.

The profiles of durian (Durio zibethinus Murr.) shell phenolics and their antioxidant effects on H2O2-treated HepG2 cells as well as the metabolites and organ distribution in rats.

Durian is a nutritious tropical fruit with potent antioxidant, anti-inflammatory, antibacterial and anti-cancer effects. However, the durian shell was mainly discarded as waste, while there were few studies on the characterization of its phenolic profiles, antioxidant activities, and in vivo metabolites. In the present study, a total of 17 compounds were identified in durian shell extract (DSE) by using an ultra-high-performance liquid chromatography coupled with linear ion trap quadrupole Orbitrap mass spectrometry (UHPLC-LTQ-Orbitrap-MS/MS), while 33 metabolites were found in rats' plasma, urine and organ. Moreover, DSE could effectively reduce H2O2-induced oxidative damage in HepG2 cells, reduce the expression of Reactive Oxygen Species (ROS), Malondialdehyde (MDA) and Lactate Dehydrogenase (LDH) and inhibit apoptosis by regulating the expression of Bcl-2-Associated X (BAX), B-Cell Lymphoma 2 (BCL-2), Caspase-3 and Caspase-9 genes and proteins related to mitochondrial pathway apoptosis. This is the first comprehensive report on Durian shell phenolics, their metabolic profiles and underlying mechanisms of the in vitro antioxidant activities.

Experimental Design, Equilibrium Modeling and Kinetic Studies on the Adsorption of Methylene Blue by Adsorbent: Activated Carbon from Durian Shell Waste.

For the first time, activated carbon from a durian shell (ACDS) activated by H2SO4 was successfully synthesized in the present study. The fabricated ACDS has a porous surface with a specific surface area of 348.0017 m2·g-1, average capillary volume of 0.153518 cm3·g-1, the average pore diameter of 4.3800 nm; ash level of 55.63%; humidity of 4.74%; density of 0.83 g·cm-3; an iodine index of 634 mg·g-1; and an isoelectric point of 6.03. Several factors affecting Methylene Blue (MB) adsorption capacity of ACDS activated carbon was investigated by the static adsorption method, revealing that the adsorption equilibrium was achieved after 90 min. The best adsorbent pH for MB is 7 and the mass/volume ratio is equal to 2.5 g·L-1. The MB adsorption process of ACDS activated carbon follows the Langmuir, Freundlich, Tempkin, and Elovich isotherm adsorption model, which has determined the maximum adsorption capacity for MB of ACDS as qmax = 57.47 mg·g-1. The MB adsorption process of ACDS follows the of pseudo-second-order adsorption kinetic equation. The Weber and Morris Internal Diffusion Model, the Hameed and Daud External Diffusion Model of liquids have been studied to see if the surface phase plays any role in the adsorption process. The results of thermodynamic calculation of the adsorption process show that the adsorption process is dominated by chemical adsorption and endothermic. The obtained results provide an insight for potential applications of ACDS in the treatment of water contaminated by dyes.

Waste-to-Resource Strategy to Fabricate Functionalized MOFs Composite Material Based on Durian Shell Biomass Carbon Fiber and Fe3O4 for Highly Efficient and Recyclable Dye Adsorption.

Recently, metal-organic frameworks (MOFs), which are porous inorganic-organic hybrid materials consisting of metal ions (clusters or secondary building units) and organic ligands through coordination bonds, have attracted wide attention because of their high surface area, huge ordered porosity, uniform structural cavities, and excellent thermal/chemical stability. In this work, durian shell biomass carbon fiber and Fe3O4 functionalized metal-organic framework composite material (durian shell fiber-Fe3O4-MOF, DFM) was synthesized and employed for the adsorption removal of methylene blue (MB) from wastewater. The morphology, structure, and chemical elements of the DFM material were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscope (TEM), and X-ray photoelectron spectroscope (XPS) techniques. Adsorption conditions such as pH, adsorption time, and temperature were optimized. The adsorption isotherm and kinetics results show that the adsorption process of DFM material to MB is more in line with the Freundlich model and pseudo-second-order kinetic model. Using these models, the maximum adsorption capacity of 53.31 mg/g was obtained by calculation. In addition, DFM material could be easily reused through an external magnet and the removal rate of MB was still 80% after five adsorption cycles. The obtained results show that DFM composite material, as an economical, environmentally friendly, recyclable new adsorbent, can simply and effectively remove MB from wastewater.

