The purpose of this review is to give the reader a thorough background to the fundamentals and applications of pressurized hot water extraction (PHWE) for the analysis of bioactive compounds. We summarize the field in the period 2009-14, and include fundamentals of water as a solvent: equipment; method optimization; applications; coupling; and, future prospects. We highlight that solvent properties of water are tunable by changing the temperature, particularly self-ionization, dielectric constant, viscosity, diffusivity, density and surface tension. Furthermore, important aspects to consider are the risk of degradation of the analytes and other potential reactions, such as hydrolysis, caramelization and Maillard reactions that may lead to erroneous results. For the extraction of bioactive compounds, we report PHWE methods based on using water of 80-175 degrees C and short extraction times. In conclusion, PHWE provides advantages over conventional extraction methods, such as being "greener", faster and more efficient. (C) 2015 The Authors. Published by Elsevier B.V. (Less)

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Pressurized hot water extraction of bioactives

The research on biodiesel production via heterogeneous catalyzed approach is continuously studied by scientist in order to gain a sustainable process for industrial production and to improve its fuel quality The green resource of biodiesel feedstock and catalyst is the major criteria to influence the biodiesel yield and sustainability of the process For the state of the art biodiesel production technology, heterogeneous catalyst received great attention for simple and low cost manufacturing process In terms of easy separation and high reusability The most special characteristic of heterogeneous catalyst is its tuning properties that generate acidic-basicity, surface area and porosity that can highly advance the variety of the feedstock for esterification/transesterification process Different traits of the heterogeneous catalysts (solid base, solid acid, acid-base and bio-catalyst) are studied in this review as each holds a specialty of features to the process Thus, the study of heterogeneous catalyst should continue to be evaluated and taken into account if the catalyst are to be employed in the commercial sector as that remains the pivotal goal of these studies In consideration to the debate of food vs fuel as well as low cost production, non-edible feedstock was further discussed by using heterogeneous catalyzed system

A review on latest developments and future prospects of heterogeneous catalyst in biodiesel production from non-edible oils

Synthesis and characterization of ZIF-8 nanoparticles for controlled release of 6-mercaptopurine drug

Background Because of the important role of bioactive compounds in functional foods and health care, more and more attention has been paid to the active components extracted by green extraction methods. However, how to ensure the extraction yield and biological activity during the extraction process is an urgent problem to be solved. Subcritical water extraction (SWE) is a promising engineering method, which provides an environmentally friendly technology for extracting various bioactive compounds from natural products. Especially, under high temperature and high pressure, subcritical water can change the polarity and dielectric constant of solvents, thus contributing to a better extraction process, improving the mass transfer efficiency of the extracts and maintaining its biological activities, which has a high application prospect. Scope and approach This review provided an update overview on the fundamental principles and bioactive compounds extraction with subcritical water. This will contribute to deepen the understanding of SWE and provide theoretical basis and reference value for further improving the application of subcritical water. Key founds and conclusions It is expected that this green and efficient extraction technology will be increasingly applied in the extraction of more bioactive ingredients in the near future. In addition, future research should consider combining SWE with other physical extraction techniques to ensure the retention of the biological ingredients better. These active compounds with SWE have great potential in health care medicine and functional foods. Meanwhile, future researches should focus on consumer acceptability, safety, legal aspects, and commercial availability of health products.

Recent advances in the extraction of bioactive compounds with subcritical water: A review

Environmentally friendly ultrasound-assisted synthesis of magnetic zeolitic imidazolate framework - Graphene oxide nanocomposites and pollutant removal from water

Nickel oxide (NiO) and phosphotungstic acid (PTA) supported on a ZIF-8 (NiO-PTA/ZIF-8) catalyst was first synthesized and it showed high activity and good selectivity for the hydrocracking of Jatropha oil. The catalyst was characterized by SEM, SEM-EDS, TEM, N2 adsorption, FT-IR, XRD and XPS. Compared with the NiO-PTA/Al2O3 catalyst, the selectivity of C15-C18 hydrocarbon increased over 36%, and catalytic efficiency increased 10 times over the NiO-PTA/ZIF-8 catalyst. The prepared NiO-PTA/ZIF-8 catalyst was stable for a reaction time of 104 h and the kinetic behavior was also analyzed. This catalyst was found to bypass the presulfurization process, showing promise as an alternative to sulfided catalysts for green diesel production.

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NiO-PTA supported on ZIF-8 as a highly effective catalyst for hydrocracking of Jatropha oil

The development of a novel non-sulfided catalyst with high activity for the hydrotreatment processing of plant oils, is of high interest as a way to improve the efficient production of renewable diesel. To attempt to develop such a catalyst, we first synthesized a high activity flower-like Ni-PTA catalyst used in the hydrotreatment processes of plant oils. The obtained catalyst was characterized with SEM, EDX, HRTEM, BET, XRD, H2-TPR, XPS and TGA. A probable formation mechanism of flower-like Ni(OH)2 is proposed on the basis of a range of contrasting experiments. The results of GC showed that the conversion yield of Jatropha oil was 98.95%, and the selectivity of C11-C18 alkanes was 70.93% at 360 °C, 3 MPa, and 15 h(-1). The activity of this flower-like Ni-PTA catalyst was more than 15 times higher than those of the conventional Ni-PTA/Al2O3 catalysts. Additionally, the flower-like Ni-PTA catalyst exhibited good stability during the process of plant oil hydrotreatment.

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A Non-sulfided flower-like Ni-PTA Catalyst that Enhances the Hydrotreatment Efficiency of Plant Oil to Produce Green Diesel.

Extraction of oil from Jatropha curcas seeds by subcritical fluid extraction

Subcritical water extraction of betulinic acid from birch bark

The invention relates to a ZIF-8 material-based hydrogenation catalyst and a synthetic method thereof. The synthetic method particularly comprises the following steps: (1) dissolving zinc nitrate, 2-methylimidazole and a surface active agent with methanol, carrying out stirring reaction for 1-6h at 20-60 DEG C, and standing for 10-18h to obtain a turbid solution; (2) carrying out centrifugal treatment on the turbid solution, placing sediments in a drying oven to be dried to obtain a ZIF-8 carrier after washing with methanol; and (3) dissolving transition metal salt with water, dipping the ZIF-8 carrier into the dissolved transition metal salt, and roasting in a muffle furnace to obtain the ZIF-8 material based hydrogenation catalyst. The hydrogenation catalyst can be used for preparing biodiesel; the biodiesel preparation method comprises the steps of placing the ZIF-8 material based hydrogenation catalyst into a fixed bed reactor to be reduced, and introducing vegetable oil into the reactor for hydrocracking reaction at 300-400 DEG C under the conditions that the hydrogen partial pressure is 2-4MPa, the air speed is 0.9-3.6h so as to obtain the biodiesel finally. The catalytic efficiency of the synthesized ZIF-8 material based hydrogenation catalyst is improved by dozens of times compared with the catalytic efficiency of a traditional aluminum oxide catalyst.

Pan Chen

Papers

NiO-PTA supported on ZIF-8 as a highly effective catalyst for hydrocracking of Jatropha oil

A Non-sulfided flower-like Ni-PTA Catalyst that Enhances the Hydrotreatment Efficiency of Plant Oil to Produce Green Diesel.

Extraction of oil from Jatropha curcas seeds by subcritical fluid extraction

Subcritical water extraction of betulinic acid from birch bark

ZIF-8 material-based hydrogenation catalyst and synthetic method thereof