Perspective Of Environmental Protection Research Articles

Influence of preheating lump ore on blast furnace smelting energy saving and consumption reduction

The ironmaking process often produces a certain amount of waste heat and pressure, the use of this surplus energy to preheat the lump ore is a commonly used process, but the quality of each process of the material, or the stability of production, the performance optimisation of the lump ore after treatment, there are certain defects, based on practice, through the use of rotary kiln to preheat the lump ore gradually becomes a green environmental protection process measure, the application of the rotary kiln, makes the efficient utilisation of the lump ore possible, but for its optimisation principle is still little research, this paper through the pretreatment of the basic physical properties, metallurgical properties of the lump ore before and after experimental analysis. At the same time, combined with production practice, the relevant smelting parameters of the blast furnace after the application of different lump ore were compared and analysed, and the excellent impact of lump ore preheating on blast furnace smelting was determined and finally based on the calculation of carbon emissions, the industrial application prospect of preheated lump ore was evaluated from the perspective of environmental protection, and the impact of comprehensive scientific analysis, field practice, theoretical calculation and comprehensive analysis of the impact on lump preheating technology was carried out.

Efficient recovery and recycling/upcycling of precious metals using hydrazide-functionalized star-shaped polymers

There is a growing demand for adsorption technologies for recovering and recycling precious metals (PMs) in various industries. Unfortunately, amine-functionalized polymers widely used as metal adsorbents are ineffective at recovering PMs owing to their unsatisfactory PM adsorption performance. Herein, a star-shaped, hydrazide-functionalized polymer (S-PAcH) is proposed as a readily recoverable standalone adsorbent with high PM adsorption performance. The compact chain structure of S-PAcH containing numerous hydrazide groups with strong reducibility promotes PM adsorption by enhancing PM reduction while forming large, collectable precipitates. Compared with previously reported PM adsorbents, commercial amine polymers, and reducing agents, S-PAcH exhibited significantly higher adsorption capacity, selectivity, and kinetics toward three PMs (gold, palladium, and platinum) with model, simulated, and real-world feed solutions. The superior PM recovery performance of S-PAcH was attributed to its strong reduction capability combined with its chemisorption mechanism. Moreover, PM-adsorbed S-PAcH could be refined into high-purity PMs via calcination, directly utilized (upcycled) as catalysts for dye reduction, or regenerated for reuse, demonstrating its high practical feasibility. Our proposed PM adsorbents would have a tremendous impact on various industrial sectors from the perspectives of environmental protection and sustainable development.

Performance and mechanism of organic solid-phase sediment composite plugging agent

The surface pipeline sediments of the Yingmai and Hade oil fields mainly contain substances such as asphalt and paraffin. The formation of sediment can increase the backpressure during pipeline transportation, and in severe cases, it can also lead to pipeline blockage. In order to solve this on-site situation, indoor experiments were conducted in the early stage, and an efficient organic unblocking system LXW was optimized and formulated. Based on this system, this article selects the wire mesh filtration method to evaluate the unblocking performance of LXW and on-site unblocking agents in the study and comparison of three evaluation methods. At the same time, based on the analysis of the chemical composition, microstructure, and melting point of organic sediments, from the perspectives of safety, environmental protection, and economic factors, further compares the performance and universality of the three unblocking systems, optimizes the process parameters of the LXW unblocking system, explores its stability and impact on the demulsification and dehydration of crude oil emulsions, and evaluates its safety performance. The LXW unblocking system has a more efficient unblocking effect and better universality, which can solve the problem of multiple block blockages on site. In addition, compared with existing unblocking agents, it has better economic benefits and is in line with the characteristics of low cost on site. On this basis, the dissolution and dispersion mechanism of the blockage system on sediment was studied through laser scattering system and fluorescence microscope, and its microscopic mechanism was further verified. At the same time, the oil-water interfacial tension under the action of the unblocking system was studied, and it was found that adding the agent can significantly reduce the equilibrium interfacial tension, which is of great significance for increasing production and injection.

