Effect of Polyethylene Pyrolysis Oil Hydrotreatment on the Pt/Al2O3 Catalyst: Experimental Characterization.

The dramatic increase in plastics production, coupled with a low recycling and recovery rate, has been a major challenge for sustainable practices and combating climate change. Hydrotreatment processing to upgrade fuel oils is a well-known process in the petroleum industry. In this work, we aim to investigate the catalyst properties before and after the hydrotreatment of pyrolysis oil derived from plastics, namely, linear low-density polyethylene, as no such report is available in the literature. Granular and powder forms of the Pt/Al2O3 catalyst were used in this study with characterization methods executed as such: transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and IR-RIS. XRD data show that the crystallinity of the catalyst support was unaffected by the hydrotreatment without any residues left, as the characteristic diffraction peaks were indicated for the crystalline phase of the support as 37.4, 39.8, 46.3, and 67.3°. In addition, the TGA experiments revealed that the carbon deposition on the spent catalyst was higher, as indicated by the higher weight loss (15.359%) compared to the fresh catalyst sample (11.43%). XPS analysis showed that the carbon deposition is more intense on the granular spent catalyst, as the intensity of the peaks is some 15 times greater than the peaks from the fresh catalyst. Also, compared to the observed peaks of the powder catalyst, less coke is formed. The band at 1624.05 cm-1 from the IR-RIS spectra was attributed to a shifted C=O band from the coke formation. The extension of these investigations using different catalysts to improve their characteristics and performance and to inhibit coke deposition will contribute to the incorporation of such processes in industry as well as the cost of fuels.

Economic Feasibility Study of a Carbon Capture and Storage (CCS) Integration Project in an Oil-Driven Economy: The Case of the State of Kuwait.

The rapid growth and urbanization rate, coupled with hot climate and scarce rainfall, makes it essential for a country like Kuwait to have several power and desalination plants with high-generating capacity. These plants are entirely reliant on burning fossil fuels as a source of thermal energy. These plants are also universally accepted to be the largest CO2 emitters; hence, they present a potential for carbon capture and storage (CCS). Having established the suitability of the existing conditions for post-combustion CCS, a techno-economic-based feasibility study, which took into consideration local power generation technologies and economic conditions, was performed. Relying on fifteen case study models and utilizing the concept of levelized cost of electricity (LCOE), the statistical average method (SAM) was used to assess CCS based on realistic and reliable economic indicators. Zour power station, offering the highest potential CO2 stream, was selected as a good candidate for the analysis at hand. Heavy fuel oil (HFO) was assumed to be the only fuel type used at this station with affixed price of USD 20/barrel. The analysis shows that the internal rate of return (IRR) was about 7%, which could be attributed to fuel prices in Kuwait and governmental support, i.e., waived construction tax and subsidized workforce salaries. Furthermore, the net present value (NPV) was also estimated as USD 47,928 million with a 13-year payback period (PBP). Moreover, 1-3% reductions in the annual operational cost were reflected in increasing the IRR and the NPV to 9-11% and USD 104,085-193,945 million, respectively, and decreasing the PBP to 12-11 years. On the contrary, increasing the annual operational cost by 1% made the project economically unfeasible, while an increase of 3% resulted in negative IRR (-1%), NVP (-USD 185,458 million) and increased PBP to 30 years. Similarly, increasing the HFO barrel price by USD 5 resulted in negative IRR (-10%) and NVP (-USD 590,409); hence, a CCS project was deemed economically unfeasible. While the study considered the conditions in Kuwait, it is expected that similar results could be obtained for other countries with an oil-driven economy. Considering that around 62% of the fossil fuel blend in Kuwait is consumed by electricity and water generation, it is inevitable to consider the possibility and practicality of having a carbon network with neighboring countries where other oil-driven economies, such as Kingdom of Saudi Arabia and Iraq, can utilize a CCS-based mega infrastructure in Kuwait. The choice of Kuwait is also logical due to being a mid-point between both countries and can initiate a trading scheme in oil derivatives with both countries.

