Great Environmental Pollution Research Articles

Design and optimization of a novel porous plate oil–gas separator

In the oil-injection compressor system, it is necessary to separate the lubricating oil by sequentially applying the mechanical separator and the separating filter element, however, the oil–gas separation filter has disadvantages such as short service life, high cost, and great environmental pollution. In this paper, a porous plate separator is proposed to achieve the coalescence of small oil droplets, and then the larger droplets can be removed by mechanical collisions driven by turbulence flow in the separator. This device is designed to be used after the primary separator, in the hope of replacing the separation filter element. The structure of the porous plate oil–gas separator is constructed through the staggered arrangement of two porous plates, and the two-phase flow characteristics in the separator are simulated through the Euler-Lagrangian method with the droplet’s behavior of collision and breakup considered. The hole diameter, hole distance, plate distance, and inlet velocity are the key parameters of the separator, and these parameters are combined through the orthogonal design method to form several different structures and working conditions. The results of range analysis and pressure difference distribution under different layers are analyzed comprehensively, so the best combination is determined in terms of particle size growth rate, oil separation efficiency, and pressure loss. The designed structure is machined, and a test bench is set up, so the performance of the porous plate separator is experimentally tested. It is found that the simulation results are in good agreement with the experimental data, and the best simulated conditions are also verified by the experiment. When the inlet velocity is 0.2 m·s−1, the optimal scheme is suggested as follows: Hole diameter = 1.5 mm; Hole distance = 3 mm; Plate distance = 1 mm; plate layers = 40.

Investigation on Catalytic Cracking Performance of Metal Catalysts for 1,1,2‐TCE

AbstractPVDC played an irreplaceable role in the field of sealed packaging, and its polymer monomer, VDC, was in short supply. At present, the saponification of 1,1,2‐TCE and sodium hydroxide was used to generate VDC in industry, which was a process with great environmental pollution. Catalytic dehydrochlorination of 1,1,2‐TCE to produce VDC was a green process route, but the selection of catalysts had always been controversial. This study aimed to screen catalysts suitable for industrial applications. The cesium based catalysts with good catalytic performance were systematically characterized and evaluated, and the overall reaction process was calculated using DFT calculation. The experimental results indicated that the cesium chloride catalyst with a 3 % molar fraction had the best catalytic performance, achieving 55.27 % conversion of 1,1,2‐TCE and 76.85 % selectivity for VDC, respectively. The reaction paths and transition state of several catalysts were calculated by DFT method. It was revealed that the activation energy required for the reaction of CsCl catalyst was the lowest, at 130.61 kcal/mol, and the energy of the product VDC was the lowest, at −63.25 kcal/mol, making it the most stable. The calculation results were consistent with the experimental data, indicating that cesium chloride catalyst had the best reaction performance. Therefore, the subsequent research could focus on the method of improving the supported dispersity of cesium chloride catalyst and the development of core‐shell catalyst to lay the foundation for further industrialization.

G-C3N4@CuO electrostatic self-assembly toward Ralstonia solanacearum: Insights from cytomembrane and motility disruption.

Ralstonia solanacearum, a notorious and refractory bacterial plant pathogen, threatens multiple vegetable crops and causes significant economic loss in agriculture. Long-term use of traditional medicines not only increases the problem of drug resistance, but also causes great environmental pollution. Therefore, there is an urgent need to develop new agents with high efficacy and low toxicity. In this study, we have synthesized and characterized graphitic carbon nitride incorporated copper oxide composite (g-C3N4@CuO), which showed higher antimicrobial effect than graphitic carbon nitride nanosheets (g-C3N4 nanosheets) and copper oxide nanoparticles (CuONPs). Ralstonia solanacearum exposed to g-C3N4@CuO exhibited higher levels of oxygen toxicity, cell membrane damage, DNA damage, motility disruption and even cell death compared to g-C3N4 nanosheets and CuONPs. In addition, g-C3N4@CuO was more effective in the control of tobacco bacterial wilt than g-C3N4 nanosheets and CuONPs. Thus, this study provides a new perspective on g-C3N4@CuO control of bacterial diseases in crops, and the mechanism is related to the destruction of cell membrane damage and motility disruption. © 2024 Society of Chemical Industry.

