MODELING POLARIZATION CURVE IN AN AQUEOUS CARBONATED SOLUTION OF PIPERAZINE

A polarization curve model is developed for carbon steel in an aqueous carbonated solution of piperazine (PZ). This model has been used to generate the polarization curve and control the parameters relevant to the corrosion rate of carbon steel in the PZ-CO2-H2O system. Electrochemical experiments are carried out for carbon steel corrosion measurements at 40 °C and different carbon dioxide partial pressure using the potentiodynamic polarization technique. The Vapor-liquid Equilibrium and the electrochemical corrosion models are the two main models used in this study. The electrolyte-NRTL equilibrium model was utilized to calculate the chemical species concentration at the carbon steel-solution interface in the PZ-CO2-H2O system. The findings of speciation were then applied to the generation of polarization curves and the prediction of the corrosion rate of the carbon steel surface. The results of the polarization curves modeling were compared to the experimental curves developed in MatLab software 2013a. Comparing experimental and modeled polarization curves and corrosion rate reveals excellent agreement

Graphene and its tailoring as emerging 2D nanomaterials in efficient CO2 absorption: A state-of-the-art interpretative review

Carbon Dioxide (CO2) Capture, Utilization and Storage (CCUS) has been introduced as the solution for increasing CO2, affecting many stakeholders. The improvement of the performance of the most mature technology among the CCUS technologies: Absorption, has been the main interest through various approaches, such as nanosuspension and ionic liquids (ILs), resulting in the emergence of nanotechnology and its unique advantages in various fields. This review aims to introduce the application of emerging 2D structured graphene-based materials in CO2 absorption. This review addresses the past five years’ application of graphene-based nanomaterials, covering the forms, characterization, and synthesis methods and means of administration (such as capsulated and nanofluids). Graphene-based materials' influence on CO2 absorption is summarized with graphical presentations and discussed. The results indicated that graphene-based materials are suitable for application in CO2 absorption either as suspension or support, which boosts absorption performances. Finally, challenges and future works are summarized

A systematic review of machine learning approaches in carbon capture applications

Climate change and global warming are among of the most important environmental issues and require adequate and immediate global action to preserve the planet for future generations. One of the essential technologies used to reduce CO2 emissions and mitigate the worst effects of climate change is carbon capture technology. Many efforts have been made by scientists, industrial sectors, and policy-makers in looking for new technology to reduce greenhouse gas emissions and achieve net-zero emission goals. Research and development in creating new technology involve complex processes and require a digital system to optimize big data prediction as well as to reduce production time. A mathematical and statistical approach such as machine learning plays an important role in solving research problems, whereby this approach provides fast results in predicting big data and cost-efficient tools. In this study, a systematic review and bibliometric analysis were used to analyze the research trend, particularly on the keywords, number of publications, citations, countries, and authorship. This information is important for future research directions for researchers who venture into this area. In this study, the bibliometric analysis focuses on 2 main categories: co-authorship (countries and organizations) and keywords (author keyword). Based on the research trend, the United States (USA), China, Iran, Canada, and the United Kingdom are the leading countries contributing to this field since they have the highest publications and citations. Furthermore, the most common keywords used in the selected articles ranked according to the highest link strength. The top 6 keyword list includes machine learning, artificial neural network, CO2 capture, CO2 solubility, metal-organic frameworks (MOFs) and carbon capture and storage. The findings from this study can be used to open a wider spectrum for the research communities by providing global research trends, current innovations and current technology on machine learning in carbon capture application, identifying the active research areas or hot topics and future research direction to help fight climate change issue using smart advanced technology

Emerging pollutants and their removal using visible-light responsive photocatalysis – a comprehensive review

Emerging pollutants (EP) are the group of contaminants newly detected in aquatic environments around the globe. Conventional water purification systems are less efficient in removing these pollutants; therefore, innovative, and eco-friendly technologies are needed. Recently, semiconductor-supported photocatalysis has attracted attention in environmental remediation for removing EP's owing to their unique characteristics of low-cost, higher thermal and mechanical stability, and excellent pollutant removal efficiency. The charge separation and effective light absorption, particularly in the visible region, are two essential characteristics in photocatalyst which are hard to achieve. Several approaches have been adopted to enhance the charge separation and light-absorption ability in the visible range, including elemental-doping, morphology-engineering, and composite photocatalyst formation. This review concisely discusses the several recently discovered EP's, their fate and transport properties, as well as recent progress in the design and development of visible light-responsive photocatalysts for degradation of EP's. Furthermore, synthesis methods, key features such as optical properties, energy-bandgap structure, crystallinity, and surface features are emphasized in this review. The influencing process parameters, reusability, and stability of photocatalyst are also outlined. Finally, the summary and future perspectives for designing a sustainable photocatalysis system are presented

