Sonocogreen Decoration of Clinoptilolite by CaO Nanorods as Ecofriendly Catalysts in the Transesterification of Castor Oil into Biodiesel; Response Surface Studies

Abstract

A CaO/clinoptilolite green nanocomposite (CaO/ Clino) was synthesized by a green modification technique using calcium nitrate and green tea extract. The CaO/Clino nanocomposite promises a total basicity of 4.82 mmol OH/g, surface area of 252.4 m 2 /g, and ion exchange capacity of 134.3 mequiv/ 100 g, which qualifies the product as an effective catalyst in the transesterification of castor oil. The transesterification performance of the CaO/Clino catalyst was addressed statistically based on the response surface methodology and central composite rotatable design, considering the essential experimental parameters. Based on the interaction effect between the studied variables, the CaO/ Clino catalyst can achieve an experimental biodiesel yield of 93.8% after 2.5 h at 120 °C with 3.5 wt % catalyst loading and 15:1 ethanol/castor oil molar ratio. The optimization function of the design suggested enhancement in the performance of the CaO/Clino catalyst to achieve a yield of 95.4% if the test time interval increased to 2.65 h and the ethanol content increased to 16:1 as a molar ratio to castor oil. The produced biodiesel over CaO/ClinO has acceptable technical qualifications according to the international requirements (EN 14214 and ASTM D-6751). The synthetic green CaO/Clino nanocomposite has better recyclability as a heterogeneous catalyst and higher activity than some investigated catalysts in literature.

Rare earth elements (REEs) recovery and porous silica preparation from kaolinite

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Synthesis of Guanine/Vermiculite Two-Dimensional Nanocomposites for Wireless Humidity Sensing in Nut Storage Environment

“…Natural minerals have advantages, such as thermal and chemical stability, common availability, large specific surface area, low cost, and nontoxicity . The structure of vermiculite (VMT) can be broken down into tetrahedral sheets of oxygen and coordinated octahedral sheets of aluminum or iron oxide.…”

“…Chen et al 24 developed Ni−Co−P hollow nanobricks, with high sensitivity (∼3.6 kΩ/ % RH), low hysteresis (∼3% RH), good repeatability in a wide moisture range from 0 to 97.5% RH, and a response (recovery) time of 95 s (27 s). Natural minerals have advantages, such as thermal and chemical stability, 25 common availability, 26 large specific surface area, low cost, and nontoxicity. 27 The structure of vermiculite (VMT) can be broken down into tetrahedral sheets of oxygen and coordinated octahedral sheets of aluminum or iron oxide.…”

CaO Catalyzed Transesterification of Ethyl 10-Undecenoate as a Model Reaction for Efficient Conversion of Plant Oils and Their Application to Depolymerization of Aliphatic Polyesters

“…Calcium oxide (CaO) has been widely considered as the efficient transesterification catalyst of vegetable oils due to its low cost and easy commercial availability with high international reserves as well as high basicity, high safety, and low alcohol solubility. ,− It has been postulated that the oxygen anion presented on the CaO surface that possesses basic properties initiates the base-catalyzed reaction by abstracting a proton from alcohol as well as by the interaction between a Lewis basic site (oxygen anion) and reactants (esters); these double activated intermediates could thus facilitate undergoing transesterification . We also recently reported that CaO catalyzed high yield synthesis of FAEs by transesterification of soybean, rice bran, and palm oils with ethanol at 150–200 °C .…”