Electrodeposition of Magnesium in Deep Eutectic Solvents Based on Magnesium Chloride Hexahydrate and Choline Chloride with Urea Added

Magnesium (Mg) alloy has small density, large elastic modulus, good heat dissipation and corrosion resistance to organic matter and alkali. At present, magnesium alloy is more and more used in automotive industry, medical devices and aerospace industry. However, the traditional preparation method of Mg has the disadvantages of high investment, high labor intensity and great environmental pollution. Therefore, it is of great significance to develop simple, environment-friendly methods of the magnesium. In this study, urea was added to adjust the electrochemical property of the deep eutectic solvent (DES) mixed by choline chloride (ChCl) and magnesium chloride hexahydrate (MgCl2·6H2O). Cyclic Voltammetry (CV) curves reveals that the addition of urea made the reduction potential of Mg shifted from -0.9 V to -1.3 V. Among the CV curves, one was proposed as the “dividing line”, which shows that the electroactive species in the two DESs, ChCl-MgCl2·6H2O and urea-MgCl2·6H2O, are different due to the changes of the component of the DESs. Fourier transform infrared (FTIR) data shows the type of hydrogen bond had been changed with the increase of urea content. Furthermore, the Raman spectra indicates that Mg2+ was coordinated with urea chains, which did not exist in ChCl-MgCl2·6H2O. Moreover, it was found that urea changed the electrochemical performance of the ChCl-Urea-MgCl2·6H2O by changing the hydrogen bond in the system and coordination form of the electroactive species, rather than adsorbing onto the electrode surface. Combined with geometry calculations at the B3LYP/6-311++G (d, p), the most probable mechanism of electrodeposition process was deduced.

Extrusion modification of prolamins from distiller's grains to facilitate the construction of biopolymer films.

Distiller's grains (DGs), which are rich in natural ingredients such as prolamins, are often used as low-value feed or discarded directly, resulting in great environmental pollution and resource waste. Prolamins from DGs (PDGs) were found to be a potential material for the construction of biopolymer films due to their good film-forming properties. In this study, extrusion processing was conducted to modify the physicochemical and structural properties of PDGs to facilitate the construction of biopolymer films with superior characteristics. Results indicated that extrusion led to improved solubility (17.91% to 39.95%) and increased disulfide bonds (1.46 to 6.13 μmol g-1) in PDGs. The total and sulfur amino acid contents of extruded PDGs were increased by 13.26% and 38.83%, respectively. New aggregation patterns were formed after extrusion according to the results of scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. Extrusion resulted in reduced surface hydrophobicity of PDGs (10 972 to 3632), sufficient evidence for which could be also found from structure analyses of PDGs. Finally, PDGs extruded at 110 °C were found to facilitate the forming of biopolymer films with superior mechanical properties, water resistance and thermal stability. Physicochemical and structural properties of PDGs were effectively modified by extrusion processing, and extrusion modification of PDGs could be a great way to facilitate the construction of biopolymer films with superior characteristics. It could provide more possibilities to extend the applications of DGs to alleviate the problems of environmental pollution and resource waste. © 2024 Society of Chemical Industry.

Are solid-state batteries absolutely more environmentally friendly compared to traditional batteries-analyzing from the footprint family viewpoint

In recent years, with the change of global climate, carbon neutralization has become a global consensus. Solid state batteries have become the important way to develop batteries in the future due to their advantages such as high safety, high energy density, wider operating temperature range, and the battery production stage is the main contributor to the environmental impact of the battery life cycle.This article selects three traditional batteries, LFP battery, NMC battery, LTO battery, and two new solid-state batteries, Li-FeS2 battery and LLZO battery, to conduct a study on the carbon footprint and other footprint family impacts during the production stage. The inventory data is collected from highly cited literature published in recent years, and the footprint family impact values generated by different types of battery packs are compared and analyzed. When using 1 kg as the functional unit, the footprint values of LLZO and Li-FeS2 solid-state batteries are higher than those of NMC and LFP traditional batteries in most footprint indicators such as ionizing radiation and ozone layer depletion in carbon footprint, material footprint, ecological footprint, and health footprint, resulting in greater environmental pollution. Considering the energy density of the battery, with a functional unit of 1kWh, the high energy density of solid-state batteries significantly reduces their environmental impact, while traditional battery LTO increases its environmental impact due to the lower battery energy density. But in the material footprint, both functional units of solid-state batteries have a significant impact. The high energy density of solid-state batteries still holds great development prospects, and cleaner technology and energy, as well as higher energy density, remain the direction of battery development.

