Arash Javanmard's research while affiliated with Malayer University and other places

This review article provides a comprehensive summary of the chemical and biological approaches for pretreating empty fruit bunches (EFBs), a byproduct of the palm oil industry that can be used as a feedstock for biofuels and biochemicals. However, the presence of alkali metals and alkali earth metals (AAEMs) can reduce EFB quality and limit their usage. To improve EFB quality, acid washing and biological pretreatment methods are commonly used. The different types of acids used for washing, such as sulfuric acid, hydrochloric acid, and citric acid, are evaluated for their effects on EFB quality under various concentrations and washing conditions, and the pros and cons of each acid-washing method are discussed. Additionally, the application of biological pretreatment techniques, such as fermentation using fungi and bacteria, is explored to improve the quality of EFBs. The impact of different fermentation conditions and microbial strains on EFB quality is assessed, and the benefits and drawbacks of each biological pretreatment method are analyzed. This review article provides a comprehensive understanding of the acid washing and biological pretreatment methods for EFBs and their impact on feedstock quality. The knowledge gained from this research can be used to optimize the pretreatment process and increase the efficiency of EFB utilization, promoting the development of a sustainable and circular bioeconomy.

Carbon nanostructures are promising materials for electrochemical energy storage devices. Whereas, the main problem of these types of materials unresolved is the difficulty of achieving high specific capacitance. The efficient strategies to prepare carbon materials with improved electrochemical performances for supercapacitors have sparked numerous demands. Here, we demonstrated that the dual-heteroatom-doped carbon can be prepared by eco-friendly, simple route on a very large scale. Phosphorus/ Oxygen co-doped carbon nanosheets were synthesized by design a layered nanoreactor including gallate and phosphate anions. Under heat treatment at 700 °C, the reaction between gallate and phosphate anions resulted in production of Phosphorus/ Oxygen co-doped carbon nanosheets which can be utilized for practical supercapacitor applications. The obtained carbon materials showed highly porous structures with suitable micro/mesopores and efficient electrochemical performance in an alkaline medium. In addition, the carbon gallate phosphate (CGP) electrode had high specific surface area capacitance of 63.05 µF cm⁻² in 1 M KOH, as well as good rate capabilities, supreme rectangular cycle performance and very low Ohmic resistance for charge–discharge curves. Thus, this low cost and facile strategy provides a new approach for designing high-performance electrodes with exceptional volumetric capacitance and prominent electrode materials for high-performance supercapacitor applications.

In the use of the electric double layer capacitors (EDLCs) with carbon electrode materials, what remains an important technological challenge is that existing carbon electrodes suffer from low energy density and low volumetric capacitance, the today's need for making energy storage architectures. The incorporation of the n-type and/or p-type dopant elements in carbon structure may result in an enhancement in the capacitance. Accordingly, the idea to use the layered nanoreactors was applied to produce phosphorous-doped and boron-doped porous carbon nanostructures with high specific capacitance (CS) values when used in supercapacitor electrodes. So that, the best P-doped and B-doped carbon electrodes show the CS values of 322 and 275 F/g, respectively, at a current density of 1 A/g in the three-electrode system. A symmetric supercapacitor device made using the best doped carbon material (CG-P) showed a CS value of 163.2 F/g at a current density of 0.1 A/g. Herein, this work shows that the high values of CS for carbon materials are due to high accessible surface area, excellent pore size distribution, the presence and uniform dispersion of the dopant agents in carbon structures.

Due to the importance of the 3D carbon monoliths and their vast applications in electrochemical energy, catalysis and gas reservoir devices, different strategies have been made on the synthesis/fabrication of 3D graphene or graphene-like products. Nevertheless, the existing 3D carbon bodies mostly suffer from low accessible surface area (ASA), poor mechanical properties and above all, high volume values, in spite of the today's need for making small architectures. Moreover, synthesis/fabrication approaches of desirable 3D bodies with particular size and shape remain unavailable, yet. Herein, we report a new simple method based on the idea of layered nanohybrids/nanoreactors for simultaneous synthesis and fabrication of 3D monolithic bodies composed of pure and N-doped carbon nanosheets. X-ray diffraction, Fourier transform infrared, scanning electron microscopy, X-ray photoelectron spectroscopy and surface area and pore analysis results indicated that the robust pure and N-doped carbon bodies have high surface area values in low volumes constructed by carbon layers with turbostratic structure. As the N-doped 3D carbon sample shows a surface area of 27.83 m² in a 0.221 cm³ volume. Moreover, the 3D monolithic carbon bodies are porous materials with large pore volume up to 2.1 cm³/g which can be used in various practical applications.

A layered nanoreactor (zinc hydroxide gallate/nitrate nanohybrid) has been designed as a nano-vessel to confine the gallate/nitrate reaction inside zinc hydroxide layers for production of metal/nitrogen-doped carbon catalysts. Metals (Fe2+, Co2+and Ni2+) doped and bare zinc hydroxide nitrates (ZHN) were synthesized as the α-phase hydroxide hosts. By an incomplete ion-exchange process, nitrate anions between the layers of the hosts were then partially replaced by the gallate anions to produce the layered nanoreactors. Under heat-treatment, the reaction between the remaining un-exchanged nitrate anions and the organic moiety inside the basal spacing of each nanohybrid plate resulted in obtaining highly porous 3D metal/nitrogen-doped carbon nanosheets. These catalysts were then used as extremely efficient electrocatalysts for catalyzing oxygen reduction reaction (ORR). This study is intended to show the way to get maximum electrocatalytic activity of the metal/N-doped carbon catalysts toward the ORR. This exceptionally high ORR performance originates from the increased available surface, the best pore size range and the uniform distribution of the active sites in the produced catalysts, all provided by the use of new idea of the layered nanoreactor.