Recycling durian shell and jackfruit peel via anaerobic digestion.

With growing popularity of durian and jackfruit, environment threats following improper management of durian shell (DS) and jackfruit peel (JP) are increasingly serious. Anaerobic digestion is a potential solution but concern on its unsatisfied efficiency from lignocellulosic recalcitrance remains. This work applied four representative pretreatments on DS and JP to determine the effects on methane generation, energy potential, and environmental benefits. The suitable pretreatments for DS and JP were 3% KOH and 5% AHP, causing 103.8% and 69.8% increase in methane yield and biodegradability than untreated, respectively. Moreover, 3% KOH-treated DS and 5% AHP-treated JP could potentially produce total energy of 2.0 × 109 MJ/year, reduce coal consumption by 6.8 × 104 ton/year, and cut emission by 2.2 × 1010 particulate/year, which might alleviate the serious energy crisis and environmental issues from the overuse of fossil fuel. This study provides important insights into efficient use of DS and JP, and a reference for other fruit wastes.

Chemical constituents and pharmacological effects of durian shells in ASEAN countries: A review.

Durio zibethnus is mainly distributed in Southeast Asia. Traditional Chinese medicine believes that durian shells have the effects of clearing heat and purging fire, nourishing yin and moisturizing dryness. Therefore, it is often used as a pharmaceutic food in the Chinese folk to assist treating diseases. At present, the chemical constituents isolated from durian shell include phenolic acids, phenolic glycosides, flavonoids, coumarins, triterpenes, simple glycosides and other compounds. Modern pharmacological studies show that durian shell has many pharmacological activities, such as antioxidant, anti-inflammatory, regulation of glucose and lipid metabolism. The chemical composition and pharmacological effects of durian shells are summarized in order to provide references for the further research and application of durian shell.

Chemical constituents and pharmacological effects of durian shells in ASEAN countries: A review / 中草药·英文版

Durio zibethnus is mainly distributed in Southeast Asia. Traditional Chinese medicine believes that durian shells have the effects of clearing heat and purging fire, nourishing yin and moisturizing dryness. Therefore, it is often used as a pharmaceutic food in the Chinese folk to assist treating diseases. At present, the chemical constituents isolated from durian shell include phenolic acids, phenolic glycosides, flavonoids, coumarins, triterpenes, simple glycosides and other compounds. Modern pharmacological studies show that durian shell has many pharmacological activities, such as antioxidant, anti-inflammatory, regulation of glucose and lipid metabolism. The chemical composition and pharmacological effects of durian shells are summarized in order to provide references for the further research and application of durian shell.

Combustion parameters, evolved gases, reaction mechanisms, and ash mineral behaviors of durian shells: A comprehensive characterization and joint-optimization.

In this work, the characteristic parameters, evolved gases, reaction mechanisms, and ash conversions of the durian shell (DS) combustion were quantified coupling thermogravimetry, mass spectroscopy, Fourier transform infrared spectroscopy, and X-ray fluorescence spectra analyses. The main stage of the DS combustion occurred between 130.2 and 481.9 °C. Its activation energy value estimated by the three model-free methods ranged from 192.82 to 213.24 kJ/mol. The average enthalpy, entropy and Gibbs free energy changes were in the ranges of 177.74-178.47 kJ/mol, 32.00-34.25 J/(mol·K), and 200.79-207.74 kJ/mol, respectively. The third-order (F3) model best described its most likely reaction mechanism. The main evolved gas was CO2, with no SO2 emission. The ash from the DS combustion belonged to K-type ash. 618 °C and 8 K/min were determined as the optimal operation conditions to jointly optimize the multiple targets of the combustion responses.

Fluorescent N/Al Co-Doped Carbon Dots from Cellulose Biomass for Sensitive Detection of Manganese (VII).

