Related Environmental Problems Research Articles

Engineering Regulation of the Weird Branches in a Branching Estuary and its Mechanics: Using the North Branch of the Yangtze Estuary as an Example

Weird horizontal shapes of branches, in large branching estuaries, often cause significant flood risks and environment-related problems. People usually resort to engineering methods to improve the horizontal shape of the weird branches and solve related issues. The responses of the riverbed evolution of a branching estuary to anthropogenic activity are complicated because of complex estuarine hydrodynamics and sediment transports, especially when the project locates specially (e.g., at estuary outlets). The North Branch of the Yangtze Estuary has a narrow upper reach which is almost orthogonal to the South Branch and has a trumpet-shaped lower reach with a wide outlet. The weird horizontal shape of the North Branch brings significant flood risks to cities along this branch, the shrinkage of its entrance, and other problems. In this study, a regulation of the North Branch, which is launched at Guyuan Sand (GYS) just outside the exit of the North Branch, is taken as an example. The GYS regulation aims to improve the weird horizontal shape of the North Branch by building new layouts of outlets, by which people decrease the flood risk of the surrounding cities. The GYS regulation is studied using a 2D numerical model. The riverbed evolution of the Yangtze Estuary in a typical hydrological year is simulated, while the water/sediment fluxes at cross-sections of branches in the estuary during a spring/neap tide are quantitatively calculated. It is found that the regulation changes the rotational flows near the shore, and further reshapes the estuarine circulations of mass inside the outlets, especially exchanges of water/sediment between different branches. The regulation directly changes the riverbed evolution at the outlet of the North Branch, and meanwhile has significant indirect influences on the riverbed evolution of the entrance of the North Branch. The varying riverbed evolution at the entrance of the North Branch and the varying water/sediment fluxes, under different designs of regulations, are related and analyzed. An essential improvement for the weird horizontal shape of the North Branch by an engineering method is shown to be possible, while the regulation mechanism of the engineering method and the response of estuarine riverbed evolution to the regulation are clarified. This study provides a new insight for improving estuarine branches with weird horizontal shapes, by reshaping the tidal processes and the accompanying sediment transports in a branching estuary.

Literature analysis of the location selection studies related to the waste facilities within MCDM approaches.

The increase in waste and related environmental problems is one of the major problems compromising health and environmental quality in urban and rural areas. There are a number of policies that can be implemented to reduce waste, but since it cannot be completely eliminated, recycling and disposal facilities for waste will always be required. Researchers and professionals are currently grappling with the issue of where to locate waste facilities. In the light of all this information, a literature review is presented so that researchers can easily access and systematically review previous studies on the waste facility location selection problem. At this point, in order to reduce the reviewed studies to a reasonable level and to conduct a more organized research, this literature research has conducted within the framework of multi-criteria decision-making (MCDM) approaches, which is one of the most applied methods in location selection problems. The subsequent strengths, weaknesses, opportunities, and threats (SWOT) analysis delves into the strengths, weaknesses, opportunities, and threats in the field, offering a concise guide for future research in waste facility location selection problem. The SWOT analysis highlights the strengths of global environmental awareness and versatile MCDM approaches, while addressing weaknesses in emerging technology integration and potential biases. Opportunities for interdisciplinary collaboration and integration of sustainability metrics provide strategic pathways, but threats such as regulatory changes and limited funding underscore challenges. This analysis serves as a concise guide for future research in waste facility location selection.

A novel approach for poly(hydroxybutyrate-co-hydroxyvalerate) production from vegetable wastes and pig manure: Potential in economy, environment and sustainability

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a promising alternative to conventional petroleum-based plastics, owing to its considerable biodegradability and physicochemical properties. However, the high raw material costs limit its large-scale production. This study established a novel integrated process by coupling the anaerobic fermentation of vegetable wastes (VW) and pig manure (PM) with PHBV biosynthesis. The results demonstrated appreciable PHBV yields of 0.326 and 0.261 gPHBV/gVFA for VW and PM, respectively. Considering the magnitude of VM and PM in China, this novel approach could result in CO2 emission reduction by up to 12.70 million tons per year, as indicated by environmental impact assessment. Additionally, a preliminary economic analysis suggested economic benefits of up to 9.81 billion USD per year. These findings demonstrate that this integrated process can play a significant role in enabling large-scale production of PHBV while simultaneously resolving environmental pollution related problems associated with conventional plastics.