Functional Construction of a Novel Lanthanide MOF for Efficient Ratio Luminescence Detection of Ethanol Vapor

AbstractIt is necessary to develop excellent sensors for volatile organic compounds (VOCs) detection from the perspective of environmental protection and human health. Luminescent lanthanide metal‐organic frameworks (MOFs) have many advantages such as porosity, luminescence, and structural controllability, making them very suitable as luminescent sensing materials. Based on a functional oriented strategy, novel Ln‐MOFs are successfully constructed and their structure and properties are characterized in detail. A series of vapor luminescence sensing tests have shown that Eu/Tb doped L1‐Eu0.1/Tb0.9 not only exhibits high selectivity for alcohols, especially ethanol vapor, but also has high sensitivity and extremely low detection limit (9.76 mg L−1). To the knowledge, there are no reports on ratio luminescence sensors based on Ln‐MOFs for ethanol vapor, especially those with such excellent performance. Crystal structure determination demonstrates that ethanol binds to the framework through multiple hydrogen bonding interactions, altering the energy transfer efficiency between Tb3+ and Eu3+ to achieve ratio luminescence detection. In addition, L1‐Eu0.1/Tb0.9 has good repeatability, the prepared thin film sensing material also demonstrates the advantages of portability and processability. This work can provide some experience for the development of VOCs sensing materials with better performance.

Thiazole-functionalized conjugated microporous polymers enable efficient gold recovery from e-waste

From the perspectives of environmental protection and efficiency, the use of clean and efficient photocatalytic reduction technology to recover gold from e-waste not only has a high economic value, but also reduces environmental pollution. However, it remains a challenge to construct adsorbents with simultaneously high photocatalytic activity, high stability, high capacity and high selectivity. Here, we demonstrate the application of D-π-A type thiazole-functionalized conjugated microporous polymer (termed BTD-TEA) for adsorption-photocatalytic recovery of gold from e-waste. The synthesized BTD-TEA not only have a narrow optical bandgap (1.75 eV) and excellent semiconductor properties, but also have ultra-high acid stability (stable in aqua regia). Surprisingly, BTD-TEA exhibits breakthrough gold adsorption capacity (4052.83 mg g−1), ultrafast adsorption kinetics, excellent selectivity and outstanding reusability under light conditions. This work provides a promising new adsorption-photocatalytic strategy for gold recovery from e-waste.

Preparation and fluorescence detection of nitrogen-doped carbon quantum dots/cotton fiber composites

From the perspective of environmental protection and sustainable development, fluorescent probes have been prepared using inexpensive raw materials for fluorescence detection in wastewater treatment. Nitrogen-doped carbon quantum dots (N-CQDs)/cotton fiber composites were prepared by grafting N-CQDs onto the oxidized cotton fibers using a silane coupling agents. Through a series of characterizations using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray energy dispersive spectrometry (EDS), it was found that N-CQDs were loaded onto cotton fibers. In the N-CQDs/cotton fiber composite, the fluorescence rate of carbon quantum dots is higher, which is 17.2 %, and the detection limit is 1.21 μM. The optimum conditions for fluorescence detection of azo dye Chrome black T(EBT) with pH 8 and concentration 10 μM were studied. This method for the detection of EBT has advantages such as high sensitivity, simplicity, speed, reusability, and a high potential for application in wastewater detection.

PH‐Responsive itaconic acid‐based villous‐like hydrogels for water‐plugging materials

AbstractThe development of new methods to improve the water absorption performance of polymeric materials, taking into account their environmental friendliness, is a promising research direction in Itaconic acid based water‐absorbent polymeric materials. In this study, from the perspective of environmental protection, we propose to design highly absorbent hydrogels with a novel villous‐like structure by using hydrophilic itaconic acid as the raw material and combining it with a novel villous‐like network structure to substantially increase the contact area between the hydrogel and water, thus improving the water absorption rate of the hydrogel. Itaconic acid is water‐soluble and renewable. The widespread use of polymeric water‐absorbent polymers from traditional petroleum sources poses a serious threat to the sustainability of ecosystems, and therefore, itaconic acid has attracted much attention as an alternative to petroleum‐based polymers. The villous‐like network structure is inspired by the villi of the small intestine, the special presence of which expands the absorptive surface area of the small intestine by a factor of about 600, and it is therefore hypothesized that the introduction of this special structure could help the hydrogel to greatly increase the contact area with water and thus achieve the high water absorption properties of the hydrogel. This is also the first time that the villus‐like network structure has been applied to Itaconic acid based hydrogels. The results show that the hydrogel has the property of rapid water absorption and swelling and the water absorption rate of the hydrogel can reach up to 2210 g/g, and the villous‐like structure formed by the hydrogel can be observed in the SEM image. The water‐absorption test of the hydrogel showed that when the molar mass ratio of itaconic acid to acrylic acid was 1:4, the hydrogel absorbed water and swelled rapidly in a short time. The results of the water retention test showed that the hydrogel still existed after 5 days, and the water retention was greater than 86%. In addition, the hydrogel had high reusability, and the water absorption performance of the hydrogel could still reach 89.12% after 6 cycles of the water absorption test. Hydrogel with high water‐absorbing property has good application prospects as fast swelling material in the field of flood control of water conservancy projects.

