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Herein, an affordable strategy was developed to form Pd@SiO2 nanostructure assembled onto monolithic AlOOH/Al nanoarrays from nano- to macro-scale by a one-step reaction process. (3-Aminopropyl)trimethoxysilane (APTMS) was employed as a dual-role reagent for the bidirectional bridging between Pd2+ and AlOOH/Al, as well as the formation of SiO2 matrix and mesopores. The effects of one-step organization conditions on the preparation process, catalyst structure, and catalytic performance were all studied. High hydroxyl contents in Al-based nanoarrays promoted the silanization reaction of APTMS deposition, resulting in a well-formed SiO2 shell and abundant mesopores during the thermal decomposition of APTMS. APTMS amount was not only related to SiO2 loading and encapsulation effect of the core–shell structure, but also affected Pd accessibility. Such proposed APTMS-assisted protocol for the in-situ organization of monolithic Pd@SiO2 catalysts can effectively prevent the growth and aggregation of Pd NPs, thereby favoring low-temperature activity and stability for CH4 combustion. Monolithic Pd@SiO2 catalysts supported on AlOOH/Al nanoarrays were successfully fabricated from nano- to macro-scale in one step for improved thermal stability of CH4 combustion. The cost-effective coupling agent (APTMS) acted as the bidirectional bridging between –NH2 of APTMS and Pd2+ through preferential chelation, as well as a silanization reaction between methoxy groups of APTMS and surface –OH groups on AlOOH nanoarrays to form Al–O–Si bonds. [ABSTRACT FROM AUTHOR]

The efficient conversion of low-grade acidic oils to biodiesel is still a great challenge due primarily to the presented free fatty acids (FFAs) and moisture that significantly activate the used catalysts. In this premise, the acidic aluminosilicates (AAS) were employed as catalyst supports for loading of molybdenum and zirconium metals to synthesize the solid acid catalysts of molybdenum and zirconium doped aluminosilicates (ZrMo-AAS). The so-synthesized composite catalysts were characterized by various physicochemical techniques, and their catalytic activities were evaluated for the efficient biodiesel production by using acidic soybean oils as feedstocks. Results revealed that the targeted solid catalysts featured dual Bronsted-Lewis acidic sites and mesoporous structure with the acidity of 719 μmol/g and surface area of 459.7 m2/g, displaying high catalytic performances for the concurrent transesterification of triglycerides and esterification of FFAs with 92.3% of oil conversion and full FFA conversion to biodiesel at a reaction temperature of 130 °C for 12 h with a methanol/oil molar ratio of 30. This solid catalyst had good water and FFA-resistance capacity even with water content to 1% and FFA content of 40%, and moreover could be easily recovered by filtration with a steady reusability with a slight attenuation in the activity after five time reuses, rendering it to have the potential of cost-effective production of biodiesel from the low-grade oils. [ABSTRACT FROM AUTHOR]

As emerging contaminants used for treating various tract infections, fluoroquinolones (such as enoxacin, ofloxacin, etc.) enter water bodies via point-source discharges of wastewater treatment plants and many of them raise environmental and health concerns. Herein, a novel adsorbent, derived from a useful renewable low-cost grapefruit peel, was prepared to investigate the adsorption behavior of fluoroquinolone antibiotics (enoxacin and ofloxacin). The obtained adsorbent was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD) and thermo-gravimetric analysis and differential scanning calorimetry (TG-DSC). Further, the equilibrium sorption of the adsorption process was analyzed with isotherm models and kinetic models. Under optimal adsorption conditions, equilibrium data conformed to the Elovich model, and the kinetics of adsorption was fitted well with Redlich-Peterson model. Combined with thermodynamic analysis, electrostatic interaction, hydrogen bond, π-π stacking interaction were the possible adsorption mechanisms for both fluoroquinolone antibiotics onto the novel adsorbent. This work explored a promising adsorbent for the elimination of fluoroquinolone antibiotics in environmental remediation. [ABSTRACT FROM AUTHOR]