Assessment of Surface Water Quality of Igarapé de Santo Antônio in Santo Antônio do Tauá, Pará

Objective: Analyze the surface water quality of the Santo Antônio stream in Santo Antônio do Tauá, in the state of Pará, based on the current environmental legislation of CONAMA nº 357, 274 and Ordinance GM/MS nº 888. Theoretical Framework: The research uses contributions from the literature regarding normative guidelines on water quality standards essential for understanding and monitoring environmental conditions and related problems, through specific laws and regulations. Method: This is an experimental, descriptive, cross-sectional study, with a qualitative-quantitative approach, developed from water samples from the study site. The microbiological and physicochemical analyzes were determined by the procedures and recommendations described in the Standard methods for the examination of water and wastewater (APHA). Results and Discussion: The results proved that the physical-chemical and microbiological parameters of surface water are in accordance with the standards established in legislation regarding water classification and bathing (CONAMA nº 357 and 274), being in disagreement only with regard to potability standards (Portaria GM/MS nº 888), at one of the points of analysis. Research Implications: The data and observations allowed a response to potential environmental problems, contributing to the quest to preserve water resources and serving as a model for other communities facing similar challenges. Originality/Value: The study provides unprecedented data regarding the water quality of the Santo Antônio stream, identifying variations and trends that correlate with local environmental management.

Hybrid optimal-FOPID based UPQC for reducing harmonics and compensate load power in renewable energy sources grid connected system.

Integration of renewable energy sources (RES) to the grid in today's electrical system is being encouraged to meet the increase in demand of electrical power and also overcome the environmental related problems by reducing the usage of fossil fuels. Power Quality (PQ) is a critical problem that could have an effect on utilities and consumers. PQ issues in the modern electric power system were turned on by a linkage of RES, smart grid technologies and widespread usage of power electronics equipment. Unified Power Quality Conditioner (UPQC) is widely employed for solving issues with the distribution grid caused by anomalous voltage, current, or frequency. To enhance UPQC performance, Fractional Order Proportional Integral Derivative (FOPID) is developed; nevertheless, a number of tuning parameters restricts its performance. The best solution for the FOPID controller problem is found by using a Coati Optimization Algorithm (COA) and Osprey Optimization Algorithm (OOA) are combined to make a hybrid optimization CO-OA algorithm approach to mitigate these problems. This paper proposes an improved FOPID controller to reduce PQ problems while taking load power into account. In the suggested model, a RES is connected to the grid system to supply the necessary load demand during the PQ problems period. Through the use of an enhanced FOPID controller, both current and voltage PQ concerns are separately modified. The pulse signal of UPQC was done using the optimal controller, which analyzes the error value of reference value and actual value to generate pulses. The integrated design mitigates PQ issues in a system at non-linear load and linear load conditions. The proposed model provides THD of 12.15% and 0.82% at the sag period, 10.18% and 0.48% at the swell period, and 10.07% and 1.01% at the interruption period of non-linear load condition. A comparison between the FOPID controller and the traditional PI controller was additionally taken. The results showed that the recommended improved FOPID controller for UPQC has been successful in reducing the PQ challenges in the grid-connected RESs system.