Soil quality of simulated landfill exposure to plastics in context of heavy metal analysis.

It is imperative to have soil guidelines that consider commodities on the market especially biodegradable plastics that are increasing in popularity nowadays. In this short communication, heavy metal in soil was investigated after degrading plastics commonly used on the market. The plastic materials included virgin linear low-density polyethylene, plastic waste of polyolefin origin, and biodegradables of oxo- and hydro-based types. Soil/water matrix that simulates arid land conditions was used. Metals including cobalt, chromium, cadmium, and nickel, among others, were studied after exposure of three continuous months. It was noted that background concentrations reduced with water indicating that leachate might contain the majority of the transferred metals from plastics. In particular, the concentration of nickel in soil was detected to be 84 ppm after exposure to type I of the oxo-biodegradable commercial plastics. Furthermore, the material of similar source started to retain nickel by day 74 of exposure. This surpasses both Canadian and Australian guidelines discussed herein. Furthermore, nickel concentrations exceeded international guidelines and point towards the need for remediation. Mean values of chromium exceeded soil control results and the USA remediation values in the case of single screw compounded plastics. It should also be noted that the work conducted points towards metal trace detection limits that are tied to waste and sludge disposal in an improper manner with time.

Can plastic waste management be a novel solution in combating the novel Coronavirus (COVID-19)? A short research note.

The year 2020 has been noted to be one of major calamity the world over, in which the majority of efforts in research and development have been dedicated towards combating the threat of the novel Coronavirus (COVID-19). Ever since the announcement of COVID-19 as a pandemic, such efforts were dedicated towards the research of its spread and vaccination. Yet still, the world might reach a resolution via an environmental solution that various entities have overlooked, with a plethora of environmental benefits vis-à-vis waste management. In this short communication, the possibility of using plastic solid waste as a substrate to employ copper, and copper alloys and their nanocomposite nanopowders to be used as permanent surface protective coats, is presented. The fact that we present such materials to be of waste origin, is an added value advantage to their beneficial advantage of developing various commodities and products that could be used in our daily lives. Furthermore, the fact that such recyclable materials are susceptible to antiviral properties and chemicals, is an added value that we should not neglect.

From gangue to the fuel-cells application.

Hydrogen, which is a new clean energy option for future energy systems possesses pioneering characteristics making it a desirable carbon-free energy carrier. Hydrogen storage plays a crucial role in initiating a hydrogen economy. Due to its low density, the storage of hydrogen in the gaseous and liquids states had several technical and economic challenges. Despite these traditional approaches, magnesium hydride (MgH2), which has high gravimetric and volumetric hydrogen density, offers an excellent potential option for utilizing hydrogen in automobiles and other electrical systems. In contrast to its attractive properties, MgH2 should be mechanically and chemically treated to reduce its high activation energy and enhance its modest hydrogen sorption/desorption kinetics. The present study aims to investigate the influence of doping mechanically-treated Mg metal with 5 wt% amorphous Zr2Cu abrasive nanopowders in improving its kinetics and cyclability behaviors. For the first time, solid-waste Mg, Zr, and Cu metals were utilized for preparing MgH2 and amorphous Zr2Cu alloy (catalytic agent), using hydrogen gas-reactive ball milling, and arc melting techniques, respectively. This new nanocomposite system revealed high-capacity hydrogen storage (6.6 wt%) with superior kinetics and extraordinary long cycle-life-time (1100 h) at 250 °C.

Top-Down Reactive Approach for the Synthesis of Disordered ZrN Nanocrystalline Bulk Material from Solid Waste.

