Life cycle assessment of environmental impacts associated with oxidative desulfurization of diesel fuels catalyzed by metal-free reduced graphene oxide

Life cycle assessment for evaluation of novel solvents and technologies: A case study of flavonoids extraction from Ginkgo biloba leaves

Innovative solvents such as deep eutectic solvents (DESs) and process intensification technologies assisted by ultrasound have been demonstrated to be promising pathways for enhancing solid-liquid extraction. Nevertheless, quantitative and systematic knowledge of their environmental impact is still limited. In this work, a case study of flavonoids extraction from Ginkgo biloba leaves was evaluated by using life cycle assessment (LCA) for comparison of three extraction scenarios. The first used DES as extractant (DESE), and the other two adopted ethanol, including heat reflux extraction (HRE), and ultrasound-assisted extraction (UAE). Among eight key midpoints investigated, all these from UAE were 10.0 %-80.0 % lower than from DESE and HRE except water consumption. The UAE was the eco-friendliest option due to its higher extraction yield, shorter duration and lower solvent consumption. The DESE exhibited the lowest water consumption, the highest freshwater ecotoxicity and human carcinogenic toxicity, while HRE had the highest impacts for the other 6 midpoints. Moreover, solvent production was the key contributor for all the categories. The standardized sensitivity analysis showed that the overall environmental footprint can be further decreased by 15.4 % for DESE pathways via substituting choline chloride/glycerine with choline chloride/ethylene glycol. Furthermore, all pathways using DESs had higher standardized impacts than those employing ethanol from sugarcane or wood. Replacing ethanol from maize with other feedstocks can significantly lessen the overall impacts, among which the UAE using ethanol from sugarcane demonstrated the least environmental impacts. The promotion of DESs as "green and sustainable" alternative to traditional solvents requires careful consideration.

Efficient Oxidative Desulfurization of High-Sulfur Diesel via Peroxide Oxidation Using Citric, Pimelic, and α-Ketoglutaric Acids

The widespread use of diesel fuel for transportation, industry, and electricity generation causes several environmental issues via an increase in the amount of sulfur compound emissions. Commercial diesel fuel must be free of sulfur-containing compounds since they can cause several environmental problems. Considering the currently available processes to eliminate sulfur compounds, oxidative desulfurization (ODS) is one of the effective means for this purpose. This work presented a simple, low cost, and efficient ODS system of high-sulfur diesel fuels using peroxide oxidation with the aid of citric, pimelic, and α-ketoglutaric acids. The aim of the study was to investigate the potential of these acids as hydrogen peroxide (H2O2) activators for ODS and to optimize the reaction conditions for maximum sulfur removal. The results showed that citric, pimelic, and α-ketoglutaric acids were effective catalysts for the desulfurization of high-sulfur diesel with an initial sulfur content of 2568 mg L−1, achieving a sulfur removal efficiency of up to 95%. The optimized reaction conditions were found to be 0.6 g of carboxylic acid dosage and 10 mL of H2O2 at 95 °C. The desulfurization efficiency of the real diesel sample (2568 mg L−1) was shown to be 27, 34, and 84.57%, using citric acid, α-ketoglutaric acid, and pimelic acid after 1h, respectively. The effectiveness of the oxidation process was characterized by gas chromatographic pulsed flame photometric detector (GC-PFPD) and Fourier-transform infrared spectroscopy (FTIR) techniques. The experimental results demonstrated that the developed system exhibited high efficiency for desulfurization of real high-sulfur diesel fuels that could be a good alternative for commercial application with a promising desulfurization efficiency.

A Prospective Life Cycle Assessment of Electrochemical CO2 Reduction to Selective Formic Acid and Ethylene

Converting CO₂ into valuable C₁ -C₂ chemicals through electrochemical CO₂ reduction (ECR) has potential to remedy the ever-increasing climate problems owing to the intensification of industrial activity. In this work, cradle-to-gate life cycle assessment (LCA) was performed to quantify the environmental impacts of formic acid (FA) and ethylene production through ECR benchmarked with the conventional processes. At the midpoint level, global warming potential (GWP) effects of FA and ethylene production through ECR recorded 5.6 and 1.6-times that of the conventional process, respectively. Although ECR currently has limited environmental benefits, the incorporation of hydropower has vast potential after evaluating four sustainable electricity sources, namely hydropower, wind, solar, and biomass. Notably, ECR to FA recorded a 24 % reduction in petrochemical usage. For ethylene production, human health damage, ecosystem damage, and petrochemical use were reduced by 67, 94, and 110 %, respectively. Sensitivity analysis indicated that a sustainable energy supply chain for ECR will accelerate the development of a circular economy.

Nanosafety: An Evolving Concept to Bring the Safest Possible Nanomaterials to Society and Environment

The use of nanomaterials has been increasing in recent times, and they are widely used in industries such as cosmetics, drugs, food, water treatment, and agriculture. The rapid development of new nanomaterials demands a set of approaches to evaluate the potential toxicity and risks related to them. In this regard, nanosafety has been using and adapting already existing methods (toxicological approach), but the unique characteristics of nanomaterials demand new approaches (nanotoxicology) to fully understand the potential toxicity, immunotoxicity, and (epi)genotoxicity. In addition, new technologies, such as organs-on-chips and sophisticated sensors, are under development and/or adaptation. All the information generated is used to develop new in silico approaches trying to predict the potential effects of newly developed materials. The overall evaluation of nanomaterials from their production to their final disposal chain is completed using the life cycle assessment (LCA), which is becoming an important element of nanosafety considering sustainability and environmental impact. In this review, we give an overview of all these elements of nanosafety.