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Surface‐modified zinc ferrite nanocomposites were successfully prepared thru ultrasonic impregnation technique by taking kapok fiber as a bio‐template. This work demonstrates a fast preparation method to produce the bio‐templated ZnFe2O4 composite photocatalyst. The templating method for photocatalyst is favorable due to the benefit of a large surface area for solar harvesting activities in the photoelectrochemical (PEC) system. Comprehensive physicochemical analyses have successfully determined the unique properties of the prepared catalysts. The pure mimetic fibrous catalysts were successfully fabricated as photoelectrodes on the fluorine tin oxide substrate using electrophoretic deposition technique for PEC measurement. The ranging ratio of precursors used to prepare bio‐templated zinc ferrite catalysts shows an effect on their surface structure then influences the photocurrent density performance of PEC analysis. The ZF1 photoanode at 1:1 Zn/Fe ratio has generated the highest photocurrent density of 58 μA cm−2 at 0.7 V vs. Ag/AgCl compare to other samples in 0.5 M Na2SO4 electrolyte solution under 100 mW cm−2 light irradiation. The high photocurrent density was attributed to the enhancement in light‐harvesting properties, fine surface structure, and high charge transfer properties that correlate with the composite ratio's alteration. The bio‐templated zinc ferrite photocatalysts are a promising photoanode in PEC activities. [ABSTRACT FROM AUTHOR]

In this study, Sovová mass transfer-based mathematical model for supercritical fluid extraction was modified by incorporating a cosolvent enhancement factor. Modeling of supercritical carbon dioxide with different cosolvent mixtures was successfully performed in the extraction of model plants (Phyllanthus niruri and Polygonum minus) with an average absolute relative deviation (AARD) of less than 7.90%. The existence of non-typical extraction curves in SCO2 with alcohol–water cosolvent was also well fitted and predicted by the modified model. In the extraction of both plants, internal mass transfer was found to be the rate-limiting factor in the first phase of extraction, namely pre-extraction. Abbreviations:A: surface area; ɛ: porosity; dp: particle size or size distribution; D: vessel diameter; EC: enhancement factor; EC,V: enhancement factor in vapor phase; EC,L: enhancement factor in liquid phase; f: total solvent flow rate; H: height; kXa: mass transfer coefficient in solid phase; kYa: mass transfer coefficient in fluid phase; mt: mass of extract; MCER: global extraction yield at constant extraction rate; N: mass of the inert solid; n i 0 : moles of solvent without cosolvent; n i cos : moles of solvent with cosolvent; n t 0 : total solvent moles without cosolvent; n t cos : total solvent moles with cosolvent; P: pressure; Qf: solvent mass flow rate; Sij: selectivity; t: extraction time; T: temperature; tCER: the end of the first extraction period; tFER: the end of the second extraction period; U: solvent superficial velocity; W: model parameter related to the diffusion in solid phase; xi, xj: solvent mole fraction in liquid phase; Xk: mass of hardly accessible solute; Xo: initial mass of extractable material; Xp: ratio of extractable material at particle surface in solid phase; yi, yj: solvent mole fraction in vapor phase; y i 0 : mole fraction of pure governing solvent; y i cos : mole fraction of the solvent in the cosolvent mixtures; Y*: solute solubility in the solvent; YCER: solubility at constant extraction rate; Z: model parameter related to convection in the fluid phase; zw: parameter of the second extraction period; ρf: solvent density; ρs: sample density; μ: viscosity. [ABSTRACT FROM AUTHOR]

Poly(vinyl alcohol) (PVA) is a biodegradable, water-soluble membrane that has low methanol permeation and reactive chemical functionalities. Modification of these features makes PVA an attractive proton exchange membrane (PEM) alternative to NafionTM. However, the pristine PVA membrane is a poorer proton conductor than the NafionTM membrane due to the absence of negatively charged ions. Hence, modification of PVA matrixes whilst complying with the requirements of projected applications has been examined extensively. Generally, three modification methods of PVA membranes have been highlighted in previous reports, and these are (1) grafting copolymerization, (2) physical and chemical crosslinking, and (3) blending of polymers. The use of each modification method in different applications is reviewed in this study. Although the three modification methods can improve PVA membranes, the mixed method of modification provides another attractive approach. This review covers recent studies on PVA-based PEM in different fuel cell applications, including (1) proton-exchange membrane fuel cells and (2) direct-methanol fuel cells. The challenges involved in the use of PVA-based PEM are also presented, and several approaches are proposed for further study. [ABSTRACT FROM AUTHOR]