Transition metal nitrides possess superior mechanical, physical, and chemical properties that make them desirable materials for a broad range of applications. A prime example is zirconium nitride (ZrN), which can be obtained through different fabrication methods that require the applications of high temperature and pressure. The present work reports an interesting procedure for synthesizing disordered face centered cubic (fcc)-ZrN nanoparticles through the reactive ball milling (RBM) technique. One attractive point of this study is utilizing inexpensive solid-waste (SW) zirconium (Zr) rods as feedstock materials to fabricate ZrN nanopowders. The as-received SW Zr rods were chemically cleaned and activated, arc-melted, and then disintegrated into powders to obtain the starting Zr metal powders. The powders were charged and sealed under nitrogen gas using a pressurized milling steel vial. After 86 ks of milling, a single fcc-ZrN phase was obtained. This phase transformed into a metastable fcc-phase upon RBM for 259 ks. The disordered ZrN powders revealed good morphological characteristics of spherical shapes and ultrafine nanosize (3.5 nm). The synthetic ZrN nanopowders were consolidated through a spark plasma sintering (SPS) technique into nearly full-density (99.3% of the theoretical density for ZrN) pellets. SPS has proven to be an integral step in leading to desirable and controlled grain growth. Moreover, the sintered materials were not transformed into any other phase(s) upon consolidation at 1673 K. The results indicated that increasing the RBM time led to a significant decrease in the grain size of the ZrN powders. As a result, the microhardness of the consolidated samples was consequently improved with increasing RBM time.

Biohydrogen Production by Catalytic Supercritical Water Gasification: A Comparative Study.

In this article, supercritical water gasification of biocrude at different conditions was performed and compared to each other. Three scenarios were considered while treating biocrude originating from cattle manure (CM) and corn husk (CH), namely, uncatalyzed feedstock, catalyzed with 10% Ni-0.08% Ru/Al2O3 and finally catalyzed with 10% Ni-0.08% Ru/Al2O3-ZrO2. It was found that 10% Ni-0.08% Ru/Al2O3-ZrO2 has performed significantly better than the other two scenarios over the 5 hour run time with a 193 and 187% higher hydrogen yield compared to the uncatalyzed and 10% Ni-0.08% Ru/Al2O3 catalyzed scenarios, respectively. Compared to CM gasification in the presence of a 10% Ni-0.08% Ru/Al2O3-ZrO2 catalyst, the catalyst got deactivated because of the high phenol and furan content in the corn husk biocrude, therefore hydrogen yield performance fell significantly. It was observed that the carbon gasification efficiency of the biocrude was independent of temperature. In terms of carbon conversion, the equilibrium conditions for the biocrude considered were attained at lower temperature. A mechanistic model based on the Eley-Rideal method was devised and tested against the obtained data. The dissociation of adsorbed oxygenated hydrocarbon is found to be the rate-determining step with an average absolute deviation of 3.55%.

Solid-State Conversion of Magnesium Waste to Advanced Hydrogen-Storage Nanopowder Particles.

Recycling of metallic solid-waste (SW) components has recently become one of the most attractive topics for scientific research and applications on a global scale. A considerable number of applications are proposed for utilizing metallic SW products in different applications. Utilization of SW magnesium (Mg) metal for tailoring high-hydrogen storage capacity nanoparticles has never been reported as yet. The present study demonstrates the ability to produce pure Mg ingots through a melting and casting approach from Mg-machining chips. The ingots were used as a feedstock material to produce high-quality Mg-ribbons, using a melting/casting and spinning approaches. The ribbons were then subjected to severe plastic deformation through the cold rolling technique. The as-cold roll Mg strips were then snipped into small shots before charging them into reactive ball milling. The milling process was undertaken under high-pressure of pure hydrogen gas (H2), where titanium balls were used as milling media. The final product obtained after 100 h of milling showcased excellent nanocrystalline structure and revealed high hydro/dehydrogenation kinetics at moderate temperature (275°C). The present study shows that primer cold rolling of Mg-strips before reactive ball milling is a necessary step to prepare ultrafine magnesium hydride (MgH2) nanopowders with advanced absorption/desorption kinetics behavior. These ultrafine powders with their nanocrystalline structure are believed to play an important role in effective gas diffusion process. Moreover, the fine titanium particles came from the ball-powder-ball collisions and introduced to the Mg matrix have not only acted as micro-scaled milling media, but they played a vital catalyzation role for the process.