Development of an environmental foamed concrete incorporating recycled cement concrete powder with carbonation

From the perspective of efficient resource utilization and environmental protection, it is an effective way to reduce waste by carbonizing recycled cement concrete powder to replace part of cement. In this study, carbonated and non-carbonated recycled cement concrete powder were selected as supplementary cementitious materials to investigate the effects of different cement substitutes (0%, 20%, 40%, 60%) on the workability, microstructure, and thermal insulation performance of foamed concrete. The experimental results show that carbonation treatment can improve the workability of foamed concrete with waste cement concrete powder, with an amplitude ranging from 1.08% ∼ 5.61%. The influence of different carbonated powder substitution on the compressive strength of foamed concrete shows an initial increase followed by a decrease, with a range of variation from 2.27 MPa ∼ 4.47 MPa at 28 d, which is attributed to the effective acceleration of hydration due to a slight increase in the content of calcite. Mechanical strength is positively correlated with the density of the matrix, and the change of the two leads to an opposite trend in thermal insulation performance, with the maximum reduction in thermal conductivity being 9.98% at a substitution rate of 60%. These research findings indicate significant potential applications of waste cement concrete powder at various substitution rates, and are of great importance for achieving the dual-carbon strategy.

Effect of surface modification of microcrystalline cellulose with ionic liquids on natural latex composites

AbstractAs an environmentally friendly biomacromolecular material, microcrystalline cellulose (MCC) enhances the performance of natural rubber latex (NRL) composites. However, MCC has strong polarity, which weakens the interfacial interaction between MCC and the non‐polar NRL matrix and reduces the reinforcing performance due to the many hydroxyl groups on its surface. In this paper, the ionic liquid (IL) modified MCC/IL material was prepared, and AIR‐FTIR, x‐ray diffraction, and XPS photoelectron spectroscopy were performed to detect it from the perspective of environmental protection. And natural latex/microcrystalline cellulose/ionic liquid (NRL/MCC/IL) composites with excellent properties were prepared by latex blending. The activation energy, vulcanization characteristics, basic mechanical properties, dynamic mechanical properties, and filler‐rubber interfacial interactions of NRL/MCC/IL composites were investigated. The results showed that the vulcanization rate constant of NRL/MCC/IL composites increase, the activation energy decreases and the mechanical properties were significantly improved. At the same time, the matrix interface interaction of composites was quantitatively calculated using Ayala parameters. The results showed that the interfacial interaction force of the composite was stronger after an appropriate amount of IL pretreatment. The whole process is not only conformed to the concept of green development, but also broadens the application of MCC in rubber materials.

Analysis of the Decisive Factors of Government Attracting Tourists in Public Management from the Perspective of Environmental Protection

Tourism is a critical sustainable social and economic activity that can empower local communities. The current study strived to explore decisive factors that might be used it promotes environmental protection. Governments worldwide might employ to improve conservation and the tourism sector. There is a need to sponsor more publications on tourism and the environment that provide rigor, insight, and significance. There is also a need to address critical impacts, including greenhouse gases for airlines, liquid wastes for cruise ships, water and energy conservation for urban hotels, vegetation clearance, and wildlife displacement for rural resorts, and a range of direct and indirect local impacts on plants and animals for nature-based and adventure tourism in parks and wilderness areas. Governments need to work on economic models that address; currency exchange rates; airfares and taxes; land tenure and wildlife ownership laws; transport infrastructure; police, quarantine, and border security; investment law; public protected-area systems; and a variety of social pressures and fashions. The most effective means to improve environmental management in tourism is through laws and regulations for development planning, pollution control, and protected areas. In developed nations, tourism threatens conservation as property developers push to build private facilities inside public protected areas. In developing nations, tourism is a tool to fund conservation in public parks and private or communal lands. Visitors to the public, and protected areas contribute political and financial capital to park agencies. A few private tourism operators have converted areas of private and communal land to conservation.