Spatio-temporal dynamics of agricultural and built-up areas in the Niaye area of Pikine urban wetland (Dakar, Senegal)

The Niaye area of Pikine, a wetland with favorable physical and climatic conditions, is a rich and varied ecosystem that guarantees a supply of water and fertile soil, conducive to market gardening. This plays an important socio-economic role in the Dakar region. However, this sensitive and fragile ecosystem is often affected by poor farming practices. The aim of the study was to analyze the spatial evolution of agricultural areas and built-up areas in order to identify related environmental problems. Interview guides, aerial photographs from 1966 and 1978 and Digital Globe Over view 2 satellite images from 2004 and 2022 were used. The interview guides were used to obtain data on the management of the market gardening activity, and also to identify the environmental problems it generates. Satellite data processing revealed, through cartographic analysis, a progressive market gardening dynamic of +5.07%. In addition, the built-up area around the lake has increased by over 200%, resulting in a 68.4% decline in upland vegetation and a migration of market gardeners to the lake. This situation leads to the destruction of market garden crops in the rainy season as the water rises. What's more, the intensification of market gardening in response to the population's growing demand for vegetables has not failed to encourage bad practices, including the use of pesticides and sewage, which is a public health problem and a threat to the future of this wetland.

State-Directed Wood Industry Upgrading for Forest Protection and Economic Development in the Global South: Insights From Teak Processing in the Lao PDR

Asymmetric timber trade between least-developed countries with large forest resources but backward processing industries and emerging economies has led to an uneven distribution of value in international timber commodity chains. Selling their raw timber with no domestic value added contributes little to socio-economic development and is associated with high rates of deforestation. The Lao PDR has served as a raw timber frontier for advanced timber industries in neighboring countries, leading to forest loss and related environmental problems. In response, since 2015, the Lao government has adopted drastic policy measures to end forest degradation and upgrade its timber industry (e.g., log export ban). Using teak as an example, our study provides empirical ex-post evidence on the effectiveness of state-imposed timber industry upgrading policies. The study relies on expert interviews with key policy actors at national and local levels, as well as an enterprise survey and cluster analysis conducted in Xayyabouly province. These drastic policies had far-reaching implications for the structure of the timber industry and the configuration of the timber value chain and rural development.

Effectiveness of green bonds on carbon neutrality and clean electricity generation: Comprehensive evidence from the leading emitting country by disaggregated level analysis

Considering increasing public interest in environment-related problems and the carbon-neutrality aims of countries, this study focuses on the effect of green bonds on enabling carbon neutrality and supporting clean electricity in China, which is the leading top carbon-emitting and energy-using country in the world. In this context, the study makes a disaggregated level empirical analysis by considering sectoral emissions and source-based electricity generation by using quantile-based approaches from January 2, 2019, to December 31, 2023. The outcomes show that (i) green bonds decrease mainly emissions in transport and international aviation sectors; (ii) green bonds have mixed effects on the remaining sectoral emissions; (iii) green bonds increase electricity generation from all sources at higher quantiles, whereas they decrease electricity generation at lower quantiles. Thus, the effect of green bonds varies across sectors, electricity generation sources, and quantiles. Accordingly, a set of policy endeavors, such as dealing with firstly such critical sectors as power and industry, supporting the allocated green bond issuance to specified sectors, and focusing on some clean electricity generation sources like solar and wind, are argued for China.

Potential of Pinus radiata, Eucalyptus globulus and Acacia dealbata for the long-term phytostabilization of copper mine tailings

Many contaminated tailings throughout the world cause environmental and human-health related problems due to air and water drift. Tailing phytostabilization is a promising solution, but only certain plant species may tolerate and grow in these contaminated areas. We analyzed the chemical properties of a vegetated and unvegetated area in a tailing site in Central Chile. In addition, in the vegetated area we analyzed the metals content of roots, stems, and foliage in 41-years old plantations of Pinus radiata, Acacia dealbata, and Eucalyptus globulus (the only three species that survived from a total of 34 species planted), and determined height (H), and diameter at breast height (DBH). The results indicated that, except for pH, Se, Pb, and organic matter, all components (nutrients and metals) were two- to three- fold lower in the vegetated tailing compared to that of the unvegetated tailing. The analysis of plant tissues indicated that Cu was higher in the roots of P. radiata (2,073 mg kg−1) and lower in the stems of the same species (4.1 mg kg−1). However, the ability to take up and transport Cu to the shoots was higher in A. dealbata and lower in P. radiata (bioaccumulation factor of 0.19 and 0.06, respectively).