Study on the fate of phosphorus, fluorine and chlorine in sludge during incineration

Sludge is often incinerated to achieve complete harmlessness and maximum capacity reduction, but the utilization of P (phosphorus) and the environmental pollution of F (fluorine) and Cl (chlorine) released from sludge incineration are usually ignored. In this paper, a series of experiments were employed to inquire into the conversion of various forms of P and the release of various forms of F and Cl after sludge incineration at different temperatures; the agriculture application prospect of P in sludge incineration ash and the environmental pollution caused by the release of F and Cl were discussed. The results show that P in sludge mainly exists as NAIP (non-apatite inorganic P) which biological effect was small. In the process of sludge incineration, InorgP (inorganic P) began to volatilize at 900 ℃, and the remaining P in sludge ash was 30.96 % at 1100 ℃. The forms of P in sludge incinerated at different temperatures varied considerably: a small amount of OrgP (organic P) in the sludge was converted into InorgP at 400 ℃; with the increase of incineration temperature, AP (apatite P) increased gradually, with 3.00 × 103–7.98 × 103 g/t in sludge ash at 700–1100 ℃. At 900 ℃, the content of AP in incineration ash was the highest, accounting for 58.98 % of Total P, which was the most suitable for slow-release phosphate fertilizer. At 600–1100 ℃, more Cl release, with a release rate of 50.61–92.70 %, among which the Cl for HCl (ClHCl) was 1.64 × 103–1.95 × 103 g/t at 700–1100 ℃. The F release rate was 1.52–37.39 %, among which the InorgF (inorganic F: mainly refers to F in HF and SiF4) was 1.13–27.91 g/t at 300–1100 ℃, the release amount of OrgF (organic F) was 1.59–1.86 g/t at 600–800 ℃. It can be seen that after incineration above 700 ℃, the sludge incineration ash may be used as a slow-release phosphate fertilizer, the release of Cl has greater environmental pollution and instrument corrosion than that of F, and the exhaust gas from sludge incineration cannot be discharged directly into the atmosphere.

Abalone shell-based magnetic macroporous hydroxyapatite microspheres with good reusability for efficient dye adsorption

Azo dye methyl orange (MO) and shell rotting cause great environmental pollution. Most of the common dye adsorbents are difficult to produce, not environmentally friendly and it is always difficult to utilize the shell resources effectively. In this study, shell-based economical and environmentally friendly magnetic hydroxyapatite microsphere adsorbents (Fe3O4 @SiO2/HAP) were developed for the removal of MO from simulated wastewater by sol-gel and hydrothermal synthesis methods. The effects of solution pH, initial concentration, adsorption time and system temperature on the adsorption effect were investigated, and the repeat recovery performance was explored. The equilibrium adsorption data follow the Freundlich isotherm and pseudo-second-order kinetic curves, and the analysis indicates that the adsorption process is spontaneously exothermic. The adsorption capacities of MO were up to 94.48% and 88.94%, under the acidic environment of pH = 4, respectively, and had good recycling performance. The results provide a high-value utilization pathway for waste shell resources and focus on the removal of azo dyes. This is expected to provide new development ideas for the environmental hazards caused by acid dye wastewater discharged into rivers and oceans, as well as the problems of soil pollution and resource waste caused by weathering and corrosion of shells.

