Biofuel production using thermochemical conversion of heavy metal-contaminated biomass (HMCB) harvested from phytoextraction process

Over the past few decades, bioenergy production from heavy metal-contaminated biomasses (HMCBs) has been drawing increasing attention from scientists in diverse disciplines and countries owing to their potential roles in addressing both energy crisis and environmental challenges. In this review, bioenergy recovery from HMCBs, i.e. contaminated plants and energy crops, using thermochemical processes (pyrolysis, gasification, combustion, and liquefaction) has been scrutinized. Furthermore, the necessity of the implementation of practical strategies towards sustainable phytoextraction and metal-free biofuels production has been critically discussed. To meet this aim, the paper firstly delivers the fundamental concepts regarding the remediation of the brownfields using phytoremediation approach, and then, reviews recent literature on sustainable phytoextraction of heavy metals from polluted soils. Thereafter, to find out the possibility of the cost-efficient production of metal-free biofuels from HMCBs using thermochemical methods, the impacts of various influential factors, such as the type of feedstock and metals contents, the reactor type and operating conditions, and the role of probable pre-/post-treatment on the fate of heavy metals and the quality of products, have also been discussed. Finally, based on relevant empirical results and techno-economic assessment (TEA) studies, the present paper sheds light on pyrolysis as the most promising thermochemical technique for large-scale electricity and heat recovery from HMCBs

Strength and Densification of Ni/Al<sub>2</sub>O<sub>3</sub> Membrane Compacted with Uniaxial Pressing and CIP for Hydrogen Separation: Influence of Pressing Process

In our previous studies, 10-40wt%Ni/Al2O3 membrane was prepared by uniaxial pressing and sintered at 900 to 1400°C for 2 h. It was found that 10wt%Ni/Al2O3 membrane sintered at 1400°C showed the highest physical and mechanical properties. Thus, this work we focused on the effect of different pressing processes on the properties of Ni/Al2O3 membrane with longer soaking time. Firstly, 10-40wt%Ni and Al2O3 powders were mixed by dried ball-milling. Then, the mixture powder was pressed to form a bar shape by two different processes; uniaxially pressing (No CIP) and uniaxially pressing followed by cold isostatic pressing (CIP) at 250 MPa for 5 min. All Ni/Al2O3 specimens from two pressing routes were sintered at 1400°C for 4h under air atmosphere and reduced at 900 °C under H2 (99.99%). From the results, it was found that the densification process affected to physical and mechanical properties of Ni/Al2O3. The CIPed - 10wt%Ni/Al2O3 membrane sintered at 1400°C for 4 h showed the highest relative density and flexural strength of 76% and 106 MPa with the lowest pore size (78 nm) and 17% porosity. The addition of nickel content gradually decreased physical and mechanical properties of Ni/Al2O3.</jats:p

A Study of Different Sintering Routes on Properties of Ni-Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; Hydrogen Separation Membrane

This work aimed to investigate the effect of different sintering routes on properties of Ni-Al2O3 membrane. Alumina powder was mixed with 10 wt% nickel powder by dried ball-milling. Then, the mixture powder was uniaxially pressed to a bar shape and sintered via different sintering conditions. First route, the Ni-Al2O3 specimen was sintered at 1300°C for 2 h under air and then reduced at 900°C for 2 h under H2 atmosphere. Second route, the specimen was sintered at 1300°C for 2 h under argon. After sintering process, the physical and mechanical properties of membrane obtained from two routes were compared and discussed. </jats:p