Cube-shaped Cobalt-doped zinc oxide nanoparticles with increased visible-light-driven photocatalytic activity achieved by green co-precipitation synthesis

From the perspective of environmental protection, the highly efficient degradation of antibiotics and organic dyes in wastewater needs to be tackled as soon as possible. In this study, an ecofriendly and green cube-shaped cobalt-doped zinc oxide nanoparticles (Co–ZnO NPs) photocatalyst using Pterocladia Capillacea (P. Capillacea) water extract loaded with 5, 10, and 15% cobalt ions were formed via co-precipitation process to degrade antibiotics. The prepared Co–ZnO NPs were tested as a photocatalyst for the photodegradation of ciprofloxacin (CIPF) in the presence of a visible LED-light source. Co–ZnO NPs have been obtained through the co-precipitation method in the presence of P. Capillacea extract as a green capping agent and reducing agent, for the first time. Several characterization techniques including FTIR, XRD, BET, XPS, TEM, EDX, SEM, TGA and DRS UV–Vis spectroscopy were applied to study the prepared Co–ZnO NPs. XRD results suggested that the average size of these NPs ranged between 42.82 and 46.02 nm with a hexagonal wurtzite structure. Tauc plot shows that the optical energy bandgap of ZnO NPs (3.19 eV) gradually decreases to 2.92 eV by Co doping. Examinations showed that 5% Co–ZnO NPs was the highest efficient catalyst for the CIPF photodegradation when compared with ZnO NPs and other 10 and 15% Co–ZnO NPs. A 10 mg/L solution of CIPF was photo-degraded (100%) within the first 15 min irradiation. The kinetics showed that the first-order model is suitable for displaying the rate of reaction and amount of CIPF elimination with R2 = 0.952. Moreover, central composite design optimization of the 5% Co-doped ZnO NPs was also investigated.

Hong Kong-Zhuhai-Macao Bridge: the environmental logic of three EIAs

This article discusses the Hong Kong-Zhuhai-Macao Bridge from the perspective of environmental protection. What is peculiar about this bridge is that three different sets of environmental impact assessment (EIA) obligations were relevant during its developmental stage. The reason why we see such an oddity is because the Hong Kong-Zhuhai-Macao Bridge, as its name tells, links three different jurisdictions, which are in the same country. As each jurisdiction has its own EIA law, different priorities, values and expectations are engendered. It will be argued that the conflicting laws only hampered environmental protection, in particular, the protection of the marine ecology of the Pearl River Estuary over which the Hong Kong-Zhuhai-Macao Bridge crosses.

Thermoeconomic performance analysis of different configurations of a combined ORC-VCR system using zeotropic mixtures

From the perspective of environmental protection, the application of new environment-friendly working fluids provides more feasibility for sustainable development. In addition, the improvement of system configuration increases the possibility of improving system performance. In this paper, the thermodynamic and economic performance model of the organic Rankine cycle (ORC)-vapor compression refrigeration (VCR) combined system is established. Four system configurations and 12 zeotropic mixtures on the system performance are researched and compared. The effect of operating parameters on system performance is studied. The results show that the recuperative-regenerative ORC-VCR (RR-ORC-VCR) system is confirmed as the optimal system configuration. Compared with the basic ORC-VCR (B-ORC-VCR) system, the coefficient of performance (COP) and exergy efficiency are improved by 14.65 % and 10.03 %, respectively. While the total cost increases by 6.85 %. The most suitable working fluid is R245fa/R1234yf (0.55/0.45). Higher glide temperature can be an important criterion in the selection of zeotropic mixtures. When the suction pressure ratio is 0.6, exergy efficiency and total cost are optimal, which are 11.95 % and 1.34 × 105$, respectively. While the highest COP with 0.73 is achieved when the suction pressure ratio is 0.65. With the increase of boiler temperature, the thermodynamic performance of the system increases obviously, but the economic performance decreases. The increase in condenser temperature has a negative impact on the system thermodynamic and economic performance. The growth of evaporator temperature is positively correlated with COP and negatively correlated with exergy efficiency and total cost.