Co-composting of sawdust with food waste: effects of physical properties on composting process and product quality

Sawdust and food waste have been part of solid organic waste causing great environmental pollution. Composting is a popular utilization method of converting waste like sawdust and food waste to sanitized and stabilized soil amendment. Unfortunately, many composting systems failed due to a dearth of information as a result of little or no scientific research focused on the effects of the physical properties of composting materials on the composting process. To fill this knowledge gap, three composting experiments of food wastes mixed with sawdust at ratio 20:80, 30:70, and 40:60 and compacted to different initial bulk densities of 15, 20, and 25 kg/m3 respectively was carried out to explore the effect of physical properties on composting of sawdust with food wastes. Physicochemical parameters monitored include bulk density; porosity; particle density, temperature, moisture content; pH, and electrical conductivity (EC). The highest temperature (65.3 oC) was recorded by trial 3 while trial 1 recorded the lowest temperature (49.3 0C). Among trials 1, 2, and 3, the maximum pH (9.2) and EC (5.1 mS/cm) were observed in compost trial 3. Additionally, the lowest pH (5.3) and EC (1.4 mS/cm) was observed in trial 1. Trial 3 had the highest percentage finest and lowest fibrosity content. A significant increase in bulk density, porosity, and particle density was observed in the three compost trials. The compost’s bulk density of (25 kg/m3) in trial 3 was observed to attain maturity and stability as compared with trials 1 and 2.

Developing two amino acid derivatives as high-efficient corrosion inhibitors for carbon steel in the CO2-containing environment

During the oil and gas exploitation, the corrosion of carbon steel pipes causes great economic loss, heavy casualties, environmental pollution, and waste of resources. The development of highly efficient and stable corrosion inhibitors is of great significance for the corrosion protection of carbon steel in oil and gas exploitation. L-cysteine is widespread in various plants (e.g. onion, cauliflower, and cabbage sprout). As a corrosion inhibitor, it usually has low inhibitive efficiency in most corrosive environment. Chemical modification is the most efficient method to solve this issue. Herein, two synthetic amino acid derivatives (2-phenylthiazolidine-4-carboxylic acid (PTCA) and 2-(thiophen-2-yl)thiazolidine-4-carboxylic acid (TTCA)) were investigated as high-efficient corrosion inhibitors to deal with the corrosion issue of carbon steel in the CO2-containing environment. The anti-corrosion property of the amino acid derivatives was investigated by electrochemical experiment, surface technique and theoretical calculations. The electrochemical results show that PTCA and TTCA present high corrosion inhibition efficiencies at the concentration of 0.8 mM: PTCA (99.1%) and TTCA (99.3%). The inhibitive mechanism of PTCA and TTCA on carbon steel surface is revealed by theoretical calculations. It is found that the PTCA and TTCA adsorb at the steel/solution interface by forming Fe-O bonds. Compared to PTCA, TTCA exhibits stronger adsorption on carbon steel surface by forming shorter Fe-O bonds with a more negative adsorption energy, which accounts for the better inhibitive performance of TTCA.

Co-pyrolysis of biomass and plastic: Circularity of wastes and comprehensive review of synergistic mechanism

Fossil fuels have provided humans with an enormous and stable primary energy source to rapidly develop advanced technologies, increasingly efficient machines and industries, as well as greater varieties of consumer products. While humans enjoy the conveniences of the modern world, critical global issues have also been created, such as an exponential hike in waste generation, rapid depletion of finite fossil fuels, greater environmental pollution, and climate change. Two major anthropogenic wastes are biomass waste and plastic waste. Each year, 464 million tonnes of plastic waste are generated globally, with only 20% recycled, 25% incinerated, while 55% landfilled. Likewise, 140 billion tonnes of biomass from the agriculture sector and 181.5 billion tonnes of lignocellulosic biomass from forestry and agricultural residues are produced worldwide annually, with only 40% and 4.5% biomass reuse respectively. This mountainous underutilised biomass and plastic wastes presented a good opportunity for recycling into biofuels instead of landfilling or open dumping, thus promoting circular bioeconomy. Pyrolysis stands out as a promising thermochemical route to synthesize biofuels, and co-pyrolysis of biomass and plastic benefits from synergistic interactions between both feedstocks, enhancing the yield and quality of biofuels. Therefore, in this review, the synergistic mechanism of biomass and plastic co-pyrolysis is described, and recent advances in this field are comprehensively presented. The importance of applying circular bioeconomy frameworks on biomass and plastic wastes are also highlighted.