Recent progress in sustainable recycling of LiFePO4-type lithium-ion batteries: Strategies for highly selective lithium recovery

The demand for LiFePO4 (LFP)-type batteries have increased remarkably in energy storage devices due to a longer life span, improved discharge and charge efficiency, and safe handling. The growing use of such batteries has raised concern about their proper disposal, where improper handling might result in hazardous material entering the environment. As a result, waste LFP battery recycling is receiving a lot of attention. To date, the recycling of spent LFP batteries has been carried with two traditional methods: (1) pyrometallurgy (i.e., direct regeneration) and (2) hydrometallurgy (i.e., the leaching of individual metals). However, the toxic off-gassing at high temperatures were eventually found not in favor of the environment. Besides, hydrometallurgical recovery of complete metal ions (i.e., Li, Fe, and P) in solution increases the cost of the process due to excess use of minerals. To this end, a hydrometallurgical derived process commonly known as one-step selective recovery of Li and FePO4 are keenly focused, where in-situ recovery of Li in leaching solution and Fe as FePO4 in residue are followed. This review is directed to the selective recovery of Li from the spent LFP cathode materials. The discussion centers on the present process of selective recovery in comparison to the traditional approaches. The structure of LFP and Li-recovery routes, which involve various kinds of leaching agents, are discussed. The effective separation procedures and their advancement are examined, which may pave the way for new and updated technologies to increase environmentally friendly recycling routes. Finally, endeavors are given to the challenges and future aspects of recycling LFP cathode materials. In general, the review will aid in understanding the evolution of a sustainable Li-ion battery recycling methods

Recent progress in sustainable recycling of LiFePO4-type lithium-ion batteries: Strategies for highly selective lithium recovery

The demand for LiFePO4 (LFP)-type batteries have increased remarkably in energy storage devices due to a longer life span, improved discharge and charge efficiency, and safe handling. The growing use of such batteries has raised concern about their proper disposal, where improper handling might result in hazardous material entering the environment. As a result, waste LFP battery recycling is receiving a lot of attention. To date, the recycling of spent LFP batteries has been carried with two traditional methods: (1) pyrometallurgy (i.e., direct regeneration) and (2) hydrometallurgy (i.e., the leaching of individual metals). However, the toxic off-gassing at high temperatures were eventually found not in favor of the environment. Besides, hydrometallurgical recovery of complete metal ions (i.e., Li, Fe, and P) in solution increases the cost of the process due to excess use of minerals. To this end, a hydrometallurgical derived process commonly known as one-step selective recovery of Li and FePO4 are keenly focused, where in-situ recovery of Li in leaching solution and Fe as FePO4 in residue are followed. This review is directed to the selective recovery of Li from the spent LFP cathode materials. The discussion centers on the present process of selective recovery in comparison to the traditional approaches. The structure of LFP and Li-recovery routes, which involve various kinds of leaching agents, are discussed. The effective separation procedures and their advancement are examined, which may pave the way for new and updated technologies to increase environmentally friendly recycling routes. Finally, endeavors are given to the challenges and future aspects of recycling LFP cathode materials. In general, the review will aid in understanding the evolution of a sustainable Li-ion battery recycling methods

Magnetic nanoparticles incorporation into different substrates for dyes and heavy metals removal—A Review

Substantial discharge of hazardous substances, especially dyes and heavy metal ions to the environment, has become a global concern due to many industries neglecting the environmental protocols in waste management. A massive discharge of contaminantsfrom different anthropogenic activities, can pose alarming threats to living species and adverse effect to the ecosystem stability. In the process of treating the polluted water, various methods and materials are used. Hybrid nanocomposites have attained numerous interest due to the combination of remarkable features of the organic and inorganic elements in a single material. In this regards, carbon and polymer based nanocomposites have gained particular interest because of their tremendous magnetic properties and stability. These nanocomposites can be fabricated using several approaches that include filling, template, hydrothermal, pulsed-laser irradiation, electro-spinning, detonation induced reaction, pyrolysis, ball milling, melt-blending, and many more. Moreover, carbon-based and polymer-based magnetic nanocomposites have been utilized for an extensive number of applications such as removal of heavy metal and dye adsorbents, magnetic resonance imaging, and drug delivery. This review emphasized mainly on the production of magnetic carbon and polymer nanocomposites employing various approaches and their applications in water and wastewater treatment. Furthermore, the future opportunities and challenges in applying magnetic nanocomposites for heavy metal ion and dye removal from water and wastewater treatment plant