Development of metallic and nonmetallic heteroatom doped carbon dots have gained attention due to their enhanced physicochemical and photoluminescence properties. In this study, a facile one pot hydrothermal carbonisation approach was taken to synthesise nitrogen, aluminum co-doped carbon dots (N/Al-CDs) with a photoluminescence quantum yield of 28.7%. Durian shell, a cellulose biomass waste, was used as the primary carbon source and compared to previously reported cellulose based carbon dots, this study presents one of the highest quantum yields. The structural and fluorescent properties of the synthesised N/Al-CDs were characterized through X-ray photoelectron spectroscopy (XPS), fluorescence spectra, and Fourier transform infrared spectroscopy (FTIR). The maximum emission was at 415 nm upon excitation at 345 nm. The synthesised N/Al-CDs were resistant to photobleaching and highly photostable within the pH, ionic strength and temperature variations investigated. The transmission electron microscopy (TEM) images showed particles were quasi-spherical and well dispersed with an average diameter of 10.0 nm. Further, the N/Al-CDs was developed as a fluorescence sensor for highly selective and sensitive detection of Mn (VII) ions. A linear relationship was developed over a concentration range of 0-100 µM while the limit of detection was 46.8 nM. Application of the sensor for detection of Manganese (VII) to two real water samples showed relative standard deviation was less than 3.9% and 1.3%, respectively.

Nitrogen-Doped Durian Shell Derived Carbon Dots for Inner Filter Effect Mediated Sensing of Tetracycline and Fluorescent Ink.

Photoluminescent carbon dots have gained increasing attention in recent years due to their unique optical properties. Herein, a facile one-pot hydrothermal process is used to develop nitrogen-doped carbon dots (NCDs) with durian shell waste as the precursor and Tris base as the doping agent. The synthesized NCDs showed a quantum yield of 12.93% with a blue fluorescence under UV-light irradiation and maximum emission at 414 nm at an excitation wavelength of 340 nm. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy showed the presence of nitrogen and oxygen functional groups on the NCD surface. The particles were quasi-spherical with an average particle diameter of 6.5 nm. The synthesized NCDs were resistant to photobleaching and stable under a wide range of pH but were negatively affected by increasing temperature. NCDs showed high selectivity to Tetracycline as the fluorescence of NCDs was quenched significantly by Tetracycline as a result of the inner filter effect. Based on sensitivity experiments, a linear relationship (R2 = 0.989) was developed over a concentration range of 0-30 µM with a detection limit of 75 nM (S/N = 3). The linear model was validated with two water samples (lake water and tap water) with relative recoveries of 98.6-108.5% and an RSD of <3.5%.

Efficient Using Durian Shell Hydrolysate as Low-Cost Substrate for Bacterial Cellulose Production by Gluconacetobacter xylinus.

Durian is one important tropical fruit with high nutritional value, but its shell is usually useless and considered as waste. To explore the efficient and high-value utilization of this agricultural and food waste, in this study, durian shell was simply hydrolyzed by dilute sulfuric acid, and the durian shell hydrolysate after detoxification was used for bacterial cellulose (BC) production by Gluconacetobacter xylinus for the first time. BC was synthesized in static culture for 10 days and the highest BC yield (2.67 g/L) was obtained at the 8th day. The typical carbon sources in the substrate including glucose, xylose, formic acid, acetic acid, etc. can be utilized by G. xylinus. The highest chemical oxygen demand (COD) removal (16.40%) was obtained at the 8th day. The highest BC yield on COD consumption and the highest BC yield on sugar consumption were 93.51% and 22.98% (w/w), respectively, suggesting this is one efficient bioconversion for BC production. Durian shell hydrolysate showed small influence on the BC structure by comparison with the structure of BC generated in traditional Hestrin-Schramm medium detected by FE-SEM, FTIR, and XRD. Overall, this technology can both solve the issue of waste durian shell and produce valuable bio-polymer (BC).

Maximization of the methane production from durian shell during anaerobic digestion.

This study systematically investigated the anaerobic digestibility of durian shell and focused on maximizing the methane yield using response surface methodology. Results showed in the feedstock to inoculum (F/I) ratio range of 0.2-2, a lower value was preferred. Meanwhile the methane yield showed a sharp rise first followed by a decline as the organic loading (OL) increased from 3 to 27g VS/L. The highest experimental methane yield (EMY) was calculated to be 170.6ml/g VS at F/I ratio of 0.2 and organic loading of 20.45g VS/L. To make the combination of F/I ratio and OL more practical, 0.5 was set as the optimum F/I ratio, when the highest EMY was obtained to be 165.0ml/g VS at the OL of 20.45g VS/L. Characteristics of final effluent implied the anaerobic system was stable. This study is important to promote the application of durian shell into anaerobic digestion from theory to practice.