Plastic management to reduce environmental pollution

There is an infinity of plastic products which have facilitated human life, but have also caused great environmental pollution that affects flora, fauna and of course the human being. Such is the use of polyethylene terephthalate (PET), which is a widely used plastic throughout the world, in Mexico and in each of the states and municipalities that comprise it. The vast majority of organizations, scientists, and others have understood this situation and have promulgated laws, designed strategies, environmental programs, etc. in order to contain or reduce their use or even recycle and reuse these materials, since once they are discarded they become polluting materials. Objective: Given this situation, this project is proposed whose objective is to design a program to reduce the contamination generated by polyethylene terephthalate (PET) mainly among other plastics in the municipality of Silacayoápam, Oaxaca, Mexico and in turn reactivate the local economy in small businesses stores through exchanges for basic basket products. Method: Using the documentary analysis technique, primary information was collected by conducting a direct survey of the inhabitants of the municipality, after which it was systematized in data record sheets, and the main challenges posed by the use of the polymer in the municipality were identified. Results: with the data collected, strategies for the use of plastic were analyzed and proposed, designing a management program for PET and other plastics for the local area that helps reduce environmental impact, and also promote environmental culture in the municipality and on the other. side and perhaps more important is to reactivate the economy of local businesses. Discussion and conclusions: the generation of this type of strategies allows, on the one hand, to have a culture of collection and recycling and, on the other hand, to support small businesses affected by the pandemic and the inflation of basic basket products, this represents an enormous challenge in the region and at the national level to define a more efficient, inclusive and sustainable waste management system, to reduce health and environmental problems.

Numerical simulation and safety evaluation of multi-source leakage of buried product oil pipeline

ABSTRACT The leakage from a buried oil pipeline has the potential to inflict great economic losses and environmental pollution owing to the long-term and concealment. Therefore, studying the diffusion law and safety evaluation of buried product oil pipeline leakage is critical. In this study, the single-hole and double-hole leakage of buried diesel pipeline are used as examples, and the variation laws of inlet and outlet pressure, flow velocity, flow rate and diffusion range of buried product oil leakage is studied by means of computational fluid dynamics (CFD) method. Then, the risk of multi-source leakage of buried product pipeline is evaluated by analytic hierarchy process (AHP) and fuzzy synthetic evaluation (FSE). The results show that the product oil leakage diffusion in front of the orifice is similar to a jet phenomenon, and the diffusion velocity decreases with the increase of the distance. The maximum flow velocity and stable flow velocity of single-hole leakage are higher than those of double-hole leakage. The flow velocity of the single-hole leakage is stable at 28 m/s and that of the double-hole leakage is 16 m/s and 14 m/s and fluctuates in a small range. When the pipeline leaks, the inlet and outlet pressures change, and the inlet pressure changes 1.6 ~ 1.8 times the outlet pressure. Moreover, the oil leakage from the single and double holes achieved a stable level after 0.4s, and the difference was only 0.008 m3/s. At the initial stage of leakage, the longitudinal diffusion range of double-hole leakage is larger than that of single-hole leakage, but the gap is getting smaller with time, while the vertical diffusion is similar, and the leaked oil reaches the ground almost simultaneously. Finally, the synthetic evaluation of leakage accident risk probability is 81.3%, and the risk level is ‘high.’

Spatial spillover effect of green finance on economic development, environmental pollution, and clean energy production across China.

Although the extensive development model carries China's economy at the forefront of the world, it has brought great environmental pollution problems. The Chinese government hopes to control environmental pollution through green finance and achieve high-quality economic development. Based on the panel data of 30 provinces and cities in China from 2009 to 2019, this paper examines the impact of green finance (GF) on China's high-quality economic development (EQD), environmental pollution (EP), and clean energy production (CEP). In order to study the spatial impact of GF, we put spatial geographic factors into the analysis category, and use the spatial Durbin model to empirically examine the spatial effect of GF on EQD, EP, and CEP. It is found that GF can promote EQD and curb EP in China. However, GF also weakens China's CEP.