The impact of economic performance on the environmental protection orientation of mining enterprises: A case study of the Yangtze River Economic Belt in China

Environmental protection and sustainable economic development are significant issues that impact people's lives and contribute to the construction of a beautiful China. The approach to corporate sustainability depends on the environmental protection orientation adopted by the enterprise. This paper takes a dual perspective of pollution-oriented and ecology-oriented environmental protection. It uses panel data from mining companies in the Yangtze River Economic Belt (YREB) from 2013 to 2020 at the micro level to examine whether the economic performance growth of enterprises contributes to achieving corporate sustainability goals. The study results indicate an inverted U-shaped curve relationship between enterprise economic performance and pollution-oriented environmental protection (POLEVP), with an initial increase followed by a subsequent decrease. On the other hand, there is a U-shaped curve relationship between enterprise economic performance and ecology-oriented environmental protection (ECOEVP), with an initial decrease followed by a subsequent increase. Mechanism analysis reveals that the structure effect, scale effect, and technology effect have different regulatory effects on the relationship between economic performance and enterprise environmental protection orientation. Further research demonstrates that companies in heavy-polluting industries and those audited by the Big Four accounting firms tend to prioritize POLEVP In contrast, state-owned enterprises show a stronger emphasis on ECOEVP compared to non-state-owned enterprises. These findings can provide valuable insights for decision-makers in promoting the sustainable development of the YREB at the micro-enterprise level and facilitating the green, low-carbon transformation of mining companies.

Literature review on waste management of online food delivery industry in China

Meituan Waimai, which was officially launched in November 2013, has created a huge market for food delivery in China. After years of development, China’s online food delivery market reached RMB 664.62 billion in 2020. In 2022, Meituan Waimai and Ele.me, two food delivery platforms, have created a duopoly in China’s food delivery industry. Due to the success of the food delivery industry, a significant amount of food delivery packaging waste has caused far-reaching harm. This literature review primarily organizes the research on the impact of online food delivery packaging from the perspective of environmental protection. It uses the criterion layer index of online food delivery waste management ecosystem to analyze the impact of the government, environmental non-governmental organizations (NGOs), garbage recycling processors, consumers, online food delivery platforms, takeaway merchants, and takeaway packaging manufacturers. The review shows that scholars generally believe that takeaway waste management is a complex process involving multiple factors. The implementation of policies at the government level is inadequate, and studies at the environmental NGO level are scant. At the consumer level, more environmental awareness education is required. Online food delivery platforms and takeaway merchants should assume greater corporate social responsibility, and manufacturers of takeaway packaging need prioritize the substitution of environmentally friendly materials. There is a consensus that paper-made and recyclable packaging boxes are more environmentally friendly than degradable packaging, which is not as environmentally friendly as is commonly believed. The academia and the industry have conducted various studies and pilot projects on recyclable packaging. If all levels cooperate well, this will be an effective way to manage takeaway packaging garbage. At last, we propose the following assumptions for future research: Besides environmental hazards, takeaway garbage has caused direct or indirect physical harm to humans and animals. Increasing consumer awareness may increase their propensity to participate in governance. Additionally, existing food delivery platforms may need to improve their corporate social responsibility awareness to provide environmentally conscious consumers with sufficient and effective plastic reduction guidance measures during the ordering process. Moreover, will biodegradable plastic products face the same ironic situation as biofuels? That is, the initial intention of technology development is to improve the environment, but the actual process of production or processing may controversially aggravate the environment.

Retracted: Path Optimization Model for Urban Transportation Networks under the Perspective of Environmental Pollution Protection

Retracted: Path Optimization Model for Urban Transportation Networks under the Perspective of Environmental Pollution Protection

Research on the factors influencing the development of green finance in Beijing, Tianjin and Hebei under the perspective of ecological environmental protection

In today's world, the contradiction between people and the ecological environment is becoming more and more acute. Green finance is an effective method to resolve the contradiction between economic growth and ecological environment pollution, which has been widely recognized by all countries. This paper analyzes the level of green financial development in the Beijing-Tianjin-Hebei region through an analytical model of green financial development influencing factors constructed by simulation, combined with ecological environmental protection, and identifies the main influencing factors affecting the level of green financial development in this region. In addition, the realization path proposed in this paper from the perspective of government-led green financial development is, firstly, to improve green finance-related standards, assessment system and green financial legal system. The second is to implement green financial regulation and improve the driving force of green policy and market integration. The research results show that the comprehensive measurement score of green finance development level in Beijing, Tianjin and Hebei region shows a steady increase between 2016 and 2020, among which the comprehensive measurement score of green finance development level in Beijing is as high as 72.13 in 2020, an increase of 17.32%. It provides theoretical guidance for the improvement of green financial public policies in Beijing, Tianjin and Hebei regions.