Nutrient quantification of livestock slurry and digestate using a low-cost handheld NIR spectrometer and multi-biomass calibration models

Real-time analysis during slurry field application can potentially ensure higher efficiency in crop fertilisation and reduce related environmental problems. Near Infrared Spectroscopy (NIRS) can predict quickly and adequately the nutrient content of the slurry but the devices are still costly. In this study, a low-cost portable device has been tested to predict total solids, total Kjeldahl nitrogen, total ammonia nitrogen, and phosphorus contents in cattle and pig slurries and digestate. Multivariate calibration models were developed for different biomass types (multi-biomass) by comparing support vector machine (SVM) and partial least square (PLS) regressions. The developed SVM and PLS models showed satisfactory and similar results, with performance to deviation ratio (RPD) values ranging between 2.22 and 2.80. The use of the handheld device with the obtained models also meets the requirements of a certification protocol for commercial NIR sensors and therefore can ensure a better slurry management at farm level.

Experimental data and modeling of sulfadiazine adsorption onto raw and modified clays from Tunisia

In recent years, the increasing detection of emerging pollutants (particularly antibiotics, such as sulfonamides) in agricultural soils and water bodies has raised growing concern about related environmental and health problems. In the current research, sulfadiazine (SDZ) adsorption was studied for three raw and chemically modified clays. The experiments were carried out for increasing doses of the antibiotic (0, 1, 5, 10, 20, and 40 μmol L−1) at ambient temperature and natural pH with a contact time of 24 h. The eventual fitting to Freundlich, Langmuir and Linear adsorption models, as well as residual concentrations of antibiotics after adsorption, was assessed. The results obtained showed that one of the clays (HJ1) adsorbed more SDZ (reaching 99.9 % when 40 μmol L−1 of SDZ were added) than the other clay materials, followed by the acid-activated AM clay (which reached 99.4 % for the same SDZ concentration added). The adsorption of SDZ followed a linear adsorption isotherm, suggesting that hydrophobic interactions, rather than cation exchange, played a significant role in SDZ retention. Concerning the adsorption data, the best adjustment corresponded to the Freundlich model. The highest Freundlich KF scores were obtained for the AM acid-treated and raw HJ1 clays (606.051 and 312.969 Ln μmol1−n kg−1, respectively). The Freundlich n parameter ranged between 0.047 and 1.506. Regarding desorption, the highest value corresponded to the AM clay, being generally <10 % for raw clays, <8 % for base-activated clays, and <6 % for acid-activated clays. Chemical modifications contributed to improve the adsorption capacity of the AM clay, especially when the highest concentrations of the antibiotic were added. The results of this research can be considered relevant as regard environmental and public health assessment since they estimate the feasibility of three Tunisian clays in SDZ removal from aqueous solutions.

Ni catalysts modified with mesoporous silica support: The role of Pr2O3 and MgO on the methanation of CO2

One way to solve environmental and energy related problems is to use carbon dioxide as a raw material along with renewable H2 to make useful chemicals and goods from those alternative energy sources. Several compositions of xNi-MCM-41/MgO-Pr2O3 were used for CO2 methanation via the hydrothermal synthesis method. Techniques such as TEM, H2-TPD, XRD, SEM, and BET were used to study the influence of the mechanism of the catalyst during CO2 methanation. The best performance was obtained for the 1.5 % Ni-MCM-41/MgO-Pr2O3 catalyst at 400 °C and normal atmospheric pressure, where the CO2 conversion efficiency and selectivity were 87.4 and 99.9 %, respectively. It was thought that the synergistic effects between the Ni active sites, the promoter, and the support were important for the high reactivity of the catalysts. These effects included better Ni dispersion and more CO2 adsorption sites due to the inclusion of MgO-Pr2O3. The promoted catalyst retained its high reactivity after 30 h on stream as observed during the stability test.