Extraction of High-Purity Native State Gutta-Percha from Enzymatic Hydrolyzed Eucommia ulmoides Pericarps by Ultrasound Treatment and Surfactant Aqueous Phase Dispersion

Herein, a method of ultrasound treatment combined with surfactant aqueous phase dispersion was proposed for the extraction of high-purity gutta-percha in its native state from enzymatic hydrolyzed Eucommia ulmoides pericarps. Firstly, the plant tissues wrapped around gutta-percha were destructed through enzymatic hydrolysis, then the plant tissues debris still attached to gutta-percha were further stripped off by ultrasound. Finally, under the “amphiphilic” action of sodium dodecyl sulfate (SDS), the entangled gutta-percha was untwined, allowing the residual plant tissue debris to be released and precipitated, thus high purity gutta-percha was obtained. The process parameters were optimized through single factor and response surface experiments. The optimal parameters for ultrasonic treatment were displayed as follows: frequency of 40 kHz, power of 320 W, time of 7.3 h, temperature of 50 °C, and material-to-liquid ratio of 1:70 g/mL, and for the aqueous phase dispersion of surfactant were SDS concentration 1.7%, temperature 80 °C, stirring speed 1200 rpm, solid-to-liquid ratio 1:60 g/mL, and time 60 h. Under optimal conditions, the purity of gutta-percha reached 95.4 ± 0.31% and its weight average molecular weight (Mw) was 20.85 × 104. Moreover, the obtained gutta-percha maintained its native filamentous form. The obtained products were characterized by IR, NMR, XRD, TGA, DSC, and tensile experiments, which showed that the obtained product was gutta-percha and maintained the natural α- and β- crystal structure. The proposed method overcomes the disadvantages of the traditional organic solvent method, which has great environmental pollution and destroys the gutta-percha structure. This is also the first reported method to obtain high purity gutta-percha while maintaining its native state.

Estimation of Hydropower Harvesting from the Hydraulic Structures on Rivers: Ramadi Barrage, Iraq as a Case Study

In recent years, Iraq suffers from exacerbation of the deficit of electrical energy as well as the great environmental pollution resulting from the use of traditional fuels. This called for serious thought to search for using clean and renewable energy sources may available in Iraq.In the present study; small hydropower (i.e. Archimedes screw turbine) are specifically used with a low head at Ramadi Barrage in Iraq. This type of small hydropower station is suitable to apply because not need high storage water or high head in Barrage. The power production in this technology depends on the parameters of the location in which it is placed such as (length L, angle of inclination α, Diameter D,….). The physical model of the Archimedes screw turbine is applied to determine the optimal α. The solid work package with a combination of Computational Fluid Dynamics (CFD) analysis by ANSYS have been used to simulate numerically a three dimensions model to determine the value of power that could be produced by the Archimedes turbine in the Ramadi Barrage. The turbine's performance are tested on two cases which represent low and high discharge investigations with different α (18⁰, 23⁰, 30⁰, 35⁰) based on different flow conditions and different water head between upstream and downstream of the barrage. The results showed that the maximum power production from the barrage is 280,000 watts with α=35° and efficiency η=89.9% for case 1; while; this power becomes 400,000 watts with α=30° but of efficiency η=84.9% for case 2. It is concluded from this research that power production from Ramadi Barrage could be investment to eliminate the deficit in the electrical energy in Iraq.

Sugarcane Industrial Byproducts as Challenges to Environmental Safety and Their Remedies: A Review

Sugarcane (Saccharum officinarum) is one of the major crops cultivated in tropical and sub-tropical countries, and the primary purpose is to obtain raw sugar. It is an important substance for sugar and alcohol production by both the sugar and beverage industries. During cane processing, various byproducts are obtained, namely sugarcane bagasse, bagasse ash, pressmud cake, sugarcane vinasse, and spent wash. There are many challenging problems in storage, and they cause great environmental pollution. This review discusses their properties by which they can be used for cleaner agricultural and environmental sustainability. Utilization of byproducts results in value-added soil properties and crop yield. Replacing chemical fertilization with these organic natured byproducts not only minimizes the surplus usage of chemical fertilizers but is also cost-effective and an eco-friendly approach. The drawbacks of the long-term application of these byproducts in the agricultural ecosystem are not well documented. We conclude that the agriculture sector can dispose of sugar industry byproducts, but proper systematic disposal is needed. The need arises to arrange some seminars, meetings, and training to make the farming community aware of byproducts utilization and setting a friendly relationship between the farming community and industrialists.