A Study on the Impermeability of Nanodispersible Modified Bentonite Based on Colloidal Osmotic Pressure Mechanisms and the Adsorption of Harmful Substances

With the growing demands of human beings, sanitary landfill, along with the increase in landfill depth and leachate water pressure, has put forward new and higher requirements for the impermeable layer. In particular, it is required to have a certain adsorption capacity of harmful substances from the perspective of environmental protection. Hence, the impermeability of polymer bentonite–sand mixtures (PBTS) at different water pressure and the adsorption properties of polymer bentonite (PBT) on contaminants were investigated through the modification of PBT using betaine compounded with sodium polyacrylate (SPA). It was found that the composite modification of betaine and SPA could reduce the average particle size of PBT dispersed in water (reduced to 106 nm from 201 nm) and enhance the swelling properties. As the content of SPA increased, the hydraulic conductivity of PBTS system decreases and the permeability resistance improves, while the resistance to external water pressure increases. It is proposed a concept of the potential of osmotic pressure in a constrained space to explain the impermeability mechanism of PBTS. The potential of osmotic pressure obtained by linear extrapolation of the trendline of colloidal osmotic pressure versus mass content of PBT could represent the external water pressure that the PBT resist. Additionally, the PBT also has a high adsorption capacity for both organic pollutants and heavy metal ions. The adsorption rate of PBT was up to 99.36% for phenol; up to 99.9% for methylene blue; and 99.89%, 99.9%, and 95.7% for low concentrations of Pb2+, Cd2+, and Hg+, respectively. This work is expected to provide strong technical support for the future development in the field of impermeability and removal of hazardous substances (organic and heavy metals).

Experimental study on hygrothermal properties of recycled aggregate concrete

Recycled aggregate concrete has great significance from the environmental protection perspective. However, the current research findings on its hygrothermal properties are sparse. In this study, the apparent density, thermal conductivity, mass moisture content, water vapor permeability coefficient, water absorption coefficient, and liquid water diffusion coefficient of recycled aggregate concrete were determined by experimental methods. The effect of temperature and humidity on thermal conductivity was also studied. Furthermore, the fitting relations of the thermal conductivity of recycled aggregate concrete with the two variables of temperature and relative humidity were presented. The isothermal moisture absorption curve and the fitting relationship of water vapor permeability coefficient with relative humidity were also developed. The results indicate that the thermal conductivity of the eight recycled concrete specimens in the dry state at 25°C ranges from 0.994 to 1.242 W/(m·K). The thermal conductivity increases with the increase in temperature. When the temperature rises from 25°C to 35°C, the thermal conductivity of recycled aggregate concrete increases by 3.8%–13.5%. With the increase of relative humidity, the thermal conductivity of recycled aggregate concrete shows an increasing trend, followed by a steady state, and finally the increasing trend, showing a cubic function relationship between them. When the relative humidity increases from 0% to 95%, the thermal conductivity increases by about 20%. The mass moisture content and the water vapor permeability coefficient increase with relative humidity. The results of this study can provide basic information for the study on the heat and moisture transfer of recycled aggregate concrete, and enhance the database of hygrothermal properties of building materials.

Tool Wear and Surface Integrity of γ-TiAl Cryogenic Coolant Machining at Various Cutting Speed Levels

High-speed machining of γ-TiAl alloy is a significant challenge due to high cutting temperatures. From the perspective of environmental protection and improving tool life, appropriate cooling strategies should be adopted. Compared with dry and conventional flood cooling conditions, the feasibility of machining γ-TiAl in cryogenic LN2 cooling conditions was discussed. The cutting force, tool wear and its mechanism, and surface roughness, as well as sub-surface morphology characteristics, were studied by combining macro and micro techniques. The results revealed that the wear morphology of the rake and flank face under the three cooling media shows different degrees. The crater wear of the rake face is expanded at high speeds and then progresses into more serve flaking and notching wear. The main wear pattern on the flank face is gradually transformed from adhesive wear to diffusion and oxidation wear at high speeds in dry machining. In the LN2 condition, the diffusion of workpiece elements and cutting-edge oxidation were restrained. The wear pattern is still mainly adhesive wear. In addition, cryogenic machining shows significant advantages in reducing cutting force, suppressing heat-affected zone, improving surface quality, and inhibiting micro-lamellar deformation.