Rootstocks: Importance in Fruit Crop Improvement

India is the second largest producer of fruits in the world with different fruit growing zones viz., temperate, arid and semi-arid, subtropical, and tropical zones. In this present era of climate change, fruit growers are facing environment-related problems such as sudden changes in temperature, irregular and heavy rainfall, and soil-related problems like compaction, salinity, alkalinity, and acidity. In addition to this, pest and disease incidence also play a major role in limiting fruit production. Objectives of rootstock breeding includes resistance or tolerance to biotic stress, adaptability to soil and environmental conditions, dwarfism, precocity in bearing, high yield and good fruit quality. The purpose of rootstock breeding varies with crops and geographical locations. Developing rootstocks resistant or tolerant to biotic stresses in apple (fire blight and woolly apple aphid), citrus (root rot, nematodes and viral diseases), grape (Phylloxera spp. and nematode) and mango (mango fruit fly and stone weevil) for specific tree characters (dwarfing, canopy management) and horticultural traits (yield and quality) are the important aspects in rootstock breeding. The reported rootstocks which are impactful in fruit cultivation like apple (MM-111), grape (Dogridge, 99-R, 110-R and 1103-P), and mango (Turpentine, Deorakhio and Olour). The use of rootstocks which are tolerant or adaptable to adverse climatic situations and biotic stress can be an alternative option for scientists and fruit growers to face the challenges encountered by the fruit industry.

Is environmental regulation keeping e-waste under control? Evidence from e-waste exports in the European Union

Waste generated from electrical and electronic equipment, known as e-waste, is increasing worldwide. Developed countries like those in Europe produce the most significant proportion of e-waste worldwide and, therefore, rely on exporting it to other countries for waste disposal. As Europe is transiting towards a Circular Economy and tackling environmental-related problems, there has been an increase in environmental policies and regulations in this area. This paper presents empirical evidence of how European Union regulations have affected the exports of e-waste. Yearly data from 2010 to 2018 for a panel of 18 European Union countries were analysed using the PCSE (Panel-Corrected Standard Error) estimator. In order to measure environmental regulation, Environmental Tax Revenues from the manufacture of computers, electronic, and optical products were selected. The findings of this paper suggest that taxation is ineffective in reducing e-waste exports, with a tax on manufacturers actually increasing them. Also, high dependence and sub-standard e-waste collection systems increase e-waste exportation. Given that countries often depend on foreign raw materials, a sensible approach would be to invest in collection points for e-waste to take economic advantage of this waste's vital elements.

Study of the Distribution of Impurity Elements in Coals and Clay Layers of the Karaganda Coal Basin

The study of the distribution of trace elements in coal has aroused great scientific interest all over the world, not only because of the harm to health and related environmental problems when using coal, but also because of the economically valuable elements contained in it. The distribution of impurity elements in coals and clay layers of the Karaganda coal basin is considered. The main objective of this work is to identify geochemical features of elements-impurities in coals, clay interlayers of the k7 formation of the Karaganda coal basin. The paper presents the latest data on the composition of coals and clay layers. 85 coal samples of clay interlayers and coal-clay interlayers contact from three mines – Saranskaya, Aktasskaya, Kuzembaeva – were analyzed. The samples were studied by the IСP-MS method at the Far Eastern Geological Institute of the Far Eastern Branch of the Russian Academy of Sciences (DVGI FEB RAS)

Impact of contrasting tillage, residue mulch and nitrogen management on soil quality and system productivity under maize-wheat rotation in the north-western Indo-Gangetic Plains