Tuning pulse frequency for improvement in the corrosion resistance of 304SS pipes inner DLC coatings deposited by hollow cathode PECVD

Metal pipes are widely used in industrial transportation system, but the inner surface of the pipes is easy to be corroded and not easy to be repaired, which leads to the great economic loss and environmental pollution. In this paper, the Diamond-like carbon (DLC) coatings was deposited on the inner surface of 304 stainless steel (304SS) pipes by the hollow cathode plasma enhanced chemical vapor deposition (HC-PECVD) equipped with the direct current power supply with the pulse frequency of 100, 500, 1000 and 1500 Hz. The aim of this paper is to improve the corrosion resistance of pipes inner DLC coatings by tuning the pulse frequency. Results indicate that the sp3-C hybridization content (16.7% ~ 26.7%), the disorder degree of carbon structure and the hydrogen content of pipes inner DLC coatings all show an increasing trend with the reduction of pulse frequency, while its stress level presents an opposite trend. Compared with 304SS pipes (0.51 V and 8.94 × 10−6 A∙cm−2), the pipes inner DLC coatings present more positive corrosion potential (−0.49 V ~ −0.27 V) and lower corrosion current density (3.62 × 10−6–4.46 × 10−8 A∙cm−2), better corrosion resistance, which is considerable as an effective protection coating. The pipes inner DLC coatings deposited at 500 Hz present the lowest corrosion current density (1.22 × 10−7–4.46 × 10−8 A∙cm−2). Moreover, the corrosion performances of the pipes inner DLC coatings deposited with the pulse frequency of 500 and 1000 Hz exhibit the better uniformity. Therefore, the pipes inner DLC coatings deposited at 500 Hz possesses the best corrosion resistance, which can provide important information for large-scale industrial production in the future.

Governmental inspection and local legislation on environmental protection: Evidence from China

AbstractUsing China's central inspection of environmental protection as a natural experiment, this paper adopts a difference‐in‐difference method to investigate how this campaign‐style governance approach can influence the legislation process related to the conservation of nature. Our empirics find a significant facilitative effect on the enactment of local environmental protection laws in terms of both number and quality, and this facilitative effect is stronger in provinces and regions with weaker legal basis and greater environmental pollution. Moreover, we show that this facilitative effect has already begun to generate favorable judicial consequences. As for policy implications, we not only provide an overall evaluation on the performance of the central inspection, but also demonstrate China's top–down campaign‐style governance indeed has a long‐lasting impact on the establishment of its institutions.

Dextran derivatives as highly efficient green corrosion inhibitors for carbon steel in CO2-saturated oilfield produced water: Experimental and theoretical approaches

During the oil and gas exploitation, the corrosion of carbon steel pipes causes great economic loss, heavy casualties, environmental pollution, and waste of resources. The development of highly efficient and stable eco-friendly corrosion inhibitors is of great significance for the corrosion protection of carbon steel in oil and gas exploitation. In this work, two amino acid-modified dextran derivatives (LDT and S-LDT) were synthesized as green inhibitors, and their anti-corrosion performance for carbon steel in CO2-saturated oilfield produced water was studied by electrochemical tests and surface analysis. The electrochemical measurements show that S-LDT exhibits an outstanding inhibition performance with a fairly high inhibition efficiency (99.5% with the concentration of 250 mg/L) and high stability of corrosion inhibition (99.7% after 72 immersion), which is significantly higher than those eco-friendly corrosion inhibitors have been reported so far. The adsorptions of LDT and S-LDT involves physisorption and chemisorption. The adsorption mechanism of LDT and S-LDT was further explored by quantum chemical calculations, molecular dynamics (MD) and Geometry, Frequency, Noncovalent, and eXtended Tight Binding (GFN-xTB) method. It is believed that these novel dextran derivatives would have broad application prospects as eco-friendly corrosion inhibitors in industry.