A comprehensive review on magnetic carbon nanotubes and carbon nanotube-based buckypaper for removal of heavy metals and dyes

Industrial effluents contain several organic and inorganic contaminants. Among others, dyes and heavy metals introduce a serious threat to drinking waterbodies. These pollutants can be noxious or carcinogenic in nature, and harmful to humans and different aquatic species. Therefore, it is of high importance to remove heavy metals and dyes to reduce their environmental toxicity. This has led to an extensive research for the development of novel materials and techniques for the removal of heavy metals and dyes. One route to the removal of these pollutants is the utilization of magnetic carbon nanotubes (CNT) as adsorbents. Magnetic carbon nanotubes hold remarkable properties such as surface-volume ratio, higher surface area, convenient separation methods, etc. The suitable characteristics of magnetic carbon nanotubes have led them to an extensive search for their utilization in water purification. Along with magnetic carbon nanotubes, the buckypaper (BP) membranes are also favorable due to their unique strength, high porosity, and adsorption capability. However, BP membranes are mostly used for salt removal from the aqueous phase and limited literature shows their applications for removal of heavy metals and dyes. This study focuses on the existence of heavy metal ions and dyes in the aquatic environment, and methods for their removal. Various fabrication approaches for the development of magnetic-CNTs and CNT-based BP membranes are also discussed. With the remarkable separation performance and ultra-high-water flux, magnetic-CNTs, and CNT-based BP membranes have a great potential to be the leading technologies for water treatment in future

Magnetic nanocomposites for sustainable water purification—a comprehensive review

Numerous contaminants in huge amounts are discharged to the environment from various anthropogenic activities. Waterbodies are one of the major receivers of these contaminants. The contaminated water can pose serious threats to humans and animals, by distrubing the ecosystem. In treating the contaminated water, adsorption processes have attained significant maturity due to lower cost, easy operation and environmental friendliness. The adsorption process uses various adsorbent materials and some of emerging adsorbent materials include carbon- and polymer-based magnetic nanocomposites. These hybrid magnetic nanocomposites have attained extensive applications in water treatment technologies due to their magnetic properties as well as combination of unique characteristics of organic and inorganic elements. Carbon- and polymer-related magnetic nanocomposites are more adapted materials for the removal of various kinds of contaminants from waterbodies. These nanocomposites can be produced via different approaches such as filling, pulse-laser irradiation, ball milling, and electro-spinning. This comprehensive review is compiled by reviewing published work of last the latest recent 3 years. The review article extensively focuses on different approaches for producing various carbon- and polymer-based magnetic nanocomposites, their merits and demerits and applications for sustainable water purification. More specifically, use of carbon- and polymer-based magnetic nanocomposites for removal of heavy metal ions and dyes is discussed in detail, critically analyzed and compared with other technologies. In addition, commercial viability in terms of regeneration of adsorbents is also reviewed. Furthermore, the future challenges and prospects in employing magnetic nanocomposites for contaminant removal from various water sources are presented

A review of novel green adsorbents as a sustainable alternative for the remediation of chromium (VI) from water environments

The presence of heavy metal, chromium (VI), in water environments leads to various diseases in humans, such as cancer, lung tumors, and allergies. This review comparatively examines the use of several adsorbents, such as biosorbents, activated carbon, nanocomposites, and polyaniline (PANI), in terms of the operational parameters (initial chromium (VI) concentration (Co), temperature (T), pH, contact time (t), and adsorbent dosage) to achieve the Langmuir's maximum adsorption capacity (qm) for chromium (VI) adsorption. The study finds that the use of biosorbents (fruit bio-composite, fungus, leave, and oak bark char), activated carbons (HCl-treated dry fruit waste, polyethyleneimine (PEI) and potassium hydroxide (KOH) PEI-KOH alkali-treated rice waste-derived biochar, and KOH/hydrochloric acid (HCl) acid/base-treated commercial), iron-based nanocomposites, magnetic manganese-multiwalled carbon nanotubes nanocomposites, copper-based nanocomposites, graphene oxide functionalized amino acid, and PANI functionalized transition metal are effective in achieving high Langmuir's maximum adsorption capacity (qm) for chromium (VI) adsorption, and that operational parameters such as initial concentration, temperature, pH, contact time, and adsorbent dosage significantly affect the Langmuir's maximum adsorption capacity (qm). Magnetic graphene oxide functionalized amino acid showed the highest experimental and pseudo-second-order kinetic model equilibrium adsorption capacities. The iron oxide functionalized calcium carbonate (IO@CaCO3) nanocomposites showed the highest heterogeneous adsorption capacity. Additionally, Syzygium cumini bark biosorbent is highly effective in treating tannery industrial wastewater with high levels of chromium (VI)