The sustainability of dominant rice-wheat rotation is under threat due to numerous water-, nutrients-, weeds- and environment-related problems, mainly, due to rice cultivation in north-western Indo-Gangetic Plains (NWIGP) of India. It needs crop- and soil- appropriate management techniques with a focus on conservation agriculture (CA) that can maintain soil health which in turn is essential for long-term sustainability of intensive cereal-based systems. Thus, rice-wheat rotation may be diversified with maize as feasible substitute for rice. But, there is a dearth of comprehensive investigation on the impact of short-term CA in maize-wheat rotation, on soil quality. Hence, an attempt has been made to assess the system productivity (SP) and soil quality in a four-year-old CA-based maize-wheat rotation. Contrasting tillage as the main plot [Conventional tillage (CT), No–tillage (NT)], crop residue mulch as subplot [residue mulch (M+), no residue (M0)], and nitrogen [50 (N1), 100 (N2), 150% (N3) of recommended nitrogen dose] as sub-sub plot was laid out in split-split plot design. Soils sampled from 0–0.05, 0.05– 0.15, and 0.15–0.30 m soil layers were examined to develop a unified soil quality index (SQI) through principal component analysis (PCA) and expert opinion. The available K, P, total organic carbon (TOC), EC, bulk density (BD), dehydrogenase activity (DHA), and soil microbial biomass C (SMBC) were identified as the crucial minimum data set for SQI using PCA. Results showed that, NT and M+ plots had 10.52 and 17.39% higher mean weight diameter (MWD) than CT and M0, respectively at 0–0.05 m soil depth. NT and M+ plots increased TOC by 5.26 and 8% than CT and M0 plots, respectively in 0–0.05 m soil layer. Available K and P were found to be significantly higher in M+ plots than that of M0. NTM+ treatments improved SMBC and DHA than CTM0 treatments. The highest and lowest SQI was registered with NTM + N3 and CTM0N1, respectively. SP was significantly and positively correlated with SQI. Diversification of rice-wheat system with maize-wheat rotation following CA practices appears to have a positive impact on soil health. Therefore, CA-based maize-wheat rotation may be recommended to improve soil quality and system productivity in NWIGP region.

A study on air pollution exposure of “first and last mile” urban commuters under space-behavior dual verification based on big data, land-use regression model and space syntax

Urban traffic-related air pollution (TRAP) exposure is a serious problem during daily commutes. Previous studies assess the TRAP exposure of commuters mainly based on fastest and lowest-dose routes. In addition, the first and last parts of the commutes (“first and last mile”) are often overlooked, wherein the commuters tend to choose active transport (walking, jogging and cycling) and are highly exposed to air pollution. This study uses a space syntax model to simulate the most likely actual commuting routes (behavior-based routes) of “first and last mile” in Changsha, China, and combine it with a land-use regression (LUR) model to assess the TRAP exposure. Furthermore, the air pollution exposure doses of commuters across the behavior-based routes are compared with those across the fastest and lowest-dose routes. The results indicate that only 5.9%–13% of lowest-dose routes do not overlap the fastest routes, and the differences in both average fine particulate matter (PM2.5) and nitrogen dioxide (NO2) exposure are below 1%. However, up to 53.1%–68% of the behavior-based routes do not overlap with the fastest and lowest-dose routes, and the average accumulated exposure of the behavior-based routes exceeds those of the other routes by 7.8%–12.9%. These findings suggest an underestimation of TRAP exposure and the potential benefits of choosing cleaner routes. The results also indicate that commuters living in sub-central areas are linked with relatively larger commuting time costs and higher accumulated exposure doses. This highlights the need to focus on the environmental issues suffered by the commuters in these areas. In addition, our study suggests that behavioral science methods, such as space syntax, can shed new light on air pollution exposure research and develop targeted interventions to address related environmental problems.

Two‐dimensional MXenes as Emerging Materials: A Comprehensive Review

AbstractBecause of their peculiar two‐dimensional layered microstructure, the existence of numerous functionalities on the surface and excellent electrical, thermal and optical features, MXenes are regarded as promising candidates for solving energy and environment related problems. It is noted that energy conversion and storge capability of MXenes could be raised by altering their dimensions, structure, surface chemistry and chemical composition. Therefore, it is critical to recognize how one can boost the relationship between structure and property from applied viewpoint. In the present study, we reviewed the synthesis, properties and potential applications of MXenes. Furthermore, several properties of MXenes including structural, chemical, optical, mechanical and thermal have been explored. In addition, the potential applications of MXenes in various areas such as photocatalysis, gas sensing, supercapacitors, electrocatalysis and environmental remediation have also been discussed. Based on reported works, it can clearly be noticed that features and potential applications of MXenes may be further improved by applying many alteration and functionalization strategies. This study also focuses on the current progresses and future prospective relating to MXene based composites, which will surely assist the scientists who are doing work in areas of academia and material sciences.

Experimental Investigation on Bio-Machining of Nickel, Titanium and Nitinol (Shape Memory Alloys) Using Acidithiobacillus ferrooxidans Microorganisms

Micromachining plays a vital role in the manufacturing industry in producing microcomponents with high sensitivity and fine dimensional tolerances for implant materials in medical applications. Micro-machining can be carried out through various machining processes like physical, chemical and biological processes, although the use of biological machining is limited. In biological machining, microorganisms are used as a source of energy to machine the components, and machining with microorganism brings a lot of advantages in the machining process like the production of components with lower energy resources, low cost, no heat-affected zone and fine dimensional tolerances, which makes it suitable for machining implant materials. In other machining process like conventional and unconventional machining processes, the heat-affected zone, dimensional tolerances and environmental-related problems are the major issues, as these processes generate more heat while machining. This damages the material, which will not be able to be used for certain applications, and this issue can be overcome by bio-machining. In this present work, nickel, titanium and nitinol are manufactured using the powder metallurgy technique. They are manufactured as a 10 mm diameter and 5 mm thick pellet. The fabricated nickel, titanium and nitinol shape memory alloys are machined with Acidithiobacillus ferrooxidans microorganisms to obtain a better material removal rate and surface roughness and to check the bio-machining performance by considering various parameters such as shaking speed, temperature, pH and percentage of ferric content for the future scope of biomedical applications. Considering these parameters, microorganisms play a vital role in the temperature, shaking speed and time of the bio-machining process, and it was observed that a better material removal rate and surface roughness are achieved at a temperature of 30 °C, shaking speed of 140 rpm and machining time of 72 h.

Review on Applications of Ionic Liquids (ILs) for Bitumen Recovery: Mechanisms, Challenges, and Perspectives

Water- and solvent-based ex situ extraction processes have been employed to extract bitumen from mineable oil sands. On the other hand, bitumen is recovered in situ from deeper deposits most efficiently by injecting steam to reduce viscosity and increasing production flow to the surface. However, the water-based process with or without solvent (including steam injection) is not sustainable due to various challenges including water requirement and treatment, high energy consumption, and related environmental pollution problems emanating from high volatility of solvents. Ionic liquids (ILs) have become desirable in several industrial applications due to many unique properties including low volatility compared with traditional organic solvents. The potential for application of ILs for bitumen extraction is reviewed in this work, with a focus on the mechanistic aspect. Depending on the properties and/or functionality, the ILs can be used in bitumen extraction (with or without organic solvents) with minimal clay fines contamination and lower water and energy requirements. In the solvent-assisted IL recovery system, the IL–clay interaction is responsible for reducing the adhesive force between bitumen and the sand, which subsequently facilitates separation. Conversely, considering the types of ILs explored in the absence of solvent, the IL–bitumen interaction plays an additional role. Hitherto, applications of ILs in bitumen recovery are at a very preliminary stage. Apart from understanding the mechanisms, the major impediment lies in the high cost and environmental impact due to toxicity. Therefore, to make ILs more attractive for bitumen recovery, concerted efforts should be intensified to reduce the cost of producing ILs, ameliorate environmental impacts, and facilitate field scale applications through technoeconomic analysis of the process.